Worn Camshafts After Just 500km Running

[B1ack_Mi16 67]

As my car is going to a RR this week I was checking the camtiming today, and adjusted it a litte, set it at 3.65mm @ tdc and 3.25mm @ tdc. Catcams specsheet say 3.8 / 3.25 but think it might give a little more at top end with a little inlet retard.

 

Anyway to the problem! After getting the rockercover off I instaneously noticed some of the lobes having strange marks on them, and if I slid my fingernail over the marks it felt a bit rough..

 

So are my camshafts just a few miles away from carnage?

 

Here's some pictures of it:

 

I did grease them up with molylube before fitting, and they're sitting in lots of oil.

Also tried to keep the revs at about 2000rpm for the first 10 minutes of running.

 

Any ideas what have happened and what's going to happend as this continues?

Anything I can do to avoid total carnage?

 

Regards

 

Kristian

[niklas 1]

Ocuh

Swarf in the oil? Do the followers have marks as well or just the lobes?

[dani959 0]

Hummm...

 

From your pictures, looks like there were bits of aluminium between the cam and the followers and got smashed. Did you clean it thoroughly before reassembly?

Try to scrape some of those bits off and the cam whith a knife or something. If they come out easily, they are almost surely aluminium and you should check where they are coming from... If your head was skimmed, probably wasn't cleaned on the oilways.

 

The best option would be to remove the head and clean it, bu maibe an oil flush will do the job. Just hope they didn't go between the followers and the head or to the cam bearings.

 

Hope this helps!

[B1ack_Mi16 67]

I can't see anything on the followers, and there's definately not aluminium, it's the metal in the camshaft itself that somehow has dissappeared from the lobe, it feels a bit rough when I run my fingernail over it.

[John_B 11]

It's probably a stupid question but you didn't forget the spray bars did you? Were they pushed in properly or blocked?

[WildCards 0]

How many oil changes have you done since rebuild? And what oil have you been using?

 

Frequent oil changes are crucial within the first 500 miles as you'll have alot of crap coming out of it during the wear in period. I'd suggest as others have said that you've cought some swarf up in the oil and it's passed underneath the cam lobes.

[B1ack_Mi16 67]

How many oil changes have you done since rebuild? And what oil have you been using?

 

Frequent oil changes are crucial within the first 500 miles as you'll have alot of crap coming out of it during the wear in period. I'd suggest as others have said that you've cought some swarf up in the oil and it's passed underneath the cam lobes.

 

Not changed oil yet, but it's got 8 litres in there!

And it's only done 250 miles yet since rebuild.

 

I've now talked to the guy I bought the camshafts from.

He said it most likely were the nitrided layer chipping off the lobes, and that I would get new ones if it continued and got worse.

 

I really can't see it beeing any other crap in the oil that's caused it.

It's only happened on 6 lobes, other 10 ones are fine.

[stux 0]

Did you use new cam followers, or do something with old ones?

Edited May 31, 2007 by stux

[WildCards 0]

Not changed oil yet, but it's got 8 litres in there!

And it's only done 250 miles yet since rebuild.

 

I've now talked to the guy I bought the camshafts from.

He said it most likely were the nitrided layer chipping off the lobes, and that I would get new ones if it continued and got worse.

 

I really can't see it beeing any other crap in the oil that's caused it.

It's only happened on 6 lobes, other 10 ones are fine.

 

I will be doing an oil change at 20 miles, at 100 miles and another at 250 miles when my rebuilt Mi is back in the car. The first few miles is when all of the swarf that you didn't realise was there gets found out and churned through your engine.

 

If not swarf then what?

[B1ack_Mi16 67]

I will be doing an oil change at 20 miles, at 100 miles and another at 250 miles when my rebuilt Mi is back in the car. The first few miles is when all of the swarf that you didn't realise was there gets found out and churned through your engine.

 

If not swarf then what?

 

As said, the guy I bought them off had seen this before, and he said it most likely was down to a failure due to improper hardening/nitridation process of the camshafts.

 

If some aluminium swarf did get between the cam and follower I really don't think it would look like it does in this case, where the material simply is chipped off.

[renault 17 1]

As said, the guy I bought them off had seen this before, and he said it most likely was down to a failure due to improper hardening/nitridation process of the camshafts.

 

If some aluminium swarf did get between the cam and follower I really don't think it would look like it does in this case, where the material simply is chipped off.

 

 

Not to state the obvious but could it have been caused by the spray bars hitting the cam lobes or the lobes hitting the inside of the rocker cover where the bolts are?

[B1ack_Mi16 67]

Not to state the obvious but could it have been caused by the spray bars hitting the cam lobes or the lobes hitting the inside of the rocker cover where the bolts are?

 

Yes I have been off with the rockercover several times. I've spaced out the spray bars with washers so they don't hit.

 

Some time since last I checked the cams condition now, so maybe it's time to see again how it's looking now.