DOHC, SOHC, NOHC Performance benefits, or hype?

Oops, typo --- I meant to say "OHV also accommodates cylinder shutoff technologies more easily than _OHC_ setups.

The only OHC engine with cylinder deactivation that I know of is Honda's

3.5 Liter in the Odyssey.
Reply to
Masospaghetti
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GM's new OHV engines have variable valve timing using a camshaft phaser. While less flexible than VTEC (as intake and exhaust timing are not independent) its a simpler system.

Correct me if I'm wrong but Dodge's HEMI engine is an OHV design...with hemispherical heads.

The engine is physically smaller, lighter, and cheaper as well.

Reply to
Masospaghetti

sorry im not that great with the english language but i do know a little about engines.

benefits to ohc: multiple valve which in most cases leads to better flow ;better flow =more hp less rotating mass ;less roatting mass means higher rev higher revs mean more hp potential

so in theory ohc will be able to produce more hp easier. now to counter that people would like to throw out the lt and ls engine which are great engine but where they get there hp is head design is displacement and the old saying "no replacement for displacement" comes to mind which is a hundred percent true but lets face it they arent as efficient and here is an example with stock gm motors

4300 vortec v6 in its highest rating made 165hp and 235 lbs of torque and is a 4.3l ohv

4200 vortec i6 in it highest rating made 291 hp and 277 lbs of torque and is a

4.2l dohc

the number speak for themselves

dont get me wrong push rods are good engines but in most applications wont live up to the ohc counter parts with the same amount of displacement

Reply to
shane

shane wrote in news:67085$547fd26a$41b57997$ snipped-for-privacy@news.flashnewsgroups.com:

ok ovh has no relatsonship to multiple valves. it has two advantages. one is valve train weight reduction (higher rpm potential) and less friction in the valve train, (more important today for gas milage)

and one reason is no pushrod holes to work around for head design

is displacement and the old saying "no replacement for

those are not compairable, both eng could make much more power in a high output build, the numbers are just what the factory was willing to build them too. the newer eng is built to higher numbers just for sales advertising. the horse power wars are back as sales advertising again. the ohc will always win the ultimate HP race but it is because of design advantages not just because its ohc.

actualy they can come close, just not as cheaply. KB

Reply to
Kevin Bottorff

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