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I'm doing a full rebuild using the the original piston heads. I've never burned oil and my motor was at 230xxx miles when pulled. Is it necessary to hone if I'm going to install new rings? Should I install new rings?
ABSOLUTELY NOTHING as of yet. I have just lined up a new crank/rods (oem) and will be reassembling soon. Just trying to decide if I should do the hone/rings or just bolt it back together.
I'm a sponge for your knowledge.
It's kinda heartbreaking to see guys all thrilled and excited to be assembling things but now--2013---know that crap we could do 20 years ago just barely--like pop open motors and freshen---we almost never can do anymore..
So that said..
You need to clean the ring grooves out absolutely spotlessly but you cannot be brutal to them. The finish and especially the fit is one of the absolute most critical things in the whole engine right up there with the con-rod big and and mainline ID sizing.
A LOT of things you can "get away with"--like cylinder wall clearance.
But "ring side clearance" is something that has to be right and you cannot fake it..
With a NEW ring in the germ-free all minty fresh groove the MAX side clearance is .004"
More than that and the ring face will not be held square against the cylinder wall.
If the ring face is not square, combustion pressure will go in the little wedge created and it WILL push the ring back into the groove and you'll have blow-by..
And hate life.
So, have the machine shop in your presence dial bore gauge the cylinders to check for size, roundness and taper.
I use gallon cans of Carb-n-Choke cleaner and dip the pistons in for a 3-4 days--soemtimes more.. A B21T we're building now had maybe 300k miles and they were so full of baked on carbon it took 10 days...
Use a section of your old rings , the finished end---to clean the goop out. then measure with a NEW RING...
When you find ONE piston that the side clearance is over .004, the set is fuxxored, and you need new pistons--and then need to budget to bore it..
Rosta ruck finding stock new cast pistons..Again, 20 years ago it was easy.
Now, custom forged is the answer..lucky for you you know somebody who supplies custom forged pistons that are the best available...me!
And if you are gonna reuse the old pigeons and not rebore then absolutely you must hone.
If the bore Is nice and straight and in really good nick you can get away with those bottle brush deglazers but for best results a proper three stone hone is the minimum.
WIthout deglazing the bores the New rings will probably never seat properly.
And if you are gonna reuse the old pigeons and not rebore then absolutely you must hone.
If the bore Is nice and straight and in really good nick you can get away with those bottle brush deglazers but for best results a proper three stone hone is the minimum.
WIthout deglazing the bores the New rings will probably never seat properly.