re-bore oversized?

[Stunned Monkey]

Hi all, the prevailing attitude in speed 6 circles appears to replace liners rather than re-bore and over-size. Anyone know why? Anyone had any experience of this crowd? These pistons seem too good to be true.

My 4, 5 and 6 bores are scored due to bore-wash but the block hails from its 2004 rebuild so quality should be good (!)

https://2performance.de/Kolben-TVR-Speed-6-Ueberna...

[leerdam23]

Seriously, why would you go anywhere other than Powers or Str8six for a speed six rebuild???

[Stunned Monkey]

Maybe because I don't like paying someone else to do something I'm quite capable of, and enjoy doing myself?

[leerdam23]

fair enough!

[PetrolHeadPete]

I share your sentiments...on both points...DIY everytime for me...and yes they seem too cheap.
I had some experience with ultra shallow skirt forged pistons...rather noisy! Ended up with some deeper JE units with offset pins and ceramic coated skirts. Way more civilized for daily use.

[Stunned Monkey]

Thanks for the info Pete, much appreciated. It seems the gudgeon pin location moved up a tad on later engines so rods are on the cards now too. They also started ceramic coating the skirts then too.

What bugs me is not being able to simply bore oversize and save the cost of replacing the liners (cheapest £750+vat). Provides quite a budget for getting some pistons made!

[Sagi Badger]

The standard pistons are probably the best bit of the engine. The main studs are tough as well. The rods are longer in later blocks as you state but still they are not long enough and you will get noise with short skirted pistons. I have found pick up on the skirts of all the 6s I have stripped so clearly an issue and most often when cold but you don't want pick up. Ask the Porsche owners about this.

I buy from Powers or TVR Parts, depending on what it is. If you build your own get Dom to line/hone it and use the Total Seal rings he supplies, don't bother with anything else especially pre gapped. The number of people who don't know how to hone amazes me. Balance the bottom end and use steel rods.

J