Overheating Confusion, Smart people Needed!

[tyoneal]

To All:

I wrote a while ago regarding the overheating issues I was having with my Bowtie 400. (See more about the car at the bottom of this post.)

Here is what I have done so far.

Replaced Radiator Cap
Checked Radiator hoses
Replaced fan with a larger one
Made sure the cowl around the radiator was sealing correctly
160 degree thermostat
Made sure Radiator had coolant and water in it
Have checked water pump (It has a March front Drive system on it.)
Have checked water temp gauge and replaced.
It does have A/C and I have added an extra fan to the condenser to promote effective cooling
Advanced Timing as far as possible.

This last item I found welded so it could be recurved. Can someone explain why this s done? The car was used at the track real often and I guessed it may had something to do with that, but I don't know, and I haven't seen any literature one way or the other about it.

Could someone please enlighten me on this, AND whether or not this would be causing the overheating?

It is now cooler here in Texas and it still keeps trying to get hot.

This is very frustrating and I would EXTREMELY thankful to whomever could solve this puzzling question and offer the correct solution.

Thanks in advance.

Thanks,

Ty O'Neal

[deuce_454]

well if the timimg is fixed you would be running alot of timimg all the time, this will generate heat like a mofo... you could try and drop in a different distributor.. nothing fancy or permanent just a HEI you propably have a couple of on a shelf...

somthing that have helped me in the past is to drill a couple of 1/4 inch holes on the flat brass part of the thermostat it helps alot for some reason... and by over heating do you mean boil?? or above 160??

lastly, are you sure that the head gasket isnt plugging any of the steamholes in the block? and are there steamholes in the heads as well?? some of the siamese bore blocks are alittle sensitive to this, and if you are blowing coolant it could be a steam pocket, not a generalized overheating problem..

[Steve Chryssos]

My money's on the steam hole issue. You need proper 400 head gaskets as well as a pair of 1/8" holes drilled between each chamber of the cylinder heads as shown in the pic below. If there is any doubt whatsoever, pull a head and check. Depending on what block/heads you are using, there is also a slim chance that casting flash has become dislodged and is blocking a water passage.

http://www.gregsengine.com/images/350400/350400-6.jpg

Other than that, (not sure what you mean by "checked water pump") I would remove the fan belt and grab the water pump pulley. Check for any free play. March uses basic Auto Zone grade OE water pumps with stock impellers and sloppy tolerances. Might as well get a true HP blueprinted pump like EMP/Stewart, Edelbrock, Moroso, etc. Cheap insurance.

Be glad I'm not there to help. My usual response to basic joe-mechanic issues is to take the entire vehicle apart and drop $50K on upgrades. :willy:

[RaceMan]

You could also check the speed of the water flow , I've had to slow the flow down before because it wasn't spending enough time cooling in the radiator , it can also go too slow , if its all stock stuff thats most likely not your problem but I have seen it.
Good luck

[BRIAN]

What do you consider overheating? What temp does car run at? What lb cap do you have?

If the steam holes were blocked wouldn't the gasket have failed?

[JamesJ]

also make sure the water pump is spinning the correct way...

Where in TX are you?

[tyoneal]

well if the timimg is fixed you would be running alot of timimg all the time, this will generate heat like a mofo... you could try and drop in a different distributor.. nothing fancy or permanent just a HEI you propably have a couple of on a shelf...

somthing that have helped me in the past is to drill a couple of 1/4 inch holes on the flat brass part of the thermostat it helps alot for some reason... and by over heating do you mean boil?? or above 160??

lastly, are you sure that the head gasket isnt plugging any of the steamholes in the block? and are there steamholes in the heads as well?? some of the siamese bore blocks are alittle sensitive to this, and if you are blowing coolant it could be a steam pocket, not a generalized overheating problem..
===============================
Based on your experience how frequently does this type of problem arise, and why would some have the distributor forzen in one location?

With a hot solid roller cam, vacuum advance is out right? need a mechanical advance.

