Camshaft wear ??

[Senior Moment]

I suspect I know the answer to this, but I thought I would just throw it out there and get some opinions.
I have the engine from my 361ci CV-8 out, and stripped for inspection. In previous ownerships It has been used sparingly over the past years with long periods of zero use.

I suspect the block assembly may have been replaced at some point, as it is painted Chrysler blue and has no engine numbers in evidence. The cylinder heads, valves & springs have been replaced with new, but the valve gear was heavily soiled and carbon has built up. Inconsistent with the new heads condition.
The crank, big end and main bearings are in good shape, but show some scuffing. Pistons look like they have seen good service, but rings are free and serviceable. There is some bore wear apparent. The cam chain is on the upper edge of its wear tolerance and needs to be replaced.
When I removed the camshaft and followers I find some odd wear marks on the cam lobes. (see pictures) The marks are on mainly on the up and down side of the cam lobe and all appear to be affected to a greater of lesser degree. The shape and dimensions of the lobes are consistent. The cam-followers do have some slight doming on the workface, but no other wear signs.
Various engine components show evidence of scuffing (Piston skirts and bearings) that I suspect come from dry starts after long periods of rest. This would fit with the vehicle history.

I look forward to your thoughts.

[slotcarone]

I am certainly no expert on this stuff but that cam looks like it was manufactured like that. It looks like flaws in the casting to me. The wear in the contact area of the lifters is normal to see a tiny amount of cupping. How was the engine running before disassembly?

[Chris_R]

DO you know what oil was used in the engine over that period of time?

[AH1951]

Maybe a manufacturing defect and fatigue spalling of the case-hardened surface.
Or poor lubrication.
Or both?

[AndrewP]

That cams good for the bin....throw away and start again.

That looks like there has a been a oil supply issue as the pick-up on those lobes is pretty bad so much that as mentioned, looks like the case hardening has failed and the softer metal underneath has started disintegrate.
This could have been because of any number of reasons but an incorrect run-in procedure being followed, manufacturing fault, poor build etc. etc.

There was a case of followers not being machined with the correct crown/convex ends, meaning the lifters stay in one spot and dont rotate so you may get more information from looking at the lifters as well.
They should have a nice even circle wear pattern on. Id wager some are very pitted.

This guy explains it pretty well. https://youtu.be/9EBsMqqu8Bo?t=214

If the engine is out, Id be looking to run a long oilway brush down the oil galleries and see if there is accumulated gunk down there as you wouldnt want to spend on a new cam and lifters and for it to do it again in a few thousand miles.

Cheers

[mikebyrne]

Either a very poor quality camshaft or very high mileage or lack of maintenance bud!! (as our friends over the pond say.)
Mike.

[Steve Payne]

It looks like bad corrosion, could the engine have got wet at some time?

Please say you are going to replace it? Yes it might work but long term I suspect it will give you problems.

Steve

[Senior Moment]

Hi all. Thanks for the feedback
To answer a few questions.
A) What oil has been used. I don't know. It was very black and smelly. Like inside a Diesel.
B) Cause, all of the above. and I think a lot of dry starts after long periods of standing.
C) Is it going to be replaced? Indeed. I may keep it under the bench in case I need to hit myself with something.
D) Cleaning oil galleries. Next job. Like I said earlier, inside it was filthy.

Lots of interesting comments. Thanks
Martin

[johnw]

This is a long one, and I am not sure how relevant! I have seen one almost as bad. It was the same almost inexplicable pitting, also with that discolouration. The previous owner of the car told me he had fitted a performance cam. He would have fitted the cam some time between 1985 and 1990. It got to look like that on a very low mileage, about 15K. The rest of the engine was pristine looking, bores spotless, cross hatch marks all visible, no sludge in the sump, oil pressure was normal, the oil always stayed clean on that motor, not like some where it looks black 5 minutes after a change. It was a fresh rebuilt short motor the previous owner then fitted a hotter cam.

However, I must confess during my ownership the engine suffered an oil pump drive failure! Total loss of oil pressure on the motorway cruising at 70! As I was driving I noticed the hydraulic tappet noise change slightly, looked and was watching the oil pressure needle fall in real time, it took about 15 to 20 seconds as I pulled off the motorway until the motor was turned off. I immediately started coasting the car, I didn't try and start the engine again, the AA recovered the car and we carried on in a hire car. The shaft sheared because a bristle from a wire wheel had (presumably) fallen off some years prior, and eventually lodged in the pump, blocking it from rotating.

So, I am not sure if less than 20 seconds running with no oil to the cam could cause that, or if the typical performance cam kits of the 80s were just poor metal. The AA man assured me no one would try and run the engine. It was rolled off the trailer when it was delivered back.

At the time I only took the sump off to check the engine, and didn't notice the cam damage. The engine started, idled quietly as before with good oil pressure after I removed the obstruction and fitted a new drive. I drove round in the car for another couple of years before noticing the cam damage one day when I removed the inlet manifold.

Edit: Obviously I swapped the cam before selling the car! The car had 3 more owners before the current owner bought back the original motor which turned up online. He said that there was nothing wrong with the old motor when he stripped it.

[Senior Moment]

Hi John.
Thanks for this. Good information.
I have checked the cam lift (not duration) and it looks to be standard. Judging by the mixed bag of wear on other block components, probably original. Whitch points to mediochre casting and lubrication issues from many dry starts. The engine sounded fine before I removed it. (to replace the transmission for a 727 unit) Whilst it was out of the car, I sw heavy carbon deposits on the valve gear (Heads were new iron units). From there I decided to investigate further. The rest you know.
Martin