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JLO L252R Point Gap?Arrow on Piston Exhaust or Intake
Posted: Fri Jan 28, 2011 7:51 am
by Red Devil 500
Well a few more of my pictures would have helped if i took some of the engine disassembly but oh no!
So Point gap for the 252 is ????
And the arrow on the stock piston goes towards??Intake or Exhaust???
Thanks guys Sean!
Re: JLO L252R Point Gap?Arrow on Piston Exhaust or Intake
Posted: Fri Jan 28, 2011 12:47 pm
by fap67
Arrow toward exhaust. Point gap is .016 of an inch.
Re: JLO L252R Point Gap?Arrow on Piston Exhaust or Intake
Posted: Fri Jan 28, 2011 3:45 pm
by Barrie2777
Hey Sean...only 15 days more.
Re: JLO L252R Point Gap?Arrow on Piston Exhaust or Intake
Posted: Sat Jan 29, 2011 3:29 pm
by Red Devil 500
RUNNING last nite!!! to be installed Sunday as i have a local vintage run next Saturday.This will allow me to get the bugs out of it.
Sean
Re: JLO L252R Point Gap?Arrow on Piston Exhaust or Intake
Posted: Wed Sep 21, 2011 2:46 pm
by huuksnatch
If i put my Arrow going toward the Intake what would happen? (This might already be done
)
Re: JLO L252R Point Gap?Arrow on Piston Exhaust or Intake
Posted: Wed Sep 21, 2011 9:36 pm
by Go Go Diablo
Not sure on the JLO, but if it was a Hirth, this is how I understand the potential problem.
The intake port is lower in the cylinder head and the exhaust port is higher in the head. During the stroke of the piston, the rings do not come down far enough to come into the intake port, but they do pass by the exhaust port. So why the arrow?
When the rings are installed on the piston, there are little pins in the ring grooves where you put the ends of the ring. Once installed, the pins stop the ring from spinning in the ring groove. That is important because you don't want the ring to spin so the ends come into the exhaust port because if they do, they can pop out of the groove slightly and then they could get caught when passing through the port.
Pointing the arrow toward the exhaust means the pins are toward the intake port and your ring ends stay on the intake port side of the cylinder where they never pass a port during the stroke of the piston.
Did that make sense?