Can a 81.5mm piston fit on a 81mm bore?

All that has to do with the power train, gearbox, clutch, fuels and lubricants, etc. Generally the mechanical side of Formula One.
Leominster12
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Can a 81.5mm piston fit on a 81mm bore?

Post by Leominster12 » Mon Mar 25, 2019 7:00 pm

Hey guys i was just curious if a 81.5mm piston can fit on a 81mm bore because in the past f1 cars this type of method (well not exactly) and makes alot of power because the gas is very compressed and tightly squeeze inside the engine and i know it is preheated before starting engine to expand the metal to let loose the piston, because of this it can create alot of power naturally aspirated like the mclaren mp4/4, if this is possible it can be used in drag racing and road racing.

gruntguru
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Joined: Sat Feb 21, 2009 6:43 am

Re: Can a 81.5mm piston fit on a 81mm bore?

Post by gruntguru » Tue Mar 26, 2019 4:51 am

Only possible if the bore is round and the peg - sorry piston - is square.
je suis charlie

Tommy Cookers
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Re: Can a 81.5mm piston fit on a 81mm bore?

Post by Tommy Cookers » Tue Mar 26, 2019 9:54 am

Leominster12 wrote:
Mon Mar 25, 2019 7:00 pm
..... in the past f1 cars this type of method (well not exactly) ....
afaik
the pistons would distort at high power due to asymmetry of temperature distribution and load distribution
this was compensated by making them more than usually out-of-round when cold
generating interference in a cold bore

re the actual question ...
a friend had persistent trouble with cylinder liner splitting in his Renault R8
the cause was finally found - pistons 10 thou 0.25mm oversize but only 3 liners correspondingly (rebored presumably) oversize
the other liner was standard size and was (at first) replaced with an identical liner

Leominster12
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Joined: Mon Mar 25, 2019 6:54 pm

Re: Can a 81.5mm piston fit on a 81mm bore?

Post by Leominster12 » Thu Mar 28, 2019 8:29 pm

Well now i know you can’t start the engine when the temp is cold
Thanks for the answer and opinion.

Saxmansaxman
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Joined: Tue Oct 24, 2017 11:07 pm

Re: Can a 81.5mm piston fit on a 81mm bore?

Post by Saxmansaxman » Tue May 28, 2019 4:41 pm

No. Just no.

munudeges
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Joined: Fri Jun 10, 2011 4:08 pm

Re: Can a 81.5mm piston fit on a 81mm bore?

Post by munudeges » Tue May 28, 2019 5:27 pm

Ouch.

Phil
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Re: Can a 81.5mm piston fit on a 81mm bore?

Post by Phil » Tue May 28, 2019 6:33 pm

gruntguru wrote:
Tue Mar 26, 2019 4:51 am
Only possible if the bore is round and the peg - sorry piston - is square.
:lol: :lol:

Sorry :oops:
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coaster
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Re: Can a 81.5mm piston fit on a 81mm bore?

Post by coaster » Tue Nov 26, 2019 4:07 am

My post on grades of fit has been pulled down, sad, there was a lesson in this story.
Yours truly,
Wolsy Esquire.

3jawchuck
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Re: Can a 81.5mm piston fit on a 81mm bore?

Post by 3jawchuck » Tue Nov 26, 2019 4:44 pm

A small 81.5 mm piston could certainly fit in a large 81 mm bore.
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