Piston slap - experiances !

[DamirGTI 323]

Gents ,

 

If anyone had no matter the engine make/model , forged or cast pistons ,  wish to hear you're experiences with the engines which developed piston slap .

 

If you opted for driving it till it goes bang , roughly how long did the engine last , oil consumption through the years/mileage of use , piston slap sound getting worse or not mileage/years wise .. any additional info also would like to hear about it .

 

I've an pretty much recently rebuild engine with de-glazed cylinders , new rings , but unfortunately old (cast) pistons which now sounds rough diesel like on cold starts ie. has piston slap on one or more cylinders/pistons (think it's just one but would need to check all of them ..)

 

Asking because info about this is very controversial , some say the engine will be no good and wont last long , others say it'll last (and it did last from a few , looks like , personal experiences) for many miles ahead .

 

Thanks !

D

[SweetBadger 91]

On the engine that came with my previous 205 race car it had forged pistons (measuring 86.4 mm), and the builder chose to use an 87mm bore. That had mega piston slap when the engine was cold, but was fine once warmed up. Made good power and compression. But... had a nasty habit of sending about a litre of oil into the catch tank by the end of every event.

 

The same pistons are now in a rebuilt engine with an 86.5mm bore. Same power, same compression, but no more issues with piston slap or oil being blown out of the breathers.

 

If it has good compression and no other obvious issues then I'd carry on using it.

Edited October 19, 2022 by SweetBadger

[DamirGTI 323]

17 minutes ago, SweetBadger said:

If it has good compression and no other obvious issues then I'd carry on using it. 

 

Yes , that's the plan for now ..

 

Compression seems good , only one cylinder is down about 0.5Bar measuring 13.5 (that one is bad with the piston slap me thinks) all the rest are 14Bar , runs and drives surprisingly good .

Hasn't yet done much mileage since the rebuild , around 1600miles , thus we'll see how will it be as it ages a bit .

 

It also quiets down when it warms up , thinking if it wont consume oil (at least not as much that it'll be problematic) and until it starts "slapping" post warm up and when under load should keep using it and see what happens ... letting it warm up for a minute or so at idle in the cold morning too and care to drive off slowly until it warms up .

 

Righto , thanks for you're insights with regards to this subject Alex !

 

D