924Board.org

PS · Joined: 25 Jun 2004 Posts: 5

Hello all:

I have a 78 924 with a damaged camshaft and a couple of bad lifters. One of the lobes on the camshaft is fairly worn down and rounded over, and the corresponding lifter has some chips in it. I was wondering if anybody else has ever taken a camshaft or a lifter to a machine shop to have it welded and ground. If so, was the repair successful?

Also, if the camshaft can not be repaired, is it necessary to replace all of the lifters when a camshaft is replaced?

Thanks for your help

Lizard · Posted: Fri Jun 25, 2004 6:39 pm Post subject:

replace lifters with any damage, replace the cam someone on the board should have a good one for sale and may even throw in a lifter for you.
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3 928s,

leadfoot · Posted: Fri Jun 25, 2004 10:34 pm Post subject:

I know that you can get the lifters resurfaced, and that some parts shop will do exchange lifters.
As for the cam, yes you can get it fixed. It kind of depends on how damaged your talking about but essentially it is the same process as offset grinding cam/crank.
Take the cam to a grinder and get their opinion as to what they can do, as it may end up cheaper to get a new billet or second hand cam.. Also look as to what caused the damage in the first place, you might consider getting the head bearing line bored at the same time.
You might consider grinding the cam on a smaller base circle to get it back to a good surface, get the bad lifters also ground down if they have enough meat on them left and then take up the slack by having the valves lengthened and ground back with stallite, which is very effective and simple to do. Then have the rest of the head looked at, valve angle and seat ground to three points, valves stem checked for wear, new valve seals, head cleaned.
Then put the head back and not worry about it for quite a while...
leadfoot

gohim · Joined: 02 Nov 2002 Posts: 4459 Location: Rialto, CA

Check the for Sale Section for a usable head with the camshaft and lifters.

I think Fuzzbeaner has one for sale. Heads and camshafts from later model year cars are better, because Porsche redesigned the lobe profile. The original cams that too sharp a nose, and high pressure caused some premature wear on the cam lobes. I would prefer a used camshaft in condition with the matching lifters instead of having a cam serviced, and used/reconditioned lifters. I don't see shops heat treating lifters after they grind them to restore the surface treatment, so the "restored lifters would probably wear rapidly.

Damage to isolated individual cam lobes is usually the result of plugged oil supply tube holes, as a result of deterred maintenance, or low oil supply pressure to the tube due to a cracked plastic elbow on the head (connector for the oil supply tube), or a vibration cracked oil supply tube.

You should make it a habit to replace the plastic elbow each time you are under the valve cover, or at least once a year. They are cheap, used to be about $1 at the Porsche Dealer. I buy mine in several at a time to make sure I always have them on hand here at home.

augidog · Joined: 03 Mar 2003 Posts: 1360 Location: New Jersey

The lifter goes first -then the cam.
I've been there.
I don't think the lifters can be resurfaced.(they are large and the hardening process after is tough to do so they would probally wear down fast.)
Go to a new modified stock if you have the loot to sink on the cam.
Or-
Replace the cam and all lifters from someone parting out a car.
I got a complete full set and good used cam for $125.
Make sure he marks where the lifters came from in the donated engine. Read the nightmare post on valve adjustment that was recently submitted.
http://www.924board.org/viewtopic.php?t=11757
My problem was also broken oil tube elbow some that hack mechanic let slide on the previous owner.

Its a fun project, and really not too bad to do yourself.
It will be nice to run on all four again.
Good luck
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1978 924 95 mile daily driver.
Audi TB/POR174M/High Flow Cat/2.25" exhaust
I knew that positive thinking thing wouldn't work.

Joes924Racer · Posted: Sun Jun 27, 2004 5:07 am Post subject:

Or you can send the cam to http://www.schneidercams.com/
they can most likely fix it for close to 150.00 and I have some
good used lifters I can sell you .. if you want. then just put it together.
_________________
1979 porsche 924 Na
1980 porsche Turbo 931GT Replica
Have u ever driven a turbo.

PS · Joined: 25 Jun 2004 Posts: 5

Thanks for the advice. I picked up a good used camshaft and a set of followers on ebay, and am hoping that I will have the time to install them shortly. I am also planing to remove the head to have a machine shop rebuild it. Has anybody had a 924 head rebuilt lately? How much should I expect to pay to have the head rebuilt (obviously it depends on how many parts need to be replaced)? Is there anything else that I should be aware of when having the head rebuilt?

Thanks,

PS

Joes924Racer · Posted: Sat Jul 10, 2004 7:59 pm Post subject:

If you go to any reputable shop they have standard rates for 4, 6, and 8 cyl. cars..the one i go to has a big billboard up on the wall with prices for all there services they offer.
_________________
1979 porsche 924 Na
1980 porsche Turbo 931GT Replica
Have u ever driven a turbo.

Joes924Racer · Posted: Sat Jul 10, 2004 7:59 pm Post subject:

as for how much i couldnt tell you off hand i could check though.
_________________
1979 porsche 924 Na
1980 porsche Turbo 931GT Replica
Have u ever driven a turbo.