Prepping new Mahle's for installation

[TT Oversteer]

I just received my brand new set of Mahle pistons and cylinders for my 3.2 build and have several questions about installation.

I would like to install the piston and cylinder assemblies as they came with the pistons already in their bores with the rings safely inside.

It would be nice to avoid having to compress the rings and possibly break one upon installation. But I am wary of rotating the pistons inside the cylinders to align them properly with the rod bushings because I don't want to scratch the bores.

Do I need to pull the pistons out and verify that the ring gaps are spaced evenly at 120 degrees apart?

Is there any cleaning required of these new parts prior to assembly?

Should I coat the rings and bores with oil for the initial start up or leave them dry to aid in ring seating?

I have a feeling I need to take the pistons out of the bores, make sure they are clean, space the ring gaps out 120 degrees apart, align the pistons in the correct orientation and re-install. What's the experts' opinion on this topic?

[unclebilly]

Olease help me to understand your concern. You are worried about moving he pistons inside the bore because this may scratch the bore?

[TT Oversteer]

I'm probably over thinking it, as usual, but the concern here is mainly should I remove the pistons from the bores to verify that the ring gaps spaced evenly and not all lined up.

Also the rings are not designed to rotate in the bores or ring grooves and don't want to drag the rings through the bores in a rotational motion.

Again, probably no real concern, just wanting to err on the side of caution with these expensive new parts.

[Flieger]

Don't worry about the ring gaps being lined up. They move around once you start the engine anyway. They find their happy place eventually no matter where they start. So no sense in going through the trouble unless you are doing a full rebuild anyway.

[Eagledriver]

I would pull at least one apart to measure the ring gaps and piston lands. It's nice to know the specs on the parts for your engine for future reference.

-Andy

[Spenny_b]

Originally Posted by Eagledriver

I would pull at least one apart to measure the ring gaps and piston lands. It's nice to know the specs on the parts for your engine for future reference.

-Andy

+1

I'm also a little more than paranoid at the moment with my build, and I know that Nikasil is supposed to be flipping hard...but...if it were me (and I totally bow to any input from the pro engine builders, I'm a mere amateur with a broken wallet) I'd be dribbling engine oil down the bores of each of the Mahle assemblies, both from top and bottom, whether I was disassembling or not, to ensure that any first movement of the piston will be onto an oiled surface.

But like I said, those that do this on a regular basis will be better positioned than me to give real-world experiences.

[JFairman]

I have a brand new set of Mahle 930 pistons and cylinders. The box was sealed from the factory when I got it.

I removed a piston from one of the cylinders to look at it and all 3 ring gaps were lined up and thats the last way you want them so I would definately remove them all, check the ring gaps in a cylinder, and then reinstall them correctly for each side of the motor.

I like to completely oil the pistons, wristpins, rings, and lands with the same motor oil thats going to be in the motor before installing them. Gives me peace of mind they will be lubricated completely before starting it up.

[356RS]

Originally Posted by JFairman

I removed a piston from one of the cylinders to look at it and all 3 ring gaps were lined up and thats the last way you want them so I would definately remove them all, check the ring gaps in a cylinder, and then reinstall them correctly for each side of the motor.

+1 on this. Also happened to me a few years back.

[304065]

Originally Posted by Flieger

Don't worry about the ring gaps being lined up. They move around once you start the engine anyway. They find their happy place eventually no matter where they start. So no sense in going through the trouble unless you are doing a full rebuild anyway.

Actually if all three gaps line up this can lead to loss of compression, Harry Pellow described a situation where all three rings lined up resulting in burning through of the top ring land-- give yourself a fighting chance and make sure the gaps are spaced 120 degrees apart. There is no reason to be afraid of a good ring compressor.