Timing Belt - I am either Really Lucky Or SOL

[Dean924s]

I have been diagnosing a low vacuum situation that occurred the other day.

Short of it it.

Car would not start Friday morning as it was really cold. Got it to fire but died and I could smell Fuel so I assumed flooded motor and took the wife's car.

Saturday I did a compression test and all cylinders were at about 80.

Added oil to the cylinders and the compression came back up to about 150150.

Car starts but was really "soggy" Like it had a vacuum leak or the timing was retarded.

Today I try disconnecting all the vacuum lines and plugging all the lines holes so I have nothing connected except the AFM to the J boot to the intake. Started it and it was still running the same.

So I decided to check the timing belt. I removed the #1 plug and put a dowel in the cylinder as I turned the motor over by hand (socket on the crank)

As I was bringing the cylinder up to TDC all of a sudden the timing belt stopped moving while I was turning it over.

I looked at the timing belt by the crank and there were 5 or so teeth missing.

SO my real question is do you all think I got the valves? I guess I will have to remove the cam and then do a leak down test on the it? Anyone got any good ideas? I have a freshly rebuilt head in the shelf that I can use I just hate to have to do it as it is dam cold out and I don't have a garage at the moment.

The attached are the results from my compression test from earlier today (you can see tht they are down from the 150 I got yesterday)as you can see all cylinders are evenly down. What do you all think?

[Arizona_928]

You are really lucky. put a new belt on and do another compression test to be sure...

[carlege]

So, i guess you didnt get the memo about replacing your timingbelt if you dont know the history of the belt change

[pigeon]

Saw your identical post on GRM and thought - that sounds like a 944! Amazon has the Gates belt for a good price, I just ordered one along with some other misc. household junk.

[Dean924s]

Originally Posted by carlege

So, i guess you didnt get the memo about replacing your timingbelt if you dont know the history of the belt change

Hummmmm. Only when the memo applies. This belt is only 2 years old and 30K miles and I did it! The motor was is a fresh rebuild for racing done in 04. I know it intimately!

[Dean924s]

Originally Posted by pigeon

Saw your identical post on GRM and thought - that sounds like a 944! Amazon has the Gates belt for a good price, I just ordered one along with some other misc. household junk.

I was actually going to do the belt this summer. I do them every 3 years no matter what the millage. My last one was actuallly done in 09 due to an early replacement in 06. I actually priced out a bunch of things (including a complete front end re seal WP and rollers) from pelican last week thinking I would place the order when my tax return comes in. Looks like I will be doing it a bit sooner than planed.

Amazon does have good prices but I prefer to give my business to Pelican especially when the cost is only a couple $$$ more. They have been a huge help over the years. Wayne actually answers emails!!! I would not know who to email over at Amazon. I want to give back when I can.

[mikepellegrini]

Just for info, what brand was it that failed?

[Dean924s]

Originally Posted by mike pellegrini

Just for info, what brand was it that failed?

I will have to look to make sure but I believe it was a conti. When I pull it off I will post up.

That actually directly related to my next question that I was going to post up.

Who makes the best timing belt these days? I don't need one of those Kevlar uber good racing belts I have seen but if there is a known better belt out there that seems to stand out as compared to the other brands it would be good to know.

I have heard good things about both gates and conti. this is the first failure I have had personally. I have seen many and I really don't have a good feel for a particular good or bad belt. The failure always seems to be the result of neglect or failure to retention / keep the belt tensioner.

[mikepellegrini]

Conti is s'posed to be good. I think I have Gates on mine.

But two years and 30K miles is way, way early.

If I was in your shoes, I'd be tempted to send the belt to the manufacturer and ask WTF? Bad batch of belts? An anomaly? What?

There wasn't any oil contamination? That'd accellerate things.

What a trip!

[HondaDustR]

The other thing I'd wonder is how old the stock was that the belt was pulled from. Do belts have a shelf life? I'm running a gates balance belt and it seems pretty good. I wouldn't mind trying their cam belt. I've been through 3 Conti belts and haven't had a problem, but I usually change them a couple thousand miles early and I'm usually doing it every 1-1.5 years.

[Dean924s]

I have a theory,

The belt was going bad and probably jumped a tooth or the area that I watched come apart was actually delaminated from the backing / cordes of the belt and had shifted by a tooth. Due to the higher rpms when cranking / running the load on that area of the belt was limited to a very short period of time. BUT when I cranked it over manual by hand the load on the delaminated section of he belt was exerted for a much longer period of time and it failed.

I am going to go with the gates belt this time. Less than $2.00 more than the conti here at pelican.

[Rasta Monsta]

Dustr, rubber absolutely has a shelf life.

One note on the kevlar belts, I am tempted by them myself for my eventual race motor, but I would think the change in materials would also alter the factory tensioning measurement. I am thinking upon installation of one of these I am likely to use the John_AZ "turn the water pump pulley" method.

[Dean924s]

Pulled it apart today. It was a Conti belt.

Dissection of the belt found that there was one tooth missing indicating that my previous theory was correct. It had lost / jumped a tooth. The extensive damage to the belt was caused by me cranking it over by hand. I got the cam tower pulled and put a strait edge on the valves and all seems to be good. I think I was REALLY lucky on this one.

For an extra 6$ I got all my stuff shipped from Pelican in three days!!! A great deal! And it was on time for my weekend of fun.

[Dean924s]

All back together and it fired up on the first shot. Let it idle for a while to burn off all the oil on the exhaust. Took it for a spin and all seemed to be in good order. I Drove it to work this am with out issue.

I also discovered that goof off is by far the best gasket remover / surface cleaner I have found to date. On a whim I tried it and it worked better than virtually any other cleaner I have tried. A scotch brite pad and a brass brush was all that was needed to get things in shape. It worked especially well on removing that grey material that is on the cam tower gasket that gets stuck to the head and the cam tower.

[John_AZ]

Amazing good luck!
Congratulations on a better than expected outcome from the original thread.

Vacuum issue after flooding on cold start.

You do know that now you have used up ALL of your Porsche "magic"--(pleading, prayers, chants, promises, begging, charity...... )

Great to hear.
John

[Dean924s]

Ya Who would have thought.

This particular car has been very good to me. The key is to drive them!! They get mad if you let them sit and then they do bad things to get your attention.

[HondaDustR]

+1. I think the people that question these cars' suitability as a daily driver are often the people that only drive theirs on weekends. Things just seem to work better when worked often.

[baby shark]

Originally Posted by carlege

So, i guess you didnt get the memo about replacing your timingbelt if you dont know the history of the belt change

yeah..........dean got the memo.....when you were in diapers, carlege....dean's an old time 44/24s lover....dean i had a good success story last month, my non interference '83 928 started rightup after i replaced a shredded timing belt. Didn't have as much success with the 968 timing belt failure, but 1 out of 2 isn't so bad.