OK, so in May 13 I posted a pic of my balance belt hanging out of the hole in the belt cover. Luckily the engine did not start, but I am unsure what potential damage the attempted start did before I found the broken belt.

When I took the broken belt off it has twisted up and looped out into a small knot around the lower balance shaft sprocket. It did not seem to be restricting the path of the cam belt, but I guess the only way to tell if there is damage is to take the head off.

The attempted start did turn the engine over, but no more than a turn over as the battery was low therefore no ignition, combined with the snapped balance belt which was still wrapped around the crank pulley and tensioner. I suspect the tension was too low and it just flapped about in there.

Anyway the covers are off and I have been assessing the job.

I think for safety I am going ot replace all belts (including the alternator and steering pumps) and also the balance sprockets, tensioner and idler, also the cam belt tensioner and idler. The ones I have look a little old, slightly rusted and I just do not want to take a chance.

Other areas of work I knew about were (and still are):

Cam tower oil seals, including cam shaft seals.
The turn indicator stalk needs replacing.
All 4 brake discs (rotors for our American friends) are worn and corroded.

Since it has been off the road 2 more years since I became aware of the above the brakes are even more rusted. So I plan to replace everything and clean/restore the calipers if possible.

Other than that (as if all tht is not enough) the other items I have visually assessed and decided they need repair/restoring/replacement are:
Front suspension strut mounting plates (once in this far may as well consider the dampers too)
Most of the rubber bushes.
Middle Exhaust silencer (muffler).
Oil pan/sump gasket needs changing as I found eombody had used silicone sealant on it when I degreased the oil stains. The sump plug seems to have been overtightened and is unable to be removed with the tools I have at home. I could call a mobile mechanic out to remove it, but as I have to take the sump off anyway it maybe cheaper to get a second hand one with new gasket and plug.

Quite a list.........

My plan of action (and if anybody can advise a better order then please do) is:
Flywheel lock on - although not sure if it is needed.
Remove cam belt, cam gear, idlers and tensioners.
Check front seals for oil leaks.
Remove and strip the cam tower, clean and replace gaskets/seals. Check cam followers for wear.
Replace cam tower and cam gear, tensioners, idlers, belts. Distributor.
Change oil, coolant and spark plugs.
Connect battery.

I wonder if it will start........... Bit worried if I should/or have to take the head off. Gut feeling is it is ok as it did not actually start.

I am sure there is more. I am in no rush, it has taken ages to get this far.

Thanks for reading this far if you did
James

 

James,
I read your post from last year,
https://rennlist.com/forums/10489684-post1.html

You have owned an unreliable 944 for 8-9 years.
You tried to turn the engine over with a low charged battery. This could have burned out the DME.
Yes you need to get a flywheel lock to replace the front crankshaft seal---the bolt is torqued at 155 foot pounds.

The oil pan drain plug is frozen and the oil pan gasket leaks. You listed many more future repairs.

You have the possibility of doing a few thousand dollars of repairs and still not have a reliable 944.

Before you do anything you should have the engine bores checked for damage. Rent a borescope.

The back to front fuel system needs to be flushed and parts replaced. Fuel filter, all rubber fuel lines. A fuel fire will distroy all your work.

When you remove the oil pan to replace the gasket and frozen plug, you need to replace the rod bearings. If the crank is damaged you may need to spend a lot more.

Have you ever replaced the clutch parts?

The cost for parts, suspension, tires, electronics, tools will not be recovered if you sell later on.

I know you "are in no rush", but why put such effort and cost in project car that may never be finished?

J_AZ

 

Here's my take on your engine project:
Remove the spark plugs and try turning the engine with a wrench (spanner) on the crankshaft bolt (proper direction please). If it turns without any restrictions, your valves are probably undamaged. After that, re-insert spark plugs and, using the starter, do a compression check. If you have a dramatic difference in cylinder pressures, then you likely have a valve issue. If not, then you may have, as we say in the Colonies, "Dodged a bullet".

On the issue of the other replacement matters, If you have indications of oil leaks from other seals, it's likely that the oil issue the other owner was trying to fix by using silicone on the oil sump was caused by a leaking rear main crankshaft seal. Usually when other leaks are present, all the other rubber seals are dried up since they're all the same age. This, unfortunately, necessitates removal of everything aft of the flywheel to replace a $10 seal. Often this leak is mistaken for an oil sump leak and as such the failed repair of the sump using over-tightening of the bolts and the silicone.

