Advanced Engineering Tech For the more hardcore LS1TECH residents

gurus, need a quick word on quench height

Thread Tools
 
Search this Thread
 
Old Jun 26, 2008 | 12:54 PM
  #21  
9000th01ss's Avatar
Banned
iTrader: (10)
 
Joined: Feb 2008
Posts: 3,235
Likes: 2
Default

Originally Posted by redbandit98
really? damn it. I hadn't looked yet, just going off what someone else had said. I just assumed they had it for a bored block. What bs. I have to find something that is no more than .030 to keep my quench below or at .055. I really dont want to use the .015 shims because im not positive my deck is 100 percent straight and .015 doesn't seem too forgiving.....

while i got you guys attention, assuming i can find a ~.030 head gasket, my static cr would be ~9.9.1. Im assuming there is no way in hell i can run this compression with iron vortec heads? im guessing Ill have to switch to aluminum?
I've run vortec heads with dome pistons at just short of 11:1 with a cam that gave it 8.4:1 dynamic compression. That engine also had the .015 gaskets, quench in the .03x range. Total timing at 34 degrees. It would actually run on 89 octane. (but I did run it on 93 regularly).

This is all part of engine building. You seem to be doing it backwards, not that it won't work. But I picked a max rpm, then pick a cam that will take it to that rpm, then pick a static compression that will give a good DCR with that cam.
Reply
Old Jun 27, 2008 | 11:30 AM
  #22  
redbandit98's Avatar
Thread Starter
TECH Fanatic
iTrader: (13)
 
Joined: Feb 2004
Posts: 1,164
Likes: 1
From: Ft.Smith AR
Default

well, according to keith blacks dynamic cr calculator, it shows my dynamic cr to be 7.9. I think that it may work if that is true.
64cc heads
7cc flat tops
.030 thick gasket (if i can find one)
4.1 gasket bore
4.040 cylnd bore
.025 deck cleareance
3.48 stroke. comes up to 9.839 static

with a 5.7 rod length and cam has 64* intake closing point at abdc @.050, it shows dynamic cr at 7.914. Do you see any discrepancies?
Reply
Old Jun 27, 2008 | 12:48 PM
  #23  
9000th01ss's Avatar
Banned
iTrader: (10)
 
Joined: Feb 2008
Posts: 3,235
Likes: 2
Default

I'd use a .015 gasket. They are rubber coated but you can spray them with perm a gasket copper, I've put new heads on old never decked blocks and never had a problem.
.055 is too much IMO.
Reply
Old Jun 27, 2008 | 12:50 PM
  #24  
redbandit98's Avatar
Thread Starter
TECH Fanatic
iTrader: (13)
 
Joined: Feb 2004
Posts: 1,164
Likes: 1
From: Ft.Smith AR
Default

really? thats a good sign. I was just worried since the block hadnt been decked. If it will seal, then i will def go that route. Still dont know about the cr though. Cant decide on if i need to get a bigger cc head or not.
Reply
Old Jun 27, 2008 | 02:53 PM
  #25  
9000th01ss's Avatar
Banned
iTrader: (10)
 
Joined: Feb 2008
Posts: 3,235
Likes: 2
Default

I really don't like running DCR in the 7's but high sevens would be ok. If you went much bigger than 64cc your dcr is going to be in the low 7's and thats not really good.
Reply
Old Jun 27, 2008 | 03:46 PM
  #26  
redbandit98's Avatar
Thread Starter
TECH Fanatic
iTrader: (13)
 
Joined: Feb 2004
Posts: 1,164
Likes: 1
From: Ft.Smith AR
Default

so you think im ok with premium gas and the iron heads? I was just looking at static cr, never knew much about the dynamic cr. Im learning alot.
Reply
Old Jun 28, 2008 | 01:21 AM
  #27  
9000th01ss's Avatar
Banned
iTrader: (10)
 
Joined: Feb 2008
Posts: 3,235
Likes: 2
Default

Yea, you should be ok in the 7.9 range or even if a .015 gasket puts you in the low 8.0 dcr range.

I've learned those DCR calculators are not 100% accurate. The one 357 I ran with close to 11:1 SCR, I used three different cams in that. Changed nothing at all but the cams and lifters, kept total timing the same. One cam was 8.4 DCR, the other two gave it 8.5 DCR. One cam and 8.5 DCR would run strong with 89 octane, the other cam with 8.5 DCR would detonate a bit on the top end with 93 octane.

As for quench, I put together a near stock 406 sbc, it had deep dish pistons, 64cc heads, small cam, .060 quench. I should have known better but that engine didn't like anything under 93 octane. It had well under 8.5 SCR.
Thats why I say keep it tight. Because it's worked for me.
Reply
Old Jul 3, 2008 | 11:38 PM
  #28  
itchygomey98's Avatar
TECH Enthusiast
iTrader: (2)
 
Joined: Oct 2003
Posts: 617
Likes: 0
Default

According to the calculator I use you're considerably lower DCR than you posted. http://www.kb-silvolite.com/calc.php?action=comp

Note where it says to add 15 degrees to the closing point at .050. According to that, you're at 6.959 DCR.
Reply




All times are GMT -5. The time now is 07:43 PM.