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Piston to wall clearances
#1
Alright let's dive right into this. My block is stamped 2222, so all my bores should be..74.98ish mm , they currently measure 75.050-75.06mm , so the engine has some wear on it. I cant even see the hone marks anymore. I have a new set of pistons that measure 75.02 mm. Im on the fence here,I seem to be right at the threshold of needing to have the engine block bored, I know the clearance stated is for NEW from the factory tolerance. What would you all do,I have the engine out everything stripped down,so if I were to get it bored nows the time. Just have to get new pistons then take it all to the shop. This by the way is the same motor that LOOKED like it was religiously taken care of,until I got all the way into the crankshaft to find a missing journal bearing. So the crank is being replaced /fixed. So I'm really tying to decide if I should just put the block in the shop,or Roll on with "standard" pistons. Any thoughts?
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#2
(08-08-2016, 09:29 AM)Helluvarush Wrote: Alright let's dive right into this. My block is stamped 2222, so all my bores should be..74.98ish mm , they currently measure 75.050-75.06mm ,
so the engine has some wear on it.
.08mm clearance there, but what are the delta's the out of round and taper. is .08mm max for all 16 measurements.

what is the out of round measurement and what is the taper. ? new rings, will not seat for for those wrong.
all 4 holes have these numbers. and all matter in the decision, think of it as 4 engines.


I cant even see the hone marks anymore. I have a new set of pistons that measure 75.02 mm (not spec why?). (not oversized, ) why buy std size new pistons? sounds like imported piston that are crude,.. why? who's name on them, "som ting wong"?

why do this backwards, ? pistons bought are dead last.
if you decide to bore, then the boring guy measures all the things you skipped, then says, you need xxxx size pistons to get a clean matching bore.
there is no other ways, cept honing, or he says, i can hone this and not break the .04mm max clearance rule.


Im on the fence here,I seem to be right at the threshold of needing to have the engine block bored, I know the clearance stated is for NEW from the factory tolerance. What would you all do,I have the engine out everything stripped down,so if I were to get it bored nows the time. Just have to get new pistons then take it all to the shop. This by the way is the same motor that LOOKED like it was religiously taken care of,until I got all the way into the crankshaft to find a missing journal bearing. So the crank is being replaced /fixed. So I'm really tying to decide if I should just put the block in the shop,or Roll on with "standard" pistons. Any thoughts?
stop
now the clearances are for using only suzuki parts, and only on a new block or bored new with new real Suzuki pistons
but we dont use those now, after 20 years. or more,we use aftermarket pistons. and bore it to an accuracy 10x better that any suzuki factory
ackfaq ,moved all his files, (again) but here it is.
http://acksfaq.com/2016bp.php?urlname=ht...kerfsm.htm

chapter 6a:
the 2222 code is telling you have badly they bored those bores back then., its pistons sizes sub, error code.... new pistons are 1 size per each grade
and perfect. as are all new bores, in a machine-shop prefect to less than 1 thou.

74.98 that number is how small the piston can be. not largest, 74.99 is largest, and wear , wins what it really is.
the bores were. 75.00 or 75.01 day 1,
the clearance was .02 to .04mm day 1 (code 2 holes all) (max is ....
those are the facts, from day1,
so we measure the bores in 4 places (pg45), 90deg apart, top and bottom,(not the top ridge, just below that ridge , we remove ridge first or the new rings will be destroyed not bored out. measured in the ring swept regions, per page 45.
the silly fsm , the data (spec) is dispersed in the text, not all at the end of chapter, sadly ..
75.15 mm is the limit. BUT
if the out of round or taper exceeds .0039mm it must be re-bored. this rule make new rings seat, honing most times cant cure this. error. is what they are saying. (page 46)
do the 16 measurements and the answer is before your eyes, 3 might be ok and one cylinder on the top and trust side my be out of spec.
engine turns CW facing crank snout, so trust side, is right side standing there. the wear side. (the machine shop thinks that as he measures,there first. saving time,,,, omg, look here .005mm out of round, over spec, no need to check further, and does#4 first, the hot cylinder,,, )


