recondition camshafts

svandamme · svandamme's Garage

just shipped out some engine parts for the inspect+recondition work...

so looked at my camshafts... ( that shop doesn't do camshafts)

tried making pictures, but didn't work... to much reflection and not enough detail to show the stuff...

basically , on the left camshaft... there's two cams that have pitting
not very deep, and about 1/3 of a square cm

i have one cam with similar pitting on the right camshaft

i also have visible wear on 3 other cams , my guess , i'de say about 0.4 mm wear from the rocker arm...

my question :

can this be fixed? if so , who's good at it? ( preferably in europe )

if not , how hard is it to find a good second had set of S cams
or aftermarket replacement...

and what would either repair, or replacement cost me???

EDIT, just got a link from these guys
http://www.webcamshafts.com/porsche-auto.html

either reweld my old camshafts
or get new ones made from scratch

does anybody have experience with these guys? any good?

repairing my own cams would be 683$ + shipping to and from the US

new ones would be 836$+ 165$for MFI pulley+shipping to europe
and would be a 4 bearing setup ( can old camshaft housings be modified or can they run without modification ??)

Tim Hancock · 10-01-2004, 03:26 AM

I had similar pitting on my SC cams and sent them to Elgin Cams in California. They charge around $330.00 to regrind your cams. They looked great and they took the time to answer any questions I had. John D. works there he posts as"camgrinder" on this forum and he was very helpful on the phone.

Jeff Alton · 10-01-2004, 08:00 PM

Camgrider is an expert. He did my cams and will be getting another set soon from a 3.0 that I am building in November for a client. Trust him. There are two highly regarded cam grinders in my home town and I still will send my cams down to Elgin.

Jeff

Jim Sims · 10-01-2004, 08:14 PM

A 3rd vote for Elgin Cams! Sent them a set out of a 1973 and the cams came back looking like new. Zero hassle and quick turnaround. Won't help you much in Europe though; someone there must do this type of work. Jim

Jeff Alton · 10-01-2004, 08:23 PM

oops, never saw the location.

Jeff

camgrinder · 10-01-2004, 09:17 PM

If the new cams have the small (47mm) bearings they should work. The extra main journal is not utilized. Most early camshaft housing do not have the bearing bore in the housing. There are a few small bearing housings with bearing bore but the oil feed hole is not drilled. You would need to drill this hole to use a 4 main camshaft.

starlifter1 · 10-02-2004, 08:33 PM

can they (elgin) only regrind back to stock or can they change the profile? I have a set of 3.0 cams that are slighty pitted and need fixed and would like a more performance oriented cam

DonE · 10-03-2004, 06:10 PM

They can regrind to your specs providing the cam is in good condition. Mine were SC's and now 964's by Elgin.

snowman · 10-03-2004, 10:15 PM

Elgin is the way to go. Call them if you have any questions. I have found Dema to be very very helpful for my race car cams.

svandamme · svandamme's Garage

thanks guys... i'll consider the option... but i checked prices , and i can get a new OEM set of camshafts for about 1200 euro's

now that is somewhat more than actually reconditioning my old ones...

but i need to add shipping to and from.. and add some extra hastle...
i'm also a little bit paranoid bout having mismatches or whatever
brand new oem gives me more peace of mind, but haven't made final decision yet...

snowman · 10-04-2004, 08:43 PM

for1/3 to 1/2 the price of $1200 euros or about $1600 US vs $600 US for reconditioned. That dosen't sound like a very hard decision to make. Especially since reconditioned cams are just as good or possibly better than new ones.

svandamme · svandamme's Garage

Quote:

Originally posted by snowman
for1/3 to 1/2 the price of $1200 euros or about $1600 US vs $600 US for reconditioned. That dosen't sound like a very hard decision to make. Especially since reconditioned cams are just as good or possibly better than new ones.

haven't decided yet, but you say better than new, or at least as good as.

i'm not the expert here, but rewelding and regrinding , it sounds like patchwork, and in a way it is patch work...no offence..
i'll admit, i'm a bit paranoid about things i don't fully understand. and i've had so much bad luck with my car, that i don't wanna upset the porsche gods anymore... desperately need some good P-Karma...

john walker's workshop · 10-05-2004, 07:59 AM

i've never been a big fan of reground cams that are ground undersize. the rocker operating angle is changed, and you have to run the adjuster in almost flush with the top of the locknut, and you often get valve tick that you can't quite seem to get rid of. new, or ground from a billet to original lobe size is the best way to go. welded and reshaped to original lobe size would be my second choice.

svandamme · svandamme's Garage

Quote:

Originally posted by john walker's workshop
i've never been a big fan of reground cams that are ground undersize. the rocker operating angle is changed, and you have to run the adjuster in almost flush with the top of the locknut, and you often get valve tick that you can't quite seem to get rid of. new, or ground from a billet to original lobe size is the best way to go.

John, what about having an old shaft welded and then reground to original spec... would you consider that as good as new?

just heard from machine shop that my case needs boring, all my valves need replacing, cylinders are toast...

so if rewelding is good, then i guess i'll go that way , budget is allready blown, need damage control ...

sammyg2 · 10-05-2004, 10:35 AM

Why do these cams get pitted? I've seen several cases that looked nearly identical. It is something to do with age, materials, original design, etc?

Jim Sims · 10-05-2004, 11:04 AM

Pitting causes: (1) Overloading (F=ma where a is a function of RPM) leading to excessive subsurface tensile stresses (Hertzian stresses) which cause a fracture which can then start the fatigue process which will spall out a chip or surface tangential (shear) stresses which can do the same thing. (2) Lack of lubricant or the wrong type of lubricant (can cause higher tangential stresses or galling). (3) Sitting idle for long times, permitting corrosion to start which makes a small initial pit which grows under normal operation. I suspect (2) then (1) are the bigger problems with most 911 engines. Jim

starlifter1 · 10-05-2004, 05:10 PM

then what is the correct lubricant syn or regular or are you talking correct weights

DonE · 10-05-2004, 07:18 PM

Lubricant failure is mostly due to breakdown of oil (old oil) or contaminants. Any good dino or synthetic oil in a 911 motor is sufficient if properly maintained (changed with a quality filter). I use synthetic in the 930 and 951 because of the turbo's operational environment.

Jim Sims · 10-05-2004, 09:12 PM

Clean oil of the correct weight (viscosity) is required. How this is achieved doesn't matter. Change the oil within it's recomended life and match the viscosity to the service conditions. Jim

snowman · 10-05-2004, 09:28 PM

I have read where elgin cams uses NEW cam billets when required. I would double check on this to see if true. If so then specify NEW billets for your cams. I suspect that it dosen't matter much if everything is done properly.