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flosho

Well my car has now jumped the timing 2 times in the last 800 miles I've owned the car. The first time was a belt breakage, possibly unrelated to the last two. But what on earth could cause this to happen only 300 miles after I get it back.

Literally 5 min after I fixed one problem(non charging alt, thanks paul and the others

) this happend. Its at the mechanics right now, the same guy who fixed it last time, wanted to look at it, and hopefully make it right since I had it back for less then a month when this happened.

Both times, I was getting on the car, the first timing belt jump was top of 3rd or 4th, cant remember(downshift on the highway) and this last time was the top of 2nd gear. Both times the car seemed to stop making any power at all, then backfire and blow a ton of smoke/something out the exhaust and then shut off on me..

Am I going to end up replacing all the crank/cam pulleys? I have no idea what would cause this. At least this time I'm having the intake honed and possibly gasket matching the head.

Anyways, sorry for the long post, but I dont have money to keep rebuilding the head. Fact is, I've changed the valves more times then I've changed the OIL!!!!

(well, regularly scheduled oil change(which has been 2)) But any ideas whats wrong with this lemon of a car I own?

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Paul · Posted: Wed Oct 12, 2005 11:16 am Post subject:

Make sure they time it using the Z1 mark on the flywheel not the O.
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White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

flosho · Posted: Wed Oct 12, 2005 11:23 am Post subject:

Thanks Paul, I saw you posted that in my other thread in the 931 forum...

You want to come up(or down?) to wausau and fix my car.. All the beer/soda you can drink..

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emoore924 · Joined: 13 Apr 2004 Posts: 2822

Also, be sure they're turning the tensioner pulley the right way when they tension the timing belt. If they twist it the wrong way to take tension on the timing belt, it will tend to throw belts.

dpw928 · Joined: 02 Nov 2002 Posts: 1860 Location: owasso, ok 74055

Are they overtorquing the cam journals? This can break a timing belt REAL fast. BTDT

Dennis
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81 931 5 sp
78 928 5 sp Silver
78 928 AT Euro Black

Paul · Posted: Wed Oct 12, 2005 12:27 pm Post subject:

flosho · Posted: Wed Oct 12, 2005 12:32 pm Post subject:

Well I'm going to see if he will cut me a REAL good deal...

I was going to apply at the eastbay up here in Wausau, as a parttime job while I go to college up here

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Tigger937 · Posted: Wed Oct 12, 2005 3:40 pm Post subject:

If the tensioner pulley has not been replaced, replace it. Cheap insurance...........$30 I seem to remember. Also, I would hope they replaced the belt with new and tightened to proper tension, ie., 90 degree twist under moderate pressure with thumb and forefinger, not undertightened or overtightened. The nibs should be sharp and square on the belt and both sprockets. Make sure all the pulleys align properly and the bolt for the tensioner tightened to proper spec. Forgive me if I'm just stating the obvious.
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1981 931 (Concours)
1982 931 (Daily Driver)

"Think outside the box"

numbbers · Posted: Thu Oct 13, 2005 10:26 am Post subject:

Has your head or block been resurfaced? If so you may be right on the borderline for valve piston interference. Just a thought.

Be damn sure that shop knows what they are doing, and that they are using a good 931 tech reference. You cannot treat a 931 like it is some American engine.
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1980 924 Turbo

flosho · Posted: Thu Oct 13, 2005 11:00 am Post subject:

I cant say for sure if the tensioner pulley was new, but he was confident that he could put it together properly.

The head was decked, before being installed, and I'm sure I've bent more valves.
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Tigger937 · Posted: Thu Oct 13, 2005 11:11 am Post subject:

jpab924 · Posted: Thu Oct 13, 2005 1:51 pm Post subject:

Time to measure the deck height? Has too much been taken off? Could be a possiblity. Easlily checked with the head off.

And what do you mean by gettin on it? Are you pegging the tach?

timstar92404 · Joined: 22 Sep 2004 Posts: 2075 Location: richmond BC

damn sounds like you spent a ton of money. Maybe you should take it to a better shop....

shouldn't they fix it for free if it was their fault?
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78 924 sold.
85.5 944

924 turbo · Posted: Thu Oct 13, 2005 3:53 pm Post subject:

Another thing. The 924 isn't particularly sensitive to this, but you should probably buy your belt from a place that reputably stores them. The dealer is a good (but expensive) source for well-treated belts. Last time I bought one, Performance Products took good care of their belts. I would really inspect the belt for cracks or strange marks in the rubber before you let them put it on. Maybe all the belts at the parts depot near your house are rotted and cracked?

Just a thought.
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Jon Furst

flosho · Posted: Fri Oct 14, 2005 3:24 am Post subject: