Even with all of its blunders over time, one factor about Common Motors that we will not actually fault is its lineup of small block V8 engines. These engines have been particularly central to Chevy’s efficiency lineup. Stuff just like the LS and the more moderen LT household have confirmed themselves in manufacturing automobiles, older fashions that had been found to be wonderful tuning platforms, and crate engines for fully customized builds.
One frequent factor amongst Common Motors powertrains of the small block V8 selection — and in some circumstances different layouts — is that they do not use single or twin overhead camshafts, like most fashionable engines do. Whereas the pushrod, or overhead valve structure, typically known as OHV, has lengthy been shunned by most OEMs, Common Motors continues to be pushing by with pushrod engines, even right this moment.
An excellent cause for that’s simplicity. Pushrod engines merely have fewer elements than SOHC or DOHC engines, and that simplicity typically means a major enhance in reliability. This is the reason it continues to be such a preferred powertrain for engine swaps, and one of many the reason why the LS can deal with a lot energy. That being mentioned, there’s a bit extra to it.
Pushrod engines supply some advantages and downsides
Positive, simplicity is a notable advantage of OHV engines, however they do have another upsides that make them extra appropriate for various functions. One such utility is low-end torque, a necessity in pickup vehicles and different autos that want an enormous burst of energy low down within the rev vary. This is without doubt one of the the reason why the elective EcoTec V8 engines within the modern-day Chevrolet Silverado are pushrod items.
Most of the time, pushrod engines have solely two valves per cylinder. Which means that even at low revs, when there’s not lots of air going into the engine, the air can get to the combustion chamber quicker than regular, that means extra energy decrease down within the rev vary. After all, this comes at the price of with the ability to rev excessive, which is why pushrod engines do not — and might’t — have notably excessive redlines.
That is an enormous draw back of the pushrod structure: you do not actually have lots of revs to work with. The design of a pushrod V8 additionally implies that, in inventory type, lots of them do not produce a lot energy relative to their measurement, and stuff like variable valve timing is a no-go. Regardless of having a number of drawbacks in comparison with fashionable engine layouts, overhead valve powertrains undoubtedly have a cause to nonetheless be round. Even the modern-day base Corvette Stingray nonetheless makes use of a pushrod V8 dubbed the LT2.
