Author Topic: Resizing Small Ends (Conrods)  (Read 4798 times)

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Offline mick7504

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Resizing Small Ends (Conrods)
« on: September 14, 2010, 06:31:45 AM »
I've been chewing over the idea of putting together a 67mm bore engine.
In the "mystery box", is a NOS set of LA Sleeves that should be put to use.
The idea is to mill the domes and use a set of CB360 pistons with 16mm pins and resizing a set of Carrillo or Super Rod small ends.
Over the years, I have pulled a couple of sets of stock rods that have had the small ends resized to 16mm without any issues. (As risky as that is)  :-\
What I'm thinking, is that the small end bronze bushing shouldn't be a concern with .020" taken from the wall.
Any thoughts about this?
Mick



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Offline Sam Green Racing

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Re: Resizing Small Ends (Conrods)
« Reply #1 on: September 14, 2010, 06:49:22 AM »
Very lucky getting away with it on stock rods Mick :o :o :o

Sam. ;)
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Offline 754

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Re: Resizing Small Ends (Conrods)
« Reply #2 on: September 14, 2010, 08:56:05 AM »
 How thick is the bronze insert?, if there is an insert,g rod strenth wont be affected. If insert gets too thin it may not last as long.
 I have roughed out lots of V8rods on the mill, leaving around 2 thou for finishing on the pin hone..
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Offline mick7504

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Re: Resizing Small Ends (Conrods)
« Reply #3 on: September 14, 2010, 04:42:35 PM »
Sam,
I was surprised myself to see these rods and knowing what abuse had been metered out to this engine.
It had some fairly serious headwork done and also running an aggressive Ivan Tighe camshaft and it did have some bad manners. 8)
Geez you just can't pick it sometimes.  ;D

Frank,
I'm thinking the same thing about the rod strength not being affected with the small end insert.
Unlike the stock rod that I mentioned in the original post that hung in there after being bored to 16mm.
The picture of the Super Rod insert appears to show a reasonably good wall thickness which shouldn't be affected with .020" removed.
It would be good to know what the thickness of those inserts are.

Mick
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Offline BLUE71TURBO

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Re: Resizing Small Ends (Conrods)
« Reply #4 on: September 14, 2010, 06:01:09 PM »
 HEY MICK !   What would be the cost of the 4 pistons + rings + piston pins + the cost of machining the rod ends ?     ???
                   Also, are the pistons cast or forged ?
« Last Edit: September 14, 2010, 06:14:03 PM by BLUE71TURBO »
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Offline mick7504

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Re: Resizing Small Ends (Conrods)
« Reply #5 on: September 14, 2010, 07:21:18 PM »
HEY MICK !   What would be the cost of the 4 pistons + rings + piston pins + the cost of machining the rod ends ?     ???
Hey Blue

A set of 4 pistons, 16mm pins, rings & clips would cut out around $400:00 US for a set of 67mm.
A new set of sleeves (4) about $350:00 US.
If you had a block that had been previously sleeved and could be bored to .25 or .5 over 67mm, a set of 4 o/size pistons would set you back about another $140:00 US.

I don't know what the labour charges are in the States, but I'd imagine that the cost to resize the rod ends wouldn't be prohibitive if it was done by someone setup for this type of work.

With all that in mind, APE have the 1000cc kits available for $900:00 US.

Mick
If I was you
I'd be worried about me.

Offline BLUE71TURBO

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Re: Resizing Small Ends (Conrods)
« Reply #6 on: September 14, 2010, 08:33:50 PM »
  The reason i asked is if you are going to seriously do this type of build i have a new MTC 67.5 mm ( 915cc ) 10 1/2 compression
  forged piston kit with sleeves that i'm thinking of selling. I'm kinda up in the air on how much $$  i should ask for it.  A.P.E want's
  $ 900.00 + tax + shipping for thier 970cc kit. 

                               
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Offline mick7504

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Re: Resizing Small Ends (Conrods)
« Reply #7 on: September 14, 2010, 09:27:19 PM »
Blue

A couple of years ago, I bought a 72mm piston kit from MTC for $200:00 US.
That was with pins, buttons and Total Seal rings.
These are the pistons that are going into Mikes Billet Block.

The last 67mm sleeves I bought from LA Sleeve were something like about $85:00 US each.
That was a few years ago as well.
The plan was to build another engine with a NOS set of RC pistons which are vertically gas ported but I've gone a bit cold on that just now.
http://forums.sohc4.net/index.php?topic=76481.0

I'd certainly be interested in your 67.5mm pistons Blue, but I first need to clear out some of my inventory.

Mick





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Offline BLUE71TURBO

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Re: Resizing Small Ends (Conrods)
« Reply #8 on: September 14, 2010, 09:45:03 PM »
 That's what i'm gonna try to do.  I'm working on a kawi project and need to sell off some things like the piston kit, mtc aluminum rods
 and the HILBORN injectors w/ pump.

                   

                   
               
                   
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Offline Retro Rocket

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Re: Resizing Small Ends (Conrods)
« Reply #9 on: September 14, 2010, 09:46:20 PM »
Geeze Mick, i have a full APE 970 kit here for a 750. It has pistons ,sleeves pins, buttons, gaskets , the whole kit and caboodle..{1st time i have ever spelled caboodle.. ;D} Might be interested in selling it.....

Mick
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If You can't fix it with a hammer, You've got an electrical problem.

Offline mick7504

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Re: Resizing Small Ends (Conrods)
« Reply #10 on: September 14, 2010, 10:09:51 PM »
Geeze Mick, i have a full APE 970 kit here for a 750. It has pistons ,sleeves pins, buttons, gaskets , the whole kit and caboodle..{1st time i have ever spelled caboodle.. ;D} Might be interested in selling it.....

Mick
Hey Mick
That's tempting me mate but I reckon if I did, I might be knocking on your door for a feed and somewhere to sleep if the missus found out.
I use to be ok at hiding goodies but she's starting to out fox me now.  ;D
Mick  ;)
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Offline Retro Rocket

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Re: Resizing Small Ends (Conrods)
« Reply #11 on: September 14, 2010, 10:13:41 PM »
Geeze Mick, i have a full APE 970 kit here for a 750. It has pistons ,sleeves pins, buttons, gaskets , the whole kit and caboodle..{1st time i have ever spelled caboodle.. ;D} Might be interested in selling it.....

Mick
Hey Mick
That's tempting me mate but I reckon if I did, I might be knocking on your door for a feed and somewhere to sleep if the missus found out.
I use to be ok at hiding goodies but she's starting to out fox me now.  ;D
Mick  ;)

No worries bud , you would be most welcome....I don't bull#$%* to the misses any more....i just don't tell her..... ;D   #$%*....here she comes.... :o
I have been talking to her about doing a Darwin trip when the 1000 is sorted.....when ever that is.... ;)


Mick
750 K2 1000cc
750 F1 970cc
750 Bitsa 900cc
If You can't fix it with a hammer, You've got an electrical problem.