22 replies to this topic

[MIJ]

Built 2 engines now and a cam follower has worn into a cone (exaggerated) shape. It started rattling when I came to junctions. Everything has been been brand new. Cam, followers etc. Really getting on my nerves now, I don't know what can cause this so much? Engine has only done 2000 miles maximum

Any ideas

[imack]

Any pictures?

[gazza82]

Where are you buying the followers from?

[sonscar]

Is the rocker box oily?I think the cam and followers are lubed by the oil running down the pushrod holes(do not know this for sure)Did you bed the can/followers in?Just my amateur thoughts,Steve..
PS the crank splashes onto the cam also I think.

Edited by sonscar, 10 July 2021 - 09:04 PM.

[Spider]

Some pictures would help without which, we can only give guesses. I know in the US they are having issues with followers and cams being too soft and not heat treated correctly. The wear you've described is a lot for circa 2000 miles.

 

Also, how are the Valves sprung ?

 

Ideally, the Oil needs to have greater than 1500 ppm or more ZDDP, but that doesn't explain the short life here.

 

,,,,I think the cam and followers are lubed by the oil running down the pushrod holes (do not know this for sure)

 

The Cam Follower Faces are splash lubricated from oil thrown off the Big Ends. If Big End Bearing Clearances are too tight, this will affect Cam Lobe Lubrication.

 

Fresh Ground Steels don't readily accept oil, so, when new, if the engine speed is low at any point, the Oil Pump doesn't move a lot of Oil and the Crank Speed is too low to get enough Oil on to the Cam Lobes. What's the instructions with all new Cams ? Something along the lines of "Do not run below 2000 rpm for the first 20 minutes. Do not crank the engine excessively until the Cam is broken in ". Even running a tall final drive is not helpful with new Valve Train Parts.
 

[MIJ]

Unfortunately I don't have pics. The worn follower got thrown away by accident. The first set were from minispares and the current set are from swiftune along with a brand new cam.

The worn follower was worn into a cone shape, the bottom of the follower had scoring marks and the wall thickness was next to nothing where it had worn away. The rattle appeared to be where it was rattling in the cam follower hole as it worn away.

Oil is getting to the top, nice covering on the tappets and although the tappets 'tap' they are all correctly adjusted and recently checked.

It seems worse when I take it for a run. Stop and switch the engine off. Go back to it and the rattle is there. Then driving along it appears to disappear again.

[MIJ]

Valves are double valve springs

[Earwax]

As suggested above, these are  guesses at best, but will throw out some possibilities for you to consider.

 

Check the push rod tips ( and follower cups) - if they dont seat then the cam follower rotation will be awry.  I would also just check that the pushrods are straight !!!! and aren't rubbing against the pushrod bores ( scraping marks midway on shaft)- again these would/could send the rotation off.

[MIJ]

Thanks all. The push rods have been checked and all ok. Also checked they were straight when put in.

I'm assuming the follower has gone again because the sounds familiar. However, reading an old post on here someone has same issue and it was suggested it could also be a worn rocker shaft
I know mine has wear as these were the only thjngs I didn't change. Woukdvgus make the same noise? Perhaps on different revs? I.e. approaching junctions and revs drop?

[imack]

Shame you don't have pictures but I'd imagine if the wall of the follower is worn away then the follower bore in the block would be equally worn.
Possibly a damaged block has worn the new follower.
Maybe time for a new block.

[MIJ]

Thanks. The second engine is actually a new block too!

[Northernpower]

On assembly, did you check the follower moved freely in the block and did you use plenty of assembly lube on the sides of the follower?

[MIJ]

Yes all checked and assembly lube used

[absx2]

Did you follow the break in procedure ?

 

Copied from Spider

 

The Cam Follower Faces are splash lubricated from oil thrown off the Big Ends. If Big End Bearing Clearances are too tight, this will affect Cam Lobe Lubrication.

 

Fresh Ground Steels don't readily accept oil, so, when new, if the engine speed is low at any point, the Oil Pump doesn't move a lot of Oil and the Crank Speed is too low to get enough Oil on to the Cam Lobes. What's the instructions with all new Cams ? Something along the lines of "Do not run below 2000 rpm for the first 20 minutes. Do not crank the engine excessively until the Cam is broken in ". Even running a tall final drive is not helpful with new Valve Train Parts.
 

Edited by absx2, 11 July 2021 - 10:55 AM.

[Tones61]

You need to run new cam and followers at 2000rpm for 20 mins,
I use 20/50 VR1 and a small bottle of zddp zinc additive,

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