Engine Tuning with Infrared Temperature Gun

J

JAKEFORD

Senior Member
Has anyone tried tuning an engine with headers by using a Temperature gun on each header to equalize the temperature? I tried this on a Ford 360 with individual pipes and found quite a range. You have to be quick as they cool fast but you get an idea.
 
Are you talking about tuning individual cylinders? Each half of a V8? How would it be accomplished? I'm not sure what the benefit would be. I'm not poo-pooing the idea...just want to hear more.
 
Taking temperature readings is the simple part. How do you equalize the readings without changing the air flow characteristics of the intake and exhaust flow. On a flathead you have two cylinders feeding one exhaust port, now what?
 
This was a 360 Ford in a truck with individual commercial header pipes into a collector and dual exhausts. I noticed 2 or 3 pipes were very hot and wanted to figure out what was going on so I used the temp gun. Adjusting the carb helped some but didn't solve the problem. Eventually those hot pipes burnt out.

I reasoned that the scavenging on those hot cylinders must have been stronger than the others. The only way to solve the problem would have been to play with pipe length which I was not prepared to do as this truck was use to haul a camper. The stock dual exhaust with CI manifolds did fine after the pipes burnt out. I lost faith in commercial headers after this experience.

On the flathead center port it probably wouldn't mean too much.
 
Capt Kirk said:
Are you talking about tuning individual cylinders? Each half of a V8? How would it be accomplished?...
Click to expand...

You'd need to use an intake with individual runners, such as one for a stack-type fuel injection or Weber-style carburetor.
 
JAKEFORD said:
This was a 360 Ford in a truck with individual commercial header pipes into a collector and dual exhausts. I noticed 2 or 3 pipes were very hot and wanted to figure out what was going on so I used the temp gun. Adjusting the carb helped some but didn't solve the problem. Eventually those hot pipes burnt out.

I reasoned that the scavenging on those hot cylinders must have been stronger than the others. The only way to solve the problem would have been to play with pipe length which I was not prepared to do as this truck was use to haul a camper. The stock dual exhaust with CI manifolds did fine after the pipes burnt out. I lost faith in commercial headers after this experience.

On the flathead center port it probably wouldn't mean too much.
Click to expand...

Doubt that the headers have that much to do with it. More likely the A/F mixture being fed into those pipes.
 
When I worked at IH in the engine lab, we used this technique to evaluate cylinder to cylinder fuel distribution. Changes were accomplished by changing the intake manifold runner design. This was done initially at wide open throttle, then reevaluated at part throttle, which generally gave a different result. As per normal, everything ended up as a compromise. When we were working on an efi system, we made a wooden intake manifold with a removable top so runner design could be easily changed. It was a real problem to just get equal air flow.
 
I have had a temp gun in my tool box for many years. They are cheaper to purchase now days and offer some great testing results. You can track water flow and temp thru a cooling system , find a hot spot on a water pump and any other heat related issues.
Exhauxt temp can be monitored and lean banks shown etc.
Got to be carefull with the reading as there doesnt seem to be a spec book on what they should or shouldnt be........

http://www.esitest.com/est75.html
 
An FE Ford engine (360, etc.) is notorious for leaking intake gaskets. The gasket gets pushed out of position during installation and those cylinders then run lean, causing your hot exhaust.
 
I rebuilt many 352-360-390 engines and never had an intake manifold problem. You have to be careful with that clumsy manifold when you put it on.

This one in particular was perfect and held good vacuum. No air leaks.
 
The end seals were a problem on the FEs. I used to pin them in place before putting the manifold on. Never had a problem around the ports.
 
@itslow. I understand that if there's individual control of each cylinder, this is possible. I based my comment on my assumption that this was a basically original flathead. I didn't see any easy layman's way of altering what the OP was asking in this case.
 
I've used individual thermocouples to monitor exhaust gas temp. on individual cylinders of large diesel engines. I can't see how it would be of value on a system where individual cylinder fuel input can't be adjusted. However, an interesting idea.
 
Henry , I dont think of it as adjusting individual cylinders. Its more of a problem solver like misadjusted valve train, piston sealing, compression ratios etc.
Its a great tol to analye a problem with.
A burnt or mis sealing valve would show a temperature difference etc.......
 
How about installing different spark plug "heats". I'd guess that individual cylinder (exhaust) temperatures would be dependent on the cooling system as well. Have some casting obstructions in the jacket restricting flow a bit would cause a hotter cylinder. Interesting to discuss but not sure of the relevance...the rear exhaust of a Harley probably runs hotter than the front. I know that exhaust temps on a 1963 VW "pancake" engine varies greatly depending on cylinder location.
 
I would also like to add that I'm a pilot and have owned aircrafts since my mid 20's.
EGT is an important instrument in the panel. Typically, the EGT probe is placed into the exhaust port that is expected to have the hottest temperature. Now there are whole engine monitors that have a probe in each exhaust port and they always vary in temperature by a certain margin...and that's fine. Planes have full control of mixture at the panel and can lean or enrichen easily. Lean to peak temp (Temp drops off past peak lean) and enrichen 75 degrees. With a full engine monitor you'd do this process to the hottest running exhaust and let the others fall where they may. All this leaning process does is save gas. During take off it's full rich and full power.
 
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