Rep Power: 0

whats the difference in engines.. like sohc, dohc, and the ovh or is it ohv engines??

 
Rep Power: 285

sohc... single over head cams
dohc duel over head cams

or is that being too general?

 
Rep Power: 0

naw that's cool.. i never knew what it was.. and what the differnce was.. i take it the sohc engines r better??

 
Rep Power: 336

SOHC - Single over head cam, 1 cam controlling both intake and exhaust duration(valves)
DOHC - Dual over head cam, 2 cams: 1 controls intake duration/valves and the other controls the exhaust

OHV - Over head valve?

 
Rep Power: 0

ohv r only in v8 cars aren't they??

 
Rep Power: 0

^^^^^^^^I'll try to elaborate^^^^^^^^^

SOHC: one camshaft that is placed above the intake and exhaust valves. This single cam has the job of keeping the intake and exhaust valves open/closed. Reliable and pretty efficient setup. Not ideal for all out HP though.

DOHC: two camshafts that are placed above the intake/exhaust valves. Has one intake cam and one exhaust cam. This setup is more complex, but is MUCH better for the quest for high HP.

OHV: Commonly called "Push-rod" engines. Again one cam that is placed inside of the engine block itself. The single cam uses its lobes to "hit" both intake and exhaust lifter arms that are connected to rocker arms to open and close the valves. Sounds complex but is more simple to build. Not very efficient compared to the OHC (overhead cam SOHC/DOHC), but are very reliable. Chevrolet Corvette still keeps this engine design (as many other GM V-6 and V-8)

Hope this helps.

 
Rep Power: 303

no gm actually still uses the ohv design in a lot of vehicles besides v6 and v8's. for instance i have a s10 2.2l 4cyl that is a ohv motor. very poor efiency but are still strong motors. we do not get very good gains out of performance mods. they do however respond well to forced induction. especially the newer flex fuel motors. which just happens to be what i have. the flex fuel models were developed to run on reg ol pump gas or e85 ethanol or in laymens(sp) terms farmers gas. it is a lot cheaper and is made by local farmers on the est coast and mid west states. the reason the flex fuel motors are good for forced induction is because they can run this e85 which is less combustable therefore it uses a lot more fuel in 1 stroke. it is fairly easy to trick this system for boost applications the fuel system is already set up to run more volume and pressure than a non flexible fuel motor. so basically with the right afr on a fmu your pretty much set to 1 bar or 14.7 psi. there is a guy on another forum i go to who has 2 of these motors set up. 1 of which made 199 rwh on 10 psi with no intercooler and just alcohol injection to cool the incoming air. not to bad for a motor that dyno less that 100rwh stock. he also has a built motor(keep in mind that there are no cranks or cams available for this motor) he had his crank and cam cyro treated some head work stock bore with forged rods and pistons. he made 296.4hp @18 psi on a chassis dyno with no intercooler or alchy injection on a 16:1 fmu the afr is way too lean with out the smt6. he has a perfect power comp model smt6 that has 164 map point adjustments that can control up to 6 extra sub injectors that was not on the motor for the chasis dyno. the motor still leans out so there is plenty of room for improvement and by calculations it should make 280 to the rear wheels. now he has a problem with over heating. the stock cooling system needs to be up graded. he will be running a ls1 corvette radiator and cooling fans. but this is what i mean by efficiency. the motor now makes 3x its origional power and cannot be ran for more than 15 min. and likes to blow head gaskets. so a custom head gasket has been made and cooling system is now on order. id assume he should make well over 300 hp to the wheels after all is said and done and probably has well over $5,000 invested. that is why a ohv motor is a lot less desireable than a sohc or a dohc

 
Rep Power: 319

to add onto what was already said:

SOHC engines produce higher ammounts of torque the reason why our civics are able to climb hills easier than 2.0l volkswagen beetles which are dohc...mustangs also have SOHC engines which is the reason for high ammounts of torque but with **** for hp

DOHC engines produce higher ammounts of horsepower but with less torque...like i already stated about the VW beetle...but with honda's Vtec and i-Vtec cam technology has come far to where in the B series motors and the k series along with the H series motors are able to produce higher ammounts of torque and horsepower

 
Rep Power: 0

soooooo if dohc engines are supposed to be good.. how come everyone wants the old sohc engines like in the later year civics???

 
Rep Power: 434

because the d17 flat out sucks. honda tuned it too well.

 
Rep Power: 0

Because in the older Civics you can swap out a D series engine...SOHC...into all sorts of years with little to no mods. The older SOHC engines can easily swap parts such as heads, internals, tranmisions, and so on and there are millions of parts for them.

 
Rep Power: 0

wow this thread has a lot of great information guys

 
Rep Power: 424

This may be coming back in a sense... its much easier for displacement on demand (cylinder shutdown) when pushrods are used vs. OHC. Of course the Japanese are gonna take the hard way out, but engines like the new Hemi are still OHV engines, as is the Viper V10 and the LS1, LS6 and the new LS2 from GM. None of which are very "low tech" motors.

 
Rep Power: 286

yeah keep it coming, i love learning specifics in car performance.
I heard Chevy is gonna make a C7 Corvette. Its going to be wicked.

 
Rep Power: 0

nice info.