Piston slapping

[Jochen]

Having problems with my engine. It´s a 4.6l cross bolted, balanced, standard piston with pockets, stage III heads with just about 7000 miles on. Because of a bad noise (low rev. full throttle), we have disassembled the whole thing. Everythings looks good. The only thing what we could see are little scratches at the piston skirt of 3 pistons.
Is piston slapping a known problem of the Rover V8.
Any ideas out there?

Jochen

[apache]

standard ones no but yours has been, er, modified slightly, could it be a tolerance issue?

[Jochen]

Hi Pete,
thanks for your reply. The pistons are the standard ones, which came with the brand new block (4.6l) from Rover. Afterwards they have been taken out to get the pockets into the piston. So far as I know, all TVR engines have pocket Piston. (My old 4.3l had them from factory). This mod. should not affect the Pocket clearence to the bore at all.

Cheers Jochen

[madcop]

I have heard of this problem before. A mate who has Griff has had exactly the same problem which I am afraid led to a rebiuld. Something to do with a very short stroke on the piston travel and all that power makes the griff susceptable to piston slap.
It is not beyond the bounds of possibility that this is what has happened to yours!

[angusfaldo]

I had classic piston slap symptoms (well the car did). Only did it when running cold. In the end it turned out to be a bit of flint that had lodged in the drive belt (seprpentine engine - drive belt is about half a mile long, you know the one!).

I spoke to Dave Batty - he told me piston slap is surprisingly common on Rover V8s.

[Boosted LS1]

Jochen, the stock pistons should run with a fairly tight bore clearance. I'm pretty sure they are eutectic jobbies. If you can still feel the knurling grooves on the skirt with your thumbnail I wouldn't think you have a wear problem. The scratches you refer to are usually caused by dirt which shouldn't have got into the engine. Has the deck been skimmed? Mike.