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Carguy

4VPC SB Northstar Replacement?

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Why not build new 4VPC,DOHC,VVT,DI heads and intake for the 4.8/5.3/6.0L SB V8 to use as a replacement for the Northstar line? We know the SB V8 can be had with an Aluminum Block and the tooling is allready there. They could use the DOHC version's as a MORE PREMIUM Caddy ect. version of the SB V8's while useing the OHV ones for Chevy/Pontiac ect. They could even use the DOHC ones as EXCLUSIVE GMC/Caddy Engines in the HIGHER END Trucks/SUV's. That way ALL GASOLINE GM V8's could be SB based in the SHORT BLOCK but different in the HEADS/INTAKE ect. I could see a Caddy optional--CTS/standard--STS with a DOHC 4VPC VVT DI 325CI 5.3L 375+HP V8. I could allso see some DOHC 4VPC VVT DI 364CI 6.0L 475+HP CTS V/STS V versions. I could see the RETURN of the ZR1 VETTE with a HIGH OUTPUT DOHC 7.0L 575HP V8! The NS V8 is NOT ENOUGH TODAY with 380HP V8 BMW's and 370HP V8 MB's running around. So GM could BEAT their COMPETITORS with little effert while COMBINING their V8 PROGRAMS together to save COST!------WHY NOT?

Edited by Carguy

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then what would would be where the cam is on the smallt block now?

wrong place to put this too i think.

maybe the question is, why can't they put 4valve heads on an OHV engine now?

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You can put DOHC on a OHV block or you could make a 4-valve OHV engine...both have been done.

When GM needed a DOHC engine for the Corvette for the ZR1, Lotus had to design an engine from the ground up for size reasons. Putting a DOHC head on an engine the size of the small block makes it rather large.

One of the reasons why the Northstar engine doesn't have 350-400hp is because it had been limited by the vehicles it was put in. FWD cars cannot take substantially more than 300hp, which is why FWD Cadillacs had no more than 300hp (305 by European standards). I'm sure the engine can (and is being) developed for more, but until the advent of the Sigma chassis, there was no reason to go above 300hp.

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Numerous engines have in the past been modified from an OHV design to one with DOHC and 4V per cylinder, as recently as this century in some cases. If I was to commision a new DOHC V8 however, I would not base it on the OHV small block, but on the L850 series Family II Ecotec (or even the latest Family I 4-cylinders).

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then what would would be where the cam is on the smallt block now?

It could stay right where it is... or like others mentioned

the possibilities are endless. I like the concept but it has

to be for the high end stuff only. Give the masses our

basic Pushrod OHV, 2/valve V8s.

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Numerous engines have in the past been modified from an OHV design to one with DOHC and 4V per cylinder, as recently as this century in some cases. If I was to commision a new DOHC V8 however, I would not base it on the OHV small block, but on the L850 series Family II Ecotec (or even the latest Family I 4-cylinders).

IIRC, the LT5, which was a DOHC engine based on an OHV block, was an extraordinarily large engine - even moreso than the Northstar or any other ground-up DOHC design.

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IIRC, the LT5, which was a DOHC engine based on an OHV block, was an extraordinarily large engine - even moreso than the Northstar or any other ground-up DOHC design.

Chevrolet considered making a DOHC 350 sbc for the ZR1.

But they did not. The LT5 was a clean sheet design that shared nothing in common excpet the 4.4 bore centres.

Apparently this was done at some morons directive and compromised the valve sizes, compromising hp.

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You can put DOHC on a OHV block or you could make a 4-valve OHV engine...both have been done.

When GM needed a DOHC engine for the Corvette for the ZR1, Lotus had to design an engine from the ground up for size reasons. Putting a DOHC head on an engine the size of the small block makes it rather large.

One of the reasons why the Northstar engine doesn't have 350-400hp is because it had been limited by the vehicles it was put in. FWD cars cannot take substantially more than 300hp, which is why FWD Cadillacs had no more than 300hp (305 by European standards). I'm sure the engine can (and is being) developed for more, but until the advent of the Sigma chassis, there was no reason to go above 300hp.

I dont think the SB V8 with a DOHC 4VPC head conversion would be a problem size wise. Shure it would be LARGER then the OHV version but the short block of the SB is really compact BY DESIGN! And with vairious sizes around today--4.8L-5.3L and 6.0L-7.0L the POSSIBLE VARIATIONS are ENDLESS. Like the 4.8L DOHC 4VPC version could be a BUICK only Engine while the DC 4VPC 5.3 could be a CADDY only Engine. GM could RETURN to BRAND SPECIFIC Engine types WITH BRAND SPECIFIC VALVE ACTUATION TO BOOT! Chevy/Pontiac OHV 3.5L-3.9L OHV V6's--4.8L-5.3L-6.0L OHV V8's. Buick DOHC 4VPC 3.6L V6--DOHC 4VPC 4.8L V8. Caddy DOHC 4VPC (VVT) 3.8L V6--DOHC 4VPC (VVT) 5.3L V8-WITH-a V specific DOHC 4VPC (VVT) 6.0L V8! And I dont think GM intended for the NS V8 to be UNDERPOWERED because all they had was a FWD platform. Shure that was a BAD LIMITATION I agree but the NS for several YEARS was one of the MOST POWERFULL STANDARD LUXURY CLASS V8's! Remember when the NS first came out what we now call the E class MB opt V8 put out only 275 or so HP. As did the BMW 5 series opt V8 and others. NO Caddy needs to be the STANDARD OF THE WORLD AGAIN (((NOT))) the FOLLOWER! And with the seeming DEATH of the ULTRA V8 PROGRAM and GM's $$$$ problems I think this idea could be a GREAT THING!-------------------------PS. Sorry for the LOOOOOOOONG post. 8) Alot to cover.

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I do not fault the capabilites of the SB nor the potential cost-savings (not sure there would be any, however- I'm sure the issue is more complex than it would seem).

However >>"COMBINING their V8 PROGRAMS together to save COST!"<< was a very large part of the Beginning of The Decline of GM.

Cadillac has only strayed outside of their own engineering department for powerplants a relative handful of years in their 104-year history. Dropping the Northstar for a corporate SB would, in the eyes of far too many journalists, be occasion for repeated typing of "Chevrolet" in Cadillac reviews, irregardless of how ill-informed that would be. Not where we need to be going. MORE autonomy is what's critical, not homogenization.

A Cadillac crest should mean a Cadillac engine, Period.

Edited by balthazar

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A Cadillac crest should mean a Cadillac engine, Period.

99 times out pf a hundred I agree... but I'd love a CTS-V more so

than a STS-V, mostly for the durability & ease of maintenance of

the LS6 and the standard 6-speed manual, you know with three

pedals on the floor. :AH-HA_wink:

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Numerous engines have in the past been modified from an OHV design to one with DOHC and 4V per cylinder, as recently as this century in some cases. If I was to commision a new DOHC V8 however, I would not base it on the OHV small block, but on the L850 series Family II Ecotec (or even the latest Family I 4-cylinders).

I'm not an engineer, so I'd like to ask you what would be the technical advantages/disadvantages of pairing 2 Ecotec blocks vs. changing the OHV engines to OHC.

Edited by ZL-1

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This is probably oversimplifying things, but take 2 2.4L Ecotecs and glue them together. In theory you'd have a 4.8L V8 capable of 320-350hp, with a HUGE upside. Remeber the Ecotec block is capable of withstanding over 1000hp.

Take 2 2.0L DI turbo Ecotecs, glue them together, and... :omfg:

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