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Fri Nov 21, 2008 12:07 pm

After a 10 minute run on the freeway at about 3200 RPM, and then surface street driving for less then 1/2 mile into the parking lot at work.

I checked the temp of the cyl heads using an infared thermometer, the kind with the laser pointer on them. I pointed at the corner of each head, the fin area near the exhaust port.

Cyl #4 area read 315 deg. and Cyl #2 read 260. This is on a late model 2liter type 1 with a doghouse oil cooler.

Is this something I should be concerned about?

My motor seems to be running a bit rough at less than 3000, but stable, otherwise fine. Around 3000 and higher, it seems smoother.

On thing I did recently was turn out all 4 idle mix screws on the dual dellortos "about" 1/4 of a turn, to richen it up because of popping in my exhaust at speeds less then 3000rpm and on decel. Sounds much better now. (no exaust leaks, verified)

If the idle mix is off balance, could this cause the wide temp diff?

Fri Nov 21, 2008 12:14 pm

Cylinder 3 is supposed to run a little warmer than the rest. No biggie. As long as your temp stays below 425, you're good. Taking a temperature anywhere other than under the plug is not going to be accurate.

Running too lean can make temps go up, sure, but making things too rich can also increase your temps. Without a wideband, you're just guessing on your mixture. I would probably give the screw 1/8th of a turn at a time, then drive it for a while to see if it's improved. 1/4 turn seems like alot to do all at once.

Fri Nov 21, 2008 12:22 pm

Thanks SkrapMetal.

The info helps me rest easier and the advise on the 1/8 if helpful considering I don't have a wide band....

...but I do have the tools with me to adjust the mix a lunch time, and take her for a spin :D

Fri Nov 21, 2008 12:41 pm

Quote: Cylinder 3 is supposed to run a little warmer than the rest

With the oil cooler out of the cooling air stream using the DH cooler why should it?

Fri Nov 21, 2008 10:29 pm

It is the non doghouse motors that have temp problems with #3. Using a doghouse the temps should be similar. You probably have a intake leak.