Piston pin bushing.

Hi there,

I'm having difficulty honing the new piston pin bushings on standard rods. No matter how careful I am a taper develops from the centre of the small end to the outer/thrust edges. The pins slide in with the correct amount of resistance but rock. The hone has new stones which are unmarked. Would I be better off trying to use a reamer? I don't recall having this problem before with previous engines. Any advice would be appreciated.

Cheers Jimmy.

I recall the workshop manual stating to use a ream not a hone. But should be able to hone with the correct type of hone.

like this one.

Thanks Vlad,

My hone isn't as high tech as the one in the clip. Have talked to a couple of V8 engine builders and they both say don't use a reamer. Are there any VW engine builders who use a reamer for this job?

Cheers Jimmy.

Ask Dangerous but I believe it's a machine only type of job, is for me anyway. Definatey a honing operation.

Take the rods to a machine shop that pin bored them, usally do both ends so it corrects any difference in the centre length, this is how Crankshaft Engineering does them in brisbane

The gudgeon pin on a VW fully floats in the small end, which is why you have a (bronze) bush to "ream".
The other type, which is what the V8 guys are talking about, is where the gudgeon pin is pressed into the connecting rod small end.
In this case, it would need to be "honed" as there is no bush to "ream".
Dave

Jimmy Wackburns wrote:Thanks Vlad,

My hone isn't as high tech as the one in the clip. Have talked to a couple of V8 engine builders and they both say don't use a reamer. Are there any VW engine builders who use a reamer for this job?

Cheers Jimmy.

Most VW bushes have about 0.5mm to remove, so really need to be bored to size.

A high quality hone machine (like a Sunnen) can acually do it,
but you have no control over the length, so each rod will likely be a different length.
Also the alignment can be difficult to maintain.

Crankshaft engineering have a Berco brand, rod boring machine that is perfect for that type of job.
It bores the holes so they are parallel , and equal length.
Their machine can bore the exact size needed,
but some shops may finish the size with a hone
if they can not get the accuracy any other way.
07 38067488

You want about 1/2 thou clearance.(five tenths of a thou)