6v53 reassemble

Get the journal ground down to an undersize that has a reasonable surface. Even if there is still a few small pits, it will be ok. If it is still too bad, you could get it built up and ground back. Up here in Mackay, the going rate for a crank grind is $30-40 per journal.

Thanks dieseldog, I'll go with that. Is there any reason I can't leave the good ones standard and run the bad one with oversize bearings? I see they are sold in complete crank packs in one size but they're not expensive

The crank would be out of balance as the bearing shell would weigh less than the metal removed from the crank.

it may be cheaper to grind them all rather than rebalance the crank?

I have yet to see or hear of a truck crank machined all over and balanced down to milligrams, let alone re-builders weighing and matching con rods. As substituting steel/iron for copper/whitemetal would result in :blush: ?? weight wise I can't see the point of worrying about it.

The "best practice" would be to grind the 3 big end journals to the same size, and if your buying the bearings for 1, you may as well fit them to all 3. However, I don't see a problem with just doing 1. Balance wise, the weight you take away from the journal will be replaced by the extra weight of the undersize bearing shell.

We obviously live in a very different world down here! I've done some shopping around and best price is $500 for just the big ends which includes $135 of mandatory crack testing, some wanted $700 without crack testing... And closest is Tamworth at 220km away so I have to get it there and back.

But then I realised I'd been overlooking another donor block I have as it looks really nasty around the head gear (as in rusted solid). But I flipped it and bottom end was nice and oily. Pulled the bearing caps and it looks pretty good - nothing spun, all bearing surfaces pretty nice just the odd rust line from the bearing edges that will clean up fine I think. Mains are 10thou and big ends 20thou with some ware on the bearings but nothing too bad. Will give it a good clean, measure and do a spray can crack testing.

But it's an early NA engine, I'm not even sure if it's even an N. Can't remember numbers can check them later. It's been upgraded to 7 hole bearings at least, so maybe other stuff... So the big question is will it be OK to use in my turbo engine? Were turbo cranks different/stronger?

EDIT - just found s photo of the numbers. The crank donor is a 5067-7041 6d82701*. Don't have a book in front of me so not sure where these put it...

Well of course it was slightly too good to be true... So after going over the latest crank with a rag there is one pit that I know won't clean up fully. I can polish it but there will be some left for sure. Given the context of the engine, how foolish would I be to use it with this pit? I could smooth the edges so it doesn't catch an edge or anything and can polish all the other stains out but otherwise just not sure...

I think ya finding all the reasons why these gadgets were not still fitted into their respective operating positions.


Pick the best looking of all the junk, buy a great big tube of silastic and smack it back together..

As long as the expectations arnt too high...
If it fires and makes oil pressure, you might get a run out of it..

If it goes bang in the first 10 minutes, you've only wasted time and a heap of typewriter ribbon..

If that isn't on the very top of a crankpin, I wouldn't worry about it. Even if it is, it's just something to keep in mind. Oil pressure should keep the bearing shell off this, anyway.

Chocs has a point here. One that I've used with good effect before

Jarrod.

Mate, unless you want this motor owing you more than what you could buy a decent ute for, I'd just whack a set of rings in it. I've done exactly that to an 8V71 about 8 months ago, and I'm doing it to an 8V92 right now. The 8V71 cost me about $12-1500 to do. The can shafts in it didn't look perfect, but it runs very nicely doesn't blow smoke, and has minimal oil coming out of the air box drains. Before I did the rings, it almost covered the lh fuel tank on a cab over KW with oil out of the exhaust.
Unless you've got a really good reason to have a reco motor, just keep in perspective that it's a hobby.
And another secret too, not that it's too much of a secret, the naturals sound heaps better than the turbo motors.
Give the liners a hone, new rings and big end bearings, and put it back together.