osbekken

I'm having troubble getting my newly put together engine to work properly. Sorry for the long tekst, but I try to include as much information as possible, to make it easier for you guys to understand the problem and help. If anything is missing, just ask, and I'll try to supply more information.

Mid 2008 I completly destroyed the engine in my car: Euro 1988 944 Turbo S silver rose. (compleete specs below)
I decided to buy and identical engine from USA on ebay (coming from an US 1989 944 turbo). I had the cylinder head rebuildt but left the block as it was. No vissible or feelable sylinder wear. I put it all together and put the new engine into the car using exactly the same external parts and electronics.

Problem:
The car is running hotter now with the new engine then it did with the old one.
Idle, 860rpm gives EGT about 650-700C. (1202-1292F) The egt sensor is at #4.
Cruising at 2000rpm gives about 750-800C (1382-1472F)
If i increase rpms to 4500+ when cruising it starts to run hot, above 900C (1652) with just enough load to keep the speed at 2nd gear. Same goes for all the gears. This is hotter then it was on the old engine. All the tempereatures above is with good AFR values, 14,7-14,9 when not at heavy load.
I can also see that my water temp is now hotter then before, now its almost touching the red sone all the time, whilst before it was rarely over the first white line.
The oil is also hotter than it was before.
I dont have all the exact numbers of the old engine as the hard-drive where the logs were stored is damaged, and i cant get the data out. However i think the temps was about 100C overall.

Whats different parts now compared to before is the compleete including flywheel (witch is now lightened). The sensors mounted on the new engine is the ones that came with it, but all the wires and harness is my old one. DME and KLR stayed the same. Same fuel rail, same injectors, same flywheel sensors. I've taken the cam-housing off, meassured the cams, and they are exactly the same on both engines.

Engine setup:
Original 2,5 8v turbo S engine
Siemens #55 injectors
Lindsey MAF kit with mafterburner
Lindsey super 48 turbocharger
3" exhaust
Original wastegate, shimmed
Bypassed cycling valve, using reliaboost VBC

My theories:
Ignition is to late. This could be caused by either difference on the flywheel, and how the pickup for the flywheelsensor is mounted, or the engine is going to the self-protect mode and retarding the ignition.

So, question nr1:
What is causing the engine running hot?
Question nr2:
If the ignition is retarded, why? How do i go about solving it?

Any sugestions on how I go about this is deeply apreciated.

Mike Lindsey

Is the timing belt tight and turning the water pump?

Was the oil thermostat replaced? Once the car is good and hot (near red as you say), feel the oil cooler and see if it's hot or ambient. If ambient, replace the thermostat.

osbekken

The timing belt is tight. I have rechecked it, and it seems to work fine.
The oil thermostat was replaced, and my external oil-coolers seems to work fine.

What worries me the most is the EGTs. (the car is driveable, but the EGTs are som much higher then before, limiting how hard i can use it, if I drive nice its just a bit to hot) Earlier the car have been used on trackdays with no problems driving 1 hour at a time, now that wouldnt be possible.

The water and oil temp is mostly indicators to back the fact that the engine is running alot hotter, and that its not a faulty EGT-sensor.

Isnt it so that if the "brain" of the engine sense something is wrong the ignition will be retarded? By how much?

hp18racer

Your EGT's don't look unreasonable to me. When I had high EGT as a result of timing I really didn't see a corresponding change in water temperature. Wrong timing means more heat out the exhaust more than it does motor over heat.
Are you confident you have bleed the cooling system correctly?
Have you tested that your fans come on as they should?
When you blew your motor did you get oil in the coolant? Considered a new radiator?
www.clarks-garage.com has a simple procedure bleed the coolant and to test the fans.

osbekken

The radiator is quite new, and im pretty sure I've bleed the coolant properly. The thermostat is new also.

Are theese EGT's really normal?
How high EGT's can i have before i should expect danger to the engine?
Pherhaps I should install an aftermarket water temp indicator.

With my home-made front i think cooling shoulndt be a problem. Norway is still quite cold, so im testing in 10-15C outdoor temperature.


Im now gonna get an ignition timing lamp and check on how the timeing really is. Ill also try to read the blink codes from the KLR to see if it has registered anything being faulty resulting in retarded ignition.

hp18racer

Look for posts by Chris White or TonyG containing EGT, they have posted some good thoughts on the subject and know what they are talking about. On the track I see 1750F at the end of a long straight.

osbekken

During testing Ive seen EGT above 980C (1800F) witch I think is to high.. and my point, it wasnt like this on the old engine at all... And i dont know what could make the difference.

hp18racer

I don't see how the motor could go together so that sensor alignment is the issue. I'd double check cam timing then look at the knock sensor. I've read that the computer will pull something like 3 degrees. Have you ohmed out the wire harness connections to the knock sensor? Tried a new knock sensor?

osbekken

I was just tried to spot the ignition mark at idle using an ignition lamp.
I was able to take this picture with the light from the ignition lamp.

This is idle at 850rpm.

How does this compare to what it should look like?
When at TDC the mark on the cam wheel is an exact match with the reference wheel. As you can see this indicates very ignition just a bit sooner then TDC at idle.

I also tried to connect a homemade blink code tester as specified here. But i didnt get any blinks. Dont know if i did it right, never done this before.

Van

Unplug your TPS to "test" your blink tester...