Pushrods vs DOHC

[Brent302]

My duramax put down 645/1226 with its 4v pushrods motor I don't see why everyone says GM needs to go to DOHC when they are doing just fine perfecting the pushrod motor for years why fix something that isn't broke lol every pushrod motor out there gives ford a run for their money while complying with emissions and they still have room to improve I'm sure so many people in here dogging on pushrod motors just because they own a ford it's sad they are all badass I love them all

It's kind of like saying "we perfected the leaf spring suspension".......

Or "we perfected the solid rear axel".....

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[5.0GT]

Nothing wrong with GM pushrod engines. Simple, easy to work on and reliable. The one advantage they have is the torque. If you are a torque junky like me, bigger displacement is better.

 

[Brent302]

Nothing wrong with GM pushrod engines. Simple, easy to work on and reliable. The one advantage they have is the torque. If you are a torque junky like me, bigger displacement is better.

The LT1 and LT4 are far from simple. They are moving into a new generation with new technologies tacked on.

Hell they arnt even cheap anymore. A Crate LT1 from GM is $11k

The LT1 has Direct Injection/Cylinder deactivation and VVT.

 

[5.0GT]

The LT1 and LT4 are far from simple. They are moving into a new generation with new technologies tacked on.

Hell they arnt even cheap anymore. A Crate LT1 from GM is $11k

The LT1 has Direct Injection/Cylinder deactivation and VVT.

They are not that hard to work on for me, even a cam swap is pretty easy when you have the experience and the right tools. That being said, D.I is defintely an added nightmare to work with.

 

[H1 GT]

My duramax put down 645/1226 with its 4v pushrods motor I don't see why everyone says GM needs to go to DOHC when they are doing just fine perfecting the pushrod motor for years why fix something that isn't broke lol every pushrod motor out there gives ford a run for their money while complying with emissions and they still have room to improve I'm sure so many people in here dogging on pushrod motors just because they own a ford it's sad they are all badass I love them all

...your Duramax is also a diesel and MUCH easier to make power out of than a gas motor in comparison. Every dbag that gets a truck throws a tuner on it and think they're hot sh*t and loves to roll coal. Wow, 450whp (along with every other truck out there). $10k in most diesels can get you a very reliable/streetable 700whp/1400ft lbs. $10k in a car can get you a big power adder(FI) and maybe a few more things, but you're still looking at quite a few thousand more in supporting mods, let alone the suspension and everything else to get that power to the ground.

Pushrods are easy when you're pushing 4k rpm. In a gas motor at twice that I'm sure you'll start to float the valves if you want tons of power on a streetable car. Of course, you could probably get some crazy valve springs, but I'm sure the streetability would slowly decline.

Every diesel I know of is pushrod except the new Cummins that is coming out in the Nissan Titan - we'll just have to wait and see if that's a game changer.

Big power in diesels was exciting when I first got into it, but now it's just not that impressive.

I have nothing for or against the pushrod/DOHC debate though.

 

[Brent302]

They are not that hard to work on for me, even a cam swap is pretty easy when you have the experience and the right tools. That being said, D.I is defintely an added nightmare to work with.

I'm just saying do you really want to mess with and grenade a $11k motor.

 

[5.0GT]

I'm just saying do you really want to mess with and grenade a $11k motor.

I've messed with more expensive motors, I never leave anything stock man....I'm a motor junky. Grenaded? never.

 

[Brent302]

...your Duramax is also a diesel and MUCH easier to make power out of than a gas motor in comparison. Every dbag that gets a truck throws a tuner on it and think they're hot sh*t and loves to roll coal. Wow, 450whp (along with every other truck out there). $10k in most diesels can get you a very reliable/streetable 700whp/1400ft lbs. $10k in a car can get you a big power adder(FI) and maybe a few more things, but you're still looking at quite a few thousand more in supporting mods, let alone the suspension and everything else to get that power to the ground.

Pushrods are easy when you're pushing 4k rpm. In a gas motor at twice that I'm sure you'll start to float the valves if you want tons of power on a streetable car. Of course, you could probably get some crazy valve springs, but I'm sure the streetability would slowly decline.

Every diesel I know of is pushrod except the new Cummins that is coming out in the Nissan Titan - we'll just have to wait and see if that's a game changer.

Big power in diesels was exciting when I first got into it, but now it's just not that impressive.

I have nothing for or against the pushrod/DOHC debate though.

Not as harshly but I agree. I hate when guys in trucks get a tune and act like they have a 24 foot weiner....it's not fast..at all

 

[Brent302]

I've messed with more expensive motors, I never leave anything stock man....I'm a motor junky. Grenaded? never.

Well that's you. Not everyone else lol. Have at it. Still the pushrod is going the way of leaf springs and the solid rear axel. I mean hell if I perfect the automatic seat belt from the 80s do you want one? No

 

[5.0GT]

Well that's you. Not everyone else lol. Have at it. Still the pushrod is going the way of leaf springs and the solid rear axel. I mean hell if I perfect the automatic seat belt from the 80s do you want one? No

Depends..if that auto seatbelt is an a GNX, then yes. Why not? lol. As long as GM has a strong fanbase those pushrods are not going anywhere.