The oil sump pan must be installed with a new gasket and tightened down using a very specific and somewhat delicate sequence. Refer to the repair manual, Clark's Garage or a Haynes manual for that information. Personally, I recommend a replacement sump, as the one you now have may be distorted from bad previous installation attempt. Secondly, I recommend using acetone or lacquer thinner to wipe off the mold-release that is on the new gasket. This will prevent slippage of the new gasket when installing it with the replacement sump. There's a lot of information of the expanded procedures and sealants used in this process on the forum.

Definitely invest in a flywheel lock. You'll use it more than once if you plan to work on this car more than once.

Also, "while you're in there", recommend replacement of the rod bearings and bolts while the oil sump is off. And, check for any cracks in the oil pick-up tube.

This is a common subject for commentary on this forum, so look for additional advice from it's members. Good luck with your project. I've been down that road and it's very gratifying when you're finished. John, from Arizona, is right about the investment of time and money in the car possibly not being worth the investment. If this is a therapy project, as mine is, then it's a moot point. But if money is a concern, this could be a questionable endeavor.

 

Hi guys

Thanks for your advice.

From what I am reading you suggest it may be too far gone to repair without spending a lot of time and money.

Another quick update on its history. It is an auto not a manual. I have had it from 2000 and it had 2 owners and full Porsche service history until it was maintained by a reputable Porsche specialist in London after that. In 2002 it suffered a major oil seal failure and the next thing I knew was the oil pressure light coming on at about 50mph then slowing down to get a huge cloud of smoke and a really horrible low end rumble. Dead engine. So much for regular servicing by main dealers and specialists, or maybe I just had a bad one....

I had a secondhand replacement engine put in which was sourced and installed by the same London specialist. He said it was a similar age engine and miles and so I spent about £3000 on it to keep it on the road. That ran really nicely, no issues and once I had the engine in there I realised the original engine was not good as the oil pressure was always too low at all revs. This replacement engine showed a higher pressure as is described by all the tech info I read on line etc.

At this point the clutch and transmission were checked over by the same specialist.
The last time I drove the car it ran beautifully, that was about 3 years or so back.

It ran at quite high speed (within UK limits of course) and then ended up sitting in heavy traffic for 3 or 4 hours on a hot day. It behaved at all times. No overheating, no problems at all over a few hundred miles.

All that forced me to take it off the road was there was a leak from the cam tower that occasionally dripped on the exhaust manifold causing smoke. It sat in my garage from then until 18 months ago when I started it and took it for a short run for a road safety test (MOT in the UK). It was fine except for the brakes and advisory notices on the oil leak and some corrosion to the suspension.

I was suspecting the fuel lines should be replaced to be on the safe side.

Are we saying that it still may not be worth it to get it back on the road?
Surely if it had no bore/valve/compression issues before then a failed start should not have caused damage? I suppose the borescope is the only way of knowing. So take it from there and make a decision.

Hmmmmm. Concerned now. Sad to see this one go when it only has about 100K on the clock.

Photo attached.....

 

Beautiful color.
Inspect the automatic transmission damper. It may not "age" as fast in the UK but the replacement cost is about 814 GBP. for the part alone plus shop fees. If origninal, it is now 28 years old +.

http://www.pelicanparts.com/cgi-bin/...2520Trans%2520

GL
J_AZ

 

Thanks, it is a nice colour, fairly unusual, but original.
The side skirting is factory fitted also from new.

My thoughts are, at the moment anyway, parts wise for the engine I have costed it up to be around £300-400, depending on fuel lines and sump etc.

This should be enough to get it started, if it runs then I will make a decision to carry on, if it fails I will have to cut my losses and call it a day.

Does this approach seem sensible?
Thanks

 

The automatic transmission damper..... Is this the rubber central clutch? If that starts to fail do you experience a strong shudder through the car as you take up drive?

If so, I have had that on occasion 1 a month, and it was checked and replaced when the current engine was installed. It was not cheap, but got one for £300-400, cannot remember exactly.

