newkie

So. About 2 months or so back i drove my 89 944 turbo to the garage to check the timing belt. And i checked the Compression. about 11 bars on all cylinders (Is that a good value btw?).

I set the motor to TDC (And im sure the mark on the flywheel lined up with the markingstick in the clutchhousing). I noticed the cam was of by 2 theeth. I realize that the motor would probably not run like that now. But back then i aligned it so that it was spot on. Cranked the engine by hand making sure nothing was wrong. Then i messured the compression again (0 compression on all cylinders). Now i tried to set the cam right again but im totaly lost.

The smartest way to get it right again has to be geting it to TDC making sure that the piston closest the the front of the car is in its highest position. Rigth?

On all pictures i have seen of the TDC tab in the little window on the clutch housing. The TAB roughly has the shape of my thumb (But smaller ). On my car it looks more lite a toothpick. At first i thought that the pictures are probably of earlier cars and that Porsche had i changed on later models is that a correct assumtion?

Spidey944

http://www.clarks-garage.com/shop-manual/eng-13.htm

use the pics here to help you. I have found the mark on the bottom of the flywheel is the easiest to see/align. Then check your cam gear mark.

F18Rep

Yep. the upper belhousing window is waaaaayyy more trouble than its worth. Its a 944 black hole - I have video of toolboxes being sucked in through that little window.
And it gets even worse with the "monkey mod"...Bruce

newkie

Well, since i have a lightend flywheel i dont have that mark under the car anymore. So that really is not an option. And i dont like that mark for other then to zero in on the OT mark...

Duke

IMHO the most important check is the cyl 1 piston location.
As long as it's in the top position you're fine.

Spidey944

If you are setting off of #1 piston location, you can have a tooth or two in each direction of piston travel that you can be off by. Regardless you should still have compression if all you are off by is 2 teeth. IIRC anymore than 3-4 teeth you start getting into overlap/piston-valve contact.

Did you over rev the engine at any point where you may have made piston/valve contact?? If you had 11 bar before hand, that sounds spot on with spec. Now to have 0 compression, and only be off 2 teeth, something had to of happened.

newkie

Theres no way anything hapend, i alwas rotate the engine 2 full cycles by hand when i mess with the timing belt. i certain nothing has broken. are you sure you can get compression if youre 2 full teeth of? thats like... 13 or 14 degres of?

Spidey944

2 teeth is only 8 degrees I think. You should still get compression, and it will run poorly, but it should run. I know at 4 teeth you start making contact. Sounds like it's time to do a leakdown test.

EDIT: maybe each tooth is 8 deg. Damn, suddenly I'm second guessing myself.... anybody??

newkie

Tonight i set the engine to TDC again. No comp, turned the cam half a cycle to se if thats the problem, but no.

My last desperate plan is the check if the woodrufkey that holds the camgear in place has broken of and the gear has somehow moved enough to screw this up.

Any other thoughts?

Spidey944

So you can turn the engine over, with the plugs still in it, and it spins freely??? Should catch on compression strokes..... sounds like a bigger problem then you think.

Duke

So you got no compression on any cylinder?
That would rule out something like a burned/broken exhaust valve.

Remove the intake and confirm that the intake valves open and closes correctly.
Also check easy things, like that the compression tester is sealing correctly.

newkie

I haven't even bothered testing it with a compressiontester since the motor goes around like there where no sparkplugs in it. i will however take intakemanifold of tomorow so that i can verifie the vavles opening and closing.

Spidey944

Let us know the results. I'd be suprised if you didnt have 4 bent valves.

95ONE

Are you 180deg off?

newkie

Really? How do you supposed that would have happend? The car ran fine, i have never done anything but set it to TDC. Theres has not been any funky sounds while cranking and no resistanse while cranking it by hand and yes, i did that every time.