. 
GM V8 4 Valve?
true i suppose.
the bottom line there would be that if they were to put money and development into furthering a new engine they would need to make it available in more vehicles but in the case of the northstar how would they market it against the LS series? i just dont see even if it were offered more widely, being picked up and ran with because why would they pic a less developed motor when the aftermarket and everything is already behind the LS series
the bottom line there would be that if they were to put money and development into furthering a new engine they would need to make it available in more vehicles but in the case of the northstar how would they market it against the LS series? i just dont see even if it were offered more widely, being picked up and ran with because why would they pic a less developed motor when the aftermarket and everything is already behind the LS series
My argument is they don't need to develop a new motor or multi-valve heads. The LS motors are more than capable of covering all of the bases from 300hp luxury barge to 400 ft-lb truck to 650hp psycho-'vette. There is no need to spend research and development money or tooling money. Supply the LS motors with higher quality forged pistons and direct injection. Offer some with VVT even. If the Northstar line was scrapped I bet that money would almost cover these improvments to the LS line.
GM should also note that the rest of the world is more and more noticing the LS series engines potential.
its a no brainer to upgrade as they have been doing. dont fix if its not broke.
3 or 4v, if it comes to that. so be it. as long as the heads can at least be used on 4.00 bores existing LS engines.
Launching!
Joined: Feb 2010
Posts: 277
Likes: 1
From: Shawnee, OK
all of those ideas sound good. if only the future of the line was left up to us lol
in my mind it doesnt make any sense to alter the already great flowing head design for more valves when like mentioned they could spend that money on forged internals and a little boost i mean hell that would be an efficient and cost effective way to make more power without having to retool machines and production lines, etc. for a different set of heads
in my mind it doesnt make any sense to alter the already great flowing head design for more valves when like mentioned they could spend that money on forged internals and a little boost i mean hell that would be an efficient and cost effective way to make more power without having to retool machines and production lines, etc. for a different set of heads
Launching!
Joined: Feb 2010
Posts: 277
Likes: 1
From: Shawnee, OK
is there even any plans for another boosted platform in the ls series or is it pretty much left up to the ls9-a? im kinda curious because i think forged internals and an ok set of twins to keep it driveable and nice to live with on an ls7 would be outrageously nasty just my opinion......
i think its doubtful gm is currently testing a brand new v8 for the next gen corvette direct injected 5.5 litre 440 horse overhead valve i believe pushrods are still in the game
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amen dude 
Registered User
Joined: Jan 2011
Posts: 1
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OHV "nutswinging" vs OHC "nutswinging" Replying to an old post blah blah blah. Yeah, I know.
I see a lot of misinformation in this thread and many posts driven mainly by the "what I do must be right" mentality. Perhaps I should expect a lot of OHV "nutswinging" given that this is ls1tech, but fanaticism is never a good thing. I especially have to laugh at the posters who claim that OHC is not a mature or reliable technology and that OHC engines are expensive to maintain. 99% of the passenger cars sold today (and for quite a while now) use OHC and are extremely reliable and require no special maintenance. Do you enjoy having a simple engine for its simplicity alone if there is no durability benefit? I'm sure that those of you who get beaten by 2011 GTs will be saying "Oh yeah? Well, my engine is simpler.". Talk about ricers.
I love pushrod engines and have driven and worked on them for decades, but I know that there are areas in which OHV is clearly inferior to OHC. Whether those are areas that matter to you is subjective, but the facts are not.
Advantages of OHC:
Lower valvetrain weight. With a mechanical bucket setup, the valvetrain is composed of only a bucket, valve, spring, and retainer; No pushrods, no lifters, and no rocker arms. The overall weight can be half as much as OHV or less and this is reflected in the lower spring rates used on OHC engines. The smaller valves used on a multivalve OHC setup also contribute to this. Multivalve OHV setups have very high valvetrain weight due to the rocker assemblies and that is the reason that they are only used on low-revving diesels.
