Pushrod vs. SOHC vs. DOHC

[FYRHWK1]

Originally Posted by texan

OHV is certainly not superior, among other things already mentioned the pushrod intrusion through the cylinder head limits port design and shape. Of course more of the airflow differences between domestic and import cylinder head flow is due to the Big 3's reliance on displacement to make airflow rather than brilliant cylinder head design and RPM, but then either approach can work extremely well.

"rather then brilliant cylinder head design" I don't know why you would say that, to be able to do what GM's done with only 2 valves is fairly impressive in my book, and tuners have found alot of room left in them as well.

[calgary_redneck]

I believe there are some good engines of the ohc design and ohv design. They have both almost been around for an equal amount of time and they both have been shown to make amazing power when being clean enough for today low emission standards. The next big step will be cam less engines that will make both pushrod and ohc engines seem obselite

[MustangRoadRacer]

OHV has been around much longer than OHC.
And Camless engines aren't that fantastic.

[SaabJohan]

Note that SOHC and DOHC are both OHV just like push-rod engines. The engines which aren't OHV are the old side valve engines.

[MustangRoadRacer]

yes, but I think the OHV in this case meant Cam in block.

[calgary_redneck]

yup saabjohan please try to pay attention to the conversation. Push rod engines are generally refered to as ohv. As for the comment from mustang I'm not sure what you are baseing your oppinion on camless engines on. In theory they will blow everything else out of the water I'm interesting why you think they are that great especially seeing how I doubt you have diven one as they haven't been released yet. And acually ohc can be traced back to at least the 1920's so yes the both have been around a simalar amount of time

[SaabJohan]

Originally Posted by calgary_redneck

yup saabjohan please try to pay attention to the conversation. Push rod engines are generally refered to as ohv. As for the comment from mustang I'm not sure what you are baseing your oppinion on camless engines on. In theory they will blow everything else out of the water I'm interesting why you think they are that great especially seeing how I doubt you have diven one as they haven't been released yet. And acually ohc can be traced back to at least the 1920's so yes the both have been around a simalar amount of time

Use the correct terms instead, it avoids misunderstanding. Over Head Valve refers to nothing more than that the valves are placed in the cylinder head, which is usually the case for both push rod and OHC.

[MustangRoadRacer]

That is true, that they have been aroud since the 20's, but Cam in block has been around since before the turn of the century.
Show me proof of the vast superiority of camless engines andI may just change my mind.

[calgary_redneck]

Well its a little bit hard to show proof seeing how they haven't been mass produced yet how even in theory a camless engines should be able to alter the lift and duration for peek performance at any rpm and driving condition. It will be like vtec only 100 times better very good hp numbers should be able to be produced from even very small engines with exelent drivablity. Now of cource there will be teathing problems as with any new tecnology and I probably wouldn't want to buy one till they get it perfected but it should be quite amazing once they get it right

[calgary_redneck]

saab everyone understood except for you

[FYRHWK1]

Originally Posted by SaabJohan

Use the correct terms instead, it avoids misunderstanding. Over Head Valve refers to nothing more than that the valves are placed in the cylinder head, which is usually the case for both push rod and OHC.

I'm not going to jump on any bandwagon here as you're right, I just always viewed it as the position of the cams relative to the valves. OHC having the cams over them or OHV with the cams under, just always made sense to me, but like I said i'm not getting into another capslock match on here.

[454Casull]

Originally Posted by calgary_redneck

saab everyone understood except for you

You're arguing over a mistake on your part. I'll have to side with SJ.

If I were to say a Honda engine used OHV, would your blood pressure rise?

[Moppie]

Originally Posted by 454Casull

. I'll have to side with SJ.

And Ill have to Ditto that.



Enginers have spent hundreds of years developing special terms and word usages to avoid confusion and allow the easy and efficant transfer of ideas, so when discussing things of a technical nature it pays to adhere to those terms.



And since OHV Hondas have entered the conversation Im wondering if Ferrari, BMW and Honda have ever made a pushrod engine?
They are generaly regarded as the three best engine builders in the world, proven by thier F1 success. (Note, Im excluding low production manufactors like Cosworth, as they normaly start with a mass produced engine design).

[MustangRoadRacer]

yes SAAB was right.
using incorrect language, regardless how common, does not make it correct.
any specs/info on the camless engine?
who makes it?

[calgary_redneck]

I believe alot of companies are running with the concept at the moment I know for sure gm is working on it and plans to have some engines using it in the not to distant future how ever it will require going to a higher voltage electrical systems for sure to supply the soliniods that will be used to open the valves