aventari

I've never seen a set of new pistons, stock OR aftermarket, come without rings in the set.

Not saying it doesn't happen, but it is the norm.

Ski

Piston rings width and height are made to fit for that piston - you buy new pistons you get new rings. The rings that come with Tom's pistons, Mahle Motorsport pistons (now being produced), Wossner or pistons from CEP - I doubt you could make a ring set from one one of the above fit the other, but I could be wrong.

You need to get matched sets, set the end gap, and set the piston to cylinder wall tolerance as recommended by the manufacturer; if you choose to enlarge that or close that, you or your engine builder need to be all warm and fuzzy with those numbers, based on the expected expansion of said piston.

333pg333

Those TC pistons look nice!

Ski

They are. They were made by Arias, the coating Tom had, was formulated by retired guy from NASA, who has a small company in Tulsa. They worked very well for us in the track car until the rod broke, 4 years after it was assembled. Some questioned the coating, as it was dry at first but when mixed with oil and heat, cured itself. Pretty interesting, but I think the guy passed away, which is why Tom C isn't selling anymore.

Pic of the broken rod with the piston in hole from #4. Almost 4 years of track time, say 6 events a year wtih two drivers a weekend, car lived pretty much between 4000-6500 rpm.

blown 944

Jeremy pretty much summed up my thoughts.

Voodoo I am not one to quetion ones knowledge, but in reading this thread I must wonder if you are familiar with the block (alusil) in regard to honing and what types of pistons can be used with it.

VOoDOoGTX

im not thats why im asking haha the block i got is damn near perfect and the guy im doing this project with builds a new race car ever year. he knows what hes doing. he said its no big deal. im asking what pistons i should be getting. Quality and bacicly wheres the best deal.

Ski

Race pistons, probably CEP or 944 enhancement but these can be used on the street as well. Mahle Motorsports, race or stock, if they have them in stock, Lindsey. Different vendors can get the Mahle Motorsport, it's just that they have to commit to a minimum number of sets on the order and they're not cheap.

You can check with Andial to see it they have any stock ones left but I think all they have are 100.5 2.8L and 104.5 3.0L turbo pistons for 944 turbos.

pic of a properly prepared block, albeit with o-ring block



courtesy of Duffin Engine Service, San Antonio TX

Ski

944 Turbo - 2.5 L 100.0 mm pistons with re-positioned wristpin to accept 3.0 Crank resulting in 2.8 displacement
100.0 mm 78.9 mm 8.0:1 MAH 1K 32 690 Standard 2 Valve Head
100.5 mm 78.9 mm 8.0:1 MAH 1K 32 690.5 Oversize 2 Valve Head

This is what Andial has in stock...need a 3.0L crank though.