Cam journal wear

[rustybronco]

I haven't done any sort of rework like you are asking.

I 'suspect' you could remove a small amount of metal from the cam bearing caps and have someone align bore or align hone the journals if the damage isn't to severe.

[tatu]

yes, that's what I'm thinking, that is a common fix in places like Africa for mains on engine blocks and it works fine.
Or even replace with removable shell bearings.
Another possibility might be to line bore and replace the whole lot and then bore again back to size.

[rustybronco]

When they were poring babbitt bearings back in the twentys and thirtys. The common fix for those, after you removed the last shim from the main cap, was to file the cap and hit the babbitt with a bearing scraper.

Every self respecting old time engine builder used to have a main bearing file and a scraper which were only used for that sole purpose.

[tatu]

When they were poring babbitt bearings back in the twentys and thirtys. The common fix for those, after you removed the last shim from the main cap, was to file the cap and hit the babbitt with a bearing scraper.

Every self respecting old time engine builder used to have a main bearing file and a scraper which were only used for that sole purpose.

I've still got my dads'.
I believe that its still done on marine engines in ships where ist impossible to get borers into the spaces so its still done by hand and those are huge bearings.

[tkent02]

I will guess the two cam caps on the right side are the two with the damage?

I think it is from letting the engine idle a long time on the side stand.

[jhillier449]

Tkent02:

You are on da money.!!!!!!!!!!

The rest of the journals are in good shape.

To bad these heads are not like a KZ1000 head, bearing shells.

Wonder if you could bore the journals for shells?

[tkent02]

Wonder if you could bore the journals for shells?

I'm sure you could, but where would you find bearings?

Really they last forever if they don't run dry.

[rustybronco]

Had another thought...

Remove the buckets, oil the journals in the head, hold a bit of 1000k crocus cloth around the camshaft, rough side down, and lightly 'dress' the high spots. The cam resting in the head should provide good alignment for polishing down any high spots.

Check often with plastigage and go slow.

[Guest]

With the spark plugs out and valve cover off hit the starter and make sure oil is flowing at a good rate and evenly.

[Footy.]

In my opinion after forty odd years in engine reconditioning, and hand scraping many such "pick up" areas of cam bearing housings, your pics indicate an "out of line" issue.

Any oil starvation would leave signs of tearing all around the housing, as would contamination. The position of the damage to one side of the cap is indicative of the cap being out of line with the head.

As has been said, the caps are in line bored. Could be the caps are mixed up? ( They are mated A for A, B for B etc) Perhaps an odd cap from another motor, or the dowels are missing or are not a good fit?

From your pics, the damage could be fixed by hand scraping provided there is no other damage to the cam/head. You do need to check out the alignment issues to try and find out why it happened.

Footy.

[jhillier449]

Footy:

Thanks for the insights. The head is a used one I bought as a spare and am in the process of fixing it up to swap out with the one that is on my 80 1000G now. I am using the cylinder block that came with the head as well, quick swap and I am back on the road. The cam caps were in the right places when I took the cams out, but who knows what happened in the last 30 years.

[Dreef1999]

I will guess the two cam caps on the right side are the two with the damage?

I think it is from letting the engine idle a long time on the side stand.

In my opinion after forty odd years in engine reconditioning, and hand scraping many such "pick up" areas of cam bearing housings, your pics indicate an "out of line" issue.

Any oil starvation would leave signs of tearing all around the housing, as would contamination. The position of the damage to one side of the cap is indicative of the cap being out of line with the head.

it strikes me that tkent has made a scientific hypothesis and prediction which was confirmed. Therefore his believed cause should be recognized seriously.

how long is too long to idle on the sidestand?

[Footy.]

it strikes me that tkent has made a scientific hypothesis and prediction which was confirmed. Therefore his believed cause should be recognized seriously.

how long is too long to idle on the sidestand?

I have no problem with tkents opinion as to such an effect, given the low pressure oil system. But given the "one sided" damage shown in the picture, my opinion is that in this case the cap has been tight in this area.

Of course slight oil starvation would effect the tight spot first, and as the owner has pointed out the history of this head is unknown.

Footy