Baffled

[Track Junky]

I ran my car at Sonoma and everything was fine. Did a rear gear swap but didn't drive the car till I installed new brake pads.

Problem......car is hesitating under load. I can goose the throttle with car in neutral with no issues but when I drive it and open the secondary's up the car is hesitating under load with slight pops out the exhaust.
So far I have torn the carburetor apart twice, replaced power valve and accelerator pump diaphragm, checked float level, checked and tightened my fuel lines, replaced plug wires, replaced dizzy cap(had a crack in it), and checked a few of the plugs to see if they were fouled.

Not sure if its a lean miss or electronic.

Any other suggestions?

[JB400]

Is your fuel pump putting out enough gph?

[Track Junky]

Is your fuel pump putting out enough gph?

It has in the past and has been on the car for 4 years now with no changes to engine. It could be on its way out though.....

Odd thing is that car was running fine at the track a few weeks ago. It sat in the trailer for a few hot days afterwards and then I took it to get a gear swap. Just seems odd that it would do this after running fine at the track.

Just did a coil swap so I can rule that out.

[Vince@Meanstreets]

Pull all your plugs and report color or condition.

[Track Junky]

1,3,5, & 7 look the same. dry and medium charcoal colored. taking five....its gotta be over 100 in my garage

[Jay Hilliard]

After checking plugs, check distributor, then check plug wires and measure resistance/ohms with meter. Wires should measure very low resistance. Under load a wire that has high resistance will cause similar issue.

[57hemicuda]

You mentioned a gear swap, what did you go from, and to?

[Track Junky]

Thanks Jay.......looked for my multimeter this morning and couldn't find it. I used it in the house last so it has to be around here somewhere. Wire are new though.

Plugs 2,4,6, & 8 look the same as 1,3,5, & 7.

Went from 3.42's to 3.73's

[Vince@Meanstreets]

Thanks Jay.......looked for my multimeter this morning and couldn't find it. I used it in the house last so it has to be around here somewhere. Wire are new though.

Plugs 2,4,6, & 8 look the same as 1,3,5, & 7.

Went from 3.42's to 3.73's

Checks them wires for cracking and arch marking....how was that bronze gear?

[Track Junky]

Plug wires are new. I'll pull distributor and check the gear next.

[Ron in SoCal]

Gae when you say hesitating under load, is it a stumble/miss and then builds rpms?

[Track Junky]

Gae when you say hesitating under load, is it a stumble/miss and then builds rpms?

Its an intermittent hesitation that doesn't stop until I let off.

Stand by for some pics.

[Track Junky]

OK, so here is a pic of the cracked cap that I replaced that I thought would fix the issue.

http://i851.photobucket.com/albums/ab73/Gitter_Dun/Distributorpics044.jpg

Hers a pic of the rotor I just pulled off. Notice the broken portion to the upper left of the screw. That's a weird deal there

http://i851.photobucket.com/albums/ab73/Gitter_Dun/Distributorpics045.jpg

[Vegas69]

So it misses from the time you matt it until you hit redline? Or is it only initially and cleans up?

Where is the timing?
Have you checked the fuel pressure at WOT?

The gear change may require you to install a slightly bigger accel pump cam on the secondary side. Meaning, more volume initially. I say this because you should be accelerating a bit quicker which means you are gaining rpm faster.

That cap looks short, are you sure it's the right one?

[Ron in SoCal]

This is a guessing game without more info, but presume fuel is getting to the carb, your wires/spark is good and timing events from the distributor are as they should be. Do you have PTFE fuel hose forward of the pump? Slight cracks (even on the return side) will do that. Also pull the valve covers and inspect just in case.

I've also seen internal detonation cause this issue (hope not!), but if you don't find the issue do a quick compression check. Fingers crossed it's something simple Bro :thumbsup:

[Track Junky]

So it misses from the time you matt it until you hit redline? Or is it only initially and cleans up?

Where is the timing?
Have you checked the fuel pressure at WOT?

The gear change may require you to install a slightly bigger accel pump cam on the secondary side. Meaning, more volume initially. I say this because you should be accelerating a bit quicker which means you are gaining rpm faster.

That cap looks short, are you sure it's the right one?

Yes...as soon as I hit the secondary's until I let off.....and that is exactly what I was thinking Todd......more fuel may be needed.

Havent checked fuel pressure or timing yet.

Stand by....more pics

[Track Junky]

Pic of rusty reluctor
http://i851.photobucket.com/albums/ab73/Gitter_Dun/Distributorpics047.jpg

[Vegas69]

Plugs all being consistent rules out compression and likely any other mechanical cylinder issue. The valve springs probably need checked but I doubt it's the problem here as it would likely be a high rpm misfire.

A worn distributor gear will retard the timing and cause a pope and misfire. Ask me how I know...

Check the fuel pressure and timing before you waste more time.

[Track Junky]

And now the million dollar question. Above is a spare MSD distributor. Below it is the one I pulled out of the car with the bronze gear (which is still in good shape.)
Can you guys tell me why one gear is higher than the other because I don't have a clue.

http://i851.photobucket.com/albums/ab73/Gitter_Dun/Distributorpics046.jpg

[Vegas69]

Different application or the gear is on upside down.

