Paint_It_Black

iTrader: (1)

Rebuilding a bottom end, stock displacement, forged rods and pistons. For an NA/small nitrous application, meduim to high RPM, what would the benefits be for:

- How low tension of a ring pack?
- oil squirters?
- dry sump?
- vacuum pump?
- coated skirts?


anything else suggested to look into?

Just looking for some suggestions!

1989GTA

For a street vehicle I would go with standard tension rings. Coated piston skirts are a good idea.

JPH

iTrader: (2)

Put the MAHLE powerpak piston setup in it. Lightweight, fully coated piston with low drag rings.

JPH

iTrader: (2)

Put the MAHLE powerpak piston setup in it. Lightweight, fully coated piston with low drag rings and maybe opt for total seal gapless rings. Then worry about oil control. What crank/rod combo?

deadhorse66

iTrader: (2)

The vacuum pump is something that must be implemented with low tension rings, however for a street application, I would not recommend either. Oil squirters would be a step backward unless you are heating the piston to insane levels with a power adder of some sort--they don't help power, they actually hurt it by creating more crankcase windage. They are more of a necessary evil in applications that really require them to maintain durability. Remember, you want to keep that oil off of your reciprocating assembly except what is absolutely necessary. Go with a coated piston, yes--thats almost free horsepower. Another thing I like to stress is plenty of oil clearance. Try to keep your rod side clearance around .025 or so, and you free up a lot of friction. Of course, your oil clearances should be around .0025 or so across the board. Keep your ring gaps at the low end of the spectrum (.016, add for nitrous) and watch it scream. All this stuff is crucial to a revver. Of course, these engines are built very well as they come with windage treys, baffled oil sumps, etc., so its hard to improve upon, but it can be done.

Paint_It_Black

iTrader: (1)

Good point about the squirters, I admit I don't know a lot about building a bottom end yet. I will leave those off, as I do not need them. I was going to ask about gas ports on the pistons as well, but figured they would get clogged with carbon over time and aren't worth it for a street/strip car. Those are the kind of numbers I was looking for deadhorse, I REALLY appreciate you sharing

JPH that is the second time someone recommended that Mahle setup for the piston, it must have it's merit and I've read good things about it. Looks like the way to go, thanks!

JPH

iTrader: (2)

Agree totally. A vaccum pump will burn the wrist pins up anyways on the street, unless coated and keep oil to them.