Highest compression with quench iron heads?
#873604
12/07/10 03:00 PM
12/07/10 03:00 PM
|
Joined: Apr 2009
Posts: 3,429
Toronto
mshred
OP
master
|
OP
master
Joined: Apr 2009
Posts: 3,429
Toronto
|
Hey guys, Planning out my 360 build right now and have a concern. My engine will be a street motor and must run on pump gas. Heads are still up in the air, but im figuring with a 67cc closed chamber head, KB107's (5cc effective dome) .30 over and zero decked, stock stroke, with a fel pro 8553 permatorque gasket (still not sure compressed thickness, but going by .051") im netting about a 10.06:1 compression ratio Punching this into an effective compression ratio calculator on wallace racing website, with about 70 volumetric efficiency, i got an effective CR of about 7.06 What im wondering is how accurate a calculator like this is and how quench can be factored into this? Should i be running a thinner head gasket, possibly even a higher compression, and still be able to run 93 pump gas or lower with close chamber iron heads? And how do i figure my cam into all of this in relation to cranking psi and being able to bleed off cylinder pressure. Bullet cams recommended me this cam for my goals dur @ .050 232/242 lift .555/.555 lsa 108 int c/l 104 Im starting to get a much better grasp on all these ideas, but im still not sure how to tie them all together to figure out exactly how to reach my hp goal with this combination on pump gas any help would be greatly appreciated...hopefully this question isnt too general or stupid lol thanks Matthew 
|
|
|
Re: Highest compression with quench iron heads?
[Re: mshred]
#873605
12/07/10 03:08 PM
12/07/10 03:08 PM
|
Joined: Sep 2004
Posts: 6,906
IL, Aurora
ademon
master
|
master
Joined: Sep 2004
Posts: 6,906
IL, Aurora
|
you could probably run 87 with that setup, i'm running 11.2cr on 93, with j heads but i have a high stall, very cold plugs, ram air, in light car, 30 total timing,cranking psi is 205, if i was going to the track i would mix 93 with race and timing up to 34.
|
|
|
Re: Highest compression with quench iron heads?
[Re: mshred]
#873606
12/07/10 03:41 PM
12/07/10 03:41 PM
|
Joined: Feb 2007
Posts: 5,080
organ
maximum entropy
master
|
master
Joined: Feb 2007
Posts: 5,080
organ
|
my guess is you'd be ok at 10:1 on pump premium. the smaller bore is a little less prone to detonation, if my info is correct.
for what is the good life if not doing things thoughtfully?
|
|
|
Re: Highest compression with quench iron heads?
[Re: mshred]
#873608
12/07/10 08:08 PM
12/07/10 08:08 PM
|
Joined: Feb 2007
Posts: 5,080
organ
maximum entropy
master
|
master
Joined: Feb 2007
Posts: 5,080
organ
|
Quote:
I have a question here- if i go to a thinner head gasket, effectively tightening quench, but also compression, what would change? would the better quench allow me to raise compression but still run the same gasoline, in other words making it the best of both worlds? Or would tightening the quench and the resulting increase in compression nescesitate a need for higher octane gasoline.
and how does my cam and cranking compression factor into this, if at all?
you don't want the pistons crashing into the heads, so make sure you have .040 or so between heads and pistons. as far as detonation resistance, my own 496 is a good example. as a 440 with open chamber iron heads and pistons .100 in the hole, it was an 8:1 (if that) pig that detonated on premium. after the rebuild, it's zero deck, .039 quench, 10.33:1 496 that never detonates. it is possible imo to raise the compression and reduce the tendency to detonate at the same time, assuming something was off with the combo to begin with.
for what is the good life if not doing things thoughtfully?
|
|
|
Re: Highest compression with quench iron heads?
[Re: mshred]
#873609
12/08/10 10:15 AM
12/08/10 10:15 AM
|
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
I Live Here
|
I Live Here
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
|
Quote:
Hey guys,
Planning out my 360 build right now and have a concern. My engine will be a street motor and must run on pump gas. Heads are still up in the air, but im figuring with a 67cc closed chamber head, KB107's (5cc effective dome) .30 over and zero decked, stock stroke, with a fel pro 8553 permatorque gasket (still not sure compressed thickness, but going by .051") im netting about a 10.06:1 compression ratio
Punching this into an effective compression ratio calculator on wallace racing website, with about 70 volumetric efficiency, i got an effective CR of about 7.06
What im wondering is how accurate a calculator like this is and how quench can be factored into this? Should i be running a thinner head gasket, possibly even a higher compression, and still be able to run 93 pump gas or lower with close chamber iron heads? And how do i figure my cam into all of this in relation to cranking psi and being able to bleed off cylinder pressure. Bullet cams recommended me this cam for my goals
dur @ .050 232/242
lift .555/.555
lsa 108
int c/l 104
Im starting to get a much better grasp on all these ideas, but im still not sure how to tie them all together to figure out exactly how to reach my hp goal with this combination on pump gas
any help would be greatly appreciated...hopefully this question isnt too general or stupid lol
thanks
Matthew
KB107's are an effective 5cc DISH (valve relief cutouts)
you'll be better off running the .039" head gaskets--yes, you'll have slightly more compression, but that will be more than offset by the tighter quench clearance. a friend has been there, done that, although it was on an 11.4-11.7:1 aluminum headed 396" small block chev. knock resistance went up with the higher compression/tighter quench. went from ONLY running on shell 93 octane w/o knock to running on any pump premium (91-93) in the area without knock.
a number of guys are running magnum headed 360's with KB107's on the board (works out to ~10.6:1 static) and a comp XE268, and running on 89-91 octane, so I'd say with your larger cam you'll be fine, it may even run on 87 if you use the tighter quench...