 

[Brent302]

Depends..if that auto seatbelt is an a GNX, then yes. Why not? lol. As long as GM has a strong fanbase those pushrods are not going anywhere.

I punch you lol

 

[Shawnski]

They're typically much larger in dimensions - True but if it fits the car who gives a rats behind? Are you shuffling engines around?

They are heavier - Wrong, OMG your Hemi is over 100 pounds heavier than a 5.0 Coyote. Cast iron block on your nose.

They are more expensive to produce - Ford has been making OHC V8s since 1991 and DOHC since 1993. They sell allot which means the scale of production is there to spread costs.

They make power by revving to higher RPM's - Wrong. What you want to look at is the power curve; the point between torque peak and HP peak. The 5.0 has between 500 and 800 rpm range advantage over LS/LT and hemis. That is a broader powerband.

They produce less torque. Again wrong. With variable valve timing and smaller valves (good low speed velocity), the little 5.0 can pull out of corners as well as other Detroit V8's even though its spotting a liter or more of engine size.

 

[Herr_Poopschitz]

Whatever, it's a big world out there and for any company the takes your attitude and says f-it we don't need to benchmark say the Germans or the Japanese is soon out of business.
For gods sake the Japanese came here and BM Henry Fords production line and turned it into a world class production system that is being BM by industries from around the world.

No doubt about the success of the Vett's, in fact the're the sweetest sounding power plant out there imop.

Whatever, I think you missed the argument at hand. Might go back and reread to try to find it again.

Keep studying up on endurance racing before trying to use it incorrectly to prove your incorrect point.

Price no object the best cars don't have pushrod V8s in them. Period.

Guess it depends on your definition of 'best'. Personally, since I don't like horrible resale due to known long term reliability issues, I stay away from German stuff. If you consider expensive parts for failures that shouldn't happen in the first place 'best', well, there's no conversation to be had.

I don't see a lot of 200k mile junkyard German engines being turbo'd to produce 800, 900, or 1000 hp.

Also, I'd say the Venom GT does a pretty good job as a world-beater w/ it's inferior pushrods.

Seems as those who are anti-pushrod have limited racing knowledge or no engineering background...coincidence?

 

[Shawnski]

I don't see a lot of 200k mile junkyard German engines being turbo'd to produce 800, 900, or 1000 hp. I know of A 30 yr old TT P 928 S4 that makes 964 RWHP.

Also, I'd say the Venom GT does a pretty good job as a world-beater w/ it's inferior pushrods. Did you know that the fastest OEM car uses a vesion of the Ford 4.6 DOHC motor? koenigsegg 1200 HP TT. Oh yea and the current fastest standing mile production based car is; A Ford GT TT 5.4 DOHC.

Seems as those who are anti-pushrod have limited racing knowledge or no engineering background...coincidence? Bring it.

 

[Daytona Coupe]

The contention was that no 4V pushrod motors exist. That's flat out wrong. There are units in the GM stable, there are diesels.

As far as RPM - what does that have to do with it? Go get a Honda CX500 motorcycle and run it to its 10K redline. That's 4 valve pushrod engine running to 10K.

Diesels run low RPM not because of 4 valves - but because that's the way to maximize the energy in diesel.

There is no inherent limit to RPM with pushrods, and there are as many applications for pushrods as there are for OHC units. The reason you see more OHC units now is they tend to allow a shorter but wider engine. Shallower hoodlines, smaller cars can usually make the tradeoff. Older cars were more upright. It's why I could just about sit inside the engine compartment on my 1962 Ford Fairlane when I rebuilt the small block 221 V8 (289/302 block), but there is precious little daylight on either side of the new DOHC units. They are quite a bit shorter than the old beast, through...

So I hope we can put to rest the myth that pushrods are for 2 valves only, and only for low RPM. There are literally millions and millions of engines out there that say otherwise.

I never said that they didn't exist, I said that they aren't practical for the application that is being discussed - this is a Mustang forum. We drive CARS that run on GAS. You keep trying to drag in other stuff that doesn't apply at all to the original question and claim that it's relevant.

Diesels turn low RPM because that is the most efficient way to burn it. 4-valves and pushrods have nothing to do with it. There is no need for a high-speed valvetrain in that application. I would be willing to betthat the Audi LeMans Diesels (probably the most advanced in the world) do not use pushrods.

No RPM limit to pushrods? Right... it's all added mass and deflection that gets out of control. Practically every racing engine that goes past 10K rpm does not use pushrods. I can think of only one (Penske Mercedes Indy engine) that might break this rule and it was finished after one race.

Motorcycle engines use much lighter valves and its easier to turn high RPM, but whatever... How many bikes that rev high use pushrods? Every current production bike engine that makes serious power or rpm does not use pushrods.

"The reason you see more OHC units now is they tend to allow a shorter but wider engine." This is completely backwards. The way they are getting the lower hoodline is due to the intakes being buried inside the V of the engine. The heads make the long-block assembly much taller and wider.

"So I hope we can put to rest the myth that pushrods are for 2 valves only, and only for low RPM. There are literally millions and millions of engines out there that say otherwise"

For gasoline powered cars that rev to 6K or more (as in all new production cars - which was the foundation of the original question and what I was responding to) - then yes, pushrods are for 2-valves only.

Im done - I'm not going to argue it with you any further.

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