Cam shaft bearing issues, am I in big trouble?

[pandos]

Today I continued stripping my MD21B. Because I came across a set of cylinders and pistons I though I'd give it a makeover...(even though I did new bearings and rings a 100 hours ago)

I was surprised to see significant wear on the three bearing points of the cam shaft and on the corresponding faces of the holes in the block.

There does not seem to be any bearing/sleeve in the block, it seems they just drilled three holes and put in the shaft.

There is metallic grit in the oil and I am missing a piece of a ring so I am guessing that something went wrong with the oil supply...my main bearings and conrod bearings are all pretty much perfect (some small shiny areas)...and the crankshaft is absolutely perfect.

Questions. Is there in all likelihood a bearing in the block which is concealed by paint /tight fit.?

If there is not a bearing in the block is the cure to get it bored out and bush the holes with the shaft reduced a little.

There are a few pretty good engine/engineering guys near me, although they know how to charge...

 

[roaringgirl]

The repair you've suggested for the worn surfaces sounds sensible. I'd be more concerned about finding out what caused the problem in the first place. If there's metallic grit in the oil and the camshaft has suffered oil-starvation, what's to stop it happening again?

 

[fredrussell]

A completely different engine to yours but early VW air cooled engines had no bearing shells at camshaft journals. So it’s not unheard of. That said, later vw engines did have cam bearing shells, so it’s preferable, obviously.

 

[B27]

Maybe easier to get the block reamed out and the camshaft built up with Stellite or something more modern?

 

[pandos]

The repair you've suggested for the worn surfaces sounds sensible. I'd be more concerned about finding out what caused the problem in the first place. If there's metallic grit in the oil and the camshaft has suffered oil-starvation, what's to stop it happening again?

I suspect I'll find a blocked oil capiliary of something like that.

The repair may not be so simple.

I have been looking at it with a straight edge. The cams on the shaft are the same height as the original bearing surfaces on the shaft.

If the bearing surfaces are reduced to good metal, the shaft will not pass through the new bush!

It's a cast iron shaft, so not sure if material can be added either as a sleeve or welded on and then reground to the original size...

 

[penfold]

Can you feel the wear when you run your nail across it? It certainly looks utterly knackered, but photos can be misleading. Cheapest solution would be a used engine and make up a runner with the best bits of the two, a cam could be ground down but it doesn't look like there's much margin for doing that before running out of spare journal, given the state of that I wonder what the crankshaft is like, probably similar.

 

[pandos]

Can you feel the wear when you run your nail across it? It certainly looks utterly knackered, but photos can be misleading. Cheapest solution would be a used engine and make up a runner with the best bits of the two, a cam could be ground down but it doesn't look like there's much margin for doing that before running out of spare journal, given the state of that I wonder what the crankshaft is like, probably similar.

Crank shaft is perfect, damage is purely the three bearings on this shaft.

The surface damage is pretty deep in places, but there's plenty of meat left on the bearings for grinding down to a consistent surface.

I am amazed that there is not damage elsewhere.

The cams themselves are all fine.

Not so easy or cheap to pick up one of these engines at this stage.

I am thinking that it maybe that some rings are heated and pressed onto the shaft and the block is just reamed out to accommodate them. I think this is in line with B27 suggestion.

 

[pandos]

Maybe easier to get the block reamed out and the camshaft built up with Stellite or something more modern?

Hadn't seen this..I think this is the solution assuming stellite can be machined into rings/bands and pressed onto the shaft.

 

[B27]

Stellite is perhaps an outdated process now.
It's basically building up with weld, which can then be ground down.

There are all sorts of 'putting metal back' processes, but it's all expensive.
The block is vehicle based? Any chance of finding a good one?
Would the vehicle engine have had a different cam?

There are people who do this kind of work to vintage and classic vehicle engines, but as you say, they know how to charge and I'm not really in those circles these days.

The thing to keep in mind is that whatever you do, it will still be an old engine.

 

[penfold]

Google suggests it's a marinised Peugeot Indenor, so any automotive engine reconditioner should be able to quote for repairing what you have. If it is an Indenor used examples are available.

 

[pandos]

Google suggests it's a marinised Peugeot Indenor, so any automotive engine reconditioner should be able to quote for repairing what you have. If it is an Indenor used examples are available.

Yep that's what it is, but Volvo replaced the timing belt with gears so not sure the original indentor shaft would be a straight swop.

Entire motors or even significant parts are getting expensive.

In any case I'll still need the block reamed.

I'll be off to local engine guy tomorrow and he is 15 feet from my favoured precision engineering place so I'll see what those two guys think.

I just wanted to see suggestions that I might like better than theirs.

 

[garymalmgren]

Kirtus doing metal spry

 

[pandos]

Can't see that being done locally to me for less than the cost of return flights to Australia...

Kirtus doing metal spry

 

[DownWest]

Just a thought, but, if the bearing is the closest to the timing gear, find some one to build it up oversize, then have the block line bored to the new size cleaning up whatever damage is there. (assuming the other bearings are OK)
BMC A series had no bearings in the block and we did something like that to a couple.

 

[DownWest]

Looked and it is a Pug 504 motor 2.1 ltr, as said, belt to chain complicates the bits, or is the cam the same?

 

[pandos]

Just a thought, but, if the bearing is the closest to the timing gear, find some one to build it up oversize, then have the block line bored to the new size cleaning up whatever damage is there. (assuming the other bearings are OK)
BMC A series had no bearings in the block and we did something like that to a couple.

The three bearings that are shot, it will need the three built up to oversize and the front back and middle of the block reamed to suit. But your scheme is probably the easiest way. No bearings or bushes needed in the block.

 

[pandos]

Looked and it is a Pug 504 motor 2.1 ltr, as said, belt to chain complicates the bits, or is the cam the same?

Yep it's a 2.1 pug I've sourced almost all parts I are use from Peugeot sources.