[carkrazy1987]

Upper distributo has Gear on upside down. Push roll pin out and flip it. Sound like a fuel pressure issue, not keeping up with demand or fuel quality?

[Vince@Meanstreets]

And now the million dollar question. Above is a spare MSD distributor. Below it is the one I pulled out of the car with the bronze gear (which is still in good shape.)
Can you guys tell me why one gear is higher than the other because I don't have a clue.

http://i851.photobucket.com/albums/ab73/Gitter_Dun/Distributorpics046.jpg

LOL....reminds me of a conversation I heard at a homes for humanity site "the head of the nail is on the wrong end".... "ahh Its upside down"

[SSLance]

That pic brings back bad memories... I put the new gear on my distributor backwards like that when getting ready to put my engine in my car. Took me about a week to figure out why the distributor wouldn't fully seat.

Was looking back through pictures i took as I pulled everything apart, saw a picture of the distributer before the gear change a BINGO...a light goes off in my head.

[Track Junky]

Upper distributo has Gear on upside down. Push roll pin out and flip it. Sound like a fuel pressure issue, not keeping up with demand or fuel quality?

LOL....reminds me of a conversation I heard at a homes for humanity site "the head of the nail is on the wrong end".... "ahh Its upside down"

That pic brings back bad memories... I put the new gear on my distributor backwards like that when getting ready to put my engine in my car. Took me about a week to figure out why the distributor wouldn't fully seat.

Was looking back through pictures i took as I pulled everything apart, saw a picture of the distributer before the gear change a BINGO...a light goes off in my head.

You want to know whats even funnier.....it came from MSD that way :lol:

[Track Junky]

So the next million dollar question..........50cc accelerator pump or bigger jets.

[Vince@Meanstreets]

So the next million dollar question..........50cc accelerator pump or bigger jets.

I got a SWAG that won't waste any more of your money.

Pull your filter off and blow through it. If your ears pop, its 30% plugged. If an eye pops out then its 50%. If you crap your pants its just Miller 30. LOL

[Track Junky]

Hey, so news flash......was talking to Joe Pecavar about springs and bushings for the new dizzy and he says go with what you had because that's how we tuned it. He asks me what bushing the old dizzy had in it. I go to look and the mushroom cap that the weight rides on was gone. Guess what cracked my distributor cap and rotor and has been screwing up my timing? :lmao:

[Shmoov69]

Well, I was going to post up and say its an ignition issue, not a carb issue. But looks like you may have found the culprit!!

[Track Junky]

Well, I was going to post up and say its an ignition issue, not a carb issue. But looks like you may have found the culprit!!

Yup....Definitely an ignition issue. Come to think of it.........if your plugs are a medium charcoal color that right there tells you your getting motr than enough fuel :sieg:

[Vegas69]

Not unless you shut it down at wot. You are looking at the idle burn.

Your total timing should still be fine without the bushing. That effects how much initial timing you have. Now, I can see the bushing bouncing around in there causing the misfire.

[GregWeld]

Yup....Definitely an ignition issue. Come to think of it.........if your plugs are a medium charcoal color that right there tells you your getting motr than enough fuel :sieg:




No --- As Todd stated -- that only works at drag racing where you're able to shut down after a WOT run....


There are also ways to read timing on the spark plug "strap"... by where it changes color. The color change needs to be a line right across the apex of where the strap makes the turn. But now we're getting really old skool in the pit dyno.


Hope the distributor is the issue -- certainly points to an issue.

What color bushing you running? I would think BLACK.... which would be the 18* stop bushing... and with good heads and good fuel your total timing should be maybe 34 to 36* all in at 2500 to 3000 rpms??

[Track Junky]

Going with the blue bushing which is basically the one that comes with the distributor and then running the blue springs. I think full advance kicks in at 2900? Have to recheck but wanted to say thanks for the help buddy.
There is a mushroom top with a stud that the weights slide over and the cap completely wore down, broke off, and them was flying around in the distributor. So glad I found out what cracked the distributor cap crack.

[GregWeld]

The STOP BUSHING is under the plate that the weights attach to... you can't see it from the top at all...

Just saying.

The two light blue springs should work well. There's a graph in the MSD installation manual that shows you all the combinations of springs and were they come in.

Blue stop bushing gives you 21* of advance total FROM the initial.... so to get 36* total - your initial has to be set at 15*


As usual -- I write this stuff so OTHER GUYS that are reading these threads -- and don't know -- can read 'em and see what we're talking about.

[Track Junky]

The STOP BUSHING is under the plate that the weights attach to... you can't see it from the top at all...

Just saying.

The two light blue springs should work well. There's a graph in the MSD installation manual that shows you all the combinations of springs and were they come in.

Blue stop bushing gives you 21* of advance total FROM the initial.... so to get 36* total - your initial has to be set at 15*


As usual -- I write this stuff so OTHER GUYS that are reading these threads -- and don't know -- can read 'em and see what we're talking about.

Got it. Thanks Greg. You cant see the bushing because its recessed in the plate and covered by the lock nut that secures it in place but I figured out which bushing was in the distributor by looking at the one that wasn't in the kit. Wasn't sure what to set initial timing at but shooting for 32.5* total so looks like I'll be looking for 11.5* initial.

