Pitting in o-ring groove in JD 6-404 engine block - Options

Hello community! We are part way through an in-frame engine rebuild on a John Deere 6-404 6-cylinder diesel engine. My mechanic notified me that he found some pitting or chips missing in the o-ring groove of at least one hole.





This 4040 tractor will continue to be worked after the rebuild. It spends 6-7 days a week feeding cows on a dairy.

Can anyone with prior experience chime in with recommendations? I'm not comfortable with continue the rebuild before addressing this issue. I have a couple ideas in mind, but would like input from others that have traveled this road before. :)
 
J & L premier Auto Tea SD can replace the counter bores as needed for you. don"t know ware you are but there must be a machine shop some ware close that can do it. last ones i had done cost $100.00 per hole thats been 5 years ago
 
Here are a couple other shots showing the pits in the o-ring grooves (counter-bore?). I also included shots of a few liners. After further inspection, we now see 3 out of 6 holes have some pitting. 1 out of the 3 is not only slightly pitted, but chipped through as well.









 
Kent,
Can you explain how this machining is done? If you machine away to eliminate the pitting at the upper liner o-ring in the block won't this alter the liner protrusion dimension at the deck?
 
When I worked for a Deere dealer when we came across this
on a rebuild we wire wheeled it clean used JB weld and sand
it down with emery cloth to repair the pitting it takes some
time saved many a block this way
 
(quoted from post at 20:43:07 04/04/14) When I worked for a Deere dealer when we came across this
on a rebuild we wire wheeled it clean used JB weld and sand
it down with emery cloth to repair the pitting it takes some
time saved many a block this way

Same with the old Olivers and Allis Chalmers in the shop I used to work at.

Adrian
 
(quoted from post at 17:24:59 04/04/14) Kent,
Can you explain how this machining is done? If you machine away to eliminate the pitting at the upper liner o-ring in the block won't this alter the liner protrusion dimension at the deck?

This is exactly what I was wondering. How would it be possible to ensure that the standard length liners protrude within the correct tolerances? Hmm.

(quoted from post at 18:43:07 04/04/14) When I worked for a Deere dealer when we came across this
on a rebuild we wire wheeled it clean used JB weld and sand
it down with emery cloth to repair the pitting it takes some
time saved many a block this way

I've heard the JB weld method mentioned before. I've also heard stories of the repair only lasting two weeks, then failing under higher coolant temps.

(quoted from post at 18:47:48 04/04/14) I have fixed a few that way to. Seems more of a problem on 202,219 and 239's.The 329 in 2840's and 4030's were bads well.

How long did the repairs hold? Are there tricks to getting the JB to adhere, and tricks to sanding it down to the correct height?
 
I would not do anything but have it bored and put new counterbores in. You must use a machine shop that has experience with this. I had a case block done, he did the lower and uppers done. I would also have the block decked, he will need a new sleeve to recut the counter bores to get the right liner protrusion. I'm not a fan of reman engines, yes this will cost some money but you should have a perfect engine when your done.
 
J D Dave no the liner is set by the depth in the top of the block. the counter bores are cut out with a boreing bar a ledge is left in the bottom and a new counter bore is installed
 
In the 5 or so years I worked there none of the JB repairs
came back Has for getting it to stick make shore it is clean
one of the guys had a larger washer cut in half and put the
emery cloth on it I just folded
It a few times and sanded away
 
(quoted from post at 13:04:53 04/05/14) Those that use the JB method why not just put it in there
and assemble it quick ???

The idea of the JB Weld is not to glue the o-rings in, but to smooth the ramp so the pits in the ramp do not cut the o-rings. If you put the sleeves in before the JB Weld is hardened, you still risk cutting the o-rings. Let it harden, then sand it down to match the profile of the ramp. Cleanliness is key to a good bond, but usually the pits don't go below the line where the o-ring seals. In the rare case where that occurs the JB Weld needs to stay in place, but mostly it just needs to stay long enough to get the o-rings in place. In all the years I repaired blocks with this method, I never had a coolant leak. YMMV. Machining out the old ramp and pressing in a new ramp still leaves the possibility of a leak between the block and the new pressed in ramp (although very rare, I'm sure). So I guess it boils down to how much you want to spend.

Adrian
 
Yes, I can see this idea working,, though I have never tried it or needed to (Knock on wood),, and I have never heard of doing it the way Kent suggested,,and his way sounds good,,and at $100 a hole it is economical too, you can soon get a couple hours into repairing one with the J-B weld method,,and time is money.. I don"t know if any machine shops around here offer that kind of repair,,but I"m going to inquire about it so I will know,,I am also looking for a shop that can turn my 6 cylinder cranks for me,, my old shop called it quits and retired last year,,Darn it..
 

The "worst" looking hole has a place where the "pit" is more of a "chip" where the o-ring seat has eroded away to where the next lower o-ring groove is. I'm not sure how to make the JB or other epoxy "stay" in place until it hardens. Please see the picture of this spot below. I've also copied a page out of the John Deere factory repair manual & edited it to show where the eroded portion is.



 

I would clean that puppy with a wire wheel, then carefully clean even more with muriatic acid (don't breath the fumes!), then sand well and clean again. Apply JB weld to the spots. Let harden. Sand to match the profile and Bob's your uncle! Install sleeves and go. Just my opinion.
Good luck!

Adrian
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top