Shane661
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posted September 12, 2010 11:20 AM
- Pistons and Bore/Plating -
Why is it required that you measure the pistons before you get your cylinder bored and plated? Are the tolerances that far off with aftermarket manufacturers?
OEM pistons last 100k miles, and they are off the rack mated to a mass-produced cylinder.
Just curious??
Shane
  
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KZScott
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posted September 12, 2010 11:50 AM
 
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01 ZX-12R 8.84 @ 156.3 no bars, DOT tires. Pump Gas, NA.... turbo 8.47 @ 164.
00 ZX-12R 8.62 @ 165.2 no bars, slicks, Pump Gas, 55 shot.... turbo 8.32 @173
00 ZX-12R Fastest NA Kawasaki in the world 1: 222.046 1.5: 226.390 Loring AFB
00 ZX-12R street turbo 1: 227.9 1.5: 234.1 Loring AFB
00 ZX-12R LSR turbo 1: 263.1 1.5: 266.5 Loring AFB Worlds fastest ZX-12R
CMG Racing RCC Turbos
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06redzx14
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posted September 12, 2010 11:53 AM
i read a while back that some drop in sets are a little larger than stock pistons
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tcchin
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posted September 12, 2010 12:02 PM
There are many reasons, but they all boil down to this: You need to know for sure what your piston/cylinder clearance is, and the only way to do that is to measure everything.
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BrooklynNYZX12
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posted September 12, 2010 05:54 PM
You would be shocked of the variations between pistons in a set. Wouldn't it be better to measure it before assembly knowing it's correct rather than scratching your head after a failure?
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entropy
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posted September 12, 2010 07:06 PM
Tim Chin taught me to assume NOTHING.
I have had a buncha piston sets custom made and a buncha blocks replated/honed.
The new piston sets have always had ea piston within a tenth or 2 of the others in the set.
But individual sets vary.
I LOVE Millennium, but they have made a couple big ooops, had to replate/rehone.
Always measure, ALWAYS.
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dougmeyer
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posted September 12, 2010 07:22 PM
EVERY TIME.
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Shane661
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posted September 13, 2010 03:00 AM
So, what about when you go with a stock bore piston? I guess you also need to bore and plate?
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entropy
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posted September 13, 2010 05:07 AM
you don't need to bore & plate unless the cyls are damaged, then OEM replacement pistons should go right in.
I'd measure em anyway.
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tcchin
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posted September 13, 2010 06:38 AM
Measuring is free. Assumptions can get very expensive.
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Shane661
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posted September 13, 2010 06:52 AM
 Edited By: Shane661 on 13 Sep 2010 17:46
quote:
you don't need to bore & plate unless the cyls are damaged, then OEM replacement pistons should go right in.
I'd measure em anyway.
I was talking about an aftermarket stock bore piston. Sounds like you need to bore and plate with those as well...
If that is the case, there is no point in staying with stock bore...it costs the same as oversize.
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WRECKSHOP
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posted September 13, 2010 09:43 AM
What is the best/safest Piston to Cylinder wall clearance number's which one should try to obtain ??
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SteddyTeddy
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posted September 13, 2010 11:30 AM
quote:
quote:
you don't need to bore & plate unless the cyls are damaged, then OEM replacement pistons should go right in.
I'd measure em anyway.
I was talking about an aftermarket stock bore piston. Sounds like you need to bore and plate with those as well...
If that is the case, there is no point in staying with stock bore...it costs the same as oversize.
No you don't need to bore and plate for stock bore pistons, but you do need to double check all clearances no matter what.
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2000redrocket
Pro
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posted September 13, 2010 06:51 PM
Edited By: 2000redrocket on 14 Sep 2010 02:52
here is a story for you shane
said person got a koler engine to bore .010 over. said person is use to car engines and everything is real close to the correct size. so he bored the block to .007 to finnish hone when he gets them.
whell koler used mahl (think i spelled it correctly) it came .005 under the .010.
had he waited he could of filed the rings (since they were also .010 over rings not .005) to the correct gap and he could of used it at .005 over. yes it was not his fault it was not the correct size but the person would of not cared it being a .005 over.
always measure. that is the safe.
