Ever seen this before?

[71RS/SS396]

Originally Posted by 69hugger

My builder's opinion/experience is way more complex than what I typed above. I didn't want to type a long diatribe, and most don't want to read it. I don't claim to know all he does, but he agrees you need oil temp. But oil temp runs considerably hotter than water temp, and (in his opinion) you don't need or want that much water temp.
A little more info... My motor has about 11.5:1 static C.R., and the cam timing provides for about 220 lbs cranking compression. I use 92 octane gas. I have a 6 speed & 3.55 gears, so in "touring" mode, I am at about 1500 rpm at 65 mph. Another factor is I can sometimes get stuck in traffic on a 90 degree day, and with a black car, want to be able to run the A/C. (What is the point of having A/C if you can't use it?) With this setup, we want to control the temperature as much as possible. His biggest concern is detonation. And I think we can all agree that higher combustion temps lead to detonation.
My car has the Vintage Air Frontrunner system, which comes with the Stewart pump. Do I need it? I don't know, but as long as it was engineered that way, I will run it if I can.
My motor is new, with more static & way more dynamic compression. I also have a new larger radiator with larger fans. And now the "new" pump. Dialing this in is a learning experience for me. I have always run a 'stat in my cars, and read years ago you needed the restriction the 'stat provides to create higher pressure in the block to prevent hot spots from locally boiling coolant in the heads. I had installed it with the new pump, but it obviously didn't do well with that restriction. I can control the fans with my ECU, and (so far) it seems to work well.
Drove about 60 miles on Saturday... it ran at 150 in 55 degree weather, and about 165 when it warmed up to 75. Drove it about 50 miles yesterday in 80 degree weather, sometimes with the A/C on, and it never went over 180. I am very happy when the gauge is under 200.
Time will tell about the city vs. highway speeds, and 90 degree days with A/C. But so far, so good.

And thanks for weighing in!


Bill

The thermostat has nothing to do with pressure.... it's on the inlet side of the pump, therefore it would create a vacuum if anything, but will cavitate before it creates much vacuum. I think you simply had a faulty water pump. From the temps you posted, you're overcooling the engine imho, these engines are designed to run hotter than the old school sbc/bbc.

[69hugger]

Tim,
I have a BBC....534 C.I. (.250" stroked 502)

[71RS/SS396]

Originally Posted by 69hugger

Tim,
I have a BBC....534 C.I. (.250" stroked 502)

Doh.... I guess I should've realized that from the pictures.
150* is too cool imho, what are your oil temps at that temp?

[69hugger]

Originally Posted by 71RS/SS396

Doh.... I guess I should've realized that from the pictures.
150* is too cool imho, what are your oil temps at that temp?

I can't honestly answer that. i don't have an oil temp gauge.
My C-6 Z06 had a temp gauge, and it took FOREVER for the oil to get hot. Who can drive for 30-45 minutes to warm the oil every time before they lean on it?
My procedure has always been (right or wrong) to warm the engine up by driving gingerly for at least 10-15 minutes and make sure the coolant is up to temp. before jumping on it. And usually longer than that. My driving is more short acceleration blasts than autocross type driving. I may run it through 2 or 3 gears, than back off.
Is the oil up to temp? I highly doubt it. But I think it would take longer for the oil to get to full temp than I'm always willing to wait. FWIW, I've never had an engine failure. I think overall I'm easier on my motor than most guys.
All this discussion led me to do some 'net research. I found a very interesting site about motor oils. It has is a series of articles that are very enlightening.

I highly recommend this...

http://www.bobistheoilguy.com/motor-oil-101/


Again, thanks for the input...


Bill

[Panteracer]

My old mustang (Chet's now.. that runs with Greg Weld)
had an oil to air cooler out front... it would take about
two laps on the race track before the Oil temp gauge
would lift off the stop that was at 140
My Pantera has a water to Oil Cooler and it not only
cools the oil but also helps it warm up quicker... very
good to have when you autocross on a cold day

Bob

[Roberts68]

Cool to hear from another Minnesotan. I am no expert but I would sooner drill some little bypass holes in the t-stat as opposed to run without one altogether. The thermostat will get you up to temp quicker and high flow stats will have minimal resistance. I think Milodon are pre drilled with a tiny bypass.

Anyway, can I ask what your 5th and 6th ratios are? ...and rear tire diameter?

[69hugger]

Originally Posted by Roberts68

Cool to hear from another Minnesotan. I am no expert but I would sooner drill some little bypass holes in the t-stat as opposed to run without one altogether. The thermostat will get you up to temp quicker and high flow stats will have minimal resistance. I think Milodon are pre drilled with a tiny bypass.

