Facts you may not know

[BlackGT2000]

Hi everyone I don't have any street racing stories because I am currently deployed overseas. I have spent a good bit of time on the internet however and have been reading the AF threads alot.
I have read a few times people question chevy's persistant use of pushrod motors, and a few times suggestions that they switch to the Northstar. I read into it and this is what I found about why they have maintained their famous small block.
First off if you think about it, why use overhead cams? Over head cams come in as a benefit when you have 4 valve engines. It would be impossible to have that many pushrods going through the middle of the block like that and it would be over complicated. So if you want 4 valves just put the cams on top and have one for intake and one for exhaust. If you only have 2 valves per cylinder you don’t really need to have an over head cam, its still doing the same job as a pushrod when you have SOHC.
Second, the having multiple cams on top of the engine adds weight to the over all engine and all that weight is basically moved up to the top of the motor, raising the center of gravity, and we all know we want low centers of gravity.
Lastly, and in my opinion the most important, it makes for a more compact engine to use pushrods. If you look at the physical size of an LS-1 vs. 4.6 SOHC or DOHC engine, or for that matter a 5.4 DOHC, the LS1 is far smaller despite its larger displacement. The size will affect the chassis of the car it goes into. For example, the Corvette has a double A-arm front suspension like a race car would have. The 2005 Mustang has a far improved front suspension than the 2004, but still it lacks the double A-arm front suspension that its Lincoln LS brethren (which it shares many design cues structurally). This is because the 4.6 liter engine it uses takes up too much space for that kind of suspension. The Lincoln LS has a smaller V8. Ford wanted to do the same but lowering engine displacement wasn’t an option (can’t argue with that).
Just wanted to let everyone in on some information I had, stick up for Chevy a little bit (even though I have never owned one), and hopefully pass some new information onto others. Maybe you knew some of this maybe not. I don't drive a chevy either so this isn't some pro V8 thread. Its just some knowledge.

[-The Stig-]

... that was kinda random...

But... welcome?.. to AF.

[BlackGT2000]

Maybe a little random but I thought it could be of interest to someone

[TatII]

of course the benefit of a push rod engine is weight and size, but it also lacks refinement. but thats also part of the attraction ( in its rawness ) but i would take my high tech dohc engines anyday even though they cost more, but trust me, i love hte way a 350 sounds or a 305 sounds with flows and a mild cam.

[drftk1d]

pretty interesting.

too bad i dont care about cams.

[Zgringo]

Originally Posted by RedNeck383

... that was kinda random...

But... welcome?.. to AF.

Kinda random???????
Well being this is about things you may not know, here goes.

Did ju no Juneau was the capitol of Alaska?

BlackGT2000, sorry to hear you've been deployed overseas. I was abrod once...

I've been drunk and shot but never deployed. I guess I missed that when I was in VietNam.

[Muscletang]

Originally Posted by TatII

i would take my high tech dohc engines anyday

I use to be all about the American pushrod muscle. Now I see Ford's DOHC engines kicking butt and taking names so I'm starting to change my views here.

Originally Posted by TatII

even though they cost more

I hear you there. I know this guy at church who races Indy cars professional. He isn't in the Indy 500 or anything like that but he does races kind of like it. Anyway he was telling me the pushrod engines are about $100,000 a piece and the DOHC will run you around $175,000.

Originally Posted by TatII

but trust me, i love hte way a 350 sounds or a 305 sounds with flows and a mild cam.

You forgot one engine though, Ford's 302

[Musashi3000GT]

interesting! I was only wondering why some manufacturers still use only 2 valves per cylinder and some use 4? like why do american cars still use only 2 and jap cars go for 4. I saw fords commercial about the new Explorer and how it has 3 valves per cylinder, well why are they bragging about three when an eclipse has 4?

the real reason I'm asking is cause some guys make fun of my Starion since it only has 2 valves per cyl.
will it make as a DOHC? I know my valves are bigger then the avarge DOHC valves but will it affect timing in any way?

[LT1MAN]

Originally Posted by BlackGT2000

Maybe a little random but I thought it could be of interest to someone

thats very interesting

[drftk1d]

Originally Posted by Musashi3000GT

interesting! I was only wondering why some manufacturers still use only 2 valves per cylinder and some use 4? like why do american cars still use only 2 and jap cars go for 4. I saw fords commercial about the new Explorer and how it has 3 valves per cylinder, well why are they bragging about three when an eclipse has 4?

the real reason I'm asking is cause some guys make fun of my Starion since it only has 2 valves per cyl.
will it make as a DOHC? I know my valves are bigger then the avarge DOHC valves but will it affect timing in any way?

usually less valves means bigger valves. thats the recipe for low end torque.

[Musashi3000GT]

Originally Posted by drftk1d

usually less valves means bigger valves. thats the recipe for low end torque.

Is that why american engines only rev to like 6K rpms, and some honda and nissan engines go to like 7500 rpms?

[caviman69]

Hey blackgt2000 i know how you feel. Im overseas in iraq. Im not sure where your at but your not home. I hate iraq. Welcome to the forums

[Schmidt]

Actually the benifit of and OHC engine over pushrod is lower rotational mass, engines using pushrod design have a camshaft located in the engine block near the crankshaft. Rods linked the cam below to valve lifters above the valves. There are more moving parts there is also more lag between the cam's activation of the valve and the valve's lifting motion. Where as an ohc engine activates the valves directly thus there is no lag in the actuation of the valves.

[TatII]

Originally Posted by Muscletang

I use to be all about the American pushrod muscle. Now I see Ford's DOHC engines kicking butt and taking names so I'm starting to change my views here.



I hear you there. I know this guy at church who races Indy cars professional. He isn't in the Indy 500 or anything like that but he does races kind of like it. Anyway he was telling me the pushrod engines are about $100,000 a piece and the DOHC will run you around $175,000.



You forgot one engine though, Ford's 302

oops i didn't mean 305 becasue those are crap, what i meant to say was a 302. heh

[-Josh-]

Originally Posted by BlackGT2000

I have read a few times people question chevy's persistant use of pushrod motors, and a few times suggestions that they switch to the Northstar. I read into it and this is what I found about why they have maintained their famous small block.

I would never buy a Chevy if the got rid of their SB's for Northstars...

Northstars are crap, they constantly have to be resealed and are only good to about 30K miles before needing new rings and pistons.