John Walker, or anyone: pitted cams

speeder · speeder's Garage

John, If you are out there, here are the pics of my cams. Not the greatest focus, but hopefully good enough.

Here is the question(s): Why do 911 cams pit so much? What will happen if I install these in my car? They came out of a running car w/ zero known problems, but are pitted on a couple of lobes on each cam. Will they tear up my rockers? The experts are not in complete agreement on this one. TIA, everyone.

speeder · speeder's Garage

BTW, sorry about the quality of the pics. Finally got inspired just now to read the owner's manual for my Canon S-30, to find out how to use the close-up feature, found out why I got such a killer deal on it online. The books are only in Espanol.

CamB · CamB's Garage

On my Canon s40 (?) it is either the set button or the one next to it. A little flower symbol comes up when it is on.

Does that help?

speeder · speeder's Garage

Sure enough, the flower button. I was looking on the wheel-thing, (auto, M, Av,Tv, etc.). I must get manual for this thing. Thanks Cam!

dickster · 05-29-2003, 10:58 PM

denis

you should use the original rockers. failing that use new ones. if you use yours they will wear at an increased rate.

maxnine11 · maxnine11's Garage

Dennis, here is a website with lots of info on operating/features of Canon S-40, which i am guessing is very similar. camera site . Sorry, but i can't help you with the cam question..

max

Early_S_Man · 05-30-2003, 12:17 AM

Denis,

You can download the manual here:

http://www.powershot.com/powershot2/customer/pdf/PS_S30S40.pdf

speeder · speeder's Garage

Warren, Thanks. I was about to go looking for that, (on the web). So while I have your attention, what do you think of using those cams? Will they cause some problems? TIA.

Early_S_Man · 05-30-2003, 12:36 AM

Denis,

Pits under 1.0 mm diameter don't usually cause any problems ... but I can't tell from the pics what is reflection or what is pitting!

Hint, hint ... post some new pics!

82SC · 05-30-2003, 01:21 AM

hey Denis

my pitting was not as bad as yours (i think)...very minor

I posted pics of mine here:
DIY: Install 964 cams in my SC any suggestions?

I know the cam shops like webcam and elgin can weld up and grind down to fill them...

EMS, engine machine services, is a machine shop that Tom@PP recommended...they are off Manchester about 5-8 blocks east of sepulveda...I had them grind off the powersteering pump and he inspected my cams and my rockers for me...he picked out my bad rockers and gave me an OK on the cams

they are a great bunch of guys...really affordable prices too...maybe you can take them down there and have someone look at it first hand...as well as garner some opinions from the BBS

good luck...let me know if you ever need a hand with the rebuild...it will give me a preview of what I have to look forward to

MJ

PS and if you need the cam tools I got em from my 964 swap

john walker's workshop · 05-30-2003, 08:30 AM

is that a felt pen circle around the pit, or is that a pit too? the pit inside the circle does look a bit larger than usual. probably best to fix it. tiny pits really don't hurt anything, and are pretty common.

dickster · 05-30-2003, 08:46 AM

john

are the surfaces not hardened?

when i built engines (many years ago!) cams with pitting had worn through the top surface and were scrap (unless reprofiled).

i even put new rockers on one of my own cars (in my youth) because the cam was noisy, and it shut it up but only for a week or two. the cam wrecked the new rockers.

or is all that diff to pitting? just curious.

speeder · speeder's Garage

Thanks everyone. John, yes, that is magic marker. I will read the manual today for the camera and try to post better pics, plus take the cams by EMS. And thanks for the offer MJ, I'll be in contact.

ruf-porsche · ruf-porsche's Garage

Quote:

Originally posted by john walker's workshop
is that a felt pen circle around the pit, or is that a pit too? the pit inside the circle does look a bit larger than usual. probably best to fix it. tiny pits really don't hurt anything, and are pretty common.

Why do pits occur on the CAM? Is it from rust?

speeder · speeder's Garage

These would be the worst two lobes, all together 4 are pitted. (All on the ends of the camshaft for some reason):

speeder · speeder's Garage

These measure approx. 3X5mm.

Doug Zielke · 05-30-2003, 06:24 PM

Denis,
From that last image, those pits look quite severe.
I just bought some used cams for a future regrind. They have some small spots of discoloration, but no pitting. That looks like corrosion or maybe the hardened surface is spalling.

82SC · 05-30-2003, 06:30 PM

yeah what is with the pitting...
mine and denis' both seem to be off center...I would expect the most wear to be on the center of the cam...

but yeah that second pic looks pretty bad...

is this the results of dirty oil???
but when my SC cams came out they looked great...and this is an 200K SC that has not been pampered and has gotten my bumbling DIY maintence for the past 2.5yrs

my rockers did have a little wear and I did end up replacing about 3 of them with good used ones...

hmmmm

MJ

speeder · speeder's Garage

Thanks guys. I can't imagine dirty oil being the cause of this, I mean how dirty would it have to be? Plus, the rest of the camshaft looks fine. Actually, all of the lobes look good, not worn, even the ones w/ the holes in them.

The pitting is off to the side, some mechanics have said that w/ the hardness of the metals involved, (cam+rockers), nothing will happen from using these. Hmmmm.........., probably wind up fixing them.