Anyway, can I ask what your 5th and 6th ratios are? ...and rear tire diameter?

Robert,
I would rather run a stat too, but given the circumstances, I won't, at least for now. My stat had (3) 3/16" holes drilled in it. It still blew the gasket out of the back of the pump. And it was wide open both times when I took it out of (the still hot) motor. Considering the mess it made & the work involved to fix it, I am going to run w/o the stat & closely monitor the temp. If it heats up in a normal fashion, and runs in the same range as it did with the stat, I am comfortable with that.
My T-56 has a .74 5th gear, and a .50 6th. I have 335/30-18 BFG Rival tires, which are advertised at 25.9" tall.
Where in Central Mn are you located?

Bill

[Roberts68]

I see what you mean on the T-stat. Since you can't determine if the gasket or cover could have been mishandled, compromised by being unclean mating surfaces etc that lead to failure I understand your decision. I can't help but wonder if that could not have been the case on the rebuild however.

I am in Monticello.

The reason I asked about gearing is I sourced a 12 bolt last summer with 3.55 that originally belonged to a '69 Z-28. I wanted it to still be 3.73 but someone had changed it.
My trans is a TUET11009 /Tremec T56 Magnum, a "close ratio" with a 2.66 1st, .80 5th, .62 6th gear. I am in perpetual build purgatory.

I have done some math or I should say used Tremecs website calculators and really just was curious if 6th will be usable as some people have told me it won't be. Or, at least one engine guru (also old school) told me that it will load up running off idle out of power band or too low on torque curve at cruise rpm etc...

Forgive the thread highjack, and granted you have BIG BBC torque on tap, but could you comment toward this? How do you like it and does this sound like a silly worry?

[GregWeld]

I'm only going to weigh in here with some food for thought. I'm not trying to make a point - or start any arguments.


There are LOTS of cars running around that are far more powerful than what this motor is (not saying your's isn't powerful)... and these motors get RACED and raced hard.... which means that they're being spun up and held there for long periods of time... AND they're running thermostats. Including my race Mustang and Lotus.

Water only builds up pressure when it meets resistance (over simplified)... so I'd be looking at the flow of the radiator or the bottom hose being sucked closed (lacking the internal spring that is in place to keep it from doing that)... or some other simple issue that is restricting the flow other than the thermostat.

[69hugger]

Originally Posted by Roberts68

I see what you mean on the T-stat. Since you can't determine if the gasket or cover could have been mishandled, compromised by being unclean mating surfaces etc that lead to failure I understand your decision. I can't help but wonder if that could not have been the case on the rebuild however.

I am in Monticello.

The reason I asked about gearing is I sourced a 12 bolt last summer with 3.55 that originally belonged to a '69 Z-28. I wanted it to still be 3.73 but someone had changed it.
My trans is a TUET11009 /Tremec T56 Magnum, a "close ratio" with a 2.66 1st, .80 5th, .62 6th gear. I am in perpetual build purgatory.

I have done some math or I should say used Tremecs website calculators and really just was curious if 6th will be usable as some people have told me it won't be. Or, at least one engine guru (also old school) told me that it will load up running off idle out of power band or too low on torque curve at cruise rpm etc...

Forgive the thread highjack, and granted you have BIG BBC torque on tap, but could you comment toward this? How do you like it and does this sound like a silly worry?

Robert,
You have deeper 5th & 6th than I do, and the same rear end gear, so you will be running a little higher rpm than me, but not by much.
We built my motor with torque in mind, for use with the 6 speed. It will cruise at 14 or 1500 rpm ok, but we had to drop the advance to 17 degrees there to completely eliminate detonation at that high load/ low RPM situation. And, I have fuel injection, so we could tailor the fuel & timing for cruising as well. In my case, I can run in 6th, but only at about 65 mph or higher. When traffic dictates slowing below 65, I have to drop to 5th. Frankly, I'd be just as happy with a 5 speed, but that's because I usually don't drive at 70 or above as I am in the metro area most of the time.
You didn't mention what motor you're running, so I can't comment on how it will work, but it will need some torque to pull 6th gear. As long as it isn't cammed too wildly, you'll probably be fine. Depending on what you plan to use the car for, you can always drop to a 3.73 rear gear, but gives you a pretty low 1st, and closer shifts all the way up. I'd start where you are, and see how you like it.
I also had a C6 Z06 and didn't use 6th very much on that either. I viewed it as high speed/ low noise/ fuel economy gear.
BTW, I am in Maple Grove, so close by.


Bill