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Old 01-04-2010, 02:29 AM   #1
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Default M-Tuned rods small end bores need honing

From the rods group buy thread:

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Originally Posted by [email protected] View Post
I've installed many without needing machining.

The odd time I may see the small end needs a little clearance work when using a Wiseco wrist pin, but never an issue when using stock or some other brands of piston.
I'm trying stock piston pins on 'em now. While it's very easy to get em on the stock rods, it is difficult to push them onto the M-Tuned rods. As I start to push them on, it feels like they're galling.

Anyone else have this problem with stock piston pins?

Looks like I need to have them honed - workshop manual says the difference in bores between the rod and the pin should be 0.0004 ~ 0.0011.

Would it be OK to take just *one* piston pin to a machine shop and have the 4 rods honed?
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Old 01-04-2010, 06:17 AM   #2
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Quote:
Originally Posted by JasonC SBB View Post

Anyone else have this problem with stock piston pins?


Would it be OK to take just *one* piston pin to a machine shop and have the 4 rods honed?
I had the same issue.

I would take each wrist pin to the machine shop with each rod and have them check clearances on every one. Just have the shop label each so they don't get mized up. IIRC two of my rods needed honing and two did not.

FWIW this was with 8.6:1 supertech pistons and supplied pins.
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Old 01-04-2010, 10:42 AM   #3
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This is common fair with any motor.
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Old 01-04-2010, 11:26 AM   #4
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Thanks.

Snowboarder, was the variance in the wrist pins or the rods?

Is there a chance the big ends need machining too?
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Old 01-04-2010, 01:13 PM   #5
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My Belfab (same?) needed honing too with Supertech pistons (from Belfab too, go figure)
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Old 01-04-2010, 01:21 PM   #6
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My Eagle rods needed to be honed also.
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Old 01-04-2010, 02:10 PM   #7
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Its standard to get the big and small ends honed if they don't mic out. Anyone not mic'ing before installing should expect that they don't have correct clearance (although they might), and that it could kill your motor.
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Old 01-04-2010, 06:25 PM   #8
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my builder measured the big ends of my belfab rods to be 1/1,000 out of round. His standard is for them to be less than or equal to 2/10,000 out of round. They were five times worse than he was comfortable installing, so they were machined to within tolerance. I understand this is common with the chinese forged and US Honed rods.

It happens - thats why I paid a professional to rebuild the engine.
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Old 01-04-2010, 06:47 PM   #9
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Quote:
Originally Posted by fooger03 View Post
my builder measured the big ends of my belfab rods to be 1/1,000 out of round. His standard is for them to be less than or equal to 2/10,000 out of round. They were five times worse than he was comfortable installing, so they were machined to within tolerance. I understand this is common with the chinese forged and US Honed rods.

It happens - thats why I paid a professional to rebuild the engine.
winner!!!!
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Old 01-05-2010, 05:15 AM   #10
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Quote:
Originally Posted by JasonC SBB View Post
Thanks.

Snowboarder, was the variance in the wrist pins or the rods?

Is there a chance the big ends need machining too?
To be honest i cant remember, but i do remember having a piston or two honed for the wrist pin as well.
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Old 01-06-2010, 03:07 PM   #11
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here, let me show you what happens when you ignore this......
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Old 01-06-2010, 05:16 PM   #12
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+1 on the eagles, i had to hone mine a wee bit, same with my biddies built 323 GTX. I believe the reason behind this is due to different piston companies making different wrist pin sizes, so rod companies leave the small end slightly smaller so as to accommodate these sizes. (ie:eagle rods with wiseco pistons, mtuned rods with ross pistons ect ect...)The reason the big ends dont need honing is because they are made to fit on one specific crank.
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Old 01-07-2010, 04:17 AM   #13
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it all makes sense now, **** my life for over looking this before
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Old 01-07-2010, 12:13 PM   #14
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I thought your oil pump busted a plug and squirted oil into the engine bay?
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Old 01-12-2010, 08:41 PM   #15
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What piston wrist pin clearance does ETD recommend?
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