Nickel plating pistons

[onetenor]

Has any one tried nickel plating pistons to restore compression. Does it work and does it last?

[Engine Doctor]

I know a few engine manufacturers have used Nickosil playing on cylinder linings with varying degrees of success. Adhesion would be critical and lapping might be a problem . I assume your talking about iron pistons in diesels ?

Playing alloy needs a different approach and item needs zincating before nickel will adhere . Probably asked to hone cylinder and make a new piston.

[Dave Garrett 1]

Hi Onetenor

I work in the aerospace industry, and nickel plate or more commonly hard chrome plate is used extensively to recover worn journals or bores. To be of any engineering use, the plating thickness is normally around 0.10mm thick (0.004" in old money). The recovery process is: Machine journal undersize by 0.20mm, plate 0.15mm thick, machine back to correct size. Unless it is an expensive component, it is not really economic.

As Engine Doctor says. plating adhesion is always a problem.

Regards

Dave

[J D 8]

To restore compression in a worn diesel we used to remove the piston and put a ball bearing inside,then on a hard surface with a punch give the ball a good firm tap.

This would expand the piston just enough to restore compression,at least for a while.

[Peter Miller]

Posted by J D 8 on 03/08/2018 15:56:59:

To restore compression in a worn diesel we used to remove the piston and put a ball bearing inside,then on a hard surface with a punch give the ball a good firm tap.

This would expand the piston just enough to restore compression,at least for a while.

I think we used to do that with the contra piston. Never heard of it being done on the piston

[J D 8]

Yes Peter you are right , it was done for contra piston's.

I do recall doing the same on a plain piston that had no shoulders for the gudgeon pin.[ can not remember what motor] Problem then it was too tight for the motor to run so I bedded it in with an electric drill.

I was young and foolish and do not recommend this method.

John.

[Engine Doctor]

I had been doing that with contra pistons for years but was told that it could be done with pistons ! I had a clapped out engine , i believe it was a DC spitfire or a saber so thought I'd give it a go. One tap and re-assembled and it felt much better so thought another tap would be better. Second tap and re-assembled and tooooooooooooooo tight #*%$ . Wont be doing it to a piston again. If engine is worth doing then its a re-bore. Similarly doing a "Cherry bomb to a clapped piston Heating it to a bright cherry red then quenching in oil can increase comp but can also make piston very brittle

[Tim Flyer]

For high performance engines I believe accepted practice is to have lightened aluminium piston running in hard liners . If u run Hard coated piston in Hard coated liner you may just be adding unnecessary reciprocating mass? Casting a new piston and machining it down to fit should produce higher performance ? Obviously all depends on application. If itx a diesel that needs to lug a load for years or a “cooking “ engine that just needs to be reliable then the spec is different but a heavy piston isn’t great for performance surely.