Engine temps?, Measured by exhaust header temps?? Options

[Kerrys914]

Engine temps
I was checking some engine temps with an IR gun and found some weird temps

The 1-2-3 side runs 500F about 2" down from the heads

The other side gets weird..
6 = 350F
4-5 = 175F

What would cause the difference and the really low temps?


Engine is a 2.2 with webers

[904svo]

From the readings on those temperture, it looks like

the 2 low reading are not firing while the other is and

heating up the pipes, This may be cause be the carb

on that side not set up correctly if these reading were

taken while engine is idleing. Just my thought on the

matter.

[Allan]

Just remember that the #3 cylinder will give the best temp....

[Kerrys914]

I took these readings at idle (10mins maybe?)

I thought they should all be very close to each other in temp readings.

I'll keep digging around.

[john rogers]

I would pull all the plugs and take a look, #6 is a bit rich and #4 and #5 are real rich I bet. They could be misfiring but then the engine would idle pretty rough. You could also take a sync meter and check each intake to see if the flows are even in all six intakes and I would guess they are not. The temps at idle will tell the idle mixture but what I would like to know is what are they at wide open throttle at about 7K RPM, that is where the bad things can happen! When they took my new 2.7L race engine to the dyno they put pyrometers on all six exhaust outlets and temps were within 5 degrees each at 6800 which means all the barrels are getting the right mixture.

[bd1308]

Or just get a CHT.

Now that I have one, I cant live without it.

Well I can live without it, but I like dirivng with it.

[machina]

i have exhaust gas temp probes and head temp probes on my TIV

i wouldn't worry too much about idle temps, may be a clogged idle circuit or out of adjusted linkage.

the temps under load are what is really important.

[Joe Ricard]

Uh there are two too many cylinders on there. THAT's the problem.

However I agree with the funky carb thing.

Too bad you don't have a trunk monkey to measure this while under full load.

[bd1308]

Actually I rent out trunk monkeys.

$155/barrel ( they wanted a contract negotiation)

b

[Kerrys914]

I was reading on the bird board that it is very easy to install the cam 180deg out and still have the engine run okay??? The engine runs fine (at least as best I can tell). I don't have another 911 2.2 to compare to but it seems okay to me.


I don't think I did this but will check it this weekend. It's just funny how the two sides are so different in temps?

I will also have the wife rev the engine to about 2000rpm while I pull some plug wires. At idle there is very little if any change when I pull #4 and #5 wires off.

I guess I could put the IR temp gun away and then things would be back to normal LOL

Cheers and thanks

[slivel]

I was reading on the bird board that it is very easy to install the cam 180deg out and still have the engine run okay??? The engine runs fine (at least as best I can tell). I don't have another 911 2.2 to compare to but it seems okay to me.


I don't think I did this but will check it this weekend. It's just funny how the two sides are so different in temps?

I will also have the wife rev the engine to about 2000rpm while I pull some plug wires. At idle there is very little if any change when I pull #4 and #5 wires off.

I guess I could put the IR temp gun away and then things would be back to normal LOL

Cheers and thanks

I would look at the the problem in this order: First rev the engine to 2000 rpm as you suggested but instead of pulling plug wires, just measure the header temps on all cylinders and see if they are close to the same values. If they are, then I think it points to dirty idle circuit and you can clean them by blowing compressed air back through the circuit. Remove the idle bleed screw and shoot some air or carb clearer in the orifice. If the temp readings are still showing misfire at 2000 rpm then it may be that the float level is not set correctly for those misfiring cylinders. You can check the ignition side by clipping a timing light to each of the wires and look for the flashing timing light to be irregular on misfiring cylinders. If idle circuit, float level and ignition are all OK, then I would look at the throttle butterflies. One or more of them may be dirty where they seat in the bore. A good carb manual and a Unisyn air flow meter come in very handy when working on these carbs. Good luck.

[Joe Ricard]

Yup Uni-syn each velocity stack. you will probably find that the cold cylinders are also not pulling as much air.

Ain't this engines great?

[Kerrys914]

Thanks. I have two Uni-sync's and will recheck my settings (added to the list of things to check)