More valve area. Two 1.5" valves have more area than a single 2" valve. A stock multivalve head (designed for a non-performance application) can easily flow 175 at .200 and 235 at .300 on the intake side and that is with a bore which is 3.75" or less. The LS series compares fairly well here due to its large bore.
Higher RPM capability. This is a result of the lower valvetrain weight. A larger RPM range means more gearing can be used and, of course, gearing multiplies torque.
Direct valve control. No rocker arms means less deflection of the valve and this allows longer valve stem life.
Advantages of OHV:
Smaller package and lower weight. Smaller cylinder heads and only a single cam mean less weight, but the gap is not as large as some may think. For example, the Coyote 5.0 crate engine is listed at 444 lbs while the LS3 is listed at 415. For comparison, Nissan and Toyota DOHC V6s are in the 350-375 lbs range.
More efficient combustion. Wedge heads have superior burn characteristics to pent-roof heads and this can result in more low RPM torque, lower emissions numbers, and lower octane requirements.
More durable timing chain due to its shorter length.
Cheaper. Fewer parts and less machining are required.
I see a lot of misinformation in this thread and many posts driven mainly by the "what I do must be right" mentality. Perhaps I should expect a lot of OHV "nutswinging" given that this is ls1tech, but fanaticism is never a good thing. I especially have to laugh at the posters who claim that OHC is not a mature or reliable technology and that OHC engines are expensive to maintain. 99% of the passenger cars sold today (and for quite a while now) use OHC and are extremely reliable and require no special maintenance. Do you enjoy having a simple engine for its simplicity alone if there is no durability benefit? I'm sure that those of you who get beaten by 2011 GTs will be saying "Oh yeah? Well, my engine is simpler.". Talk about ricers.
I love pushrod engines and have driven and worked on them for decades, but I know that there are areas in which OHV is clearly inferior to OHC. Whether those are areas that matter to you is subjective, but the facts are not.
Advantages of OHC:
Lower valvetrain weight. With a mechanical bucket setup, the valvetrain is composed of only a bucket, valve, spring, and retainer; No pushrods, no lifters, and no rocker arms. The overall weight can be half as much as OHV or less and this is reflected in the lower spring rates used on OHC engines. The smaller valves used on a multivalve OHC setup also contribute to this. Multivalve OHV setups have very high valvetrain weight due to the rocker assemblies and that is the reason that they are only used on low-revving diesels.
More valve area. Two 1.5" valves have more area than a single 2" valve. A stock multivalve head (designed for a non-performance application) can easily flow 175 at .200 and 235 at .300 on the intake side and that is with a bore which is 3.75" or less. The LS series compares fairly well here due to its large bore.
Higher RPM capability. This is a result of the lower valvetrain weight. A larger RPM range means more gearing can be used and, of course, gearing multiplies torque.
Direct valve control. No rocker arms means less deflection of the valve and this allows longer valve stem life.
Advantages of OHV:
Smaller package and lower weight. Smaller cylinder heads and only a single cam mean less weight, but the gap is not as large as some may think. For example, the Coyote 5.0 crate engine is listed at 444 lbs while the LS3 is listed at 415. For comparison, Nissan and Toyota DOHC V6s are in the 350-375 lbs range.
More efficient combustion. Wedge heads have superior burn characteristics to pent-roof heads and this can result in more low RPM torque, lower emissions numbers, and lower octane requirements.
More durable timing chain due to its shorter length.
Cheaper. Fewer parts and less machining are required.
On The Tree
Joined: Jan 2011
Posts: 129
Likes: 0
From: Ohio
OHC does have the potential to make big numbers, but at the cost of low end torque as you noted. Which in a street car is not a good thing. Look at how poorly the 4.6 engines performed in comparison to the pushrod LS engines. It took Ford going the forced induction route to become competitive against the N/A LS engines.
Both have potential, but as the LS9 has shown by spanking many an exotic OHC engine that pushrod technology is far from dead and far from inferior like the Ford fanbois like to claim (and also note that the OHV Gm engines are once again outperforming the OHC Ford engines, ha).
