What are the technical benefits of an OHV engine?
Posted by sub-a-dub-dub@reddit | askcarguys | View on Reddit | 8 comments
Years ago Donut did a video on the Corvette and they discussed how GM experimented with an overhead cam V8. This was pre Lotus ZR-1, around 87 or 88. I remember finding some other literature that supported that story and supported that the consensus was the OHV L83 and L98 produced torque sooner than the experimental OHC V8. What would cause the torque to come alive sooner in comparison to a S/DOHC engine?
Aside from the known benefits of OHC V8s being smaller packages, lighter, simpler, what other actual technical benefits, like torque production if its true, does the OHC V engine have? Im not looking to start a OHC vs OHV flame war here lol engines are application specific and I agree that S/DHOC engines can offer a wide range of abilities as well.
LOGGATO@reddit
All the engines you are talking about are OHV (overhead valve) engines...
I believe they produced different numbers because the combustion chamber in the head was probably different. Torque is usually pretty easy to achieve as it requires less compression and timing etc.. tons of variables. OHC exists because it's far less moving parts in the valvetrain, especially when you want to run more and more valves per cylinder.
CarsandTunes@reddit
Yes, all engines are overhead valve. But the term OHV refers to engines with a camshaft buried in the block, that uses pushrods to move the lifters, and thus open the valves. Where ohc engines have the cam up in the head directly above the valves, for going the need for push rods, but adding other complexities of their own.
LOGGATO@reddit
Those are usually just called Pushrod engines.. But I guess I've heard it either way.
CarsandTunes@reddit
Correct. Referring to those engines as either pushrod engines, or overhead valve end are both universally correct.
Equana@reddit
An OHV engine is smaller and simpler than an OHC, either single OHC or double OHC.
Power is made at a lower rpm in an OHV engine because revving an OHV engine to 8000 rpm is techically more difficult that an OHC. So for similar HP numbers, the OHV engine must be bigger.... 5.0 Mustang DOHC vs 6.2 Camaro OHV.
Ask this question in Chat GPt or Gemini and see what each says.
PetriDishCocktail@reddit
It has to do with the number of valves, the size of the valves, and the velocity of the intake tract to fill the cylinder. Basically, small valve engines do better at lower RPM because you get higher air speeds going through the small valve, leading to better torque numbers at a lower RPM. At high RPM multiple valve engines can breathe better and make higher horsepower.
gutentight69420@reddit
I think its mostly about cost. Engine performance at low speed is mostly going to depend on the cam profile.
Stock-Swing-797@reddit
wat??