IceWater

OK, so my '93 968 suddenly had no power below 2000 RPM or so and was making a dull clackety sound in that range. Pulled off the belt cover and saw that the timing belt is starting to fall apart. Its not broken, but some of the teeth are separating from the belt. So I assume that the belt slipped a few teeth and screwed up the valve timing. The dealer was supposed to have replaced the belt before I bought the car (40,000 mi ago). Looks like yet another way US Auto Exchange in Boston has f**ked me.

So here's what I need from y'all, as I will be doing all of the work myself:

1) What are the chances that the timing was off enough to damage the valves? It ran fine from 2000-2500 rpm and up.

2) Is there an easy way to inspect the valves?

3) Should I rent the belt tensioning tool from Pelican Parts or is there an inexpensive tool that I can buy that will work well?

4) Can someone email or fax me the procedure from the repair manuals? This is one that I would rather not wing.

5) Are there any other things that it makes sense to do at the same time?

6) How long should I expect the job to take and how frustrated should I expect to get?

Thanks in advance for the help. My email addresses are:

tgurski@dekaresearch.com (business hours)
tqgurski@yahoo.com (home)

Thanks again,
Tom

Perry 951

That is no good. If it did skip more than 3 or 4 of the teeth, chances are you dinged the valves. It will run if you have a valve that is barely bent. You need to replace the belt first, and rather quickley. You shoulden't have to get the tensioner since I believe the 968 has the auto tensioner. Get a Haynes manual. They are ok for this type of repair.

After you get the belt on and it all back together, do the compression check. Anything less that 5% of normal and you might want to pull the head and see what you bent.

Wish I had more tipes, but I haven't worked on many 968's, so my info is based on the 951. Best of luck.

jim968

A) 40K miles is not unreasonable life for a belt on a 968, tho' maybe a bit on the low side.

B) Ouch. Consider yourself lucky the engine apparently grenade the whole top end.

1) Possibly.

2) Not really, until, as Perry posted, you fix it & get a compression check.

3) You don't need it for the timing belt (auto tensioner), but you do need it for the balance shaft belt.

4) I think Pelican Parts has this as a part of their procedures; if not, someone else can no doubt supply a link to an on-line procedure. It's pretty well the same as the later 944's.

5) How many total miles on the car?

6) Depends on your mechanical skills, availability of tools, & personal luck. Minimum, maybe 4-6 hours(???). Maximum, with bad luck, maybe 16-20 hours, for a first-timer with less-than-optimum tools.

One possible money saver on the tensioner tool; if you've got an agreeable wrench, reassemble everything but the top belt cover & air box. Drive it directly to him & pay for 1/2 to 1 hour's labor for setting the balance shaft belt tension. It worked for me.

Jim, wishin' you luck....

Tabor

Porsche says 60K miles for the 968 Timing belt, 45K miles for the 944. So, according to Porsche, you should have been okay. As to changing it, get the Haynes manual for the 944 and you should be fine. I have done it on my 944, and I was looking at my new 968 engine and they look the same.

IceWater

Thanks everyone!

The car has 130,000 miles on it. I've had it for 40,000 without any major problems.

I'll look at the Haynes manual and the Pelican sight, replace the belt, and then do a compression check. Hopefully I dodged the bullet on this one.

Thanks again,
Tom

Danno

Also check the cam-chain tensioner between the cams as well. That has the possibility of causing even MORE expensive damage than just a slipped belt (anyone price TWO 968 cams lately?).

Tabor

Danno is correct. This tensioner should be replaced every 100,000 miles.

jim968

Ditto on Danno & Tabor on the cam chain tensioner.

At 130K, I'd seriously consider all front engine seals while you're in there, and the water pump. Also a good time to do the PS & alt. belts, since they'll be off.

And while the factory may be OK with 60K miles on the cambelt, I'm not, since it has to transmit a little more torque than on the 944 (smaller springs, but more of 'em). Just my overly-cautious nature, probably. The first 944 I ever saw up close was an '83, in the shop because of a cam belt failure at ~30K. It made a lasting impression.

Jim, where's the coffee....???

IceWater

Thanks yet again.

Where's the best place to get the cam chain tensioner? I checked at Pelican, but only saw the belt tensioner.

Tom

IceWater

OK, so several people suggested getting a Haynes manual for reference when doing this job. I checked the Haynes website, and they seem to only make a 944 manual for '83-'89 SOHC. I figured this must be the one people were talking about, so I picked one up. To my surprise, there is no section on replacing the timing belt (they claim because the tensioning tool isn't availablt to the public). Do I have the right manual? If so, what exactly do I have it for?

Thanks!
Tom

Tabor

Tom G: You got the right book. Page 55, Chapter 2A section 8. It is called Balance Shaft/camshaft belts and sprockets - removal and installation.

IceWater

Roger that, Tabor.

Thank you for your help.

Tom