Both have potential, but as the LS9 has shown by spanking many an exotic OHC engine that pushrod technology is far from dead and far from inferior like the Ford fanbois like to claim (and also note that the OHV Gm engines are once again outperforming the OHC Ford engines, ha).
Teching In
Joined: Apr 2008
Posts: 14
Likes: 0
GM doesn't care how tough these engines are once they leave the dealership and their warranty has expired... The Northstar engine is reliable enough for them, so figure that out.. The LS series isn't likely to be removed by GM "for" any DOHC... But may be BECAUSE of government intervention. They're already on it, and have been for about 4 decades. They're convinced that OHV engines produce too many emissions and unless they're stopped(by voting in people with working brains), WILL end such performance oriented engines. When that happens, OHC will be the way to go, because they "burn cleaner"... never mind the fuel economy isn't often better, and in many cases is worse... They "burn cleaner"... That is, even burning MORE isn't a problem, so long as it's cleaner as you burn... Forget the fact burning more means more emissions... anyway... At the rate we're going, the GOVERNMENT will be the end of OHV performance regardless what GM chooses...
Reliability isn't a big concern. As good as the LS series is, there are several OHC engines with better track records. Not to "bust out with" Ford, but the 4.6L modular is known to cross 300K and never be opened... Well, I've heard that many times, anyway. My dad had a 99 F-250 and not only did it not have problems(at all) in the engine, he sold it with a bit over 171K and not even a hint of trouble. The guy who bought it still drives it all the time and when last I asked, he'd crossed 200K and had no trouble. Police cruisers get abused and I still hear of them going over 200K... That's reliability in my mind... That's also something helped by lower power... Look at all the 200k+ foreign jobbers with OHC engines... They run and run and run... Like an old Dodge slant 6 or Ford 300... Ya can't hardly kill 'em! The manufacturer doesn't have to care though, what happens beyond warranty... Plus, they KILLED several, indeed all of those old push rod engines even though they were very reliable. The old SBC was quite reliable, even with it's leaks and so forth... But it's gone too. That one was because of the LS series, but others weren't. Ford had no logical reason to kill the 5.8L, but BLAM! GOVERNMENT INTERVENTION!
PS... The 97+LS1 was indeed a great engine from the start, but as for sheer durability, there are several other LS series engines I'd choose over it. Indeed, I'd prefer most other LS series as for durability with aftermarket modification. The quickest GM's aren't likely to have that block under the hood... And there are reasons which have been discussed many times by now. The best engine block durability doesn't often come in aluminum..
Reliability isn't a big concern. As good as the LS series is, there are several OHC engines with better track records. Not to "bust out with" Ford, but the 4.6L modular is known to cross 300K and never be opened... Well, I've heard that many times, anyway. My dad had a 99 F-250 and not only did it not have problems(at all) in the engine, he sold it with a bit over 171K and not even a hint of trouble. The guy who bought it still drives it all the time and when last I asked, he'd crossed 200K and had no trouble. Police cruisers get abused and I still hear of them going over 200K... That's reliability in my mind... That's also something helped by lower power... Look at all the 200k+ foreign jobbers with OHC engines... They run and run and run... Like an old Dodge slant 6 or Ford 300... Ya can't hardly kill 'em! The manufacturer doesn't have to care though, what happens beyond warranty... Plus, they KILLED several, indeed all of those old push rod engines even though they were very reliable. The old SBC was quite reliable, even with it's leaks and so forth... But it's gone too. That one was because of the LS series, but others weren't. Ford had no logical reason to kill the 5.8L, but BLAM! GOVERNMENT INTERVENTION!
PS... The 97+LS1 was indeed a great engine from the start, but as for sheer durability, there are several other LS series engines I'd choose over it. Indeed, I'd prefer most other LS series as for durability with aftermarket modification. The quickest GM's aren't likely to have that block under the hood... And there are reasons which have been discussed many times by now. The best engine block durability doesn't often come in aluminum..
Launching!
Joined: Feb 2010
Posts: 277
Likes: 1
From: Shawnee, OK
