Quench

[JimNolan]

Guys,
   I've been sitting here playing with Dyno Software trying to figure out how I'm going to get the best performance and longivity out of this FE engine I'm building.
I know there's some experience on this forum that might be able to help me. I'm trying to choose the right quench for my engine. I've read articals telling you to put it a .035-.060. All these articals are good I guess but they are conflicting. Soooo, I thought I'd ask you guys what experience you've had with manipulating quench on the engines you've had. For a little background, the engine is going to have @ 375-400 HP with an @ 10-1 compression ratio. The L2291F30 flat top pistons will have .004 deck height. The Cam is 282/288 with .515/.540 lift with 110 sep/108 cl.
   Soooo, what quench have you guys had luck with and why did you choose it. Thanks, Jim

[ranchero57]

Hi Jim
  Sounds like you are putting a nice durable  street engine together.I have a lot of experience with quench areas in motorcycles then v-8 hydroplanes and drag race automobiles and finally oval track cars.dirt and paved.The reason you are getting so many different clearances is because different race type engines require different quench clearances.For what it sounds like you are building I would use a head gasket .041 thick minumum to .048 maximum.This would give you 45 to 52 thou.quench,I would like to stay at 45 for what you are building.If you would like to know why you can give me a call.Campy 1-985-290-6327

[JimNolan]

Campy,
    Thanks for spending the time to talk with me this morning. I enjoyed our conversation. For those wanting to know the results, this is what I got out of the conversation about quench (or squish). Campy, correct me if I'm wrong.
1. A quench of @ .035 is for drag racing where you don't let off the accelerator pedal. On the pedal, off the pedal as in dirt track racing won't work with that tight of quench due to fact valve clearance could become an issue.
2. A quench of @ .045 -.058 is best for street/strip applications as I have. Small enough to help prevent detonation with pump gas but large enough to prevent damage by valves.
3. Quench manipulation is only available on engines with enough flat area as in flat top pistons with half moon type cylinder head configurations. Hemi-heads aren't quench motors.
4. Without a cam with enough overlap, cranking pressure could be too high for the starter to overcome it.
Thanks, Campy

[ranchero57]

Hi Jim
  You got it pretty close except about the valves.Quench doesnt effect the valves,its just that detonation sounds like valves rattling! Campy

[canadian_ranchero]

the one thing you need to watch for is the space between the piston and the head.the closer you can run it the more efficient the engine will be.if you want more info,just let me know

[JimNolan]

Canadian Ranchero,
     Campy helped me out on quench some. He's done a lot of motor building and recommended .045. The guy that's doing the machine work on my block and heads and doing the balancing builds Sprint Car engines and he recommended .045. As luck would have it, the block was off .005 on both sides so my machinest is decking the block .010 to straighten it out. That gives me .004 piston to deck height and I'm using .041 Fel-Pro gaskets and I'll have what everyone so far has advised for quench. The biggest advantage I see to the whole quench deal is being able to run 10.3 compression and not need a lot of timing. I can run pump gas with a 400 hp engine.
    If you've got anything to add, please do. I enjoy knowledge. Jim