Balance shaft bearings

[pdub]

Rebuilding my 4d55.

My machinist installed the balance shaft (silent shaft) bearings into the block today. They are a split bearing design (from ITM), and I can feel the seam with my finger. Is this normal? It just doesn't seem very round!

His installation method was to put them onto an adjustable tool and hammered them in. Was he supposed to ream them smooth afterwards?

Warme - do you have any tips on installing these bearings?


Thanks

pdub

[mikewarme]

Vannoy, The diesel bearings are same as gas engines. I have the correct silent shaft bearing installer. Now very important. Did you MIC the silent shaft at the nose and the journal?? They are always undersize which will cause the following....... Lower oil pressure, Leakage out the front of oil and more slop in the front resulting in the wear gewtting worse faster and faster. I just sent out 4 sets of silet shafts for Chrome plating on the Journals. We ground them first. When they come back we will grind the chrome to spec. They will never wear again. Also check the oil pump shaft that turns the right side silent shaft. If it has a groove in it, National makes a repair sleeve for it. I am working on a fully documented write up on the silent shafts and oil pump rebuild with Photos for others. Don't overlook any detail on these engines. YOU WILL BE SORRY. THEY WON'T LAST IF YOU SAY GOOD ENOUGH.

[wrngwae]

Don't overlook any detail on these engines. YOU WILL BE SORRY. THEY WON'T LAST IF YOU SAY GOOD ENOUGH.

and how!!!!!!!!!!!

[pdub]

Well, I tried to take some photos, but the end result was they look like round bearings.

It turns out the "non roundness" I was feeling with my finger was where the seam was ground down. In a fit of paranoia I got worried and asked for advice here.

But when actually putting the silent shaft in, I find it turns very smoothly.

Warme - I measured the journal with a caliper and found it to be within spec. I did not measure the front end journal (or 'nose' as you say), though.

How serious does the groove in the drive gear need to be to require a repair sleeve? I think I could feel a little variation in the surface with my fingernail, but I don't have a measurement. Do you have a part no. for the repair sleeve? How about a sleeve for the rear main seal?

I guess that brings up the topic of oil seals. The manual mentions using a special tool with a kind of cone shape to ease any seal onto its shaft. How necessary is that tool? is it OK to simply lube everything up and work slowly?

Your point about not overlooking any details is well appreciated - but since this is my first rebuild, I am not sure where being conscientious ends and becoming neurotic begins. For example - should I send the crank out to be nitrided? Should I balance the con rods? Am I installing the seals correctly? At some point I do need to stop and say good enough, and then when it fails later on down the road I can learn from my mistakes. (And I'll probably think, "I was told this would happen if I didn't do X.")

Thanks for your advice.

[mikewarme]

I personally use pipe couplings of a matching size to tap my seals on. Just keep them square. Balancing and nitriding isnt necessary. But checking the nose of the shafts is. New drive gears for front of crank cost $26.00 cheaper than the repair sleeve. The rear crank will need a sleeve. $30 at rockauto.com
The silent shaft drive gear will need one at the oil pump. Same cost. Fix those areas. THEY WILL LEAK!

[moparducati]

This aint about the bearings but I hate to start a new topic just for this.
Anybody know what size plug goes in the side of the silent shaft housing? previous guy had a bolt crammed in there and after about 1/4 turn it fell out... I can't believe it didn't fall out while I was driving it!

plug.JPG

[mikewarme]

I have them new Nos 7.00 shipped

[moparducati]

think I can get em locally? or are they some oddball plug? are they metric pipe?(if there is such a thing) or something else?