[Vegas69]

I found that my engine needed all the initial advance I could get. It cleans up the plugs at idle, better cold idle performance, and improved low speed drivability. I know you have a mechanical cam. I'd run the biggest bushing. I actually had a custom bushing in mine that would render 24 degrees initial with 34 total.

[Flash68]

but shooting for 32.5* total

Best power was at 32.5* on the dyno? Didn't think your 23* heads were that efficient...

[Track Junky]

I found that my engine needed all the initial advance I could get. It cleans up the plugs at idle, better cold idle performance, and improved low speed drivability. I know you have a mechanical cam. I'd run the biggest bushing. I actually had a custom bushing in mine that would render 24 degrees initial with 34 total.

Going with the blue bushing because that's what we dyno tuned the engine with. You cant really tell if your running the right jet sizes in your carb when dyno tuning because you don't have the air cleaner on and the temps are a lot cooler which means the carb is getting fed cooler, cleaner air. With air cleaner on and in 90* plus weather at the track air intake and quality changes. The plugs have had the same light charcoal look from the last time I looked at them which means I am getting a bit to much fuel but didn't bother changing jet sizes in the carb because I want to play it safe and splash a bit more fuel in there but this next time around I'm going to drop a couple jet sizes and see how the car feels. I'm running 84's in the secondary side now but cant remember what I'm running on the primary side.

[Track Junky]

Best power was at 32.5* on the dyno? Didn't think your 23* heads were that efficient...

Yup. Good point though.

[GregWeld]

Yeah that motor isn't going to like 10 degrees initial... and the rule is always -- the most initial advance you can get without having the starter motor struggle too much or you get engine kickback...

Stock baby cam no compression motors in Buicks idle at 10*'s....


If you ran the black bushing --- that's 18*'s... so you'd end up with 16* initial and that motor can handle 16* initial easy....

You're probably idling around 900+ RPMS is my guess...

I think the Mustang is up around 1200+ and then it barely idles... Sounds like a thrashing machine.

In the old drag race days we'd run a lockout and just dial in the total timing and lock the distributor... then we'd add a coil cut off switch so we could spin the motor around without any spark until she was spinning good - then hit the switch and WHAM! She's fire off good! LOL ---- You need one of those set ups!!

[Flash68]

Yup. Good point though.

Thems some pretty good heads! :thumbsup:

I think Rob's old dinosaur heads made best power at like 48* :lol:

[GregWeld]

Okay -- 32 -- whatever --- The point was more that 10* at idle isn't what I'd be aiming for.


And yes FLASHIE --- small blocks can run down in the 32 and 34 range if the parts are right - he's probably running close to zero quinch - ported heads - race gas....

The dinosaur --- not so much.

Now --- back up til about 1970.... fire up an Ed Pink Hemi Nitro motor -- with 70* in it.... oh yeah baby....

[Track Junky]

Yeah that motor isn't going to like 10 degrees initial... and the rule is always -- the most initial advance you can get without having the starter motor struggle too much or you get engine kickback...

Stock baby cam no compression motors in Buicks idle at 10*'s....


If you ran the black bushing --- that's 18*'s... so you'd end up with 16* initial and that motor can handle 16* initial easy....

You're probably idling around 900+ RPMS is my guess...

I think the Mustang is up around 1200+ and then it barely idles... Sounds like a thrashing machine.

In the old drag race days we'd run a lockout and just dial in the total timing and lock the distributor... then we'd add a coil cut off switch so we could spin the motor around without any spark until she was spinning good - then hit the switch and WHAM! She's fire off good! LOL ---- You need one of those set ups!!

I'm idling at 1200 also Greg. You might be right on the bushing but I'm running along the lines of "going to run it as we tuned it".

I am going to take a second look at my old distributor though and make sure on the bushing. I never remember changing the bushing in it but in the 8 years of running the same distributor I may have forgot.

When we dyno'd I remember the distributor acting like it was locked out......not sure how to explain that one.

[GregWeld]

Well --- many people fuss around with A:F ratios trying to find power -- but the real power comes from getting the timing RIGHT....


I just checked with Ed Pink and he said we used to run around 60+ish degrees not the 70 I misstated above. Obviously Nitro burns a little slower than our race gas. LOL


Did you guys know that the headers in a fuel car can create a 1000 pounds of downforce? Why don't we just run our headers out the bottom and point 'em up in the air... HAHAHAHAHA that would be so bitchin!!!

[Vince@Meanstreets]

Joe asked me why you didn't have the advance locked in. I replied, Its a street car

[intocarss]

Well --- many people fuss around with A:F ratios trying to find power -- but the real power comes from getting the timing RIGHT....


I just checked with Ed Pink and he said we used to run around 60+ish degrees not the 70 I misstated above. Obviously Nitro burns a little slower than our race gas. LOL


Did you guys know that the headers in a fuel car can create a 1000 pounds of downforce? Why don't we just run our headers out the bottom and point 'em up in the air... HAHAHAHAHA that would be so bitchin!!! Run some Bull Horns

[Vegas69]

I don't know what dyno tuning has to do with a distributor bushing? Most of these guys worry about one thing, wide open throttle, power, and air/fuel. As long as the exhaust temps are in the ball park, the tuning is left for the chassis.

