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Author Topic: Opening up the small end?  (Read 1666 times)

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Marty

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Opening up the small end?
« on: June 21, 2008, 10:02:59 AM »
On quite a few ford engines the pin hole is 20.638mm on the con rod. I know people have opened these up to 21mm to use XE pistons but would it be safe to go as far as 22mm? I have a con-rod here and it looks like it has enougth meat on it. 1.362mm isn't exactly loads

What would the best way to go about doing this? I was thining of an adjustable reaming tool? then hone afterwards for final fit.

Opinions?



Offline capri v8 driver

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Opening up the small end?
« Reply #1 on: June 21, 2008, 10:37:25 AM »
what rod's  and pistons are you using? what engine?

0.4 mm and 1.362 mm is quet a differance. why do you want to use a 22 mm? 1.362mm maybe doesn't look like exactly alote, the loads on the con rod are very heavy. drilling out the pin hole leaves you whit a weaker rod. most stock rod's are not designed to do this.

the best way to drill the rod's is do it on a machine, a decent machine shop would be able to do it. depending if you want a pressed fit or a floating pin, the tolerance's need to be spot on. to lose or to tight will give problems very fast. doing it by hand whit a adjustable reaming tool will never be 100% straight compaired to the rod. so thats not such a good idea.

also keep in mind that if you do use other pistons, you need to rebalance the whole rotary assemble.

greetz paul.

capri v8 driver.
greetz Paul.

Capri V8 Driver.

Marty

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Opening up the small end?
« Reply #2 on: June 21, 2008, 10:40:26 AM »
There is alot of choice for 22mm pin size pistons

Offline Taps

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Opening up the small end?
« Reply #3 on: June 21, 2008, 14:38:56 PM »
Dont you ever stop      


Marty

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Opening up the small end?
« Reply #4 on: June 21, 2008, 14:55:28 PM »
No  never

Offline Mikey J

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Opening up the small end?
« Reply #5 on: June 21, 2008, 16:55:42 PM »
This is precision engineering work.  You need a jig to clamp the rod to which can then be clamped onto a milling bed. This will get the bores drilled correctly.  Then find an engineering firm with a honing tool.  This will centre on the bore and hone to the final size.

Mike.

 

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