Wanted: Cylinder Head Temperature Distribution Data


Anybody have any factual data on cylinder head temperature distribution for a stock LC2? Or coolant temperature distribution in the cylinder heads? I'm curious about both the back to front as well as the left head vs. right head variations. And even better would be before and after data with respect to cooling system modifications like high flow pump, rear coolant crossover, "steam holes" next to center cylinders, etc.

One thing I've come to believe about our engines is that as we push it beyond it's original operating parameters, it becomes more and more critical to bring critical variables (temperatures, air/fuel ratio, etc.) under control. Whether it is air distribution within the plenum (let's hear it for the RJC power plate), fuel flow through the injectors, or cylinder head temperatures, we can only perform as well as the weakest link (i.e., cylinder) will allow us. So, among many other things, I'm trying to decide on how much effort to expend on the cooling system on my current rebuild. I'm particularly intrigued by Smokey Yunick's y-pipe for our little V6! I've already got an aluminum radiator, flowkooler coolant pump and lots of Evans NPG+ standing by. I'm toying with the notion of separate, remote thermostats for the coolant return off each cylinder head (rather than the rear coolant crossover) as a natural extension of Smokey's y-pipe concept to reduce the temperature spread between the hottest and coolest cylinders.
It will also allow me to use a larger, less restrictive thermostat than our dinky stock size and get more benefit out of the high flow pump. And I sure need it here in Houston with a front mount!

Unfortunately, I can't collect any before data because I'm out of commission with a flat #3 exhaust lobe. And I probably couldn't afford the instrumentation either!

Anybody seen any GM data from years gone by?

Anyway, enough rambling.

Buzz White in Houston, TX (sumnerw@flash.net)
**My** answer is just not putting heat into the head/coolant, this time. Barrier coating of the combustion chamber, and exhaust ports.
Plus plugging off the EGR ports in the heads to reduce the exhaust port surface area, and heat transfer into the head.

Smokey was working on a Chev head and that was alot longer, and of a poorer design then the GN, coolant wise.
Thanks for the response, Bruce. I knew I could count on you. So which product did you use and from where did you get it? Or did you have some shop do it for you?

Best regards,
Buzz White in Houston, TX (sumnerw@flash.net)
Hey Buzz -

do you have that publication with Smokey's mods to the buick V6? I've been wanting to take a look that. If you've got it, can I come over and take a look? Maybe borrow it for a few days?

re: coatings, Polydyn is right off 45 between 610N and downtown. I've had stuff coated there, and they do work for some big name guys. Pretty reputable I think, and no shipping since you can just drive it over there.

Originally posted by sumnerw
Thanks for the response, Bruce. I knew I could count on you. So which product did you use and from where did you get it? Or did you have some shop do it for you?

Techline coatings.
My *Engine Guy* been using it on and off for quite some time with good results.

Thing is Read The Manual, and do it correctly. Once on properly you have to grind the stuff off, and even doing that takes some effort.