forged pistons and fitting

[david nelson]

can anyone give me an idea of cost for fitting forged pistons? I understand the pistons are around £500.

Can I just do the pistons or is it new liners as well? 

 

thanks

David 

[Graham Howard]

Hi David

There will probably be true experts along to answer your question soon.....

I did this as part of a rebuild a few years ago and a bigger issue is that the gudgeon pins on the standard rods and pistons are a press fit. Forged pistons will need the rods machining so that the gudgeon  pin is fully floating. So for a bit more money than the cost of machining the rods I fitted steel rods which are fully floating as standard. 

I guess you only need to replace the liners if they are worn. Probably you could get them glaze busted to give a surface for the new pistons to bed into. I fitted new liners.

You are probably looking at a bit over £1000 to do this.

Dave Andrews will give you advice on all this (and sell you the parts)

Graham

[oilyhands]

Pretty much as Graham says, it's not safe to reuse the interference fit on your conrods despite what other might tell you, either these can be bushed or reamed and honed to allow them to accept the pistons fully floating or you can replace the rods with steel rods which are ready bushed (and have ARP bolts). You may find that your liners are within tolerance on wear, ovality and taper, in which case they can be cleaned, glaze busted and re-used. If not then good quality liners with higher hoop strength can be had. Take the opportunity to fit uprated big end bearings while you are at it.

Oily