You are getting away with that small bushing because you idle it at 1200. If you dropped it down to 900-1000, you may foul plugs. Also, you may be getting a bit of advance at that rpm. I'm not sure but the timing light would be the moment of truth.

[intocarss]

Joe asked me why you didn't have the advance locked in. I replied, Its a street car

I was going to ask that queston but you answered it HAHAHAHA

[Track Junky]

I don't know what dyno tuning has to do with a distributor bushing? Most of these guys worry about one thing, wide open throttle, power, and air/fuel. As long as the exhaust temps are in the ball park, the tuning is left for the chassis.

You are getting away with that small bushing because you idle it at 1200. If you dropped it down to 900-1000, you may foul plugs. Also, you may be getting a bit of advance at that rpm. I'm not sure but the timing light would be the moment of truth.

I'm pretty sure the most important thing when dyno tuning would be to get the timing set where the engine runs most efficient. From there I think its getting your AFR's where they should be.

I agree that at 1200 I'm probably getting the advance that I need.

Just checked my old distributor. though I couldn't tell by color anymore, by size I'm running the blue bushing.

[GregWeld]

The rate of "advance" added in a mechanical distributor is controlled by the advance springs.... it has little to do with idle speed -- provided the springs installed are controlling the weights.

The timing is SET for initial using the timing light to tell you where the timing is AT that particular RPMs... So unless you're loping so badly that your motor is adding and then subtracting timing - it should be fairly stable. If not - you should be looking for other adjustments to smooth out the issue.

I always check the actual timing curve being used - with a dial back light - and I actually map the timing in 500 rpm increments until ALL the timing is in. It's easy to map it with a pad of paper and a pencil and a dial back light that will read RPM's... you just screw the idle up from idle - 500 rpms - dial the light back til you see 0 on the balancer - write that result down... and add 500 rpms and repeat the process. Until you've reached your maximum timing degrees.

Since the timing should be all in around 2500 or 3000 rpms -- that's not hurting a thing to spin the motor for the brief amount to make this map. Now you can sit back and know exactly what your advance curve looks like - what your initial is - and what the total is. Once you know that what you EXPECTED for total timing is what you thought --- now you can subtract your bushing size -- in your case 21* -- and that better match up with the number you're seeing on the balancer or the digital readout on the dial back. Then you're done.

Now -- if you want to mess with timing -- you can just change the spring combo... and you should be able to be secure in the knowledge that the distributors inner workings are okay, and know that the advance is working as it should be.

Changing the curve can have profound affects. Want to see -- just put back the two garage door springs that come stock on all MSD distributors... talk about turning a good motor into a pig.... OH BUDDY!

[Vince@Meanstreets]

I'm pretty sure the most important thing when dyno tuning would be to get the timing set where the engine runs most efficient. From there I think its getting your AFR's where they should be.

I agree that at 1200 I'm probably getting the advance that I need.

Just checked my old distributor. though I couldn't tell by color anymore, by size I'm running the blue bushing.

If I remember right it was full in at 2K

[Track Junky]

If I remember right it was full in at 2K

Among other things to go over we'll have to recheck it before Sonoma Vince. Let me know what day works best for you.

[GregWeld]

Going to be all in at 2000 RPMS - with a blue stop bushing? Then you've got to run the TWO light silver springs....

[Track Junky]

Or I could throw the black bushing in and shoot for 2500 rpm :headscratch:

We'll see

[GregWeld]

Or I could throw the black bushing in and shoot for 2500 rpm :headscratch:

We'll see




STOP BUSHINGS only control the AMOUNT OF ADVANCE the advance weights can ADD....


So depending on which color stop bushing you have --- really controls your INITIAL timing.... the initial -- whatever that is set at --- and the color bushing you use determines how much timing will be added in total.

SO ===

Black bushing allows for 18* to be added to whatever number you set the idle (initial) timing at. If you set that at 10* --- and added the 18* --- your total would only be 28*..... So if you wanted to be total timing at 32* you subtract the 18* for that particular bushing (the black) and set your initial.... i.e., 32 total is the desired timing --- then 14 initial is what you would be at idle.


Blue bushing is a 21* bushing --- so then you could set initial at 11* to get to your 32* total


And so on.


The SPRINGS and their various combinations -- are what CONTROL the RATE of the timing advance.... So when and how quickly you can get to your max advance (total timing).


So two light silver springs with the black stop bushing gets you in near 2000 rpms

One light blue and one light silver - gets you all in around 2500 rpms


and so on.


There's a chart - that can be found here -- showing the various spring combos' and where -- with what bushing choice -- your timing curve is going to be AS SHOWN ON PAGE 3 --- so just scroll down....


https://www.msdignition.com/uploadedFiles/MSDIgnitioncom/Products/distributors/8545_instructions.pdf



If it was my motor --- I'd be running the BLACK bushing and either the two light silvers or the light silver/light blue combo. I'd set the initial timing to 14*
Adjust the idle to where I want it - double check my timing and go drive it.
Initial timing being "off" won't hurt a thing --- it's the total timing and how fast it gets there that can cause "pinging" or pre-ingniton.

Too much timing can cause bucking (like a miss) at light loads at freeway cruising... much like a lean miss... but at 32 or 34 total and NO vacuum advance - you're not going to be too far off.