these set of 4 x 4 measurements tells use all things, ID inside diameter, top and bottom and taper and out of round. the out of round is a big deal for new rings.
the machine shop does that and the he says "you need xxxx size pitons to clean up all that wear and be round again" 0.25mm oversize cleans most up
but only the bore tool proves that.... 16 checks.
that is how its best done.
other wise hone it and stuff in new rings,
Ch.6a page 64 has more numbers there. "clearances" (ex oversize pistons sizes are there but useless for new aftermarket pistons, they be more prefect)

if he bores it....
the new pistons will be more accurate, for .25mm OS, and that pro machine shop measures them all first to be sure they are,
then targets the perfect bore size for the NEW PISTONS, and numbers he found there. on them. (they are not round they are cam ground. )
measure them off the bosses. (pin holes) low down.
the target new clearance is in the book.

lets talk new pistons, .25mm OS, the maker of said piston has a name and a product number for said piston
and he publishes the prefect clearances on those new pistons, end to end. (ring gaps. lands , all)
if savvy use his rules, not suzuki. see why,
answer, its his metallurgy.! (his expansion rates, rule this...)

Suzuki spec for piston clearance, is .02 to .04mm (pg 64)
id not use that , id use BRAND xxxx rules, but .03mm would be the first guess.
but we dont guess, we measure, the new pistons, read the datasheet on said piston and use his rules on his new piston.
the new pistons If not relic NOS< parts, will be super accurate and all 4 will match same, if not, then were mixed by someone, on the shelf.
that is why we check everything, no guessing, as you dont want surprises.

page 42 shows how to measure a piston the correct way, (cam ground piston)

90deg from boss.
and 15mm up from bottom skirt.


for sure the hardest decision,
1: just run what came out. (can be done putting parts back in exactly as removed, the Rings spin so, they spin again) but only if the measurements are good.
2: bore ,hone and rings. ( getting this to remove all out of round and not go over max bore, is tricky)
3: the real full deal, (always works best and longest)


refr. chapter 6a covers all this, line by line, but not how to work with new AFTERMARKET PARTS.

the block in the factory was gang bored, (4 at once) crudely.
today we do 10x better.
2222 means , his gang machine was equally worn that day. LOL
if 1212 the piston guy (day1) picks a pair of 2 different pistons only suzuki makes, no body else.
250k miles later...
once at .25mm (or 50s) then the rules change, to aftermarket rules. (dead accurate is now)

the only real large cost is a set of oversized pistons, in a matched set. and is worth the cost.
the best way, is just take the block and pistons (old) the the machine shop and let them tell you the correct path.
they do this 10times a day or more, its old hat there.
ours has 3 crank guys turning cranks all day long.
just cranks. and they do all sizes.
same with blocks.
first he cleans it then pressure tests it.
then measures it very carefully to see what the options are... this really is the best way. but
I most admit , i like check the bores my self, very due care.

cheers.
http://www.fixkick.com
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#3
that is my opinion
seen others hone engines, in car, sad to watch.
http://www.fixkick.com
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#4
the boss is the piston pin side boss that very thick part of the piston front and rear. pin boss.
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#5
Thanks fixkick, the measurements I provided were after I had honed the cylinders , ( hand honed) ,measured, then debated. I'm a bit of a perfectionist, and it drives me crazy if things aren't like they should be. Think I will take the block in to be bored over,let the machinist look it over and tell me what he thinks. I'll post what measurements he comes up with to compare.

I used telescoping gauges,and measured at 8 different points below the ridge. Let's take cylinder #4 measurements 75.06mm just under the ridge and tapered to 75.055mm at the bottom, all these measuremen's were taken after I gave a quick clean up of the walls with the hone. It had an out of round of .0001 in. So when I said the cylinders measured 75.05- 75.06mm that was a pretty vague thing to say,sorry, I'm still new to rebuilding engines and playing catch up
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