TeeJay3800 Posted October 18, 2003 Report Share Posted October 18, 2003 This may not be a new topic, but I didn't find anything on it when I searched. Both valve trains have their advantages, but personally I prefer pushrod motors, by a long shot. A pushrod engine has far more low end grunt and usually a broader torque band. A multi-valve over head cam motor has more peak HP and a stronger pull at high revs. I also don't think any amount of variable valve timing on a DOHC will ever simulate the low end pull of a good pushrod engine. I think the OHV design offers more driveability for around town, every day use. Very few drivers drag race their car on a regular basis, and that is the situation where a DOHC motor will show its strengths. So, I will always buy a pushrod as long as GM makes them. But thats just what I think. What do you all think? Link to comment Share on other sites More sharing options...
topless94style Posted October 18, 2003 Report Share Posted October 18, 2003 I also like pushrods because of the lowend. But i love the pull of the highend on my DOHC, and as long as i have this motor its my first choice. Although, having a pushrod with multiple valves per cylinder would be nice. Link to comment Share on other sites More sharing options...
Redfox340 Posted October 18, 2003 Report Share Posted October 18, 2003 It's funny, because this exact criteria is being currently discussed in my Machine Design / Dynmaics course. And it's more than just a "power / tunability" issue; it's application, purpose and flat out price in the end. From a pushrod veiw, it's extremely well engineered for durability but a great deal of efficency loss compare to an overhead camshaft(s); but there is less linkage since there is only one central camshaft. Overhead valves keep the size down of the motor, and like you said keeps great low end power for stop-and-go driving. However, the overhead camshaft has a less components (valvetrain wise) which gives you the higher RPM's and powerband with such a design. It also produces less wear on the camshaft and you can use an aggresive lift with rollor follower; something that a pushrod longs for. But again the downsides is the linkage to run two or more camshaft (whether belt or chain) and there's a greater risks if failure occurs due to increased tolerance. Bottom Line: Does this mean there's a winner? No. Not at all, and let me be the first to say I've played both sides of the game and there's always an exception. I recall having this escapade on a seperate topic where I finally bellowed my opinion because many were so close-minded that no one saw the other sides' case. And personally, digging up that thread could start a whole 'nother case of arguements. - Erik Link to comment Share on other sites More sharing options...
89oldscutlass Posted October 18, 2003 Report Share Posted October 18, 2003 I like the OHV pushrod engine but I think that the DOHC has more to offer in the long run if GM would get all the kinks out of them. Im just waiting around for them to build a good DOHC 350 V8 for the fwd cars. There going to have to do it just to keep up with imports perfomance if they want to stay competitive market world wide against stuff like Skylines and stuff. There only option is to get more hp out of the supecharged 3800 which would be fine say 350hp from the factory with at least 24mpg on the highway. Link to comment Share on other sites More sharing options...
bumpin_z Posted October 18, 2003 Report Share Posted October 18, 2003 Overhead valves keep the size down of the motor, and like you said keeps great low end power for stop-and-go driving. I just have 1 ? then. If this is the case why is the 3.4DOHC a 60 v6 but can barely fit in the same engine bay as a 3.1 60v6? The heads make the engine too bulky to fit inside the engine bay of a cavalier w/o some modding and even then you practically have to pull the motor to perform routine maintenance on them. For that reason I have heard of only one guy attempt it and he actually had it in and running but something happened and he got rid of the car. Just my $.02 Link to comment Share on other sites More sharing options...
Redfox340 Posted October 18, 2003 Report Share Posted October 18, 2003 I just have 1 ? then. If this is the case why is the 3.4DOHC a 60 v6 but can barely fit in the same engine bay as a 3.1 60v6? First, I think we should all be familar with the terms: An overhead valve motor is a pushrod motor. Those terms for go hand in hand. A 3.4L DOHC is an overhead camshaft motor; not to pull an ego-trip, but my post was accurate. Thanks for the question. Maybe I should edit my previous post, seems like everyone is getting tripped up on the termonology. - Erik Link to comment Share on other sites More sharing options...
SmokesGTP Posted October 18, 2003 Report Share Posted October 18, 2003 This topic is useless. Link to comment Share on other sites More sharing options...
Guest RedCutlassSL Posted October 18, 2003 Report Share Posted October 18, 2003 Nothing wrong with this topic, got a stick up your butt? Link to comment Share on other sites More sharing options...
SmokesGTP Posted October 18, 2003 Report Share Posted October 18, 2003 It's been done to death. I don't know of any stick in my butt but fuck the yankees! Link to comment Share on other sites More sharing options...
89oldscutlass Posted October 18, 2003 Report Share Posted October 18, 2003 Link to comment Share on other sites More sharing options...
Guest RedCutlassSL Posted October 18, 2003 Report Share Posted October 18, 2003 that had nothing to do with this thread. your gonna eat your words Link to comment Share on other sites More sharing options...
conley3.1 Posted October 18, 2003 Report Share Posted October 18, 2003 I like the OHV pushrod engine but I think that the DOHC has more to offer in the long run if GM would get all the kinks out of them. Im just waiting around for them to build a good DOHC 350 V8 for the fwd cars. There going to have to do it just to keep up with imports perfomance if they want to stay competitive market world wide against stuff like Skylines and stuff. There only option is to get more hp out of the supecharged 3800 which would be fine say 350hp from the factory with at least 24mpg on the highway. A dohc 350 for fwd cars? They've done a DOHC 350 before, for the ZR-1 corvette... 411 hp. But for fwd? No offense, but that would be stupid, and hard as hell. Just make it rwd. Rwd is better anyways (IMHO) Link to comment Share on other sites More sharing options...