[Track Junky]

Tried blue springs/blue bushing.......car hated it. Went to silver springs and she was as crisp as ever.
Took her out for a ride and I'm still getting the hesitation under load. Looked for a broken valve spring but couldn't find one.
Replacing MSD box tomorrow. :hairpullout:

[Che70velle]

I could have missed this earlier in the thread, but have you checked your fuel filter? Sure sounds like a fuel related issue to me.

[Track Junky]

I could have missed this earlier in the thread, but have you checked your fuel filter? Sure sounds like a fuel related issue to me.

Thanks Scott, going to be checking that tomorrow also. I pulled the line off on the carb side of the filter a couple of weeks ago and fuel kept dumping through the fuel filter freely and what appeared to be a healthy flow so I assumed it was good but going to pull it out tomorrow if its not the MSD box.

[Sieg]

I could have missed this earlier in the thread, but have you checked your fuel filter? Sure sounds like a fuel related issue to me.

I'm sure it's better than the distributor cap.


:lmao:

[Sieg]

Tried blue springs/blue bushing.......car hated it. Went to silver springs and she was as crisp as ever.
Took her out for a ride and I'm still getting the hesitation under load. Looked for a broken valve spring but couldn't find one.
Replacing MSD box tomorrow. :hairpullout:

I put the two light silvers on today (all in at 2,500) and bumped the initial to 15* with the 21* advance stop and my motor loved it. Idle is set at 1,000.

As mentioned fuel filter or maybe pump failing?

[GregWeld]

I put the two light silvers on today (all in at 2,500) and bumped the initial to 15* with the 21* advance stop and my motor loved it. Idle is set at 1,000.

As mentioned fuel filter or maybe pump failing?





Nothing an LS swap won't cure and he has plenty of time to git 'er done!

[Track Junky]

I put the two light silvers on today (all in at 2,500) and bumped the initial to 15* with the 21* advance stop and my motor loved it. Idle is set at 1,000.

As mentioned fuel filter or maybe pump failing?

We'll find out about the filter tomorrow Sieg. I don't think it is cause there was a lot of fuel dumping out of the filter end when I disconnected it but I'll pull it off and take a gander at it.
Pump could be it also but I already have an extra MSD box laying around so I'll try that before I need to spend on a fuel pump.

[Track Junky]

Nothing an LS swap won't cure and he has plenty of time to git 'er done!

Yup....tomorrow and two weekends is plenty of time :RunninDog:

[GregWeld]

You should just put a saddle on your ass so I can keep riding it.




You know -- the new fuels do like to eat the old style rubber parts.... so the diaphragm in the fuel pump --- or any rubber lengths in the fuel system -- maybe a short length from the tank to a hard line or? Sometime they APPEAR fine from the outside but are shot on the insides...

ASSume all the spark plug wires have been looked at.... where they might be fine at low rpms and power ranges until you put the boots to it. A quick check I've done is to wait until dark -- pull into the garage with all the lights off - and fire it up and open the hood... and look carefully for any arcing on headers - or a cracked boot to head - or ??

Plugs in good order?? Again they might be able to light off light loads but can't light the richer A/F ratios when the throttle is banged....

Valve adjustment? ASSume you're running solids....

[Track Junky]

You should just put a saddle on your ass so I can keep riding it.




You know -- the new fuels do like to eat the old style rubber parts.... so the diaphragm in the fuel pump --- or any rubber lengths in the fuel system -- maybe a short length from the tank to a hard line or? Sometime they APPEAR fine from the outside but are shot on the insides...

ASSume all the spark plug wires have been looked at.... where they might be fine at low rpms and power ranges until you put the boots to it. A quick check I've done is to wait until dark -- pull into the garage with all the lights off - and fire it up and open the hood... and look carefully for any arcing on headers - or a cracked boot to head - or ??

Plugs in good order?? Again they might be able to light off light loads but can't light the richer A/F ratios when the throttle is banged....

Valve adjustment? ASSume you're running solids....

Need to check diaphragm in pump, secondary accelerator pump diaphragm has been replaced, spark plug wires have been replaced with new, should probably check fuel line from filter to carb.

Spark plugs are new and looks like I can lean her out a couple sizes, solid roller......valves were adjusted two track days ago.......that's on the to do list under "Before you spend money do this" :rules:

[Sieg]

Fuel pump pick up?

MSD boxes aren't exactly known as bullet-proof reliable so definitely can't rule that out. But typically don't they just have a major coronary and go to the grave?

.........new fuel cell installed.......and this problem occurred?

[Track Junky]

Fuel pump pick up?

MSD boxes aren't exactly known as bullet-proof reliable so definitely can't rule that out. But typically don't they just have a major coronary and go to the grave?

.........new fuel cell installed.......and this problem occurred?

Car ran great at Sonoma after all the recent changes Sieg. When I brought her home from Sonoma she sat in the trailor for a couple of days and then I took her to a local shop for a rear gear change.
Noticed issue after the shop made the rear gear change.

[clill]

What gasoline is in it ? Can it be crap gas ?

[Sieg]

What gear ratio before and after?

[Track Junky]

What gasoline is in it ? Can it be crap gas ?

I was running out of fuel trying to figure this out so I picked up 5 gallons of 114 at Sonoma last week and through it in yesterday. We'll see.