Thanks,

Ty

[tyoneal]

My money's on the steam hole issue. You need proper 400 head gaskets as well as a pair of 1/8" holes drilled between each chamber of the cylinder heads as shown in the pic below. If there is any doubt whatsoever, pull a head and check. Depending on what block/heads you are using, there is also a slim chance that casting flash has become dislodged and is blocking a water passage.

http://www.gregsengine.com/images/350400/350400-6.jpg

Other than that, (not sure what you mean by "checked water pump") I would remove the fan belt and grab the water pump pulley. Check for any free play. March uses basic Auto Zone grade OE water pumps with stock impellers and sloppy tolerances. Might as well get a true HP blueprinted pump like EMP/Stewart, Edelbrock, Moroso, etc. Cheap insurance.

Be glad I'm not there to help. My usual response to basic joe-mechanic issues is to take the entire vehicle apart and drop $50K on upgrades. :willy:
===========================
Steve:

Thanks for the reply. I'm using the Bowtie 400 Block, and the head are Brodex Track 1 Heads. This is the same engine Mark was using when I bought his car. The water pump when the march pulley system was going on didn't have a lot of slope in it. The overheating has slowly started to get better, but I'm not sure if it is the season, or the fact I have changed so many things.

Ty

[tyoneal]

You could also check the speed of the water flow , I've had to slow the flow down before because it wasn't spending enough time cooling in the radiator , it can also go too slow , if its all stock stuff thats most likely not your problem but I have seen it.
Good luck

How can you tell if it is going to slow or not?

[tyoneal]

What do you consider overheating? What temp does car run at? What lb cap do you have?

If the steam holes were blocked wouldn't the gasket have failed?

Overheating is meant that it continues to get hotter the longer the engine is running. It has gotten to 240 before, maybe a bit further, but I watch it all the time. I always wind up shutting it down.

Now it gets hot slower, but it NEVER seems to find a level and stop. A/C on or not.

I was kind of hoping it was the distributer, but as many answers that I am reading, it could be anything in sounds.

[tyoneal]

also make sure the water pump is spinning the correct way...

Where in TX are you?

I am located in Frisco, Texas. Just north of Dallas about 25 Miles. Last time I checked I thought it was, however that is always and easy thing to check again.

[rockdogz]

This sounds a lot like what happened to me recently, and it was my water pump. The pump only had about 2000 miles on it, so the bearing was fine and there was no free play in it. What happened was that the impeller separated from the shaft... see the picture here. (http://www.camarorestoration.com/gallery/Reassembly/waterpump_002) Needless to say it wasn't moving any water around the cooling system.
It was a Stewart pump too, so I guess you never know when something freaky like this will happen. They did rebuild it for me so that's good.

[AM.MSCL]

The purpose of welding a distributor is to lock the advance to a set amount. This is very common for roundy-round racers, it is suppose to keep the delay in acceleration out of the corners from happening. Most of the time timing is set higher then normal engines would be for racing; this will create the engine to run hotter. From what I have seen 240-260 for a roundy-round racer is normal temps.

If you are using this motor for street driving then I would swap out the distributor due to the timing is locked in.

How slow is slowly rising to 240 degrees? 10 minutes, half hour or a hour?

It is hard to tell if the water pump is to high volume by watching but I have experienced this on a 85 Z28 I had. I had a high volume water pump and the car ran 240 but someone suggested going back to the stock pump and the temps dropped down to 210 after that.

[BRIAN]

I know what overheating means what I was looking for is what temp you thought overheating was.

Where is temp sender located?

240 is what a newer aluminum headed small block can run at. Is the radiator boiling over?? Do you have erratic temps? Does it stay stable at 240? Everybody goes by the old 180-190 but modern systems run hotter.

And what radiator cap do you have? Going by memory every 1lbs ads 10 degrees?? Of course staying within your systems limits. I am not a parts changer as that just gets you know real answers.