Thanks

 

If I understand this correctly, the balance belt broke, but the cam belt is OK? Just to be safe, I'd recommend removing the spark plugs so you can rotate the engine by hand and feel for any unusual resistance. Put the engine at TDC and check that the crank and cam marks are still aligned. Sometimes a piece of the balance belt gets caught under the cam belt and causes it to skip a tooth or two. If the cam timing and overall resistance feel OK then do a compression test to make sure the engine is healthy enough to justify additional work.

Overall, these cars are old and need frequent work to keep them in good condition. It's not unusual to accept minor oil leaks as a normal part of ownership since some of the oil leaks are mere nuisance and troublesome to repair. OTOH some leaks are more serious, like your cam tower leaking on the exhaust, or if there was a rms leaking onto the clutch for example.

 

If you think you may have an issue with the damper you can remove the starter and look through the mounting hole with a torch. If it is perished you will typically see cracks in the rubber and small rubber bits inside the housing. If the whole works disintegrates there are metal tabs that will allow you to limp home, if you get to this point you will know - it will make a rather loud clanging noise. Today the damper typically cost ~$1500 usd.

 

I am very sure my damper is fine, but I will check it when I remove the starter to install the flywheel lock.

 

Update
Borescope on the way.
Managed to get the flywheel to TDC by looking at both the "OT" in the flywheel window and checking the cam sprocket alignment on the casing.
All aligns fine and the crank turned (clockwise) without any restrictions or resistance.
Going to install the flywheel lock this weekend then start stripping down the cambelt and rollers/sprockets.
Remove plastic covers and generally clean and degrease. Then onto removing the cam tower.

When I get to the oil sump I am not sure what to do.

I notice there are what look like 2 plugs, looking from the front, 1 LHS and one on the RHS.
I know the LHS is the normal plug, what is the RHS? Can I drain oil from there?

The usual LHS plug head is damaged, it maybe possible to use a bolt/nut remover on it, failing that it may need a mobile mechanic to weld a rod or bar to it to try and shift it.
If I have to replace the sump it looks like engine out, which I cannot do without getting it picked up and taken to a garage. Main reason is that it is parked in position where there is no room for a hoist/crane.

The only other option I can see is to dismantle the front suspension (got to do that anyway) and take what looks like a cross member out. That looks a nightmare.

Your thoughts?

 

Don't know that you really need the boroscope. If the timing belt looks like it is in good condition and the engine turned over by hand without a problem, I doubt that you have any valve or cylinder issues.

The second plug on the oil sump would be for the oil return line on the Turbo variant.

Removing the cross member is not all that difficult, the biggest pain is releasing the universal joint on the steering rod from the steering rack. Install an engine support fixture, split the track rods from the steering knuckle, split the ball joints, disconnect the power steering supply/return lines, unbolt the camber blocks, unbolt the engine mounts, unbolt the locking bolt for the steering shaft universal joint. While lowering the cross member you then want to pry, pound, wiggle, etc to get the steering shaft universal joint to disconnect.

Forgot to mention removal of the front sway bar - it will also need to come off

While you have the sump off you may want to give some thought to replacing your connecting rod bearings. You should also check your engine mounts, while the cross member is out it makes access for the job relatively easy. Oh, and while you have the cross member out, you also have ready access to replace the seals on the oil cooler.

 

Ah interesting. Thanks for this info.

Can you drain the oil from the second plug as this is a non-turbo?

Thanks

 

Don't see why not - I don't believe the plug is as low in the sump as the normal drain plug so you may not get as complete of a drain.

 

Update.

Flywheel at TDC and lock installed.
Belts removed and covers removed.
Cam sprocket off and the source of my oil leak is found. The main rubber O ring.
It does not look like the crank has been leaking at all around the front where I found the sealant.

Next planning to de-grease front of engine and clean up as much as possible. and remove the cam tower and clean up and re-seal.

On the negative side I think I have found that I have a leaky radiator too.

If I can drain the oil from the turbo's oil return plug then with any luck I do not need to replace the sump, however I may drive it (once roadworthy) to a garage for attempted removal of the seized plug. I will need to do a couple of oil changes if I cannot get this old plug removed, then plan to change more regularly than normal to avoid problems associated with not draining all the oil, only 95%.

Fingers crossed.