Saw pix of this before somewhere - searched to no avail.

These are from what I'm currently wrenching on:


Rocker arms have some galling on the pressure side.


Trunnions exhibit similiar features, wear on pressure side is right at .001"

What's acceptable wear on these?
Won't polishing the rocker bores and trunnion ODs to remove the galling be fine, especially in addition to HPC-coating the trunnions?

All rockers & trunnions show more wear on their rearward side than the front - any ideas as to the cause of this phenomenom?

 

I think Ty(Tritont) posted some pics of some wear on the rockers.

 

According to the service manual, It's not uncommon for the rocker lever shaft to have a polished appearance.

these are the specs :

Rocker Lever Bore

Maximum - 22.027mm /0.867in.

Rocker Lever Shaft

Minimum - 21.965mm / 0.865in.

this broken tip I posted is apparently very common as it's also mentioned in the manual to be inspected and replaced if necessary. You have to replace the whole rocker though cause just the tip and keeper can't be purchased.

 

Thanks Ty - I like the polishing, it's the significant galling that's ... I'll try to get RJ to approve a sacrificial coating.

 

Funny how this seems to be popping up all over right now...

I'm in the middle of doing injectors, springs, cam, etc right now, and found some disturbing things.

I began looking closely at the rockers, and they exhibited alarming wear for only 57k miles. The wear is all on the lower 180°, and is primarily confined to the "inner" portion of the rocker, if that makes any sense.

The pin in the middle is diagonally bored for oil passage, and has a circumferential ring roughly an 1/8" from the end. The hole that feeds the ring is on the bottom of the pin, and seems to provide adequate oiling...to the outside of the pin only!

I'll try to get some pictures, but from the ones Mike posted, you can see the small black line on the rocker from the circumferntial ring on the trunnion pin...and on mine, the wear was minimal at this point. However, the 1/4" or so of the pin toward the inside had some significant galling/pitting/scratches. Because the wear is much less where the oil ring is, it would appear that there is a lack of oil on other pressure points of the pin.

Mike, since you're into the same thing right now, I'll try calling to discuss some ideas...

--Eric

 

Mike,

I would be willing to do some free of charge coating on these parts for testing. We are using this coating on some other engine parts with great success. It takes some time to apply and get set up though. In other words, I cant turn these around in a day or so. I would need more time.

 

Hey Don,

I'm sending my injectors to you this week through Timinva for upgrade to some Flux 2.5s.

I may be willing to try to coating if available as well. I've got a few other questions for you too, if you have a chance to call...

865-567-3508

Thanks Don, Eric

 

Thanks Don - that's a great idea.

I'm not in a rush to get the bits & pieces back, since I'm taking the head to Raymac tomorrow.

Sacrificial coating didn't fly!
So, I was thinking of using a tungsten disulfide coating (same process we're looking at for the G56 internals) - but I trust your judgement if it's different.

Do you want the rockers & the shafts?
Let me know what you need and I'll send them over.

This engine will make a good test-mule, since I'll be leaning on it pretty hard for the foreseeable future, and it's had a pretty bad oiling history.

 

Nice talking to you Eric!

I think the rocker shafts' additional annular oil grooves & cross channel to lube the insides of the bearing surface can only help, but the dry-start wear issue remains... I'll keep your solution for that on the QT.

 

Funny, I have the same problem.

 

Send 'em to me Mike

 

Thanks Don - FedEx is my friend.

 

Finally, after 2 months we got them done!

We had to be careful not to remove too much material during the surfacing phase, but they turned out great considering how bad they were before.

We surface finished them to get a good smooth finish and coated them with a durable, low friction coating. They are butter smooth in the rocker arm now. Very nice.

First photo was taken pre-coating. You can see most of the wear scaring is removed. Second photo is a closer pre-coat and the 3rd is after the coating is applied.

https://www.dieseltruckresource.com/...hp?photo=37465

https://www.dieseltruckresource.com/...hp?photo=37466

https://www.dieseltruckresource.com/...hp?photo=37467

 

very nice Don. Is this something you're going to start offering ?

Will it be just what you described... shafts are sent to you or your dealers for refinishing or will they be a kit ?

 

Don, I may be interested in this as well. Did you clean up the existing rockers and re-use them? If they're like mine, both the trunions and the rockers exhibited scarring/galling/wear.

Merry Christmas to you and yours...

--Eric