944S Starter Spins, Engine Doesn't Turn

[Sideways]

It's an ’87 944S, with 137,000 on it.
The last 50,000 were mine, always treating the engine with respect.
Last week I replaced the rear brake pads.
Fuel pressure regulators were replaced at 120,000.
The clutch was replaced at 110,000.
Water pump and belts at 100,000.

During the last month a soft clunking sound that followed engine speed has been coming from the engine ~somewhere~,
maybe the valve train area.
The sound was not always present, occurring randomly.
Very recently (last 20 miles), the clutch has gained a strange feel to it.
A bit of pedal vibration when releasing.
Comparable to a rough cable activated clutch.

Now the big problem:
I just started the car, while I was loading things into the trunk,
I heard several loud clunks from the engine area, then it stalled.

I tried to start the car again.
The starter spins, the engine does not turn.
I put it into 1st and tried to start.
The starter moves the car forward.

So there it is, and I don’t quite know where to start pulling things.

Any knowledge out there?

[SoCal Driver]

If the engine truly does not rotate when you engage the starter then there is a big disconnect between the flywheel and the crank. This is because the toothed ring that the starter engages is bolted to the flywheel which is bolted to the end of the crank.

If the engine does rotate when you engage the starter but rotates with out much resistance then you have lost a timing belt and the exhaust valves are bent so there is no compression.

Since you did the cranking in first gear check it can be assumed that the clutch is working.

I'd say you lost a timing belt because I really don't think the crank broke.

There is a little hole to the upper right of the distributor cap. Get a flash light and look through it as some one cranks the engine. The cam gear should be turning. If it's not and the pulley sticking out of the lower front of the engine is: It's a broken timing belt.

[Sideways]

Not the reply I was hoping for, but one I had considered.
That would mean those ugly clunk sounds were my valves.
Only 40,000 on that belt.
I’m 10,000 past the recommended belt tension check interval.
Dang.


Thanks,

[todwic]

I agree with socal, if car didn't move in gear when you tried to start it, there's other things it could be...but the way you described it, I think soca is dead on, my condolences.

[SoCal Driver]

40,000 miles or kliks?

If miles that's about 10,000 past a belt change. 25,000 miles past a tension check.

Thinking about your engine speed following clunk. The cam gear has a tendency to come loose. There is a large bolt behind the rotor. I found the cam gear on my recent dead engine, rear main or rod bearing, loose.

Keep us posted.

[Sideways]

Well, this here is what I've found.
I'm guessing more teeth are off elsewhere.

I'm figuring on trying to replace the belts first.
Hope for the best, expect the worst.

I've got the porsche workshop manual, but I'm hoping for something more.
(I'm quite mechanical, but I don't know what to look out for)
Can anyone point me in the direction of more resources on timing belt removal / installation for the S?

Thanks alot,

[overkill]

Yo, get the factory manuals,... expect a private message.

[SoCal Driver]

Try to align the engine to TDC and see how far off the timing is.

The little V shaped notch in the aluminum cover directly above and a bit to the right of the cam gear and the dimple on the cam gear need to line up.

On the back drivers side of the engine just above the speed and reference sensors is a small rectangular opening. Inside that opening is the edge of the flywheel and on the flywheel should be an inscribed line an the capital letters "OT".

You might have to turn the engine back and forth to find the line and count how many timing belt teeth you are off. Any more than two or three and it's a head job.

A quickie head job is replace the exhausts and a couple of intakes and just lap them in and a gasket set. About $500 in parts and a couple of tools. Two days of labor.

Check the idler pulleys for the belt too. Their bearings are probably dried out and could have momentarily froze to help rip the teeth off of the belt.

[Sideways]

Well, got under the car to check where the flywheel was sitting.

Looks like my driver side steering boot has a hole in it.
Fluid was splattered everywhere, and I assume this got onto the belts.
This is a recent development, so I think I know what happened.
Damn gravel mountain roads being so fun!

I'm poor, self employed, and without $500.
But this Porsche will run again!

Thanks a lot for the help SoCal, I really appreciate it.

[SoCal Driver]

What happened to your timing belt is you went past the 30,000 mile replacement and possibly one of the idler pulleys is sizing.

There should be absolutely no power steering fluid coming out of the boots. The boots are there as just a dust cover not to keep in high pressure fluid.

You could shop around for a head at a junk yard. Might just be cheaper than rebuilding the one you have.

[RJ Santangelo]

Since i just went through finding a USED head for my 87S i have a list of people that might have a head for you around $1,500-$1,800 complete give or take $100 or a bare head for $1,100-$1,300. I have one source that may have a bare head for under $900.

[overkill]

Yo, have it rebuilt. It's cheaper.

[todwic]

Originally posted by SoCal Driver
What happened to your timing belt is you went past the 30,000 mile replacement and possibly one of the idler pulleys is sizing.

Just how large or small should the idler pulley get before I start to become worried

[SoCal Driver]

I would worry if the circumferential radius exceeds the inverted parabola of the hypodermics at aphelion.

[Sideways]

Originally posted by SoCal Driver
I would worry if the circumferential radius exceeds the inverted parabola of the hypodermics at aphelion.

I was worried about that.
Didn't realize what would happen.

[SoCal Driver]

Marshall, You need to pull the cam cover and check the cross over chain. While getting "clubed" (went to a members discount store) getting the massive amount of viddles the 14 year old boy requires, my little gray cells finally connected a few random inputs.

Besides having the chain between the two cams break the support for the pressure pad has a tendency to disengage (break off) from the rest of the head casting. If so this has to be professionally restored -- rewelded.