Too much cam noise?
Discussion
spitfire4v8 said:
You say you've done 400 miles since rebuild, presumably the cam wasn't like that already then. SO, the follower has marked up and the cam is wearing after 400 miles. Did you flood the top end with oil before starting? The ajp is normally very kind on its cams because the followers sit in an oil bath so never run dry on that all important startup period.
Is the follower that's marked up the one you changed by any chance? I saw an engine that had not long had a rebuild, was in for valve check and mapping and two followers were already scored and one was taking the cam lobe with it.
I was half expecting to find the cam with a problem when I removed the cover, in my first post I said the only thing not changed was the cam. I was just really hoping it wasn't the case!Is the follower that's marked up the one you changed by any chance? I saw an engine that had not long had a rebuild, was in for valve check and mapping and two followers were already scored and one was taking the cam lobe with it.
Yes that follower was the new one. That was the valve that stuck & made a mess of the old bucket, this is what the old lifter looked like before everything bar the cam was replaced:
I was worried at the time that cam lobe was damaged also, the edges of the lobe were rounded over (as you'd expect with the bucket lifter looking like that!) You can see the scuff marks from the edges of the lobe on the old lifter there. The valve stuck, the shim came off then punched lumps into the the follower, it was off centre so only the edges of the cam showed any sign of damage at the time, but it's clearly toast now! I think it's safe to say that is when it was damaged. Because I was worried about it I was very careful to be sure it was all very well lubed before staring it up, I got good oil pressure very quickly after staring too. I'm not going it to more than that now till I've spoken to the machine shop again.
Interesting what you found with those followers though.
Edited by Luckyone on Wednesday 17th December 12:44
plasticman said:
It does not look like that bucket can rotate properly
The bucket in that pic above certainly could not rotate properly, it was locked to the valve cap by bits of smashed shim. That's not the bucket that's in it now though, it had a new one. But the cam was the same one that was acting on the bucket above.
ridds said:
Ahhh, so you put the old damaged cam lobe onto the new follower after the valve had stuck previously.
Whoopsie, that won't have helped matters as the lobe nose loading wouldn't be even at all after that sort of damage.
Yes as I said in the first post the machine shop didn't want to stretch to a new cam & set of followers when they gave me all the other stuff to fix the stuck valve for no charge. I wasn't too sure about the life span of the cam after that kind of damage, guess I know now! Makes sense about the side loading. I didn't insist at the time as cams aren't too hard to swap. Whoopsie, that won't have helped matters as the lobe nose loading wouldn't be even at all after that sort of damage.
It looks like the machine shop will now provide a replacement cam FOC so will hopfully be back on the road soon. Hopfully with no lasting damage...
Xmas got in the way a bit & they forgot about it, I've just reminded them hopefully a cam will appear soon. Not really the weather for fully rebuilt cerbs at the mo anyway.
I'm busy pulling the engine out of an old 325i that a mate killed by putting engine flush in right now. It was a perfectly good car before he put the flush in 10 miles later by the time he got to me for a quick oil change a big end bearing had totally gone, so much for a quick oil change!
I need to stick to body work....
I'm busy pulling the engine out of an old 325i that a mate killed by putting engine flush in right now. It was a perfectly good car before he put the flush in 10 miles later by the time he got to me for a quick oil change a big end bearing had totally gone, so much for a quick oil change!
I need to stick to body work....
After quite a long wait the machine shop finally tracked down a replacement cam for me, so a brief moment of hope till I checked it against my old one. A quick measurement of them showed the replacement cam was about 0.5mm bigger overall, but worse the profiles looked different, so I checked them.
Click on pics to make them big if you want
A cast taken from a good lobe of my old cam:
Then placed on the replacement:
I think my old one is a clatter cam & the replacement is a later one. The hex drive on it seems like a good idea though!
So now I'm a bit stuck with two odd cams, the machine shop may have the other cam to match the replacement they sent, but I don't really want to swap a perfectly good cam with an unknown one.
Anyone got a clatter(?) cam they want to swap with a later one?!
Click on pics to make them big if you want
A cast taken from a good lobe of my old cam:
Then placed on the replacement:
I think my old one is a clatter cam & the replacement is a later one. The hex drive on it seems like a good idea though!
So now I'm a bit stuck with two odd cams, the machine shop may have the other cam to match the replacement they sent, but I don't really want to swap a perfectly good cam with an unknown one.
Anyone got a clatter(?) cam they want to swap with a later one?!
Jhonno said:
I am not sure the non clatter will work so well..?
Yes that was the impression I got from odd posts on here. However the two cams have just about the same overall dimentions so will give the same max valve lift but the later one has a fatter tip or longer duration so keeps the valve at a higher lift for longer, I've forgotton anything I did know about cams other than its a black art & bigger isn't always better....So it seem there are three types of cam used in the AJP, no difference between 4.2 or 4.5 as far as I can tell, just in age.
First there was the clatter cam the one with the hex drive in my pics, this has the fattest lobe.
Then there was the type originally fitted to our 98 4.5, the one in my pics that hasn't got the hex drive on it.
Lastly there is the only type available to buy now, the chill cast (not sure how the older ones are made), this apparently has the softest profile. These two have the hex drive section on them like the first clatter cams.
No one has got a good non hex drive to match my good one (even bank), so at the moment I've got one good clatter cam & one good second type that's always been in the engine.
I'm told by my TVR machine shop it will run fine with these mismatching cams in, though they do have the other clatter cam to go with the one I've already been sent if I want it to be right only they want 100quid for that. Probably worth the money & they said the used clatter cams would be fine with my old followers. I'm not so sure about that though.
So my options are:
Run with two different cams - No more cost don't really like that idea
Have two clatter cams on my old followers - "should be fine" 100 quid
Have two clatter cams with new followers 400 quid (though I would have a good cam with matching followers to sell then)
Safe option two new cams & follower , down the best part of 1,000 quid then
Were there any problems with the old clatter cams, apart from the noise?
Any other opinions? Helpful or otherwise...
First there was the clatter cam the one with the hex drive in my pics, this has the fattest lobe.
Then there was the type originally fitted to our 98 4.5, the one in my pics that hasn't got the hex drive on it.
Lastly there is the only type available to buy now, the chill cast (not sure how the older ones are made), this apparently has the softest profile. These two have the hex drive section on them like the first clatter cams.
No one has got a good non hex drive to match my good one (even bank), so at the moment I've got one good clatter cam & one good second type that's always been in the engine.
I'm told by my TVR machine shop it will run fine with these mismatching cams in, though they do have the other clatter cam to go with the one I've already been sent if I want it to be right only they want 100quid for that. Probably worth the money & they said the used clatter cams would be fine with my old followers. I'm not so sure about that though.
So my options are:
Run with two different cams - No more cost don't really like that idea
Have two clatter cams on my old followers - "should be fine" 100 quid
Have two clatter cams with new followers 400 quid (though I would have a good cam with matching followers to sell then)
Safe option two new cams & follower , down the best part of 1,000 quid then
Were there any problems with the old clatter cams, apart from the noise?
Any other opinions? Helpful or otherwise...
I have the cams that came off my 4.2 during the 4.7 conversion. I am fairly sure they are the middle type as I have a receipt for it having the original clatter cams replaced before I got it. One of them has a worn/scored journal but I believe the other one is fine. I just had a look and cant see any sign of the hex that you mention. My good cam is the longer one - not sure which side that is off. PM me if it is any use to you.
Edited by Tanguero on Thursday 7th May 15:33
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