AFR at cruise vs head temps, and an oil leak ? too Options

[agrump]

I kind of freaked this morning because my head temps this morning were at 400f on #3, 380 on #1. After awhile I remembered that the gauge is calibrated for 70f so the real temp on #3 is around 365. I am still wondering if this is too high for just cruising on the hwy at 65-70 mph. I pulled the plugs the other day and 1,2 and 4 were tan with some deposits but #3 was white with just a very light coating. Going by the receipts I got with the car my engine is a 2056 running a 280 degree cam (Fat 442), 96 "euro" pistons with TS rings. I’m not sure about the static compression ratio but I did check with a gauge and found all the cylinders to be within 112-120 psi.

I’m currently running 13.7:1 afr, should I make it richer, say 13.0:1? The car use to have carbs and the afr was around 12.0:1 but I didn’t have my head temp gauge then.

One more thing, the motor runs strong but has a mysterious oil leak, doesn't leave puddles, does show any obvious signs of burning or dripping but the oil level drops significantly every once in a while. I had the head vent hose attached to the wrong nipple on the air cleaner so it may have been pulling a vacuum; I’m not sure if moving it has worked yet. Jake warns against using TS rings so I wonder if that could be the problem.

Thanks

[ArtechnikA]

aircraft guys like to run 50F LOP (EGT) in cruise...
you got room for another gauge ? :-)

[Joe Ricard]

So this is an aftermarket FI car?
having one cylinder going lean could be a clogging injector.
Carb then you got a freaking clogging idle jet. I freaking am going nuts clogging idle jets. I have cleaned, cleaned cleaned inlcuding the engine compartment being spotless. Obviously not enough yet.

[DNHunt]

I just went through a scenerio similar to yours. The plug in #3 was very light. It turned out to be bad injector with only 110 miles on it since new. Mine was lean with more throttle and fine at cruise.

I have mine set up to run with a target of 13.7 at cruise in cloosed loop.

Since my FI is batch fired and each injector fires twice per 720 degrees, fuel sits in the manifold and I was able to swap the injector wiring around so bank 2 was really on the bank 1 injectors. (Does this make any sense?) Anyway, the problem did not follow the wiring. Fuel pressure was OK and fuel was returning to the tank so fuel volume was OK. That kind of left the injector. Swapped it out and the problem disappeared.

I hope this helps

Dave

[agrump]

It's a closed loop megasquirt installation using d-jet hardware. I do have a spare injector so I'll try swapping it out. #3 has always been a little funny, when I had carbs on it I would have to open the air equalizer screw a good bit to get it to match the rest of the cylinders. Required the same thing with 2 different sets of carbs. Weird.

Dave , what kind of head temps are you seeing?

Thank

[mudfoot76]

Before my rebuild, my engine had TS rings. It had a voracious appetite for oil. Then after reading this board, and in particular Jake's insight on TS (I believe he said that really stands for Total Sh*t (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif) ) I am thankful to no longer run them in my new motor. My oil level had hardly budged, and the oil doesn't foul after 100 miles either!

[DNHunt]

VDO gauge with sender under # 3 plug. Most of the time a smidge under 300.

Swap the wiring first and see if the problem follows the connector. #3 should be getting plenty of fuel supply as it is first served.

Since it was a problem with carbs. I wonder about something funny with that cylinder. Check valve adjustment, compression check, and leakdown. Or could it be a problem sealing the manifold to the head (vacuum leak). Spray a little starter fluid ner the intake and see if the engine speeds up. Have someone with a fire extinquisher handy just in case.

Dave