opening quench 080

[modok]

Make the quench clearance under .060 .040"
or make it 1/8 more than 3/16" inch.

Avoid .080, it's the worst place to be.

modok, please excuse the edit.

Can you get E85 or E98?

50-50 water-methanol injection might do it with the 85 octane pump gas, but ??

ok, I'll go with it, for emphasis
Now that you mention it I would lean towards setting tighter if running ethanol or water mix, as there is virtually no carbon build up.

[Frankshaft]

Ever try it? That's all I am sayin.

[user-612937456]

Quench is more important than most give it credit for greater than a 15% surface area and less than .040 clearance has more benefits negating the benefits of lowering compression. Tightening quench raises the detonation threshold by 1/2 to 1 compression point, via increased chamber turbulence near TDC thus faster flame travel. Dish pistons will be much prefered. Also consider removing and smoothing the point in the chamber between the valves which impedes flame travel above 5000RPM you should be able to gain a couple cc's there also can you get a head gasket a little larger than the bore as a few little things can add up. I need to give David Vizard credit for some of this knowledge.

[wyrmrider]

I would avoid a big bore head gasket
keep the seal over the cylinder walls and avoid dead spaces other ideas are great

[KnightEngines]

Buy some pistons or have yours dished, opening up the quench will make it a det pig.

[Geoff2]

I think you will find most builders accept 0.060" as the maximum distance from the piston crown to the quench pad, for there to be any real quench action. So you should try and select the parts accordingly.

[moparian]

Buy some pistons or have yours dished, opening up the quench will make it a det pig.

i can get a 20 cc dish piston it will give me a comp 14.4 and 040 quench ,which is not to bad .

[psychomotors]

Quench is more important than most give it credit for greater than a 15% surface area and less than .040 clearance has more benefits negating the benefits of lowering compression. Tightening quench raises the detonation threshold by 1/2 to 1 compression point, via increased chamber turbulence near TDC thus faster flame travel. Dish pistons will be much prefered. Also consider removing and smoothing the point in the chamber between the valves which impedes flame travel above 5000RPM you should be able to gain a couple cc's there also can you get a head gasket a little larger than the bore as a few little things can add up. I need to give David Vizard credit for some of this knowledge.

THIS is the info I was trying get when complaining about the lack of a good quality thin head gasket. Thanks gvx

[moparian]

thanks for the reply s ,there is great advice here and shows more than one way to skin a cat .if i set it up with the 14.4 and 040 gasket 4.100 bore 4 inch stroke and 400 cfm 276/284 800 lift what power would i expect on a 105 race fuel

[wyrmrider]

really changing the subject now as the last question depends on heads, cam, etc
IDK about making the max compression work vs the 14.5
As posted above some restricted classes would die for that high compression and it could work with a lot of work and give you a few more hp- but I'd do it only in a competitive heads up class
what heads?, get the flows and get together with Jones on the cam- he may have a been there - done that on the compression He will give you an excellent "second opinion" on your build"
what rockers etc

[moparian]

really changing the subject now as the last question depends on heads, cam, etc
IDK about making the max compression work vs the 14.5
As posted above some restricted classes would die for that high compression and it could work with a lot of work and give you a few more hp- but I'd do it only in a competitive heads up class
what heads?, get the flows and get together with Jones on the cam- he may have a been there - done that on the compression He will give you an excellent "second opinion" on your build"
what rockers etc

from the start .the car is a 3550 lb street/strip car was running 9.50@143 with a little spray 11.6 comp deal ,i was doing a new engine for it hoping to go 8.9 but the heads i was using was found to have 8 leaking cracks in them i have had the heads repaired b4 6 leaks then ,so i mocked up the ex prostock head which has no leaks ,but the comp is to high ,the car sits most of the time and does not do much racing or street driving and i do not race any class .but i do like driving my car to the track and driving home only 50 mile trip . i am not a fan of e 85 yet but it is cheap ,the fuel i have been running will handle 15.1 ,my old combo had 11,6 comp 256/262 050 on 107 l/c 420 lobe heads went 325 @700 and 1.6 rocker 230 cc intake runner 59 cc chamber ,the xps head goes 400 cfm@700 298 cc intake runner 36 cc chamber 1.85 intake rocker and 1.7 ex 440 lobe 276/284@050 800 lift .i like running full street trim .thanks