Piston and cylinder assembly, Tips? Options

[TheCabinetmaker]

Doing a top end on a 1.7L. New c/p's. New heads.
The p/c assemblies seem to be quite dirty. Should I take them apart and clean and relube evetything? what should I clean them with. I read about weighing the pistons. Should I check the ring gap, or assume(I hate that word) the were checked when assembled.

This ain't my first time, but it has been a "few" years.

Thanks, Curt

[Mark Henry]

Mark,

This guys has done every engine known to man. One time he said something about Merlin (sp?) engines. I replied, "They make nice boat stuff." He chuckled. He was talking about about WWII aircraft engines.

Maybe I communicated wrong. The crank must be dynamincally balanced (but does not get weights put on it like a V8 crank would). The pistons, rods, and pins all have to be balanced (to each other). So yes, everything gets balanced, but not like in a V engine.

Matt

Balancing a VW or a Porsche or a V8 what’s the diff???
If a customer pays for a balance job he gets a lower quality job because it's a VW or a four??

The rotating mass of any engine needs to be balanced, the stock balance on a VW or a V8 is OK for a stocker, but any hipo or high-end engine build will benefit from being balanced.
The VW engine is not a naturally balanced engine, in hipo form the balance is critical. The engine has only 3 main (not counting #4) journals to hold 4 rod journals, this is why all flat four cranks are forged. Porsche knew this was a problem that’s why the six has 7 mains (8 total) between the rods. Yes, a V8 has two rods between 2 mains but they share 1 rod journal, so that mains are closer to each other. If your talking counterweights, well any of the stroker (and most T1 stock stroke) T1 and T4 hipo engines I build will have counterweights.

I think you are confusing the fact that V8 crankshafts had many problems when they were first being designed and that counterweights were employed to elimanate one set of design problems. This has little to do with the dynamic balance, as a matter of fact if you put a VW and a V8 crank back to back on a balancer, the factory balance would be about the same on both cranks.

BTW That's a Rolls Royce Merlin engine used in Spitfires, Hurricanes, Mosquitoes and Lancaster's.