1979 SC Chewed a Valve - Total Rebuild

[OsoMoore]

Originally Posted by mikedsilva

double nut and heat on the case.

Sounds good, time to acquire a torch and some gas. My initial research says to get a MAPP torch.

[targa72e]

Double nut can work most times. Best way is to use a Snap on stud tool with appropriate collet. I little heat doesn't hurt either.

https://b2b.snapon.com/productDetails/CJ500-1/2

This tool does a great job of removing studs without damage. You can get different size collets for all the different studs.

john

[draw]

You lucked out that the stud stripped and not the case, good for you!

A cheap propane torch is fine. Heat the stud until a spritz of water sizzles. Since that stud is toast, I would use some vise grips to remove it.

[OsoMoore]

I got the original stud out with double nut, still need to work on its inner neighbor that was damaged but not initially stripped.

I have a MAPP torch now, and can try with locking pliers tonight. Or stop and pick up a more specialized extractor.
There isn't enough good thread exposed on the second to enable double-nut because of the alignment sleeve.

I'm cleaning my rocker arms and barrels. One of the heads has some moderate pitting. Unsure if I need to replace it, or if it will be OK. My camshafts themselves have been redone by a shop.

[911 Rod]

^^^ I've replaced better.

[rwest]

I’m not sure, but would think that best practice would be to have the rocker arms re-bushed and faces restored?

I sent mine to Craig when I did my top end.

[OsoMoore]

Originally Posted by rwest

I’m not sure, but would think that best practice would be to have the rocker arms re-bushed and faces restored?

I sent mine to Craig when I did my top end.

Hmm, I didn't realize you could get the faces restored. Which Craig is that?

EDIT: Figured it out: it is cgarr at g2 performance.

Related question: If I borrow cam timing tools and time, will that end up thrown off if I pull the cams later to be re-finished? I think not, based on what is actually being set.

[Flat6pac]

Just a note, everything being in spec on the build, if the cams aren’t timed correctly, the motor will not run.
The shim on the stud will pull out with pliers if you twist and pull.
Bruce

[snbush67]

Originally Posted by OsoMoore

Hmm, I didn't realize you could get the faces restored. Which Craig is that?

EDIT: Figured it out: it is cgarr at g2 performance.

Related question: If I borrow cam timing tools and time, will that end up thrown off if I pull the cams later to be re-finished? I think not, based on what is actually being set.

When you reinstall or install any cam you will have to install it as new. Measure everything check chain sprocket alignment and set timing.

[OsoMoore]

Originally Posted by Flat6pac

Just a note, everything being in spec on the build, if the cams aren’t timed correctly, the motor will not run.
The shim on the stud will pull out with pliers if you twist and pull.
Bruce

Great tip on the shim. That should make the extraction easier. Thanks!

Originally Posted by snbush67

When you reinstall or install any cam you will have to install it as new. Measure everything check chain sprocket alignment and set timing.

I am planning a full timing operation of the cams. The challenge is that I'm borrowing the timing tools from a local shop over the weekend, but I won't have new rocker arms that soon.

My understanding is that I can time my camshafts with the current rocker arms. Then with the shafts set and chains permanently pinned, I can remove rockers and get them fixed/replaced. No need to borrow the timing tools again.

Is that right?

[callard]

You only need to install rockers on the intakes of cylinder 1 and 4 to time the cams. You can replace them later because the cams remain timed.

[PeteKz]

Yes. The wear is at the location on the rocker pad near max lift. That won’t affect the opening ramp of the cam, which is where you measure lift/timing. Then you can replace the rockers later.

I strongly recommend that you replace or rebuild those rockers for two reasons: 1. That pitting will continue to get worse and damage your cam. 2. The pitting is mostly to one side which indicates the rocker is out of line, probably die to excessive wear on the bushing and/or shafts. Inspect those carefully .

[OsoMoore]

Originally Posted by PeteKz

Yes. The wear is at the location on the rocker pad near max lift. That won’t affect the opening ramp of the cam, which is where you measure lift/timing. Then you can replace the rockers later.

I strongly recommend that you replace or rebuild those rockers for two reasons: 1. That pitting will continue to get worse and damage your cam. 2. The pitting is mostly to one side which indicates the rocker is out of line, probably die to excessive wear on the bushing and/or shafts. Inspect those carefully .

Thanks for the clarification and info! I'll plan to replace that rocker (we'll call it A).
Here are two other rockers B and C with potential issues as well. The rest looked pretty good.

B - Pitting at an inner corner


C - Pitting near a corner, and a nick at the top. Nick may be from bits of debris when the piston died horribly.

[OsoMoore]

Related question - are "triangle" rockers functionally identical to mine? Looking at replacements for my bad ones.

[Henry Schmidt]

Some of those are not rebuild-able but for the ones that are:
Supertec offers a rebuild program that is unparalleled.

BTW: Rocker are rebuilt in batches and sold on an exchange basis. Like for like.
That means they are generally on the shelf ready for immediate shipping.

We remove the old bushing and adjuster (if present)
Clean adjuster threads with 8x1.0 forming tap.
Ream the bushing hole
Black Oxide the rocker
Press in the new DP4 bushing and burnish
Surface the contact pad
Coat the contact pad with Moly dry film (TLML 2)
Treat the rocker to a Cryogenic conversion process




Forged rocker reconditioning
Media blast [Potters AD]
Remove bushing
Ream rocker to size for DP4 bushing
Press in new bushing
Send out for hard chrome face
Aluminum oxide blast chrome face
Apply Dow Molycoat dry film lubricant
Bake at 250 for 2.5 hours
Clean adjuster threads with forming tap
Drill oiling hole and deburr
These are not cryo treated because we have found no benefit to cryo on forged steel.

[OsoMoore]

Does this one look recoverable? Trying to figure out how many will need replacement vs just refurb. I missed the defects at first, until I looked up close with a bright light.

[OsoMoore]

Got five replacement rockers from another Pelican. I'll plan to send the set out for refurb later. But these should be fine for finishing the rebuild. Ice comes in November and I can pull them out then.

As I recall, I can get them out without too much trouble just by removing the valve covers.