gkamysz

My Feedback: (19)

I've had a few engines now that exhibit peeling of the plating on the camshaft. This is specific to the Surpass II and higher engines. Previous engines did not have plating. I don't think I want flakes of the plating wandering around the cam well.

Is there an explanation for the cause?

Is there a solution. I would prefer to just remove the plating, nickel I assume. Anyone here know how?

Cobra1

My Feedback: (42)

Interesting, I would like to know about this as well. I did not think the cam shaft would be plated with anything because of the pressure applied on a small area. Engine experts please chime in.

w8ye

My Feedback: (16)

The OS 91 Surpass II has a plated camshaft. The plating does come off. I heard the Senior pattern guys talking about it. They use this engine almost exclusively.

I would try to remove the rest of the plating from that cam?

gkamysz

My Feedback: (19)

Yes, I do want to remove the plating. Mechanically this is impossible. I'm thinking chemical or electrochemical reaction. I've had it happen on the FS-91SII and the FS-120SIII. OS started nickel plating these parts to prevent corrosion, common with four strokes.

w8ye

My Feedback: (16)

Try some hydrochloric acid? That's the way chrome is stripped

Cyberwolf

My Feedback: (4)

I would just replace the camshaft, even if you do get ther plating off who says the lift and duration is going to be right with it removed.

Kweasel

My Feedback: (29)

Maybe an original Surpass cam will fit.

DarZeelon

Could it be?

An 'ABN' camshaft for OS; peeling like my (former) .40FP's sleeve???


I have only seen solid cast-iron flat-tappet (mechanical or hydraulic), or steel (roller) camshafts in full-size engines... never have I seen a plated/coated one.
...But some Briggs & Stratton engines have a plastic camshaft... And surprisingly, it lasts.



Greg, as it goes in full-size engines, I suggest to replace the lifters/cam-followers too, when replacing the camshaft.
...And to use zinc-dithiophosphate cam assembly lube...

That would make it even more expensive...

The [link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXCD43&P=Z]cam followers[/link] appear in the [link=http://www.osengines.com/parts/ev35920aa.pdf]parts break-down[/link].

speedster 1919

My Feedback: (3)

The trouble with removing plating chemicaly or mechanicly will remove metal and decrease lift and bearing boss may get smaller if done chemicaly. OS is probably aware of this problem , so the replacenent might have a better plating or your old one might have an extended warranty. Ask BAX --When ever changing cams or regrinding --the lifters should be replaced or at least be refaced. Sometimes they may be just surface hardened and refacing gets you into the softer metal which could wear like butter.

w8ye

My Feedback: (16)

The original Surpass cam fits very well and runs good but you cannot buy them. Only the new Surpass II cam which has the plating. There is no difference in lift or profile that I can tell.

gkamysz

My Feedback: (19)

I'll post a picture shortly.

I could deal with .0001-.001 less lift, by removing the plating. There are chemical strippers that will remove the plating without touching the base metal. Now I'm faced with buying chemicals to do the job or replacing it. Tower does list both the old and the new camshafts, but at almost $50 to fix a problem they created, I'm not really interested. Who thought of plating a high pressure area like that?

I reface the cam followers but they look pretty good.

w8ye

My Feedback: (16)

If you strip the coating from the cam it will not reduce the lift.

Whatever plating that comes from the peak of the lobe will also be removed from the base circle therefore the net difference in height will be the same.

OS at Tower only sells one cam for all the OS 91's. However it explicitly states in the caption that this cam only fits the latest pumped 91, it is the only one they offer and it actually fits all the 91's.

http://www2.towerhobbies.com/cgi-bin...?&I=LXCD55&P=7

Harry Lagman

Is it really peeling (with evidence of metal flakes or particles) or is it just wear? I wouldn't think that a nickel plating would last very long on a cam lobe anyway, so I'd expect that the nickel on the load bearing part of the cam lobe itself would wear off in a matter of an hour or two of running.

The intention behind the nickel plating of the steel parts was to reduce corrosion.

w8ye

My Feedback: (16)

I think the OS lifters probably are hardened? They seem to hold up well in a high time engine whereas a Saito will go through lifters like they were made of cheese. Every time I replace bearings in a Saito, I generally replace the lifters.

gkamysz

My Feedback: (19)

This is what mine looks like now. This is from an FS120SIII I got used. The engine is in great shape except for this.

[link=http://www.dieselrc.com/images/fs120cam.jpg][/link]

Click the pic for a 1200x800 view.

The base shows the worst peeling on this one. I have a .91 cam that is also peeling between the gear teeth.

w8ye

My Feedback: (16)

Looks like the plating is coming off the gear too. It also looks like the base metal is not damaged. Just the plating is gone.

gkamysz

My Feedback: (19)

Yeah, I noticed the rusty spot on the gear after taking the pic. The .91 cam shows the worst peeling at the ramp where the edge of the cam follower rides.

It's probably a process issue. I think it just isn't adhering well to the base metal. Once it starts peeling and corroding beneath the nickel, it's history.

Motorboy

To be sure the base metal are hard enough, take a file test with needlefile, if impossible to file off material from edge at basemetal then you are safe against worned camshaft in short time.

Some time i am thinking about the camshaft from SC/Magnum/ASP will fit in OS engine, it is a worth try to replace with a better camshaft..

w8ye

My Feedback: (16)

http://www.hobbypeople.net/gallery/284107.asp

http://www.hobbypeople.net/gallery/284285.asp

NM2K

My Feedback: (14)

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Where's Iskanderian when you need him? <G>

Ima

gkamysz

My Feedback: (19)

Bax posted in the support forum that they are the same profile, at least for the 1.20. Magnum parts, well I'm not sure.

Waco Driver

I had the camshft lobes peel on my OS 52 FS several years ago. I blended the peeled edges with a smooth Arkansas stone lubed with oil and it has run many hours since with no performance degredation or wear problems. Lifters were not affected.

gkamysz

My Feedback: (19)

That sounds like a good idea. I'll start with that, I have some stones around here.

asmund

I guess they are using the same "advanced bimetallic multilayer" process on the camshafts with the same success as they do with their sleeves It is sad to see how OS is going down in quality resent years[:'(]

proptop

My Feedback: (8)

That's about what I was thinking...

Is there really that much of a rust problem on the cams?

A phosphate coating or something similar (it seems ) would be better...yes/no!?