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Posted by: George H. Jul 28 2008, 07:13 PM

OK

I have head temp sensors on # 1 and 3 on a type 4

# 1 gives me readings at 180 after idle warm up 4- 5 min

# 3 gives me 260

after a short ( 1/4 mile ) drive # 1 is the same, but # 3 is climbing towards 350


what can cause this?

is this a tuning issue?

can this be a timing issue?

can this be a assembly issue?

the factory sensor tells my fuel injection the the temps are as high as the gauge reads

I'm just looking for all of the possibilities so I can start to run thru them

Posted by: orange914 Jul 28 2008, 08:58 PM

QUOTE(George H. @ Jul 28 2008, 06:13 PM)

Posted by: roadster fan Jul 29 2008, 04:14 AM

The experts will certainly chime in here, but the #3 cylinder is gonna be the hottest because it is the farthest from the cool air source and it's air (along with #4's) are on the side of the engine with the oil cooler.

If one CHT is used it is place under the #3 sparkplug for this reason. The #3 valve seat is usually the one to fail due to the extra heat there.

FWIW, I may be completely off base but that is my understanding.

Jim

Posted by: Gint Jul 29 2008, 07:39 AM

#3 runs the hottest anyway. But I'm no expert. Just a cheap and a note to George. How's that bumper coming?

Posted by: ericread Jul 29 2008, 11:01 AM

QUOTE(orange914 @ Jul 28 2008, 07:58 PM)

QUOTE(George H. @ Jul 28 2008, 06:13 PM)

OK

I have head temp sensors on # 1 and 3 on a type 4

# 1 gives me readings at 180 after idle warm up 4- 5 min

# 3 gives me 260

after a short ( 1/4 mile ) drive # 1 is the same, but # 3 is climbing towards 350

since the temps. are so different i think i would first switch the wiring to from gauge #1 to #3 and visa versa. that way you can confirm possible false reading.

mike

Posted by: tornik550 Jul 29 2008, 11:10 AM

Valve Lash Issue?

Posted by: benalishhero Jul 29 2008, 05:30 PM

pull a plug. could be lean.