Mecaparts MP0316 - question

[R8RX]

Do anybody here have used the Mecaparts MP0316 piston and liner kit in their engine?

I am assembling my engine now with this kit, but the arrow on the piston is pointing in a different direction (to the side of the engine and not in longitudinally direction). Should the arrow point toward the camshaft?

 

[R8RX]

Found out on some french forum that the arrow should point toward the exhaust side of the engine.

 

[angru]

Hijack of original thread…. But has anybody used mecaparts piston 0347? (Forged 1596). I bought a set of these but compression height is higher on the top of the dome than the 1596 set that came out if it (12G). Not enough meat in the piston to skim a bit off the top, and it seems like the valves are in the way of taking much off the head.
I’ve now got the correct set ti use in this motor, but wondering if anybody has used the 0347 forged set sucesfully?

 

[chris hartwell]

Hijack of original thread…. But has anybody used mecaparts piston 0347? (Forged 1596). I bought a set of these but compression height is higher on the top of the dome than the 1596 set that came out if it (12G). Not enough meat in the piston to skim a bit off the top, and it seems like the valves are in the way of taking much off the head.
I’ve now got the correct set ti use in this motor, but wondering if anybody has used the 0347 forged set sucesfully?

I can't comment on the 12G pistons, however I purchased a set of forged pistons for my R8 Gordini engine from Mecaparts but they didn't have the required number of oil holes below the bottom oil control ring resulting in excess oil escaping up the piston to be burnt (producing much smoke). So the engine was stripped down, with four extra holes milled into the skirt of each piston which cured the problem. But clearly Mecaparts don't do quality control on parts they supply, I have other examples with other supplied items.

 

[Frans]

Hi R8RX. This does not always help because there are pistons that are different.

One way to find out is if it is a dome piston, then the big chamfer should be on the intake valve side.

If it is a flat top then you could check the pin offset. The piston pin has only sometimes an offset and it is not center of the piston. If you are lucky to have this type then have a look at the drawing. The small side should be on the left if you view the engine from the crank pulley side, Clockwise rotation.

If none of these mentioned above are on the piston then look further.

 

[R8RX]

Hi Frans!

Yes, measured the offset as well. And the big chamfer on the piston is pointing towards the intake valves

 

[Stan W]

I had the same question with the Aprotec piston set I used in my 4cv. The arrow points in the direction of rotation due the the offset. Exactly as Frans showed in his post. The same piston could be used in a Dauphine or R4, but mounted opposite ways due to the differences in direction of rotation.