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KZScott
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posted September 13, 2010 07:24 PM
i believe that most stock bore drop ins are an RCH larger and you hone the cylinders to get the correct clearance(and to be sure the rings seat)
i could be wrong...
____________
01 ZX-12R 8.84 @ 156.3 no bars, DOT tires. Pump Gas, NA.... turbo 8.47 @ 164.
00 ZX-12R 8.62 @ 165.2 no bars, slicks, Pump Gas, 55 shot.... turbo 8.32 @173
00 ZX-12R Fastest NA Kawasaki in the world 1: 222.046 1.5: 226.390 Loring AFB
00 ZX-12R street turbo 1: 227.9 1.5: 234.1 Loring AFB
00 ZX-12R LSR turbo 1: 263.1 1.5: 266.5 Loring AFB Worlds fastest ZX-12R
CMG Racing RCC Turbos
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06redzx14
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posted September 13, 2010 08:06 PM
Edited By: 06redzx14 on 14 Sep 2010 04:06
JE drop ins use OEM rings so I'd imagine they would be real close to stock size
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06 alien head, no flies, PC+hub, 16/45 44 43, air shifter, dry shot
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2000redrocket
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posted September 14, 2010 02:35 PM
kz scott i thought BCH was finer for better resolution. but not as smart??
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tcchin
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posted September 14, 2010 09:34 PM
Most of the stock-bore aftermarket pistons I've seen have been slightly looser than stock. My stock used pistons were all within .0001" of each other, and were nice and tight (in the words of Borat, like a man's anus). In contrast, my aftermarket pistons were typically +/-.0003". Having the largest piston .0006" larger than the smallest piston borders on excessive for me. If those pistons weren't matched up properly to the cylinders to offset some of the size difference, things could get out of hand.
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tcchin
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posted September 14, 2010 09:34 PM
Edited By: tcchin on 15 Sep 2010 05:36
RCH is the smallest unit of measure known to man. I think it's half the diameter of a hydrogen atom.
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entropy
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posted September 15, 2010 05:52 AM
quote:
Most of the stock-bore aftermarket pistons I've seen have been slightly looser than stock. My stock used pistons were all within .0001" of each other, and were nice and tight (in the words of Borat, like a man's anus). In contrast, my aftermarket pistons were typically +/-.0003". Having the largest piston .0006" larger than the smallest piston borders on excessive for me. If those pistons weren't matched up properly to the cylinders to offset some of the size difference, things could get out of hand.
bahahahahahahahahaha
that ole Borat, has a phrase for every occasion?
Tim,
on RCH units of measure.
I assume Mcmaster-carr has a good selection on digital mics etc using the RCH system of measurement?
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aliveagain
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posted September 15, 2010 08:10 AM
Wouldn't aftermarket pistons be made smaller due to a differant expansion rate than stock? cast vs forged
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tshultz
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posted September 15, 2010 12:26 PM
bahahahahahahahahaha
that ole Borat, has a phrase for every occasion?
Tim,
on RCH units of measure.
I assume Mcmaster-carr has a good selection on digital mics etc using the RCH system of measurement?
we use the rch form of measurement at work all the time. And some times bch.
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rtbain
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posted September 18, 2010 04:30 AM
And don't forget to clay the motor to check the top end.
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Randy
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2000redrocket
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posted September 18, 2010 02:54 PM
just did my car engine. .150" we are good for a bigger cam later on easy. only 44deg of overlap on this one.
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dubious
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posted September 19, 2010 05:54 PM
quote:
Most of the stock-bore aftermarket pistons I've seen have been slightly looser than stock. My stock used pistons were all within .0001" of each other, and were nice and tight (in the words of Borat, like a man's anus). In contrast, my aftermarket pistons were typically +/-.0003". Having the largest piston .0006" larger than the smallest piston borders on excessive for me. If those pistons weren't matched up properly to the cylinders to offset some of the size difference, things could get out of hand.
I agree.
I have found the zx14 engines have astounding tolerances! near perfect.
within .0001 on all 4 bores, and symetrical the entire bore
albeit my zx14 bores were right on the upper limit,
My JE and MTC pistons were also within .0002.
the alternative is give them your dimensions, and have them custom machine your pistons, with your motor apart for 8 weeks waiting
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Some are not worthy of the effort.
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