To Bore Or Not To Bore????
 

I'm replacing the Cracked 53 block in my truck finally!:yeah: I have a complete engine out of a bus, that has the stronger Mexican block. I want to completley rebuild this engine before I put it in my truck.
My question is would there be any performance gains by boring the cylinders? I'm thinking the added displacement with a helix2 cam, and a port/polished head, might help with cutting down on low boost smoke, and maybe lowering EGT's.
That leads me to my next question about pistons. Cummins pistons, or aftermarket? in what ways would an aftermarket brand of piston be better than an OEM piston? I'm also thinkin getting the pistons thermal coated.
sorry for the long post, I'd appreciate any input!:U:
Eric

IMO, and I am NOT an expert with Cummins, but I would think that boring them would only help, if you did everything. I believe you should thermal coat them. and as far as the diff between after makrket or OEM cummins pistons? IDK...

:w2::humm::pca1::U:

if your gonna go to that much trouble mite as well go with alumatherm pistons and carillo rods, and a full stud kit for head, rods, and mains, and boreing it out seemed to help my friends truck, but his truck is insane, [ more money than sense ]:c:

What are the advantages of alumatherm pistons??? (I'll do a search on them as well) In what department did the boring help you're buddy's truck, smoke, EGT's, power?? and how far did he bore his engine?
It seems to me as well that boring could only help, I read on another forum, that the bore to stroke ratio on our engines is better left alone. :humm:I'm just tryin to get as much input as I can. Keep the advice coming!:c:


Eric

Stock these pistons are insanely big and sweat torque already, I just don't see where the need would be to bore em unless you were lookin specifically for a sled puller or somethin. Just my uneducated opinion.:humm:

There's no performance gain to boring one of these blocks unless going low compression for meggaa big numbers (1,000+). Unless the block is scored or has damage just do a light hone on it and use factory pistons!

There's very few company's that design parts of the quality that the factory 5.9 carrys.

Rod's and crank are normally much stronger than aftermarket in the Non 3rd gen trucks.

If I remember some of the 3rd gens had some issues!

THERES A PILE OF TRUCKS MAKING 900+ on stock internals!!

#1 has some scoring, I can just catch the score marks with my fingernail, #6 has some visual score marks. the rest look fine and all of the pistons are the STD. size. I'm thinkin bore .010 and get 6 pistons from cummins, and get 'em thermal coated.
I did notice what looked like copper shavings on all 6 pistons, can anyone explain that? when I pulled this engine from the bus, I did see signs of dirt entry in the intake.
I really appreciate the input!

https://www.dieselbombers.com/genera...d-pistons.html

here is a good place in FL that i found for coating. might be worth looking into as the price seems real good.


copper.... couldn't that be valve guides?

Yes , Probably valve guide. Mahale makes a great piston as well! The coating is well worth the extra money!
10 Over will probably get it. Some try to just hone them out but in that case I would say bore it!

Valve guides, dunno why I didn't think of that. :argh:I did find an outfit here in Denver that does ceramic coating, so far I've heard nothing but good things about them, The outfit in FL would cost me about the same after shipping, BTW they do look like they're top notch! Havn't been able to find a price for Mahle pistons yet, I'll check with the guys at the machine shop when I drop the block off hopefully next week.