Is there anyone who has actually had it done or who knows the details?
To understand what Mahle do to make the 98mm set, I suggest contacting
Andial. I most definitely could be wrong.
This makes sense if you drop the sealing ring and the groove for it when you go from 95 to 98mm cylinders. Carrera's don't have the sealing ring so it must not be absolutely necessary.
This is a picture of a whole p&c - I think I did need sealing rings - I have an invoice for 6x part number 930 104 194 02 but these look to be the ones at the base:
Mahle would simply bore the original casting out to 98mm and omit the groove. They wouldn't necessarily even have to re-bore, just bore it 98mm the first time.
This is what I was told (mechanic has made approx 1/2 dozen short stroke 3.2s).
The cost... well it depends. Assuming you are rebuilding anyway:
1) If you are replacing p&c, the cost of the Mahle 98mm set is <$3000 (I think I paid ~2800??) from Andial. This is offered in:
- CIS friendly with low (single plug) compression. Not sure if twin plug compression available
- carbs/MFI required (for wilder cams up to RSR) for single or twin plug
This compares to Pelican's price for 95mm of $2000 or $2500 (depending on the set). I dunno if Pelican can get the 98mm ones. Thus the difference is probably not much (comparing $2500 to the Andial price). Do some research.
My mechanic was able to tear down my engine, swap 95mm p&c for 98mm and reassemble without needing more than $100 of miscellaneous seals (the engine had been recently rebuilt with the 95mm p&c). So it is just labour which is "free" as an upgrade if you are already paying for a rebuild.
2) If you are not replacing pistons and cylinders... the upgrade is expensive (obviously).
I have no experience with boring and resleaving or boring and replating so have no comment on the cost, etc. But personally, if I was rebuilding an SC that needed new p&c, the change to 98mm would be a no-brainer.