[Track Junky]

What gear ratio before and after?

3.42 to 3.73

[Vince@Meanstreets]

just to rule it out try swapping out that RPM chip for a higher one.

Did you move your MSD ground wire? Run it direct from the battery.

[Track Junky]

It's starting to look more and more like Charlie nailed it. I ran the car today with the new batch of fuel till almost empty and it started feeling like it was getting better the longer I drove it. I get on it now and it doesn't start to hesitate/pop until the upper rpm range as opposed to when it would hesitate at initial throttle engagement. Seriously thinking I had a batch of crap gas in there at this point.

[GregWeld]

Race gas doesn't go bad like the sh!t at the pumps....


114 is a little strong.... Charley and I run 110. Gotta be careful with fuels -- more isn't always better. Ask Dave.


114 is for very high compression ratios like 14:1 and real high (8000) RPMS.... I don't think you're running that high of compression or need the extra protection from detonation at this level... LOL

[GregWeld]

It's starting to look more and more like Charlie nailed it. I ran the car today with the new batch of fuel till almost empty and it started feeling like it was getting better the longer I drove it. I get on it now and it doesn't start to hesitate/pop until the upper rpm range as opposed to when it would hesitate at initial throttle engagement. Seriously thinking I had a batch of crap gas in there at this point.

I hate it when he's right.

[GregWeld]

Pump Gas Versus Race Gas
Octane rating is defined as the resistance to detonation a fuel has in an internal-combustion engine. The higher the number, the more resistance it has. That is why engines with higher compression require higher-octane fuel. As a result of its resistance to detonation, it has a resistance to burn as well. This resistance to burn is a non-issue in motors tuned to the edge; the edge being just before detonation occurs. When a pump-gas engine is subjected to a higher-octane race fuel, it may result in a decrease in power from an incomplete burn.

Read more: http://www.popularhotrodding.com/tech/0901phr_difference_between_pump_race_gas/?__federated=1#ixzz37OfIyWcx


Conclusion
Filling your tank with high-octane fuel, when your engine runs fine with 91 octane, is a waste of money. In this engine's case, minimal gains were achieved after a dozen dyno tests were made, and would be too small to notice at the track. The higher 118-octane fuel made less power than both the 110 and 91 octane. It would be interesting next time to see what effects the fuel has on a boosted engine. We would expect to see more impressive changes there.

Read more: http://www.popularhotrodding.com/tech/0901phr_difference_between_pump_race_gas/?__federated=1#ixzz37Og87p1u

[Track Junky]

The last 5 gallons I put in the car prior to this last fill was from a local station in Placerville. He was down to the bottom of the barrel with 110 and had to tilt the barrel to get me 5 gallons.

BTW, my engine builder is the one that recommended 114 and my compression is 14:1.

[GregWeld]

The last 5 gallons I put in the car prior to this last fill was from a local station in Placerville. He was down to the bottom of the barrel with 110 and had to tilt the barrel to get me 5 gallons.

BTW, my engine builder is the one that recommended 114.



He doesn't know what he's talking about. Unless it's tuned and dyno'd on 114... the whole gas and octane thing is so misunderstood.


I think Dave's engine builder is the one that talked him into blending race gas with his pump gas.... that was good for about a day's worth. LOL

[Vince@Meanstreets]

I agree, stick with what you know works.


Without knowing how long that tank was sitting or if it was refilled. You have no idea what to expect.

[Track Junky]

Race gas doesn't go bad like the sh!t at the pumps....


114 is a little strong.... Charley and I run 110. Gotta be careful with fuels -- more isn't always better. Ask Dave.


114 is for very high compression ratios like 14:1 and real high (8000) RPMS.... I don't think you're running that high of compression or need the extra protection from detonation at this level... LOL

I repeat......my motor is 14:1

[Track Junky]

I agree, stick with what you know works.


Without knowing how long that tank was sitting or if it was refilled. You have no idea what to expect.

Get some sleep Vince.....your not making any sense

[Vince@Meanstreets]

The last 5 gallons I put in the car prior to this last fill was from a local station in Placerville. He was down to the bottom of the barrel with 110 and had to tilt the barrel to get me 5 gallons.



f-you, I just woke up. LOL

[GregWeld]

I repeat......my motor is 14:1



Well no wonder it won't run worth a sh!t.....



How much timing are you running total?? That motor might need some more -- 114* octane can take more timing...

Have you tried 38* total?

[GregWeld]

14:1 compression ratio -- big ass cam -- 114 octane race gas... MORE TIMING needed! Holy smokes dude -- who built you a 14:1 motor!??!


I'm being serious here -- that motor can take 36 or 38* of total.

Pump gas - great heads - might make best power on 32 to 34* but pump premium with oxygenated etc - is going to take less (retarded) timing

[Track Junky]

That's some interesting info Greg. I didn't know higher compression likes more timing. When I originally dynode this motor in Muncie, Indiana at the builder shop we went with 38* total timing.

When I dyno tuned down here after the timing chain incident Joe thought it ran best at 32.5*.

[Track Junky]

f-you, I just woke up. LOL

Now your making sense LOL

[Flash68]

I disagree with Greg to a point on timing needed. Compression is part of it but the efficiency of the heads/combustion chamber has a big part to do with it.

