6v53 reassemble

Zuffen wrote: Wedge,

Can I suggest you clean up the Liners and take them to a machine shop/engine reconditioners and have them measure them with a proper bore micrometer.

It may cost $50.00 but well worth it to save wasting a bunch of cash if the liners aren't in a usable condition.

yep that's the plan - engineers shop in town has the gear so will be taking them there when ready. Won't charge hopefully as am a very regular customer...

Some idea of US pricing for GM stuff here, some bits look pretty cheap.

www.detroitdieselpartsdirect.com/detroit-diesel-53-series-parts

Paul

yeah they're prices are always depressingly good. But our dollar is getting worse cf the US, would have thought trump would be crashing it but oh well...

Anyway I did some measuring a couple of days ago on what I'd honed/cleaned up. Pistons are well within rebuild spec, big ends just (although didn't tighten the caps much so I think it would have got better). They couldn't find the right ball gauge so couldn't measure piston pin bush...

The liners I salvaged however are not within spec, they're fairly round (ORO 0.0013 max 0.003) but on avarage 0.019" under size - giving on average 0.027" of liner-skirt clearance, book says 0.012 max (rebuild spec) for a turbo. It didn't really seem to vary between ones I'd honed a little and ones I'd honed a fair bit more. I'm guessing 25 thou wouldn't be too flash? Old mate at the shop said 14 and over produces horrific blow by but he was referencing landcruisers and I'm not sure he was familiar with GM pistons with their lower oil rings. Would it really burn the lube with 25 thou? I guess Liners are $120+ meaning a pistonless kit is $252 or $1511 total. It seems a bit crazy buying all new parts apart from reusing my (slightly) ugly pistons, even if they are in spec. I'm now trying to get a better price in a P&L kit as cutting edge's $2442 (inc) is too much for me, plus I'll need all the gaskets etc.

Before I actually commit I need to roll the block over and have a good look at the crank too, maybe get some plastigauges. But for that I have to fork a heap of stuff out the way, get the blitz started (so sort out its zero oil pressure issue) and squeeze into the back of the small shed with the oversize tractor... It's great shoe horning bits of a project into various random spaces

Hey mate, I'd check those measurements if it was me. I feel it's highly unlikely if you have less than 3 thou out of round to have that much bore clearance. Most wear will occur on the thrust side of the Pistons and liners. 53's mabe but generally Pistons are not round either and need to be measured in the correct spot on the skirt.
Don't worry to much about piston/rod bushes they only ever see load in one direction basically so a lil wear won't matter. If it were mine I'd just re-ring ,new gudgeons and shove it back together, can buy a lot of mono 40 for the price of new p and L's.
Ps. Possibly should have new rod bolts also.

Thanks for the prompt neily, your post also got me thinking about another test in the GM manual. They say to find a feeler gauge the pulls out of the liner/piston with 6lbs of force and the clearance is 0.001" more. So I spent a while doing it and between one piston and three liners it's in between 0.008" and 0.009", and that's at four points each liner. So based on these measurements I'm actually feeling a bit more positive about my parts stash and maybe reusing is realistic! Might put the extra effort into cleaning up all pistons and liners and doing a more thorough measuring, then pulling the crank have a good look and if all ok going for an order of seals and rings/pins (mine really are ordinary I think) etc..

Have been thinking about rod bolts - so it's standard practice to put new when putting a 53 back together?

Wedgie, I reckon you should just put it back together with a new set of rings, gaskets and seals and see how it goes. Keep in mind that it was running before it sat and that these engines were a 1930's design built with technology from the 60' and 70's and many are still screaming their guts out in military service. They were designed to be tough and run in less than perfect conditions. I mean, how often do you hear about a GM having a dead cylinder or two and still screaming away happily? Now think about a modern Volvo engine meeting Euro 6 standards with a dead cylinder. I know what I'd prefer. Keep up the good work.

You're a good enabler DD... Reckon I just need to check crank and cam condition then the epic clean before reassemble. Would like to get it acid bathed but not going to happen. Am thinking steam cleaner, compressed air and parts washer for the small bits

OK so I've just been through my cranks - not as good as I thought... The one in the turbo crank is all good apart from big end journal where the masking tape used to protect it has harboured rust. Quite a lot of it too... Hit it with a wire brush and it's not superficial. Shame as everything else looks good, and still supports the story it had 300hrs into a rebuild. Bearings are std and hardly any ware.

Max available undersize bearings are 0.040", so question is - will that clean up this rust? What's the going rate per journal for somewhere like Dubbo?

If not one of my donor engines has a usable crank, but would need most journals regrinding as big ends have light surface rust and mains are scored. It has 0.010" bearings and I think would clean up. But it's a 1979 N engine, would the crank be the same or usable in a turbo?

I would clean that up with fine wet and dry (~1200) with kero / diesel and then see what it looks like. I'll admit it doesn't look good as is.

Jarrod.

asw120 wrote: I would clean that up with fine wet and dry (~1200) with kero / diesel and then see what it looks like. I'll admit it doesn't look good as is.

Jarrod.

by the depth of it, I'll be at it a very very long time with 1200... I guess a 40 thou cut takes a lot off though? I assume there's no harm in having one 40thou bearing and the rest standard?