KZScott
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posted May 01, 2009 05:34 PM
rod bolt stretch
how are you guys measuring it? whats the acceptable amount? Ive never done it, but i want to start measuring bolt stretch on my 12 (experiments!  ) I have a new set of rod bolts and nuts and Im going to size my rods so i can use a set of black bearings i allready have. the rods are slightly egg shaped so i wanted them done anyway. I think i read about just putting a small mark in one end with say a 1/16 drill bit to allow the use of a ball tip on a mic??
instructions for a beginner would be greatly appreciated!!!
thx!
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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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osti33
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posted May 01, 2009 05:53 PM
 Edited By: osti33 on 2 May 2009 02:05
I don't know the amount of strech for a stock bolt but measuring the stretch is real easy. You only need 2 tools. The right size box end wrench and a rod bolt stretch gauge. You also will need a small dimple on the end like you mentioned.
1. Put the rod on the crank.
2. install nuts on rod bolts and take the nuts down until they touch
3. slip box end wrench on nut
4. put stretch gauge on bolt
5. tighten with your box end wrench until you get the desired stretch
If your not familiar with a rod bolt stretch gauge you can buy a cheap one for 30 or 40 bucks all the way up to 200 or 300 for a top of the line model and they look like this:
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tcchin
Zone Head
Posts: 867
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posted May 01, 2009 07:38 PM
Edited By: tcchin on 2 May 2009 03:42
I have a Lunati stretch gauge with a Mitutoyo 543-693 indicator on it.
Carrillo's instructions can be found here:
http://www.carrilloind.com/LinkClick.aspx?fileticket=iQV08XDeYQQ%3d&tabid=99
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KZScott
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posted May 02, 2009 06:59 AM
can i just use a mic to check as Im doing it? would i need an extra ball adapter? (saves buying an extra tool right now) plus i want to drop the rods off on monday 
thx
____________
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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entropy
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Posts: 8671
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posted May 02, 2009 08:48 AM
quote:
can i just use a mic to check as Im doing it? would i need an extra ball adapter? (saves buying an extra tool right now) plus i want to drop the rods off on monday
thx
i use a mic. Not sweet, but works.
put the assembled rod in a vice, careful not grab the split
measure the bolt length with it finger tight, then hit it w/35#, measure length w/just one ball on the mic. hit wth 38# measure, hit with 40#, measure.
find the tq that gives spec stretch, then tighten all bolts to that tq. That's per the Carrillo directions.
you gotta fiddle around a bit measuring, but i can get reproducible measurements to a thou.
it always seems to come out to 38-42#
one o' these days i will pick up a stretch gauge.
I betcha Tim can rattle off the McMaster-Carr part number from memory
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osti33
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posted May 02, 2009 09:25 AM
Edited By: osti33 on 2 May 2009 17:40
Edit. Double post.
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osti33
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posted May 02, 2009 09:35 AM
Edited By: osti33 on 2 May 2009 17:38
quote:
quote:
can i just use a mic to check as Im doing it? would i need an extra ball adapter? (saves buying an extra tool right now) plus i want to drop the rods off on monday
thx
one o' these days i will pick up a stretch gauge.
I betcha Tim can rattle off the McMaster-Carr part number from memory
Karl,
This is the stretch gauge I have. It was about 150 bucks. I bought it at the time because it was the only one I could find that would read .0005" most only read .001". If I was going to do it again I would do like tcchin. The cheaper stretch gauge and spend the money on a real good indicator. Anyway, this is the one I use and it works fine. Can be purchased at Summit or Jegs or anyplace like that.
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KZScott
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Posts: 7235
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posted May 02, 2009 03:23 PM
quote:
i use a mic. Not sweet, but works.
put the assembled rod in a vice, careful not grab the split
measure the bolt length with it finger tight, then hit it w/35#, measure length w/just one ball on the mic. hit wth 38# measure, hit with 40#, measure.
find the tq that gives spec stretch, then tighten all bolts to that tq. That's per the Carrillo directions.
you gotta fiddle around a bit measuring, but i can get reproducible measurements to a thou.
it always seems to come out to 38-42#
one o' these days i will pick up a stretch gauge.
I betcha Tim can rattle off the McMaster-Carr part number from memory
ok, so when exactly do you know the bolt is not reuseable? when you have to put too much torque on the nut to get proper stretch, or not enough torque? Ive been going by the manuals instructions of 16# and 120 degrees for stock rods and bolts(not sure what the final # value is). the manual says replace them every time, but ive been giving them 2-3 uses as im not torquing them down on plastigauge to measure clearances.
the manual gives a range of acceptable stretch for new and used rods. for used its 0.20-0.32mm (0.0079- 0.013in) i guess new rods compress a tiny bit the first time(?) as the range is slightly larger
thx!!
____________
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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tcchin
Zone Head
Posts: 867
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posted May 02, 2009 04:12 PM
1) You're supposed to use your used bolts to torque for plastigauge.
2) Factory bolts are rated for one preload cycle only and should be replaced every time, if that's what the manual says. Carrillo bolts are rated for 12 preload cycles, I believe.
3) I think the service manual lists the stretch range so you can identify a bad bolt.
4) Rod bolts are cheaper than anything else in their immediate vicinity. A rod bolt failure could get very expensive very quickly. Replace them every time.
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entropy
Moderator
Posts: 8671
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posted May 02, 2009 04:13 PM
i don't use stock rods but i'm guessing when the req'd tq results in too much stretch they are are cooked.
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Y2KZX12R
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CompetitionCNC.com
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posted May 03, 2009 04:59 AM
Repeatability is the key here. You need to have the stretch gauge register in the same location every time and use the same lube on the threads and under the nut or bolt head like on a Busa. If it says to use oil don't use Moly and vice versa. It does effect things.
Dimpling the ends of the bolt is important for consistency.
As you guys said..... prick punch the center of both ends and use a 1/16" drill bit to make a small shallow dimple.
I've reused stock bolts in my zx12 stroker. They have 4 cycles on them and ran for 7000 hard street miles without a problem.
They had the factory cycle.
The honing cycle to make sure they were round and sized properly..
The mock assembly measuring cycle.
And the final assembly cycle.
Each time the stretch was compared to the stretch from the previous times.
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Y2KZX12R
CompetitionCNC.com
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