brian.moritz

Just throwing the idea out there for a discussion. I've had this discussion with some gear head friends, I think all engines today should be dual overhead cam. The only downside I can see to a DOHC motor is the timing belt. Other then that they are far less complicated, rev better, make more power etc.. I think it would be pretty sweet to have a LS DOHC motor.Why not GM? Or am I missing some good reasons there not used?

Only V8 DOHC motor GM made that I've seen is the Northstar and that think from what I gather reading wiki was junk.

Z28_LT1

iTrader: (2)

I don't wanna pay for that many cams when I mod a motor....

Latch

iTrader: (8)

Exactly. GM knows how to do something well and that's make pushrod V8s. It's a perfectly fine design that keeps the cost down as well as keeps the size and weight of the motor down.

AgentLS1Z

It'd be more complicated with 4 cams and a lot more expensive. DOHC engines have a higher rev limit with creates more wear on the engine. I'd rather stick to a SOHC engine that doesn't struggle to make its power. I'm no expert on engines that's my opinion. I just sold my '96 Cobra because I was concerned about reliability issues. Apparently DOHC Cobra engines last a maximum of approximately 150K miles and I've seen a few LS1s on here that are going upwards of 200K miles.

eseibel67

iTrader: (10)

All engine designs are a compromise based on what the priority is.

Ultimate performance would require 4 valves/cyl.

But the highest piorities in the LS1 design was high performance at low cost. That means 1 cam in the block.

And isn't that really the reason we love them so much?

cad2k3

iTrader: (2)

correct me if im wrong but a DOHC engine wouldnt be a LS engine. an ls engine IS a pushrod v8.. And i believe the LT5 was DOHC so its not just the northstar. correct me if im wrong

RPM WS6

iTrader: (3)

I would be very disappointed to see a DOHC replace the LSx series of engines.

Single cam/pushrod is simple and cost effective. Stick with what works, IMO. GM has been kicking *** with pushrods for YEARS while Ford was struggling to stay within 100hp of the NA GM V8 competition.

AgentLS1Z

Yep, plus less parts to break and less issues to deal with in general than a DOHC engine.

JD_AMG

They are far MORE complicated, not less.
Similar thread:
https://ls1tech.com/forums/advanced-...8-4-valve.html
https://ls1tech.com/forums/13401768-post55.html
Summary: DOHC engines are heavier, bigger, more expensive and don't make any more power.

Arc00TA

iTrader: (17)

OHC was invented before OHV to begin with. It offers better port/valve spacing and ability to phase cams independently, and less worry of valvetrain harmonics. As far as less complicated? Not likely. Have you ever disassembled a DOHC motor? Just because it doesn't have long pushrods doesn't mean it is any less complicated to deal with. Basically you just eliminate the pushrod and manipulate the rocker with the lifter, or some kind of follower.


EDIT: nice ninja edit there, you realized that DOHC does not mean your cam moves the valve by itself necessarily.

brian.moritz

Hmm, cool. That's why I bought it up, learned something... I always figured they were less complicated since the valves rode directly on the cams but that pic says a lot.

Arc00TA

iTrader: (17)

Valves DO NOT normally ride directly on the cam for car applications (I've seen bikes like this). Normally a follower or lifter is still used to actuate the valve.

Hi Volume

iTrader: (3)

its gonna weigh 10,000lbs and add way more complication. I hate those goofy *** ford DOHC engines. 80 extra pounds in cams alone.

PitchblackC3

iTrader: (3)

A lot of the advantage of DOHC is negated now that VVT is available on the GENIV engines.

itsslow98

iTrader: (18)

whats the highest displacement DOHC ford motor made in a production car? I think there is a reason 03/04s are 281 ci, if it were any bigger the bastard would need a widebody kit.

93sspcoupe

nope, there is now a dohc 302.. and someone correct me if i'm wrong but isnt there a 330ci dohc also

devonsZ28

iTrader: (3)

this is what i got out of that question, why doesnt gm rename the camaro to mustang

Arc00TA

iTrader: (17)

Theres some 5.8L stroker mod motors with DOHC 32v heads running around. Stroked 5.4's. I'm sure they could be made bigger than that as well.

93sspcoupe

the 5.8 is the ford pushrod 351 not a modmotor. biggest stock modmotor i have seen is the 5.4.

Arc00TA

iTrader: (17)

You're right stock 5.4L is the biggest. I have seen 5.8 mod motors but it is a stroker like I said, they built one out of a 5.4 ford GT block in engine masters magazine a while back, and I have seen a few around but not many.