Venolia Piston Feedback

[gsjohnson]

Has anyone used Venolia pistons during a rebuild? I'm looking for feedback on the use of these pistons.
Thanks in advance

[Steve@Rennsport]

The problem with Venolia's (and a few others) Porsche pistons is their design. JE's, CP's, Omega's can be set up with less piston-to-cylinder wall clearance so they run quieter and last longer.

JMHO, but I would leave the Venolia's to the domestic applications.

[gsjohnson]

Thanks for the responses. I wouldn't be buying off the shelf pistons. Venolia is telling me to send them my original pistons and they will duplicate them exactly. I have heard of excessive piston slap when using JE, Venolia, CP, etc. And you say the answer to that is to decrease the piston to cylinder wall clearance? At the price Venolia is quoting (and JE too) I just thought it was worth looking into...

[chris_seven]

I have a set of Venolia pistons in a Supercharged Lancia 037 engine. It is a 2.1 litre Water Injected Group B engine producing around 310 BHP.

The pistons are not too bad but have picked up slightly on the skirts and do seem a bit heavy.

We are going to replace them this time around with some lighter cross braced slipper pistons to try to reduce piston weight.

I think the choice of piston, its design and selection of material really depends on the application.

Most aftermarket pistons now seem to be made in 2618-T16 which is a material originally designated RR 58. This is a very high strength alloy and has very good high temperature performance but it expands quite signficantly and needs more cold clearance than a typical Mahle piston.

Most Mahle production pistons are made from higher Silicon Alloys such as 4032-T6. Higher Silicon Alloys also tend to have better ring groove life as they are harder and more wear resistant.

If I were building a road engine with Cast Iron or Biral Cylinders I would favour a 4032-T6 piston as this could run with much lower cold clearance than a 2618-T16 part which is, I believe, wher the reputation for piston slap has come from.

I would be a bit less concerned with a Nikasil cylinder but again for road use I think 4032-T6 is the optimum choice.

If I were building a high end race motor - particuarly a Turbo or a Supercharged engine then I would chose 2618-T16 and have the ring groove are wear coated.

If you precisely copy an ealry 2.0 or 2.4 Mahle piston made froma high-ish Silicon Alloy in 2618 and run it in a Biral cylinder you could have some problems and it may well pick up.

I would ask what the material is and how much clearance they are allowing.

We have 3.0 SC pistons made in 4032-T6 with a 10.5:1 compression ratio and have had great results.