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Is a .050" quench height still effective? #878836 12/13/10 10:58 AM 12/13/10 10:58 AM
Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually B BradH OP Taking time off to work on my car
BradH OP Taking time off to work on my car B Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually	Looking into how I can tweak (lower) the CR a tad and one option is to run a .050" head gasket vs. the standard .040". If I open up the quench to .050", is it still going to be effective?

Re: Is a .050" quench height still effective? [Re: BradH] #878837 12/13/10 11:05 AM 12/13/10 11:05 AM
Joined: Jan 2003 Posts: 74,970 U.S.S.A. JohnRR I Win
JohnRR I Win Joined: Jan 2003 Posts: 74,970 U.S.S.A.

Re: Is a .050" quench height still effective? [Re: JohnRR] #878838 12/13/10 11:25 AM 12/13/10 11:25 AM
Joined: Feb 2004 Posts: 3,441 Mo. S supercomp master
supercomp master S Joined: Feb 2004 Posts: 3,441 Mo.	Better be, can't run any less with aluminum rods.

Re: Is a .050" quench height still effective? [Re: supercomp] #878839 12/13/10 12:10 PM 12/13/10 12:10 PM
Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually B BradH OP Taking time off to work on my car
BradH OP Taking time off to work on my car B Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually	FWIW, mine is a steel-rod application.

Re: Is a .050" quench height still effective? [Re: BradH] #878840 12/13/10 12:18 PM 12/13/10 12:18 PM
Joined: Sep 2004 Posts: 6,906 IL, Aurora A ademon master
ademon master A Joined: Sep 2004 Posts: 6,906 IL, Aurora	How much difference is a .010 thicker gasket going to make in CR??? The tighter the quench the cooler the charge, If your having detonation/pinging you might be better off backing off the timing a couple degrees.

Re: Is a .050" quench height still effective? [Re: ademon] #878841 12/13/10 12:31 PM 12/13/10 12:31 PM
Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually B BradH OP Taking time off to work on my car
BradH OP Taking time off to work on my car B Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually	Between using a thicker gasket and choosing a gasket w/a larger ID (e.g. 4.45 or 4.50 vs. 4.38), I can "adjust" the CR down about .2 (from 11.0 to 10.8). The concern is the cranking pressure w/ 11.0 and the cam on hand could be pushing it w/ the available pump gas octane (93), so I'm considering ways to address this w/o actually taking a step backward.

Re: Is a .050" quench height still effective? [Re: BradH] #878842 12/13/10 12:52 PM 12/13/10 12:52 PM
Joined: Sep 2004 Posts: 6,906 IL, Aurora A ademon master
ademon master A Joined: Sep 2004 Posts: 6,906 IL, Aurora	I'm running about 205 cranking psi on 93, But i run ram air, no heat crossover, very cold plugs, hi stall in lighter car and keep total timing at 30.

Re: Is a .050" quench height still effective? [Re: BradH] #878843 12/13/10 12:55 PM 12/13/10 12:55 PM
Joined: Nov 2003 Posts: 5,160 Texas dannysbee master
dannysbee master Joined: Nov 2003 Posts: 5,160 Texas	I would rather have the tighter quench with 11.00 to one than the .050 with 10.8 to one. I ran a 10.8 to one cast iron head with .038 with a .223 at 50 cam for years on 92 pump gas. Only time I had any problem was when the temp got in the high 90's. You would hear just a little in high gear. Couple gallons of race gas would fix it. With aluminum heads better combustion chamber shape and more cam duration I would think you would be OK. Getting old just means you were smarter than some and luckier than others.

