How tight do you guys run your piston to cylinder wall clearance?
#1
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How tight do you guys run your piston to cylinder wall clearance?
The spec for my pistons (Endyn RW) calls for .0022". The machinist who is boring/honing my block said that sounded a bit on the tight side. I'd like to run the clearance as tight as possible to increase ring seal life.
As a side note, on my direct drive kart engine, I ran the clearance as tight as .0005". However, that thing has no clutch and has an RPM range of 2000 to 18000 rpm.
Sonny
As a side note, on my direct drive kart engine, I ran the clearance as tight as .0005". However, that thing has no clutch and has an RPM range of 2000 to 18000 rpm.
Sonny
#2
Re: How tight do you guys run your piston to cylinder wall clearance? (Sonny)
i dont have a clue what the clearence is but do you think that you could record your kart @ 18,000 rpm? That would be sweet. I dont think I've herd a engine rev over 9k.
Blaze
Blaze
#4
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Re: How tight do you guys run your piston to cylinder wall clearance? (Blaze45)
i dont have a clue what the clearence is but do you think that you could record your kart @ 18,000 rpm? That would be sweet. I dont think I've herd a engine rev over 9k.
Blaze
Blaze
http://www.ekartingnews.com/media/main.html
Some of the Italian Formula A engines rev to 23,000 rpm+. That is necessary because they run without a clutch and have no gearbox.
Sonny
EDIT-The link has been changed, so I updated it.
[Modified by Sonny, 10:12 AM 7/17/2002]
#6
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Re: How tight do you guys run your piston to cylinder wall clearance? (TurbochargedSER)
I run piston to wall clearances @ .0030" - .0035"
Good to see that you're still around. The machinist was telling me generally, he shoots for about .0010" inch of clearance per 1 inch of bore size. My bore is 75.5mm = 2.97 in = about .0029 of clearance. The SR20 is an 86mm bore, no? The same logic would yield .0034" of clearance, so I guess that's about right.
With the 2 strokes, I always had the best luck with running the clearance as tight as possible. The ring (only 1 ) seal would usually last a lot longer although I did stick a few pistons by getting too crazy during break-in.
Sonny
#7
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Re: How tight do you guys run your piston to cylinder wall clearance? (Bryson)
I race RC cars....those little engines scream like no other.
Do you race Bryson?
Do you race Bryson?
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Re: How tight do you guys run your piston to cylinder wall clearance? (Sonny)
I run piston to wall clearances @ .0030" - .0035"
Hey Louis:
Good to see that you're still around. The machinist was telling me generally, he shoots for about .0010" inch of clearance per 1 inch of bore size. My bore is 75.5mm = 2.97 in = about .0029 of clearance. The SR20 is an 86mm bore, no? The same logic would yield .0034" of clearance, so I guess that's about right.
Sonny
Hey Louis:
Good to see that you're still around. The machinist was telling me generally, he shoots for about .0010" inch of clearance per 1 inch of bore size. My bore is 75.5mm = 2.97 in = about .0029 of clearance. The SR20 is an 86mm bore, no? The same logic would yield .0034" of clearance, so I guess that's about right.
Sonny
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Re: How tight do you guys run your piston to cylinder wall clearance? (TurbochargedSER)
Looking at the suggested and the factory specs- why is there such a difference? .0001-.0005 from the factory is a bit different than .003
Thanks
Ben
Thanks
Ben
#10
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Re: How tight do you guys run your piston to cylinder wall clearance? (Bnjmn)
Looking at the suggested and the factory specs- why is there such a difference? .0001-.0005 from the factory is a bit different than .003
Thanks
Ben
Thanks
Ben
Sonny
#12
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Re: How tight do you guys run your piston to cylinder wall clearance? (rice4life)
The spec sheet that came with my JE pistons says to use a .0035" for the piston to wall clearance. Then continues to state that some applications may require more clearance.
#13
Re: How tight do you guys run your piston to cylinder wall clearance? (93LSivic)
My JE's paperwork call for .004'' for a B20B. I have heard this is too loose though. Any suggestions?
#14
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Re: How tight do you guys run your piston to cylinder wall clearance? (magicwand)
I have a custom turbo piston done at JE and their specs say .0045 or MORE
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Re: How tight do you guys run your piston to cylinder wall clearance? (Sonny)
That's what I thought, just wondering if there was some advantage (other than necessity) to running greater clearance.
What gives with the JE clearance being double that of the Endyn? That much more expansion?
Thanks
Ben
What gives with the JE clearance being double that of the Endyn? That much more expansion?
Thanks
Ben
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Re: How tight do you guys run your piston to cylinder wall clearance? (Bnjmn)
That's what I thought, just wondering if there was some advantage (other than necessity) to running greater clearance.
What gives with the JE clearance being double that of the Endyn? That much more expansion?
Ben
What gives with the JE clearance being double that of the Endyn? That much more expansion?
Ben
to orig poster: stick with 0.0021" clearance ... Endyn forging process is different than most aftermarkets.
Greg
#19
Re: How tight do you guys run your piston to cylinder wall clearance? (Arturbo)
Im running .0040" on my motor with ross custom pistons, yup sounds like a diesel engine, they're much louder than srp @ warmup
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Re: How tight do you guys run your piston to cylinder wall clearance? (Arturbo)
basically, he means the general shape of the piston. Endyn designs the combustion area, Wiseco does everything else.
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Re: How tight do you guys run your piston to cylinder wall clearance? (VaporTrail)
Im running 0.005 with my 85mm JEs and they rattle a little bit on idle and decel. The more boost or nitrous your gonna run leave a little more clearance, or if you plan to do endurance racing. We have run 0.003 with JEs and they were fine on 20 psi, no problems as of yet and we have logged many miles.
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