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thinking about buying a 968 for cheap - with a few bent valves.

Guys,

I have an opourtunity to purchase a '92 968 that lost the belt tensioner, which caused the timing belt to slip. Several valves are bent. The shop that my friend has the car at wants to replace both cams, all 16 valves, and a few other things. the total bill, including labor is somewhere in the ballpark of 6k. I know i could do it MUCH cheaper. I have seen used heads with good valves go for less than $500. I saw a complete, running engine go for 2700 on ebay.

What does everyone think, if i could pick up the car for somewhere in the neighborhood of $5K NADA blue book lists this car for 12K - 15K

I can do all the work myself, and this would probably be a good winter project for me. after i was done, maybe i would sell the car, maybe i would keep it. If i do decide to keep it, i may try to do a turbo conversion on it.


Bottom line, do yoiu think it's worth picking up for 5K? (about 75K miles)
Old 10-01-2003, 12:05 PM
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Sounds like a deal. If I had the time and place and resources I sure would give it a try.

I question as to why they want to replace the cams? The only reason I can think of is if the teeth on the chain sprokets are broken off. If this is so then there could be serious damage to the head making it unuseable.

I also question $500 for a used S2 head.
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Hugh - So Cal 83 944 Driver Person
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When was the last time you changed your timing and balance belts and/or cam chain and tensioner?
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Old 10-01-2003, 12:14 PM
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Worst case, if i can't fix it. I can DEFINETLY sell more than 5K worth of parts off it.

I don't know why they want to replace the cams. They did not say they were going to replace the lifters (WTF?????)

I think they might just be trying to gouge the guy.

The head is off the car. I can go down to the mechanic and inspect it if i want.

Mike
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Last edited by mike944; 10-01-2003 at 12:26 PM..
Old 10-01-2003, 12:24 PM
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Yes visit the car-engine.

Look for a broken mount for the chain tensioner. If that is OK then look for loose or broken valve seats and damaged valve guides.

Check the pistion too. Sometimes they crack from the valve hitting them.

To bad you can't stick an 8 valve head on the engine.
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Hugh - So Cal 83 944 Driver Person
NOT a 'real' Porsche -- Its Better!!!!
When was the last time you changed your timing and balance belts and/or cam chain and tensioner?
New Users please add your car's year and model to your signature line!
Never break more than you fix!
Old 10-01-2003, 01:23 PM
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Quote:
Originally posted by SoCal Driver
Yes visit the car-engine.

Look for a broken mount for the chain tensioner. If that is OK then look for loose or broken valve seats and damaged valve guides.

Check the pistion too. Sometimes they crack from the valve hitting them.

To bad you can't stick an 8 valve head on the engine.
Why would you want to stick a 8 valve head on it? Economics? Surely, not for power, eh? I'm just wondering here....
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Old 10-01-2003, 01:36 PM
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Economics. The 16 valve heads, in useable condition, are hard to find. Shame to let a good chassis go to waste.
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Hugh - So Cal 83 944 Driver Person
NOT a 'real' Porsche -- Its Better!!!!
When was the last time you changed your timing and balance belts and/or cam chain and tensioner?
New Users please add your car's year and model to your signature line!
Never break more than you fix!
Old 10-01-2003, 01:42 PM
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Dave,

How do i find a broken chain tensioner mount? What or where is the mount located? I know nothing about the 16V engines.

I have read that the factory used a 951 head, with no variocam on the 968 turbo version. I may decide to go that route. Would that drop the compression to an appropriate level for a turbo, without machining the pistons? Anybody have combustion chamber CC numbers for various 944/951/968 engines?


Mike
Old 10-02-2003, 05:56 AM
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Mike......I think you want to ask Hugh that....I'm just a spode, man!

Hugh's the man...I'm just the trouble maker!
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83 944 N/A 5 sp. (mine)
90 Acura Integra auto (sons)
2000 Honda Odyssey EX auto (wife)
83 Suzuki LT 125 (4 wheeler) (wife)
92 Honda XR 80 (son)
97 Honda CR 125R (son)
98 Honda CR250R (MINE)
2000 Kawasaki KX 65 (son)
2003 Honda XR 50 (Son and daughter)
Old 10-02-2003, 06:31 AM
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Great news! (well, great for me anyway) I just talked to my friend with the 968. he only wants 4K for it SWEET DEAL!!! That's such a good deal, I offered to pay his mechanic for the 6 hours labor that he already has into the car, pulling the head off to check the damage. That should be somewhere in the neighborhood of $400. So, for $4500 i'll have a decent 968, that i have to do some head work to.

I'm going to go look at the car on saturday. Unfortunately.....it's white. The paint is not great, so i may decide to repaint it silver. I can strip the car completely to do a "proper" color change

Mike

P.S. Anyone want a nice '84 944? Runs great. All maintenence is up to date. New waterpump & belts in the lask 1K miles.
Old 10-02-2003, 07:39 AM
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Hang onto the 84. It's going to be a while till you can drive the 968.

Head damage: There is a cast in mounting for the chain tensioner. When the plastic pressure pad that pushes against the chain wears out or embrittles and breaks into pieces, the chain catches on the steel and tears off the tensioner and the mounting area. This will also cause teeth to shear of off the cams. Yes the sprockets are machined into the cams. Personally I would have gone to a double chain, a split sprocket and an idler after the first series of failures but I don't work at Porsche. Hmmm. Maybe this could be a retro fit thing!