Based on your theory Greg, tell me why my motor likes 30* timing (13:1 compression) and Rob's FE likes near 40* (less than mine, around 12:1 give or take).

It's mostly due to the difference in combustion chamber, valve angle, etc.

Typical 23* headed engines do not run low timing (relatively) like 32* so that is very surprising. 36-38* sounds more like it. I am thinking Joe built in a lot of safety for you? I dunno else why. That doesn't make much sense to me based on what you've shared.

[Flash68]

I think Dave's engine builder is the one that talked him into blending race gas with his pump gas.... that was good for about a day's worth. LOL

Wrong. The motor blew because I DID NOT add some 100 octane in that weekend like previously. Constant beating with shaky unpredictable 91 octane on a high revving 11:1 motor was not the best thing to do, but it is what it is.

I repeat......my motor is 14:1

Weren't you 12.5 to 1 before?

[Track Junky]

Wrong. The motor blew because I DID NOT add some 100 octane in that weekend like previously. Constant beating with shaky unpredictable 91 octane on a high revving 11:1 motor was not the best thing to do, but it is what it is.



Weren't you 12.5 to 1 before?

Nope. Build sheet shows 14:1. Piston part number shows 15:1

[Flash68]

Nope. Build sheet shows 14:1. Piston part number shows 15:1

:eek:

You should be running $3 race gas IMO......



E85

:D

[Track Junky]

My car is going to use gas like a Prius compared to yours. I filled my tank at Sonoma and then ran a full session. Went back to the pumps and refilled just to get an idea of how much fuel I used........only 4.3 gallons

[Flash68]

My car is going to use gas like a Prius compared to yours. I filled my tank at Sonoma and then ran a full session. Went back to the pumps and refilled just to get an idea of how much fuel I used........only 4.3 gallons

Sounds like a part throttle session to me. Step on it would ya? :lol:

[Track Junky]

Sounds like a part throttle session to me. Step on it would ya? :lol:

That's fricken funny......and you could be right :headscratch: :lol:

[Shmoov69]

Sounds like a part throttle session to me. Step on it would ya? :lol:

Sheesh! That's what I was thinking!! 4.3 gallons on a track day?!? The only time didn't use more (like 2-3 times that!) was wen it was broke on the trailer after a few runs! LoL!

[intocarss]

I disagree with Greg to a point on timing needed. Compression is part of it but the efficiency of the heads/combustion chamber has a big part to do with it.

Based on your theory Greg, tell me why my motor likes 30* timing (13:1 compression) and Rob's FE likes near 40* (less than mine, around 12:1 give or take).

It's mostly due to the difference in combustion chamber, valve angle, etc.

Typical 23* headed engines do not run low timing (relatively) like 32* so that is very surprising. 36-38* sounds more like it. I am thinking Joe built in a lot of safety for you? I dunno else why. That doesn't make much sense to me based on what you've shared. ;) :hello:

[Track Junky]

Sheesh! That's what I was thinking!! 4.3 gallons on a track day?!? The only time didn't use more (like 2-3 times that!) was wen it was broke on the trailer after a few runs! LoL!

You do realize I'm just talking about one session out of the 4 total for the day right Jimmy :headscratch:

[GregWeld]

That's some interesting info Greg. I didn't know higher compression likes more timing. When I originally dynode this motor in Muncie, Indiana at the builder shop we went with 38* total timing.

When I dyno tuned down here after the timing chain incident Joe thought it ran best at 32.5*.



Well a dyno is the PROPER way to build a real tune on any motor....

I'd be running 36* in that motor to start with and see if it likes it.





I disagree with Greg to a point on timing needed. Compression is part of it but the efficiency of the heads/combustion chamber has a big part to do with it.

Based on your theory Greg, tell me why my motor likes 30* timing (13:1 compression) and Rob's FE likes near 40* (less than mine, around 12:1 give or take).

It's mostly due to the difference in combustion chamber, valve angle, etc.

Typical 23* headed engines do not run low timing (relatively) like 32* so that is very surprising. 36-38* sounds more like it. I am thinking Joe built in a lot of safety for you? I dunno else why. That doesn't make much sense to me based on what you've shared.



It has EVERYTHING to do with combustion efficiency.... and heads and the propagation of the flame travel etc. However..... High compression only tells you what gas you're going to have to run -- it doesn't tell you what timing a motor is going to need / want.

The fuel - in this case - is what leads me to the timing in question. So assuming he has good heads - aluminum - we know he has high compression -- and the numbers he's tossing out is the STATIC compression number of the piston --- because what really counts is the CYLINDER PRESSURE -- and that depends on his cam numbers. But 114 octane gas is going to want more timing than pump fuel.







Nope. Build sheet shows 14:1. Piston part number shows 15:1




Really doesn't matter except the high compression is going to want high octane fuel in order to stave off detonation. Thus the only real reason to understand that part of the motor.




You do realize I'm just talking about one session out of the 4 total for the day right Jimmy :headscratch:




I burn about 9 gallons per session.... might have something to do with how often a guy is WOT..... LOL

[GregWeld]

BTW -- For the record --- WE ARE ALL JUST GUESSING....


Mines just a more educated guess.

