951jamie

Usually it bends the valve upward out of the way so you get the free spinning sensation!! Good Luck!
jamie@944online.com

sebastian944

I can't imagine spending the money to replace belts/rollers only to have it slip off just a few years later and only a few miles. How much does it cost to replace the head anyway?

Zero10

Denial is a powerful thing. Been there, done that, luckily it wasn't with a broken timing belt, but I've had enough other things break in my time

If you put a new belt on with bent valves the heads can break off and rattle around in the cylinder. If this happens you will require a replacement head (and pistons and whatever else it breaks). The bill will be much higher. That said, you can remove the cam tower and measure valve height to verify if any valves are stuck open, also, with the cam tower off all valves should be closed, so with a leakdown tester you can verify if they are all sealing.

That said, you can be nearly 100% sure you have bent valves, and at this point you should be assuming the worst.

nsyr

Ok I got the cam tower off and put a straight edge across all eight valves and four did not touch. The four that didn't touch are the intake valves even though when I look down into the intake chamber everything looks fine. Then I hooked up compressed air to each spark plug hole and all four intakes ports blew carbon deposits pieces back up at me. So needless to say I have four bent intake valves. The exhaust headers are still on the engine so I wasn't able to check leaks there. How likely is it to have four bent intake and no exhaust valves bent?

Zero10

pretty rare to bend all intake valves but no exhaust. Are there carbon trails all over the intake ports? I wonder if they are bent, or just not seating properly?

Mine weren't sealing properly for a long time and I could see black trails going up the intake ports from combustion gases seeping by.

Either way, the head should come off to repair the issue. Both are serious enough to warrant removal of the head. (bent valves or really dirty non-sealing valves)

nsyr

It is plausible that they are not seating properly now. But the amount of leakage is to great for the engine to run. I assume it is possible they are being held open by the loose carbon deposits. I did find that the cam belt tensioner had a little play in it. This could of led to weakening the belt.
The real suprise came when I took out the cam tensioner stud from the block. Appearently it must of stripped at some point and the P.O. filled it with JB Weld and redrilled and retapped it. Although it seemed to hold well I don't trust it. I am considering mounting a later style tensioner. What are your thoughts on this?

Chris White

All you have to do is pull the engine out, weld on some material because you don't have the mounting bosses and then drill and tap the three mounting points....my expert guess is that it is probably not worth it!
If you are really worried about it I would pull the radiator (to get more room) and helicoil the existing mounting point, not a big deal.
BTW – where are you located?

nsyr

I am in Clearwater, FL. The helicoil sounds interesting. I'll look into doing that instead.

nsyr

Just watch a video on youtube about helicoil and looks like it is the way to go. Interesting enough I found a receipt from when the PO had the 'jb weld job' done and turns out a very reputable Porsche service shop had done the work. At the customers request of course.

nsyr

come to think of it, what size helicoil kit would I need?

nsyr

And now for the carnage.

All 4 Intake valves are bent and only 1 exhaust valve. I did the solvent in the port test to verify.

There is a lot of carbon build up on the pistons and head. The cylinder walls appear to be in great shape though.

Unfortunately the ceramic in the exhaust ports is cracking. see pics.

nsyr

What are the recomondations for a street daily driver.

KuHL 951

Looks like you would be better off just buying a good used head with the liners intact. You should be able to find one for $200-$250. Check with Lart951 or Josh B. I've seen several heads for sale here lately.

gt37vgt

you can do leak down it wile take a while it takes a bit of torque to turn the cam remeber
if the cam was in a magic phase were nothing was at full lift and the cam just took off you may have got away with it .
new belt and comp test is not a heap of time wasted

gt37vgt

doh how did i miss all the pics what a horrer show