Perkins Prima M50 Camshaft broke

[chris-s]

On behalf of a friend out in Greece who has just refitted his newly skimmed head after head gasket failure (not sure what other damage), took it out for a run this morning, wouldn't maintain revs in gear then stopped. A quick inspection showed the timing belt was slack and the camshaft pulley 'loose' (not loose on the shaft. Whilst the head was in the shop, they fitted new valves, guides and set the valve clearances - no idea if he checked them after refitting.
I don't think he has even taken the rocker cover off yet, so not a lot to go on I know, but are there any 'most likely' causes for this?

Chris

 

[Bobc]

It's critical on these engines that you tighten down the rocker cover exactly evenly and in the right order, as the top camshaft bearings are in the rocker cover, and if not done right, the camshaft can snap, which sounds like what's happened here. Taking the rocker cover off will release the camshaft and the valve springs.

The head's got to come back off, whatever's happened.

 

[chris-s]

Thanks for the reply. Think he will be having words with the mechanic.

 

[chris-s]

 

[chris-s]

So when the head was removed after the head gasket went, it needed welding, but the guy used too much heat and ‘warped’ the head, how much I have no idea. He took it too a different shop and they skimmed it and apparently the mechanic said he had problems reseating through camshaft so that rings bells straight away. I wonder if the cam bearing journals ended up out of alignment

 

[RichardS]

Unless he is Greek, good luck with getting this mess sorted, and even then he will need to know his rights.

Richard

 

[chris-s]

He’s half Greek, but I don’t think it’s gonna help much! The head is truly fubar’d.

 

[Bobc]

He’s half Greek, but I don’t think it’s gonna help much! The head is truly fubar’d.

Yup, that head looked finished. The cam bearing face looks scored.

The only answer is a complete replacement head, which are hard to find these days, especially as these heads are well known to be made of cream cheese.

Best of luck getting it sorted. I had many fights with my one before I finally gave up on it and fitted a Beta.

 

[penfold]

So when the head was removed after the head gasket went, it needed welding, but the guy used too much heat and ‘warped’ the head, how much I have no idea. He took it too a different shop and they skimmed it and apparently the mechanic said he had problems reseating through camshaft so that rings bells straight away. I wonder if the cam bearing journals ended up out of alignment

If it was warped enough to need skimming then the cam journals would need line-boring; this is entirely on the spanner monkey.

 

[MAURICE]

out of interest how old and how many hours did the engine have?

 

[chris-s]

Not sure of the age, it’s the original engine in a gibsea 42 and the control panel was replaced last year so I’m guessing previous hours would have been lost.

Looks like he has found a ‘used’ head in the UK so fingers crossed.