More head damage: The smaller valves and with the angle they are designed in the head, causes them not only to hit the pistions but bend severly. On the 8 valves you see a 15 to 20 degree bend in the larger exhaust valves. In the 16 valve head you see almost 90 degree bends. This pushes the edge of the valve into the valve seat pushing the seat back into the head and even splitting the seat and the head. Heads can be welded back up and machined for new seats. Cracked heads can be welded -- where you can see the crack.

Pistons can be scared by the bent valves and even cracked. Even the cylinder bore can be scared or cracked if the valve has broken off and fallen into the bore.

So your whole repair plan depends on the condition of the head, pistons and cylinder walls.
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NOT a 'real' Porsche -- Its Better!!!!
When was the last time you changed your timing and balance belts and/or cam chain and tensioner?
New Users please add your car's year and model to your signature line!
Never break more than you fix!
Old 10-02-2003, 08:16 AM
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Thanks for all the great info! I'll take a digital camera on saturday, and snap alot of pictures.

Are you sure it's not a timing belt? The current owner told me that he recently had the belt done (unless the shop was scamming him) and pelican lists a belt, not a chain for the 968. We were actually discussing why porsche called the tensioner a "chain tensioner" when it really tensiones a belt. It's a '92 if that makes any difference.
Old 10-02-2003, 09:49 AM
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AWSOME....you lucky SOB....car sounds like a great project!!!!!!!!1
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Old 10-02-2003, 09:53 AM
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Quote:
Originally posted by mike944
Thanks for all the great info! I'll take a digital camera on saturday, and snap alot of pictures.

Are you sure it's not a timing belt? The current owner told me that he recently had the belt done (unless the shop was scamming him) and pelican lists a belt, not a chain for the 968. We were actually discussing why porsche called the tensioner a "chain tensioner" when it really tensiones a belt. It's a '92 if that makes any difference.
Dual over head cams?

Chain tensioner.
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Hugh - So Cal 83 944 Driver Person
NOT a 'real' Porsche -- Its Better!!!!
When was the last time you changed your timing and balance belts and/or cam chain and tensioner?
New Users please add your car's year and model to your signature line!
Never break more than you fix!
Old 10-02-2003, 10:11 AM
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Yes,

Dual overhead cams.

Does anyone have a picture, or an exploded diagram of the 968 head?

Anyone have a service manual on CD? P.M. me if you have one
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Old 10-02-2003, 10:27 AM
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Quote:
Originally posted by SoCal Driver

To bad you can't stick an 8 valve head on the engine.
I'm pretty sure the 8v head from the 2.7 944 will fit - the 2.7 was the only 8v with the same 104mm bore as the S2 & 968.

Would this make for an easier turbo conversion using 951 parts? I don't know, but it sounds like fun
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Old 10-02-2003, 02:17 PM
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Quote:
Originally posted by Alex Cook
I'm pretty sure the 8v head from the 2.7 944 will fit - the 2.7 was the only 8v with the same 104mm bore as the S2 & 968.
I would go that route if you could source a 'big-bore' 2.7 head...you would have to machine the tops of the pistons for the VERY LARGE '89 valves... the throttle body bore, manifold, intake/exhaust ports etc, etc...are all a lot bigger then the 2.5 heads...and with a good p&p...

fast, cheap & reliable (when else could you pick any 3 ! )
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Old 10-02-2003, 03:29 PM
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I think you should part it, I want the door panels.




Just kidding of course, I think you should throw a used 951 engine in it and mod it a bit.
then while you have that in there, you could always rebuild the ultimate 968 turbo motor while you have it out
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Old 10-02-2003, 09:18 PM
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Mike:
I am curious what shop the car was at. I too live in the greater Hartford area and have an '87 944S with 10 (yes 10) bent valves. I have the head off and in the back of my Pathfinder waiting to take it to a reputable shop for the valve work. I obviously want the work done right, but I would love to hear from anybody in our neck of the woods with a good referral to a shop. Also, maybe we can get a two fer special on 16 V heads! Thanks.
Old 10-03-2003, 07:51 AM
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I have had excellent luck with Automobile Associates of Canton. They are a Porsche specialty repair shop, and their prices seem pretty good as well. I do most of my own work, but when i can't do it myself, that's where i take it. I have had machine work done at Precision Automotive in Simsbury, but i've never taken Porsche parts there before, only old american V8 stuff. They're well known in the area for good work, but a little expensive.

That's not the shop that my friend has the car at, i don't like the shop he takes his cars to. Everything i've asked them for prices on comes back substantially more expensive than auto associates, and i've heard too many good reccomendations for auto associates to take it anywhere else.

I would call them and ask them if they have a machine shop they can reccomend.

By the way, i was just planning on buying a used head for mine. It seems cheaper than rebuilding the old one. 968 head, with valves, without cams $900. With cams, $1500 I would be amazed if they can rebuild it for less. Then again, with a rebuilt head, you know everything's good.
Old 10-03-2003, 12:39 PM
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Quote:
Originally posted by mike944
Dual overhead cams.

Does anyone have a picture, or an exploded diagram of the 968 head?
There are pictures of a 968 head in this Ebay auction [I know the seller and the cylinder head] with pictures. You can clearly see how the timing belt drives the exhaust cam and the intake cam is chain driven with the Variocam tensioner between the two cams directly in the center:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=33617&item=2436108990
Old 10-10-2003, 08:06 PM
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