Last edited by patrick; 12/08/10 10:18 AM.
1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
|
|
|
Re: Highest compression with quench iron heads?
[Re: mshred]
#873612
12/08/10 10:45 PM
12/08/10 10:45 PM
|
Joined: Jan 2003
Posts: 27,421
Balt. Md
383man
Too Many Posts
|
Too Many Posts
Joined: Jan 2003
Posts: 27,421
Balt. Md
|
The 440 in my 63 has 10.0 comp and about .045 quench with iron 906 heads. I can run 92 pump with no ping and no problems at all and timing is at 37 total. Ron
Last edited by 383man; 12/08/10 10:46 PM.
|
|
|
Re: Highest compression with quench iron heads?
[Re: 383man]
#873613
12/08/10 11:24 PM
12/08/10 11:24 PM
|
Joined: Apr 2009
Posts: 3,429
Toronto
mshred
OP
master
|
OP
master
Joined: Apr 2009
Posts: 3,429
Toronto
|
Quote:
The 440 in my 63 has 10.0 comp and about .045 quench with iron 906 heads. I can run 92 pump with no ping and no problems at all and timing is at 37 total. Ron
Hey Ron,
Are 906 big block heads closed chamber? if they aren't, what kind of pistons are you using to achieve the quench affect?
|
|
|
Re: Highest compression with quench iron heads?
[Re: mshred]
#873614
12/08/10 11:54 PM
12/08/10 11:54 PM
|
Joined: Nov 2003
Posts: 5,160
Texas
dannysbee
master
|
master
Joined: Nov 2003
Posts: 5,160
Texas
|
He is running the reverse dome KB pistons.
Getting old just means you were smarter than some and luckier than others.
|
|
|
Re: Highest compression with quench iron heads?
[Re: mshred]
#873617
12/09/10 07:25 AM
12/09/10 07:25 AM
|
Joined: Dec 2009
Posts: 1,074
detroit, mi
POS Dakota
super stock
|
super stock
Joined: Dec 2009
Posts: 1,074
detroit, mi
|
Quote:
Thanks for the info guys! This confirms my initial inquiry...i guess it makes more sense to tighten up the quench, even if it raises compression, since it seems like it only helps instead of worsening things
Quote:
The 8553 felpro is .054 compressed IIRC.
They come as the old LA replacement gasket I think and they also make a heavier duty version with an "SD" designation in the part number.
Trying to go off memory here.
I think these are one of those gaskets that they dont advertise the compressed thickness on summit.
I am using them in my 408 with a .036-.037 quench distance, 10.3:1 static and 9.3:1 dynamic compression. This is a pump gas engine.
The 8553 is not listed for specs on summit, you are right. You mention another gasket as well- which ones are you running? the 8553's or the others? with the 8553's and .036 quench, are your pistons above the deck?
Yep. I am .017 out of the hole which is why I needed to use these. I am using the straight up blue 8553 and not the heavy duty one.
These gaskets are listed as a factory LA replacement gasket for LA engines, some of which I believe had more compression than 10:1, so there should be no problem. They have the armored fire ring and should give no problems as long as there are no engine tune issues just like anything else.
I was going to have cometics made for me, but honestly, I would rather blow a head gasket if there was a problem, than a piston is my logic.
Plus they are dirt cheap to replace. I think they are about 30something bucks for the 8553 and the heavy duty version is like 65 bucks IIRC.
|
|
|
Re: Highest compression with quench iron heads?
[Re: 383man]
#873618
12/09/10 02:27 PM
12/09/10 02:27 PM
|
Joined: Jul 2009
Posts: 413
Norway (old world)
Oyvind Mopar
mopar
|
mopar
Joined: Jul 2009
Posts: 413
Norway (old world)
|
Quote:
Quote:
Quote:
The 440 in my 63 has 10.0 comp and about .045 quench with iron 906 heads. I can run 92 pump with no ping and no problems at all and timing is at 37 total. Ron
Hey Ron,
Are 906 big block heads closed chamber? if they aren't, what kind of pistons are you using to achieve the quench affect?
I am using these KB quench pad pistons to get some quench. They are alot of work to even out the chambers and get the quench close on all cylinders. But they seem to do the trick and have been trouble free. It is much easier to build a zero deck flattop piston eng with closed chamber heads and use the .039 head gasket for good quench. I only built this setup because I had these parts laying around. My new eng will be a zero deck closed chamber eng. Ron
Hey, Ron! It looks as your #8 piston is not correct, it should have been mirrored to the # 6 to enable intake valve clearance.... Is it for mockup only? My 
|
|
|
Re: Highest compression with quench iron heads?
[Re: POS Dakota]
#873619
12/09/10 02:28 PM
12/09/10 02:28 PM
|
Joined: Apr 2009
Posts: 3,429
Toronto
mshred
OP
master
|
OP
master
Joined: Apr 2009
Posts: 3,429
Toronto
|
Thanks for all the info guys! Its much appreciated...I atleast know im on the right track in my thinking with how im going to put this thing together... Only thing left im wondering is if i should bring the pistons above the deck some like POS so that im getting about .039" quench with the 8553's, or if i should just buy a different gasket all together. A friend of mine might have some used cometics for sale, have to see what thickness they are though...although the availability and price of the 8553's is tempting me to stick with them (especially since they come in the gasket set im buying lol) thanks!
|
|
|
|
|
