Cam journal wear

[jhillier449]

I am rebuilding a head for my 1980 gs1000G. When I removed the cam caps I noticed some scoring, attached is the worst one.

Is this serviceable? Can I give it a little rub with some emery or sand paper?

Cheers

John


http://s1112.photobucket.com/albums/k481/jhillier449/?action=view&current=CamJournal.jpg

 

[7981GS]

Response's coming.

I'll wait...
(Not enjoying the flaming parties of late.)

 

[jhillier449]

I did a quick search, but I needed an opinion on "my" cylinder head.

Nothing jumped out at me during the search to answer my query.

 

[Agemax]

is the cam scored as well? if not then buy a new cam cap, or a decent second hand one.
personally i would carefully dress it up and run it, making sure you have good oil feed to the head and there is nothing untoward up there that caused the scoring in the first place

 

[Nessism]

I'd measure the cam to journal clearance with plastigage. Half the journal looks okay so if the wear isn't too bad you may be okay.

Oh, and you should not attempt to swap around cam caps unless absolutely necessary. The caps are line bored to the head and should stay as a matched set with the head.

 

[Agemax]

with scoring like that plastigage will not give you an accurate result. what should the clearance be if measured accurately?

 

[hampshirehog]

As long as there are no raised bits where it's scored and the cam isn't toast that'll be alright. I've seen way worse run ok.

 

[jhillier449]

Cam itself looks good, so I think I will run it as is seeing this is the worst one and only on one side.

Maybe an opinion from Ray or Chef will cement it for me.

The more positive opinions the better eh?:lol:

 

[headsbikesmopars]

As stated above,..you should be ok as long as there are no raised burrs. Small grooves hurt nothing and actually hold oil which is good. you said the cam looked ok so I think you are good. Use a wheel cylinder hone and a variable speed drill with the cap torqued down and turn S L O W L Y . oil while turning . You only want to clean it up and not remove any material. I have used this method on aluminum overhead cam auto engines where the cam has seized completely . An easy fix. After the hone clean up, install camshaft with caps torqued. Cam should rotate easily and smoothly with no tight spots. No valves of course.

Terry

 

[jhillier449]

Thanks guys, great replies. This is my first head rebuild and a can't wait to see how it turns out. Got to clean everything, lap the valves, new valve stem oil seals, run all the threads.........

 

[1980GS1000E]

Two things to check: Oil pressure and oil supply to that journal.

 

[jhillier449]

Will do.

I guess I can blow some compressed air through the oil galleries.

Cheers

John

 

[rustybronco]

Everyone has an opinion so here's mine. Measure the cam journal first, then if it's within spec's, go ahead and plastigage the cam journal.

If you can find an old timer with a bearing scraper you can borrow, you might be able to remove any high spots, if there are any that is, without resorting to a light hone of the bore.

http://www.ebay.com/itm/Disston-Bea...690?pt=LH_DefaultDomain_0&hash=item19d0c729ca

 

[rustybronco]

(Not enjoying the flaming parties of late.)

Only tried to correct erroneously given information.

On the other hand, trolling cannot be tolerated.

I'll let someone much more knowledgeable than me reply.
PM sent.

Eric

Now, to the facts. Pictures don't lie, people do.



Is it just me or can you almost "hear" the "experts" leaving the thread?


People with zero actual personnel experience shouldn't be giving advice. Or should they?

 

[tatu]

Has anybody here done, or know of a refurb of this problem yet? because as time goes on and heads get scrapped for what is a theoreticaly a simple fix, ie; shell bearings we're going to run out.
As Nessism says the cam bearings are all matched pairs. the number of times I've seen on ebay heads without caps or vers visa.

 

[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.