Recently, car suffered a timing problem, however it has been hard to truly diagnose the problem. After removing the timing cover, we were going to attempt to bring the engine to TDC. When turning the crank manually, the timing belt and the cam appeared to be turning normally. Then, suddenly the cam would fail to turn and the belt would develop slack at which point the crank became near impossible to turn, as though it were in a compression stage. Spark plugs were then removed in case it was simply the result of being in a compression stage, but the problem persisted. We could not visibly find any reason why the belt would get stuck, nor could we decipher where the belt was gaining slack from.

In order to change the timing belt, we have to bring the engine to TDC. But, we really want to avoid removing the cam tower and timing the engine and the cam seperately.

Does anyone have any suggestions? I can probably post pics this weekend

 

What do you mean it suffered a timing problem?

 

well... the car shut off during idle. Would not start. There was spark in one spark plug, (the distributor rotor came to rest touching one contact). The camshaft does not turn when the car is cranked.

Everything acts like the timing belt has slipped or broken. When we visually inspected the belt, we find that it is alarmingly loose on the rollers, but it does not appear to have slipped.

When we tried to turn the crank manually, the cam and timing belt turned normally for a second or two... and then the belt begins to build slack and will no longer turn. The cam will not turn, and then the crank will not turn.

Obviously, when a timing belt goes, valve damage occurs if the engine operates at all out of timing. But everything appears to still be timed properly... its as if the belt got caught, disallowed the crank to turn, and shut the engine off while still properly timed. We can't figure it out... And we can't find where the belt is getting caught, or building slack... or... really anything. Beyond being alarmingly loose, we really can't figure out what is wrong.

 

If the camshaft does not turn when you crank the car, then the belt has probably stripped teeth off it around the crankshaft. If it is as loose as you describe, then there is no way it has not slipped. You are looking at extensive valve damage, so you might as well pull the cam tower off and the head off without bothering going to TDC.

 

After seeing Porsche Docs response I have decided that I may as well go ahead and replace the cylinder head with a rebuilt head with all valve work done.

However, this puts me in a larger bind. I need this car for school, it was my commuter car. (I know... a car this hard to maintain should not be a college commuter...). I do not have the money to have the cylinder head changed professionally, and only barely enough to buy the cylinder head. The best prices I have found are $495 for a rebuilt from 944online.com, and $500 for a rebuilt head from lindseyracing.com. Does anyone know anywhere else I can find one? Also, I know that such a project is a massive undertaking, and that much is likely to go wrong. Particularly, I'm told, with the head studs. Is there any method or secret to prevent damge to the studs? I lack any pneumatic tools, lifts, and other such helpful tools...

And, I know that some will tell me to just go buy a new car... but even that at this point is beyond my reach. There is little I can find that will be reliable enough for my budget right now. And, with the money I have sunk into this car, I really am not ready to say goodbye yet.

Does anyone have any suggestions for me?

 

I would pull the head and see if there is any damage to the valves first. If you got lucky, and only 1 or 2 valves are shot, you can rebuild the head with 1-2 new valves, put in guides and seals, and slap it back on for probably $250-400. If you have 4 or more valves bent, then buy a rebuilt head. Plan on about 120-150 for a head gasket kit, etc.

 

I got all the gaskets and the timing belt from Autohausaz.com for $100 shipped. I'll see if I can pull the head this weekend. Thanks PorscheDoc.

 

Pulled the fuel rail, the intake, and the camshaft. Pulling the exhaust and the head tomorrow. Is there anything I should be aware of?

 

Thanks for the photos tarheel. I have the same problem now since I tried to put a new timing belt but it slipped.
What new parts did you have to get?
Is it worth just getting another engine? I have found one for about $2000.
Please post more photos as you go along.

Thanks.

 

Zorin,

As for getting a new engine, that is simply a matter of preference. If you have the money to get one, and you are willing to do so, then go for it. If you can do the work yourself, and have the proper tools, it may turn out cheaper than having your current problem fixed professionally. (I called a few local foreign auto shops (one knows these car's particularly well -- the owner's son had two) and all of the estimates I recieved were beyond $2000.

But always remember, unless that engine is rebuilt, you don't know what kind of condition it is in. If it is a high-mileage used one, you may want to buy a rebuild kit for it. (Lindseyracing.com has a rebuild kit already assembled, but you can go to any number of vendors and purchase all the components of one... Autohausaz.com will likely have everything, and at a much lower price than Lindseyracing.com)

Also, its possible that the valves may have gouged the pistons. Obviously, buying a new engine would rememdy this problem as well.

So far, I have bought a set of gaskets and a timing belt, (from Autohausaz.com), a balance shaft belt, a balance sprocket holder tool, and a porsche timing tool, (from 944online.com). I am looking at a few possibilities for the head. If I find that few valves are damaged, I will have my head remachined and have the valve work done on it and replace the bad valves. If the head looks bad, or if the majority of the valves are damaged, I will order a rebuilt head.
Currently, I have found two online vendors that supply rebuilt heads at a decent price. Lindseyracing.com and 944online.com both offer cylinder heads for around $500.

Because I am doing the work myself, right now the total cost has come to around $750 - $800 (pending my decision about the head). If I happen to mess anything up... well, lets just hope that doesnt happen.

I'll post more pics as I progress.