Do loose engines like nitrous?
Do loose engines like nitrous? Has anyone ever heard of over honing an engine block's piston bore to make it looser. I have been told that engines built looser like nitrous. Has anyone on here ever done this?
I've been reading some engine building articles for the past few hours and have determined my question is poorly worded. A better question would be what is a common piston to bore clearance for forged pistons (JE specifically) used on 4 inch bore iron blocks. Does adding nitrous to the mix demand an increase in the piston to bore clearance.
FormerVendor
Joined: Nov 2001
Posts: 3,065
Likes: 6
From: Houston, Tx.
I've been reading some engine building articles for the past few hours and have determined my question is poorly worded. A better question would be what is a common piston to bore clearance for forged pistons (JE specifically) used on 4 inch bore iron blocks. Does adding nitrous to the mix demand an increase in the piston to bore clearance.
Robert
FormerVendor
Joined: Nov 2001
Posts: 3,065
Likes: 6
From: Houston, Tx.
Robert, I would gap the second ring the same or larger than the top which will help you a little. I think your top gaps are fine though. I would do say .028 / .032 or the top ring gap lets enough gas by to fill up the space between the top and second rings and then the top ring unseats. Some NOS people actually run way more on the second ring although with bigger cold gaps you will have a little more blowby at idle etc. probably no matter what.
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Robert, I would gap the second ring the same or larger than the top which will help you a little. I think your top gaps are fine though. I would do say .028 / .032 or the top ring gap lets enough gas by to fill up the space between the top and second rings and then the top ring unseats. Some NOS people actually run way more on the second ring although with bigger cold gaps you will have a little more blowby at idle etc. probably no matter what.
Robert
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Verdad Gallardo FormerVendor
Joined: Nov 2001
Posts: 3,065
Likes: 6
From: Houston, Tx.
No they have nothing to do with each other. The gas ports are for where you have tighter ring grooves and/or need more area for the combustion gas to act on the top ring or want even more total pressure on the rings to keep them seated on the ring land and out again the cylinder wall. Usually you are using low radial tension backcut rings with gas ports and have tighter groove clearances so you need the gas ports to make the system work right. If you just put gas ports on a regular piston with full tension rings and normal clearance ring lands it usually just accelerates ring and bore wear.
FormerVendor
Joined: Nov 2001
Posts: 3,065
Likes: 6
From: Houston, Tx.
I would call Mike Panetta or Eric Simone at Diamond and they will tell you what extra clearance if any you need for your application. I know Mike Panetta form Diamond posts on here from time to time too.
No they have nothing to do with each other. The gas ports are for where you have tighter ring grooves and/or need more area for the combustion gas to act on the top ring or want even more total pressure on the rings to keep them seated on the ring land and out again the cylinder wall. Usually you are using low radial tension backcut rings with gas ports and have tighter groove clearances so you need the gas ports to make the system work right. If you just put gas ports on a regular piston with full tension rings and normal clearance ring lands it usually just accelerates ring and bore wear.
Robert
Again it just depends on what you are doing and how much NOS you are running. Running a little extra clearance is always safer. If the piston is actually made from the get-go for a certain amount of power adder a piston company like Diamond will engineer that clearance right into your piston at the same bore size so it will already have a slightly different skirt shape with different starting clearance. If you are using a shelf stock piston then you might have to add some clearance since they didn't set it up for that usage.
I would call Mike Panetta or Eric Simone at Diamond and they will tell you what extra clearance if any you need for your application. I know Mike Panetta form Diamond posts on here from time to time too.
I would call Mike Panetta or Eric Simone at Diamond and they will tell you what extra clearance if any you need for your application. I know Mike Panetta form Diamond posts on here from time to time too.