PaPaPooh Posted October 18, 2003 Report Share Posted October 18, 2003 I like the OHV pushrod engine but I think that the DOHC has more to offer in the long run if GM would get all the kinks out of them. Im just waiting around for them to build a good DOHC 350 V8 for the fwd cars. There going to have to do it just to keep up with imports perfomance if they want to stay competitive market world wide against stuff like Skylines and stuff. There only option is to get more hp out of the supecharged 3800 which would be fine say 350hp from the factory with at least 24mpg on the highway. A dohc 350 for fwd cars? They've done a DOHC 350 before, for the ZR-1 corvette... 411 hp. But for fwd? No offense, but that would be stupid, and hard as hell. Just make it rwd. Rwd is better anyways (IMHO) not to mention that the front end would have to be bigger than the mid 90's caddys with v8's that are FWD Link to comment Share on other sites More sharing options...
TeeJay3800 Posted October 18, 2003 Author Report Share Posted October 18, 2003 First, I think we should all be familar with the terms: An overhead valve motor is a pushrod motor. Those terms for go hand in hand. A 3.4L DOHC is an overhead camshaft motor; not to pull an ego-trip, but my post was accurate. Thanks for the clarification, Erik. I assumed everyone knew the difference between the two. Just to reiderate, OHV means a pushrod engine with one camshaft inside the block operating the valves through pushrods, rocker arms, etc. A DOHC (or OHC), has the camshafts located in the heads directly above the valves. Every pushrod engine (so far, to my knowledge) has had two valves per cyliner, while many, if not most, OHC have four our more valves per cylinder. Link to comment Share on other sites More sharing options...
Brian P Posted October 18, 2003 Report Share Posted October 18, 2003 ugh. Link to comment Share on other sites More sharing options...
topless94style Posted October 18, 2003 Report Share Posted October 18, 2003 I am a twins fan personally. The yanks are getting kinda old. A monopoly of baseball if you will. GIVE THE TWINS A CHANCE!!!!!!!!!!!!! JK not a big fan of baseball in the first place. Link to comment Share on other sites More sharing options...
TeeJay3800 Posted October 19, 2003 Author Report Share Posted October 19, 2003 ugh. Ugh yourself Link to comment Share on other sites More sharing options...
sonyman87 Posted October 21, 2003 Report Share Posted October 21, 2003 I like them both but lets face it its alot cheeper to run a 3.8 then a 3.4dohc... i have to go with pushrod. more aftermarket and easier to work on. did i mention reliability? Link to comment Share on other sites More sharing options...
Vegeta Posted October 21, 2003 Report Share Posted October 21, 2003 This is not a 3.4 DOHC vs 3800 debate....so please do not turn it into one. I prefer DOHC for the higher VE and more power at higher RPMs. It works well for how I drive, since I never start races and usually wait for the other person to get on it. This lets me sit there and wait for them to jump, while getting myself into the powerband without worrying that I am gonna be out of the powerband too soon. With a 5 speed, I don't have to worry about low end anyway (though I know of a 5 speed with more low end than a 3.1, lots more). The reason DOHC engines normally have no low end is by their higher VE. No real effort to get air in means no torque down low...but if you create more effort via tuned runners, you can get some low end out of them. Look at the SHO. OHC allows for seperate timing of the intake and exhaust cams, at least in a DOHC setup. This is good for tweaking the engine for your needs/powerband. The heads are a hemi design with the spark plug in the center, which is the ideal spot for it, having an equal flamefront go across the piston. Also, boost and nitrous go a lot further on a DOHC setup, because again, the higher volumetric efficiency of the engine. Link to comment Share on other sites More sharing options...
AWeb80 Posted October 21, 2003 Report Share Posted October 21, 2003 but fuck the yankees! Link to comment Share on other sites More sharing options...
Vegeta Posted October 21, 2003 Report Share Posted October 21, 2003 damn it, brian, just lock this stupid thread....its always fucking baseball this, yankees that. Link to comment Share on other sites More sharing options...
TeeJay3800 Posted October 21, 2003 Author Report Share Posted October 21, 2003 damn it, brian, just lock this stupid thread....its always fucking baseball this, yankees that. Yeah no shit, where did baseball crap come from? I'm just glad to see the poll is 50/50. I expected most people to select DOHC, but its cool there are so many fellow pushrod fans out there. I think for the most part its just personal opinion, and how you plan on using your engine and your personal driving style. For someone like me who rarely races, the low end punch of my pushrod is all I use. Even if the 3.1 was strong about 5,000, I would never even get it up there to use the power. I only have one last point. People have talked left and right about OHC motors high RPM HP. I want to point out the valve train used in NASCAR motors: its a pushrod! Winston Cup motors produce around 800 HP at 9,000 RPM and keep making power beyond 9,000! I know they get this power through ultra high compression, alcohol for fuel, and many other things, but its interesting to note that these high HP, high RPM motors use pushrods to operate their valves. Link to comment Share on other sites More sharing options...
runt Posted October 21, 2003 Report Share Posted October 21, 2003 whoops....just made the split a little bit more in the Pushrod direction. Ok, all of you say that this topic has been done to death, but I actually just learned a lot by reading this shit over. Link to comment Share on other sites More sharing options...
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