LS and LS based engine head questions, also forum question
06-27-2016, 03:33 PM
#1
Teching In
Thread Starter
Join Date: Apr 2015
Posts: 2
Likes: 0
Received 0 Likes
on
0 Posts
LS and LS based engine head questions, also forum question Hi guys,
I have a 5.3L (ls based?) engine in my truck and was thinking the other day would a 4v per cylinder head be possible? 32 total valves?
I know that GM had the northstar v8's in the Cadillac with 32 valves, were those OHC engines? or pushrod v8's? perhaps they were based on the gm 350 sbc and wouldn't fit anyways but just curious.
also, in regards to the forum sub-forums, what are internal and external engines?
for instance there are subforums for Gen III internal and Gen III external engines...didn't know what this meant.
I have a 5.3L (ls based?) engine in my truck and was thinking the other day would a 4v per cylinder head be possible? 32 total valves?
I know that GM had the northstar v8's in the Cadillac with 32 valves, were those OHC engines? or pushrod v8's? perhaps they were based on the gm 350 sbc and wouldn't fit anyways but just curious.
also, in regards to the forum sub-forums, what are internal and external engines?
for instance there are subforums for Gen III internal and Gen III external engines...didn't know what this meant.
06-27-2016, 04:16 PM
#2
32V - Theoretically, time and money, anything is possible. With the power one can make from the LS engine with only two valves, the question, to me, is "is it worth it?"
The answer, to me, is "no." IMO there isn't enough room for twice as many lobes on the cam, so you end up with a forked rocker of sorts with one lobe/lifter actuating two valves. Messy. There were some really cool heads that tried this for SBF/SBC 10-15 years ago but obviously it just wasn't worth it as they aren't blowing the doors off at strips across the country now.
Yes, 32V Northstars were/are OHC. But it doesn't take a genius to see what GM's opinion is when you look at the fact that as late as 2009 there was the STS-V with a supercharged Northstar while today the CTS-V continues with a pushrod engine and the STS is non-existent.
The engine that was 32V/DOHC that was closest to the SBC would be the LT5 in the 90's ZR1. Awesome for the time, but still not practical:
http://www.nookandtranny.com/Info_ZR1LT5.html
Finally, internal vs. external: same engine(s) but referring to conversations re: things internal to said engine vs. external to said engine. Internal basically stops at the long block (though read the stickies for further explanation) and external is everything north and south of that.
The answer, to me, is "no." IMO there isn't enough room for twice as many lobes on the cam, so you end up with a forked rocker of sorts with one lobe/lifter actuating two valves. Messy. There were some really cool heads that tried this for SBF/SBC 10-15 years ago but obviously it just wasn't worth it as they aren't blowing the doors off at strips across the country now.
Yes, 32V Northstars were/are OHC. But it doesn't take a genius to see what GM's opinion is when you look at the fact that as late as 2009 there was the STS-V with a supercharged Northstar while today the CTS-V continues with a pushrod engine and the STS is non-existent.
The engine that was 32V/DOHC that was closest to the SBC would be the LT5 in the 90's ZR1. Awesome for the time, but still not practical:
http://www.nookandtranny.com/Info_ZR1LT5.html
Finally, internal vs. external: same engine(s) but referring to conversations re: things internal to said engine vs. external to said engine. Internal basically stops at the long block (though read the stickies for further explanation) and external is everything north and south of that.
Last edited by Mercier; 06-27-2016 at 11:04 PM.
07-09-2016, 02:28 AM
#3
Teching In
Join Date: Jun 2016
Location: Georgetown OHIO
Posts: 14
Likes: 0
Received 0 Likes
on
0 Posts
Ok i gotta question! Hopefully somebody can help. If I put 799 heads on my 04 5.3 the compression will drop ,right ? I'm running all ls6 top end if that helps. The block has been decked and I'm gonna run forged pistons and rods. And was thinking about running a ms3 cam. What can I do to bring this compression back up? I want to do this right the first time. And once I get the money for the turbo I'll be switching cams. Idk what head gaskets to run or nothing I'm a bodyman/ painter building my first hot rod and i hate to build something that won't run. Plz help me out lol !
07-09-2016, 02:34 AM
#4
Teching In
Join Date: Jun 2016
Location: Georgetown OHIO
Posts: 14
Likes: 0
Received 0 Likes
on
0 Posts
How far should I mill the heads ? How much compression do i want knowing it's gonna get a turbo. I've searched this site and Google for 2 weeks now and I can't figure out what to do ! I'm wanting like 400 to 500 hp n/a if possible with this setup before turbo. Any help would be awesome!
07-10-2016, 11:51 AM
#6
Teching In
Join Date: Jun 2016
Location: Georgetown OHIO
Posts: 14
Likes: 0
Received 0 Likes
on
0 Posts
Quench is another thing I don't understand to well. Is their some kind of app that can figure this stuff out. I've ask this question on 3 different threads and nobody has gave me any kind of anwser. And i have another question to my motor is a 04 avalanche motor. In 05 the l33 5.3 started coming out with 243s on them and flat top pistons. Can I run those flat tops and connecting rods in my lm7 or is the crank made different. I hope I'm just over thinking this to much ! I just want my truck to run like felon escaping prison.. lmfao