Re: Is a .050" quench height still effective? [Re: dannysbee] #878844 12/13/10 01:26 PM 12/13/10 01:26 PM
Joined: Jan 2008 Posts: 795 Glendale Az D Darryls-Demon super stock
Darryls-Demon super stock D Joined: Jan 2008 Posts: 795 Glendale Az	My 440 is 11:1 and I run 91 octane. The cylinder pressure is 170 PSI, the pistons are .005 out of the hole with a .039 gasket. Also the tops of my pistons are thermo coated as are the cumbustion chambers, valves, intake and exhaust ports and the inside and out side of the intake manifold.

Re: Is a .050" quench height still effective? [Re: BradH] #878845 12/13/10 01:31 PM 12/13/10 01:31 PM
Joined: Jan 2003 Posts: 16,923 NC 440Jim I Live Here
440Jim I Live Here Joined: Jan 2003 Posts: 16,923 NC	I don't have any data, but my feeling is that what you reduce the octane requirement by with the lower the CR, you will gain back with "less" quench. I don't think the quench is on/off, but more gradual change to the engine's octane requirement. So I wouldn't do that change in an attempt to need less octane fuel.

Re: Is a .050" quench height still effective? [Re: BradH] #878846 12/13/10 01:45 PM 12/13/10 01:45 PM
Joined: Feb 2007 Posts: 5,080 organ M maximum entropy master
maximum entropy master M Joined: Feb 2007 Posts: 5,080 organ	i know how much you value my input ( ), so i urge you to keep that quench as tight as possible! i've built several hot street engines with compression ratios close to 11:1, with very good results, as long as the quench is super tight. they've all been between .035 and .039. my personal mill started at .055, and had some issues in hot weather, that were completely ameliorated when i brought it to zero deck. i am the quench nazi because of this experience. for what is the good life if not doing things thoughtfully?

Re: Is a .050" quench height still effective? [Re: maximum entropy] #878847 12/13/10 02:09 PM 12/13/10 02:09 PM
Joined: Aug 2004 Posts: 2,128 sweden S sshemi top fuel
sshemi top fuel S Joined: Aug 2004 Posts: 2,128 sweden	just use a bad battery and a slow starter when checking crank comp and the pressure will decrease. Problem solved.

Re: Is a .050" quench height still effective? [Re: sshemi] #878848 12/13/10 02:13 PM 12/13/10 02:13 PM
Joined: Feb 2007 Posts: 6,295 U.S. M moparniac master
moparniac master M Joined: Feb 2007 Posts: 6,295 U.S.	I raced on 93 pumpgas with more quench than that at 11 to 1 Mopar Performance

Re: Is a .050" quench height still effective? [Re: maximum entropy] #878849 12/13/10 02:41 PM 12/13/10 02:41 PM
Joined: Aug 2004 Posts: 2,128 sweden S sshemi top fuel
sshemi top fuel S Joined: Aug 2004 Posts: 2,128 sweden	Quote: i know how much you value my input ( ), so i urge you to keep that quench as tight as possible! i've built several hot street engines with compression ratios close to 11:1, with very good results, as long as the quench is super tight. they've all been between .035 and .039. my personal mill started at .055, and had some issues in hot weather, that were completely ameliorated when i brought it to zero deck. i am the quench nazi because of this experience. Was that the only change you did???

Re: Is a .050" quench height still effective? [Re: sshemi] #878850 12/13/10 02:46 PM 12/13/10 02:46 PM
Joined: Jan 2004 Posts: 27,347 Today? Who Knows? 1_WILD_RT Management Trainee
1_WILD_RT Management Trainee Joined: Jan 2004 Posts: 27,347 Today? Who Knows?	As others have stated tighter is better, your better choice is probably to use a thinner gasket, raise the compression but tighten the quench down to the low .03 range... "The Armies of our ancestors were lucky, in that they were not trailed by a second army of pencil pushers."

