First Real Build

[shownomercy]

I run a thick MLS HG from cometic, no issue yet but who knows.

[kevloc77]

I've heard good things about Cometic. I'm just wondering if a .050 - .070 will hold up to nitrous. I will be using ARP hardware.

[shownomercy]

I run a .040 compressed on mine, so far so good. The initial spike of cylinder pressure is more with nitrous so not a direct comparison.

For a 700fwhp motor, I would say you should be ok with MLS, but as always talk to Cometic.

[firebird_1995]

I would be leery about running a thick head gasket on a nitrous build. On an engine built for boost (low compression), the dish of the piston makes quench basically non-existent so it's not as much of a concern to run a thick head gasket. On a n/a or nitrous setup, you want to try and keep the quench under .045".
So if you end up with a deck height of .020" and run a .060" gasket you would have a .080" quench.

[shownomercy]

I would be leery about running a thick head gasket on a nitrous build. On an engine built for boost (low compression), the dish of the piston makes quench basically non-existent so it's not as much of a concern to run a thick head gasket. On a n/a or nitrous setup, you want to try and keep the quench under .045".
So if you end up with a deck height of .020" and run a .060" gasket you would have a .080" quench.

I am not N20 expert, or an expert in anything really, but just from reading across the bullet, quench on nitrous cars is moot. Making it larger gets you a better tuning window and a downside of needing a larger first stage to get off the line. Ranges from .040 to .100 on YB lol

What does Kyle say about this? @dawdaw He has that friend of a cousin, who knows that guy

[kevloc77]

Well I am having the machine shop do minimal removal off the deck when he squares it up so it leaves me a bit of room to work with. As of right now I'm looking at a static compression ratio of about 13:1. Of course I wont get exact numbers until I do a mock up but that's with a deck height of .015 and a head gasket of .039. I'm trying to research info about quench and static vs dynamic compression ratios. I don't know if I'm getting too high of compression for this build. This crap isn't as easy as throwing a bunch of parts in a block then hitting the skinny pedal...

[Catmaigne]

13:1 isn't gonna jive well with pump gas. If you are desperate to drop compression then consider switching to pistons with more dish or heads with larger chambers. Aftermarket heads like Trick Flows or AFR commonly get up to the 60-70cc range... although some might not flow as well as ported stock castings.

[dawdaw]

I am not N20 expert, or an expert in anything really, but just from reading across the bullet, quench on nitrous cars is moot. Making it larger gets you a better tuning window and a downside of needing a larger first stage to get off the line. Ranges from .040 to .100 on YB lol

What does Kyle say about this? @dawdaw He has that friend of a cousin, who knows that guy

Nah its a friend of a cousin of a neighbor or a girlfriend of a mother

[Injuneer]

Might be time to start over.

Did you decide to go with a 383 crank?

The piston specs you listed show they are for 6.00" rods and a 3.75" stroke. When you were going with the 3.50" 2-piece rms crank you said you would go with 6.125" rods to compensate.

You said you were buying 6.125" rods. But you said you were going to a 3.75" crank.

Confusing. At any point have you checked to see where this combo (whatever it is) puts the wrist pin with regard to the ring pack?

[kevloc77]

Sorry if it got confusing. So the combo is as follows:
Same pistons listed as before with a compression height of 1.125. wrist pin is in
Scat H beam rods at 6.125 length
Scat Crank with a 3.50 stroke. its a two piece seal and I have the adapter for that.