help again:p new engine!!

[wilko7]

hi
just had new engine 4 my l1
this engine is a l8
took head off to check it all and that and have found that the piston on the exhaust side has been machined out
does any1 know why this is?? performance or wot?
thanks

[zimm]

thats not been machined, thats been hammered by the exhaust valves due to incorrect cam timing.

[wilko7]

all vlaves have to come out agen then
these pistons are scrap aint they

[rmkd177]

Sorry to disagree Zimm but i think they have been machined by some 'clown' ....you can see the cicular marks from the cutting 'tool' 'equipment' ?? i have some in an engine that came to me...i wouldnt use them personaly... if they are marks from the valve 'clapping' the piston i wouldnt use the valves either.

[wilko7]

ye u can c the circular marks thats why i thought they had been machined and theres no signs of the valves been hittin the piston.
on me last engine wen the piston hit the valves you could seen the imprint but nothing like this.
if it has been machined out does any1 know why people do this?
cus i would of thought that the compression ratio wold be reduced wich inturn reduces power.
thanks for all your feedbck

[wilko7]

and they are all identical.
same depth
so if valves had done they wouldnt all be the same cus 1 out of 8 should have gid up
i think??

[zimm]

Sorry to disagree Zimm but i think they have been machined by some 'clown' ....you can see the cicular marks from the cutting 'tool' 'equipment' ?? i have some in an engine that came to me...i wouldnt use them personaly... if they are marks from the valve 'clapping' the piston i wouldnt use the valves either.

i have some too, out of both a zxr400 that had never had the head off before and a tuned zx6r with JE pistons that clattered like mad then snapped 3 valves the first time it was red-lined, the circular nature of the marks i believe to be down to the fact that the valves rotate each time they open..



either way, twatted or "modded" they ought to head bin-wards, and i'd check the rest of the engine carefully

[wilko7]

how come the vlves dont have signs or wear?
i thougt the valves would hve gne b4 doin this to the pistons.
i am think ill use my bottom end n get the head reconed