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Rifle or Gun drilled Conrods

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Wed Mar 07, 2012 9:25 am PostPost subject: Rifle or Gun drilled Conrods
Willie
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I think this is a relatively new thing in conrods, but I might be wrong.
Anyway, I'm looking to get uprated rods as mine are only rated to 320 ft-lbs and I hope to be close if not making higher torque than this this year.

The rods I'm looking to get are not drilled but are a good price.
Conversly the rods that are drilled are more expensive.
Does anyone have any experience with retro drilling rods and a place who would do them in Aberdeen?
Even if someone has the specs for doing this to supply to the machine shops and see what they think?

Any help or pointers appreciated.
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Wed Mar 07, 2012 10:27 am PostPost subject:
AK
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why do you need them drilled?

Save rotating mass, and/or help with balancing?

I'd just fit off the shelf rods...
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Wed Mar 07, 2012 11:23 am PostPost subject:
Willie
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The drilling is a pressure fed oil supply to the wrist pins to reduce wear by aiding lubrication, increase cooling and increase the shells life.
This means you don't have to have very expensive precision made shells and hopefully the rods themselves will last longer.
I've been told not to fit rods without this done as its that good, especially for cars that are raced/tracked.
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Wed Mar 07, 2012 12:15 pm PostPost subject:
AK
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were you told this by the seller?

I'm not really clued up on the subject but I'd always opt for decent bearings/shells (full film lubrication) regardless. Rods and shells normally fail for reasons (when they come into contact or just power/rpm).... oil starvation. If there is no oil there will still be no oil!

I'll google the subject when I get some quiet time Laughing
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Wed Mar 07, 2012 2:10 pm PostPost subject:
Willie
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No not told this by seller as there are very few doing it.
This is info from other LCR owners and what I have gleaned from googling and reading up.

So basically is there a machine shop in Aberdeen who could or would be able to do this?
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Wed Mar 07, 2012 9:24 pm PostPost subject:
Matty.H
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Can't picture where the hole would be in the rod Embarassed Over what kind of length and what diameter of hole do you need drilled?
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Wed Mar 07, 2012 9:55 pm PostPost subject:
alistairolsen
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right up the middle of the rod from the main to the small end if its what Im thinking of to bleed oil to the small ends. I suspect youll be on a hiding to nothing with machine shops, especially ones Id trust, it's a VERY specialist operation to drill such a small diameter hole straight. As others have said either fit undrilled ones with decent bearings or shell out for the drilled ones, all it takes is the machine shop to write off one rod and you're stuffed.
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Thu Mar 08, 2012 6:17 am PostPost subject:
Willie
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Matty.H wrote:
Can't picture where the hole would be in the rod Embarassed Over what kind of length and what diameter of hole do you need drilled?

1.5 mm from the wrist pin end to the big end with a groove around the shell too.
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Thu Mar 08, 2012 6:18 am PostPost subject:
Willie
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alistairolsen wrote:
right up the middle of the rod from the main to the small end if its what Im thinking of to bleed oil to the small ends. I suspect youll be on a hiding to nothing with machine shops, especially ones Id trust, it's a VERY specialist operation to drill such a small diameter hole straight. As others have said either fit undrilled ones with decent bearings or shell out for the drilled ones, all it takes is the machine shop to write off one rod and you're stuffed.

Yeah, I think your right.
Thank you for your help.
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Mon Mar 12, 2012 9:36 am PostPost subject:
Willie
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So it seems my OEM rods are rifle drilled so it will be the only option for me.
It seems like it's best to get them supplied drilled rather than risking this getting done or fucked by someone else.
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Tue Mar 20, 2012 1:23 pm PostPost subject:
Aragorn
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OEM rods on the 1.8T are drilled.

Many folk run undrilled rods, and on track type use at high rpms they're usually fine, as theres plenty oil splash to keep the little ends lubed.

The problem comes more with daily driven cars, as the piston oil squirters shut off below around 3bar of oil pressure, so if your driving the car around town etc with low RPM's the pins will be getting little in the way of lubrication, and this can cause accellerated pin wear.

A chap on Audi-sport posted some photos of the pin wear on his undrilled IE rods.

I fitted Brute rifle drilled rods to mine when i rebuilt the engine, got them shipped over from pagparts in the states. IIRC the order came to $600, and that was for the rods, a set of coated bearings, and shipping to the UK.

You can just about make out the drilling on the left most rod:

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Thu Mar 22, 2012 12:10 pm PostPost subject:
Willie
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Cheers Aragorn.

As I suspected.
IE rifle drilled are the favourites just now, got a price from Badger Bill but will check out pagparts.
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Thu Mar 22, 2012 12:19 pm PostPost subject:
sunny_cullen
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What sort of power are you going for willie? Standard rods should be good for 300bhp ish?
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Fri Mar 23, 2012 4:16 pm PostPost subject:
Willie
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sunny_cullen wrote:
What sort of power are you going for willie? Standard rods should be good for 300bhp ish?

The OEM rods are good for about 320 ft-lbs.
As I'm running an OEM KO4 turbo she's a spikey mo fo so can see more than that before the ECU rains in things.
I'm currently running 288bhp and 300 ft-lbs on a fairly conservative map.
With the other mods I have planned there's a good chance of breaking 300 bhp and 320 ft-lbs.
I've always over engineered everything I change on the car.
This allows me to drive it how I want as often as I want without having to worry about things.
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