[Track Junky]

I burn about 9 gallons per session.... might have something to do with how often a guy is WOT..... LOL

We've chatted about this before. That is weird. Not sure why your using so much fuel.........Same deal at T-Hill. I use about 5 gallons a session there and our lap times as of late have been pretty close.

[Shmoov69]

You do realize I'm just talking about one session out of the 4 total for the day right Jimmy :headscratch:

No, actually I didn't realize that. Not sure how big the track is there and how many laps, so I can't comment on what mine "would be" there. All I know is that I had to fill like 3 times at Putnam park when I ran there a couple different times. And that was going in with a full tank.

But glad that you may be figuring it out that it could be the gas. It sounded to me like an ignition issue, but if for some reason fuel isn't burning, then it would seem like ignition. I'm anxious to see what you find to be the real issue. Lots of discussion and learning going on here

[GregWeld]

I disagree with Greg to a point on timing needed. Compression is part of it but the efficiency of the heads/combustion chamber has a big part to do with it.

Based on your theory Greg, tell me why my motor likes 30* timing (13:1 compression) and Rob's FE likes near 40* (less than mine, around 12:1 give or take).It's mostly due to the difference in combustion chamber, valve angle, etc.



Totally agree with you --- until we toss in the 114 octane.
You can not compare two completely different motors -- all that will tell you is that they are completely different. For many obvious reasons.


A good running MOPAR 440 --- wants 40* total on PUMP gas with good heads. That's NOT a SBC.... or a FORD for that matter. Different motors want different timing.







23* headed engines do not run low timing (relatively) like 32* so that is very surprising. 36-38* sounds more like it. I am thinking Joe built in a lot of safety for you? I dunno else why. That doesn't make much sense to me based on what you've shared.



Good heads -- tight quench -- etc -- my 408 motor ran 34* and made best power. A dyno is going to tell you -- you don't tell it. You find it. The numbers don't lie. It was also running PUMP GAS not 114.

[GregWeld]

We've chatted about this before. That is weird. Not sure why your using so much fuel.........Same deal at T-Hill. I use about 5 gallons a session there and our lap times as of late have been pretty close.



Oh I don't really use 9 gallons per session buddy - just pulling your leg.... But it is 9 gallons per fill up ---- and that's about 2 sessions... so 4.5 to 5 gallons per is similar to what you're seeing.

[GregWeld]

Gaetano ---- Regardless of all the gas and timing discussion ---- you need to FIND the right timing for YOUR motor. That could be 32* or it could be 36* and anywhere in-between.


I don't think you can find that with just seat of the pants driving. And damage can occur if you get it wrong - so it's more than just a little important.

[Vince@Meanstreets]

dyno time is the only imho. Your engine numbers and AFR's will tell you what it wants.

[Track Junky]

Gaetano ---- Regardless of all the gas and timing discussion ---- you need to FIND the right timing for YOUR motor. That could be 32* or it could be 36* and anywhere in-between.


I don't think you can find that with just seat of the pants driving. And damage can occur if you get it wrong - so it's more than just a little important.

Yeah I get it. Joe said the same thing when he was dyno tuning my motor. 32.5* total is what he came up with. Don't know or remember exactly how he came to that conclusion but we made over 20 pulls and a few changes and he would pull spark plugs and inspect them with some sort of spark plug magnifying scope gismo.
I'm trying to schedule Joe for a chassis dyno tune at Sonoma the Friday before the event since I put another distributor in and the springs on the original distributor don't look the same as the ones I'm using now.

[Vince@Meanstreets]

Yeah I get it. Joe said the same thing when he was dyno tuning my motor. 32.5* total is what he came up with. Don't know or remember exactly how he came to that conclusion but we made over 20 pulls and a few changes and he would pull spark plugs and inspect them with some sort of spark plug magnifying scope gismo.
I'm trying to schedule Joe for a chassis dyno tune at Sonoma the Friday before the event since I put another distributor in and the springs on the original distributor don't look the same as the ones I'm using now.

Don't forget we can schedule a chassis dyno session with Joe over at Borelli's. They can set up fo AFR's and it may save down time. Aaron say saturdays would be good.

[GregWeld]

Yeah I get it. Joe said the same thing when he was dyno tuning my motor. 32.5* total is what he came up with. Don't know or remember exactly how he came to that conclusion but we made over 20 pulls and a few changes and he would pull spark plugs and inspect them with some sort of spark plug magnifying scope gismo.
I'm trying to schedule Joe for a chassis dyno tune at Sonoma the Friday before the event since I put another distributor in and the springs on the original distributor don't look the same as the ones I'm using now.




GOOD 'cause it's way cheaper than new motors.

[Track Junky]

Don't forget we can schedule a chassis dyno session with Joe over at Borelli's. They can set up fo AFR's and it may save down time. Aaron say saturdays would be good.


That sounds good Vince as long as its convenient for Joe. Joe lives over by Sonoma. Where is Borelli's located?

[Vince@Meanstreets]

That sounds good Vince as long as its convenient for Joe. Joe lives over by Sonoma. Where is Borelli's located?

http://borellimotorsports.com/newsite/auto-services/dyno-tuning/

He would be down for a dyno day. Especially if he can schedule a few cars and rent the dyno for a full day and give him time to prep.