rocker arm shaft wear

[robmog]

how much wear is acceptable?
mine range from #1 light polish
#2 smooth yellowish discoloration
#3 roughness you can feel
i see on searching some suggest rotating the shaft to change the load surface.
is #3 still usable?
engine is a 72 e 2.4 mfi. was rebuilt once before my ownership.
thanks

[Flat6pac]

I like to have a smooth side but I like to have it smooth all around. There is enough of these floating around available used there is no use of fooling with rough shafts. As long as the oil was there I dont see any problem with finding a new bearing surface.
Bruce

[hcoles]

are you putting in new rocker bushings? On my rebuild many of those were worn. I made some and my machinist honed to exact fit.

[robmog]

rockers have already been rebushed by cgarr.
i plan on replacing any with a rough surface.
probably the right thing to do.

[Mark Henry]

I'm starting a rebuild on a '79SC 3.0 that's going into my 914, I also have a 69T 2.0 and 75S 2.7 core.

Are the rocker shafts all the same?
Are the rockers all the same ? (This is the real question)
Are the adjusters all the same?

If yes then I'll pick and choose till I have the best set possible.
Thanks

[BURN-BROS]

Bob,

Dispose of any shafts that require removal of material in order to renew the surface. This is more important on Bronze bushings than the teflon.

Check for splitting at the ends of the shafts. This area is designed to expand and as a result can fatigue after years in service.

Mark,
stock 69 rockers are flat black in color and have no bushing. These are to be avoided if you do not have an appropriate shaft.....and the bearing surface is usually shot anyway. They would require machining to install bushings. Most of these cars would/should have been updated years ago.

The design of the rockers are the same up until say a late 3.2. Then there was a small change to the adjusting end of the casting.

Oil choices are not as they once were, so take care when you buy.

or you can travel down this road. Hardened tool steel shafts and needle bearings...

[camgrinder]

Originally Posted by robmog

is #3 still usable?

Doesn't look good. I junk them with more than .0003" of wear. Probably toss 3 or 4 out of every 100 I inspect. turning them can work in some cases, but like already mentioned you can find a good used one.

[JFairman]

Just a little fwiw trivia...

The old R series air cooled BMW motorcycle engines also had cast iron rocker arms with needle bearings on the rocker shaft.
Been a long time and I don't remember the dimensions but I remember the rocker shafts were the same diameter as the M10 and M30 4 and 6 cylinder automobile engines of the 1970's.

[robmog]

aaron,
thanks for the advice.
i'm using the 2.4 crank and rods you sold me(about 3 years ago!) in my rebuild.
bob

[BURN-BROS]

Originally Posted by robmog

aaron,
thanks for the advice.
i'm using the 2.4 crank and rods you sold me(about 3 years ago!) in my rebuild.
bob

Ah! I forgot about that. LOL, It's taking me about the same amount of time to get my engine going!