Re: Is a .050" quench height still effective? [Re: 1_WILD_RT] #878851 12/13/10 03:00 PM 12/13/10 03:00 PM
Joined: Jan 2003 Posts: 9,872 Weddington, N.C. Streetwize master
Streetwize master Joined: Jan 2003 Posts: 9,872 Weddington, N.C.	I shoot for and have seen the best results at a target of .040, I've run as tight as .036" on a 12:1 combo; To my mind you alsos have to be mindful about piston rock and remember the rock at TDC effects the quench area oppositely on each bank of a V8. I would consider anything above ~.045" the same as "no quench" and this applies only to steel rod combos. WIZE World's Quickest Diahatsu Rocky (??) 414" Stroker Small block Mopar Powered. 10.84 @ 123...and gettin' quicker! https://www.youtube.com/watch?v=-mWzLma3YGI In Car: https://www.youtube.com/watch?v=PjXcf95e6v0

Re: Is a .050" quench height still effective? [Re: Streetwize] #878852 12/13/10 04:19 PM 12/13/10 04:19 PM
Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually B BradH OP Taking time off to work on my car
BradH OP Taking time off to work on my car B Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually	I'm seeing a pattern here... FWIW, the pistons stick out of the deck .002", so quench will be .038" w/ a typical composition gasket. I haven't assembled the thing, yet. However, I've collected most of the parts already. I don't know if I'll have to band-aid the 11.0 CR w/ a longer duration cam or not at this point.

Re: Is a .050" quench height still effective? [Re: sshemi] #878853 12/13/10 04:40 PM 12/13/10 04:40 PM
Joined: Feb 2007 Posts: 5,080 organ M maximum entropy master
maximum entropy master M Joined: Feb 2007 Posts: 5,080 organ	Quote: Quote: i know how much you value my input ( ), so i urge you to keep that quench as tight as possible! i've built several hot street engines with compression ratios close to 11:1, with very good results, as long as the quench is super tight. they've all been between .035 and .039. my personal mill started at .055, and had some issues in hot weather, that were completely ameliorated when i brought it to zero deck. i am the quench nazi because of this experience. Was that the only change you did??? i put in a slightly smaller cam, which would have made the problem worse. i hoped that the improved quench would help the situation (not that it was that bad), and to my surprise, the hot weather pinging has vanished. the car is faster, too btw. 1/2 a tenth. for what is the good life if not doing things thoughtfully?

Re: Is a .050" quench height still effective? [Re: BradH] #878854 12/13/10 06:24 PM 12/13/10 06:24 PM
Joined: Feb 2007 Posts: 6,295 U.S. M moparniac master
moparniac master M Joined: Feb 2007 Posts: 6,295 U.S.	Quote: I don't know if I'll have to band-aid the 11.0 CR w/ a longer duration cam or not at this point. I also was at 11.12 to 1 in my challenger and I raced on 93 pump gas with that also! with a puny 248/254 @ 50 roller with more than .050 quench.... however The cam was 69 Intake valve closing ABDC..... ever wonder why wallace wants to know this on his dynamic calc? the higher the number the more its bleeds of cylinder pressure... Ive seen miller post about this a few times also! good luck man http://www.wallaceracing.com/dynamic-cr.php Mopar Performance

Re: Is a .050" quench height still effective? [Re: moparniac] #878855 12/13/10 08:16 PM 12/13/10 08:16 PM
Joined: Dec 2008 Posts: 1,200 UK 6 602heavy pro stock
602heavy pro stock 6 Joined: Dec 2008 Posts: 1,200 UK	Quote: Quote: I don't know if I'll have to band-aid the 11.0 CR w/ a longer duration cam or not at this point. I also was at 11.12 to 1 in my challenger and I raced on 93 pump gas with that also! with a puny 248/254 @ 50 roller with more than .050 quench.... however The cam was 69 Intake valve closing ABDC..... ever wonder why wallace wants to know this on his dynamic calc? the higher the number the more its bleeds of cylinder pressure... Does early intake valve closure have a direct bearing regards detonation? , maybe excessive overlap (ex bias) has more influence than we think.. , lots of variables to think about regards valve events.

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