No, I just choose the easier way

 

I'd be interested in knowing the plastigauge reading from the top of the crank journals. that's where they wear the most and I'd hate to see him go through the motions and find his journals are out of round.

 

too much oil clearance there.

 

I doubt it. I'll bet he's a virgin.....doooh!

Good point, Kirk. It would be simpler to mic it, but if one ain't got the tool......plastigage.

On second thought, all one would have to do is note the wear pattern on the bearing surface.....atleast, that's what I'm thinking.

 

a dial gauge micrometer would definitely tell him if the journals are out of round.

to be honest, I've only used plastigauge when determining the what size bearing I need after having a crank turned. I always use a mic to check the journals, but only if the bearings are showing noticeable wear or if the oil pressure at idle was less than 5 psi above minimum recommended.

 

So, you want me to re-install all the cylinders and use the plastigage on top of the bearings? I'll do one, not all

 

Do two.....at cyl. 1 and cylinder 3.

 

the truck's on jackstands, no?
you don't have to reinstall the pistons, just turn the crank so that the rod journal points at the ground and let the rod and piston hang down towards the ground. it'll be a little beatch tightening the bearing caps, but you don't have to torque them, just get them tight.

and check every rod that has the copper showing in the bearing.

 

Yeah, right....you might miss the one that's out of round...hahaha!

Interesting technique, Kirk. Where'd you learn that one? (No, I'm not being sarcastic...)

Wouldn't not torquing them to spec give an inaccurate reading?

 

And, Kirk.....you really must tell me what you wrote in Spanish in that other thread. PM me, if you care to share. Sorry.....I just have to know.

 

lol... what did I write? hehe.

anyhow, learned the technique with the plastigauge from a fleet maintenance mechanic. he used it in the field doing in-frame rebuilds on big Cummins diesel engines. great engines actually- you can buy a new matched set: piston, rings, rod and cylinder separately; and basically have 1 rebuilt cylinder. The only uncertainty was the rod bearings.
you just use a 1" piece of plastigauge. any longer and it'd be pulled and stretched as the rod and bearing are pulled together around the journal.

as for the torque- the bearing cap doesn't get any closer than touching the rod, which means for the plastigauge it only has to be tight. All the torque really does is tension the bolt so it doesn't pull out of the rod when the rod hits tdc on the exhaust stroke.

 

Ah, so why do I need to check all of them if all the lowers are in a tad bit out of spec?

Also, I'll just reinstall the pistons...as that seems much easier than your technique...

Anyway, copper is showing on all 4...just like the pics

 

Ring a bell?

https://www.yotatech.com/forums/f116.../#post50850211

 

ok...
imagine a hammer pounding on a steel bar... won't the side the hammer keeps hitting become flatter?
now picture your piston and the top section of the rod as the hammer...
getting why you should check the top side?

we're just trying to prevent premature failure when you get it back together.

so here's the compromise- get a full set of standard sized tri-metal bearings and plastigauge them. if the clearance is .001 - .002, use them and the problem's solved.

the more I think about it, there's really no point in gauging your worn bearings- you don't know anything about how much is worn off them. so how can we tell if the excessive clearance is from the worn bearings or worn journals when they're both worn?

 

how nice... you're a great man
and, matthew, you can speak (or say) "allan. friend. you have a good heart."
where is the bathroom?

 

Oh my god...I just replied and now its not there...I LOVE redoing this crap

 

Ooohhh, I get what your saying. I guess we will find out when I get some standard size bearings...we all agree on that right???

When I get the new ones I should plastigage the bottom AND the top right?

 

yep- top and bottom, do them separately though. and if the top is looser than the bottom, you know the journal is flattening out at the top and needs reground or replaced.

 

I'd asked a couple of different people about that when I rebuilt mine.....wondering whether or not I should mic the crank. The way it was explained to me by a fellow who's been building engines for long, long time...(I'll do my best to relay the info)...was that the plastigage tells the whole story. Regardless of which are worn, as both the bearings and crank will be, you have a tolerance. Changing one side of the equation....in this case, the bearing inserts... still gives you a tolerance whether or not the journals remain as they are or are machined. Change the bearings to a tighter tolerance and you still have clearance. Only now, it's a bit tighter than what you had with a worn bearing. So, if the crank is not out of round, put in an oversized or standard set....whichever you need to bring the clearances back within an acceptable range....and you're good to go. But, like I said earlier, the crank shaft is less prone to wear than bearings given the nature of the material each is made from......designed that way.

Soooo....I think the only question here is whether or not the journals are out of round. Needs to be checked, I suppose.

Hope that made sense...

Well, I did mean it. Allan is a good guy and people give him so much caca. He just takes it all in stride, and I admire that. If that causes you the urge to visit the bathroom, well....take plenty of toilet paper with you. That's just how I am.

 

You guys never make sense

Yeah, I get what your saying. How much is the dial tool to check it? Wouldn't that be easier?