Hemi Challenger

Yes, OHC engines have some advantages. My point is, under NORMAL use the advantages are negligable. The engines must be wound tight to make use of most of the advantage - Horsepower alone tells only a small part of the story. Today's AVERAGE car runs somewhere around 2000 RPM at legal highway speeds in top gear. Under NORMAL HIGHWAY DRIVING an engine with dual overhead cams and 4 valves per cyl has little if any advantage over a pushrod 2 valve engine of the same displacement. It has NO advantage over that pushrod engine in durability or longevity, all else being equal. It has a definite DISADVANTAGE when it comes to cost to repair. It is also at a disadvantage packaging-wise- as it is significantly larger in virtually all dimensions than a pushrod engine. It is also generally HEAVIER if made of the same materials. Yes, many high output OHC engines are lighter than the equivalent OHV engine, but just because the "low tech" engine elected to stay with cast iron heads and block instead of the aluminum used by many/most OHC engines for at least the heads, and most often the blocks.

That said, today's thin cast iron blocks suffer only a small weight penalty over the average aluminum block of only a few years ago.

So - if you are talking no-holds barred performance engines, and maintenance/repair costs (as well as production costs) are a secondary consideration - yes, OHC engines have an advantage. DOHC has a marge larger advantage over SOHC than SOHC has over OHV technology when you get into the higher output higher speed engines because variable cam geometry is so much easier on a dual cam setup.

This does NOT make a pushrod engine necessarily a lesser engine for some 90+% of owners and drivers.

Reply to
clare at snyder.on.ca
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Pulling a cam from a transverse mounted OHV engine usually means pulling the engine. In a longitudinal mount it usually means removing the radiator at a minimum, or worse. Depends on the car.

In today's world most new cars are throw aways no matter what engine they have. It doesn't make sense to put $4,000+ worth of repairs into a car that is worth maybe $2,000. One thing I will say about today's cars is they are much more durable, on average. Getting 100,000 miles from a car 30-40 years ago was considered good. Now they are just getting broken in if they are maintained well. Plus, the maintenance regime is heaven nowadays compared to the good old days of condensers, points, short lived spark plugs etc. Remember when Ziebart treatment was necessary to keep vehicles from rusting apart by the time they reached

100,000 miles?

I wouldn't say they screwed up the engine design as much as they screwed up the head gasket specifications.

Reply to
Michael Johnson

You can build a 1966 Mustang totally from parts for significantly less than you can restore a "decent" Cuda , Challenger, Charger, or virtually any other Mopar of the period. And Chevy falls in between somewhere. A Camero or Chevelle is easier / cheaper to rebuild than a Mopar because there are more parts available, at a significantly lower cost.

Reply to
clare at snyder.on.ca

AND the 413 was a car engine long before it was a truck engine...

Rob

Reply to
trainfan1

Truth be told we could all get by with three cylinder shoe boxes for basic transportation. People don't buy high performance car because they need them. ;)

I disagree with the above. With VVT, multiple intake and/or exhaust valves, dual tuned runners etc. the power band can be enhanced from idle to redline. In the OHV engines I have run to high mileage the bigest chance of parts failure has rested with the valve train. It can be a ticking lifter, bent push rod or a bum rocker arm. IMO, these components are the Achille's heals for OHV engines. They don't exist in an OHC engine and therefore con not be the cause of failures. The durability of Ford's 4.6L is legendary already and I chalk a lot of it up to the OHC design. Fewer reciprocating parts mean greater reliability and longer life, IMO.

I will give you that OHC heads are more a throw away part the their OHV counter part. That being said the infrequency of early catastrophic engine failure in today's engines (OHV and OHC) makes this a minimal issue. If today's cars are maintained well engine failures are few and far between.

I agree. But I think we also both agree that for high performance applications OHC engine have inherent advantages that OHV engines can't match. Remember the 427 SOHC engine Ford had in the 1960s? The OHC design made it one of the best engines of that era. It was the only engine that NASCAR banned because it was eating the Hemis alive. The OHC design made it too durable to run with push rod motors. This also reminds me of the only turbine car to run in the Indy 500. It bitched slapped the entire field of cars that year until its gearbox failed with two laps remaining. I wonder what we would have in today's cars if they hadn't banned the turbine and SOHC engines? At a minimum I think we would have seen OHC engines in production cars much sooner.

Reply to
Michael Johnson

Was the 1967 Lincoln 462 the same engine as the 460? The 460 stroke was shorter and the bore was larger (marginally) Was the 462 a bored and stroked 430?

Reply to
clare at snyder.on.ca

The 413 hit the cars in '59 I know the 1960 LCF had the 413 as the "standard" engine, so "long before" is only 12 months max. I think the C series (LCF) truck came out aboutJune or July 1959 - making "long before" closer to 10 months

Reply to
clare at snyder.on.ca

And the bearing specs. Any bearing that cannot stand2% glycol in the oil is JUNK.

Reply to
clare at snyder.on.ca

Comparing to FORD OHV engines I'll give you that. The valve train on the 551M/351C was definitely inferior. As was the Bos 351 (and the Chevy 396)

They all had rocker and/or valve spring issues (but they ran insane speeds for pushrod engines)

The Chevy SBC was also legendary - and with proper oil changes could EASILY go 200,000 miles in the good years (when they didn't have "butter" camshafts)

So could 318s and even 225s.

If those engines had the advantage of today's oil technology and leadfree gasoline (with the proper valve materials) and EFI they would have run extremely stronly against today's engines as far as reliability is concerned.

The logenvity of todays engines has as much to do with those 3 items as anything else.

Leadfree fuel is the major advantage, followed by fuel injection and electronic engine controls, followed by lubrication technology (up untill about 2000). Today's oils are headed back due to emission demands reducing the EP additives etc.

Reply to
clare at snyder.on.ca

I know a guy with a 413 Max Wedge on a stand.

Reply to
WindsorFox

And we'd probably have those flying cars that tehy promised us back in the late 50's. In general that echoes my thoughts on the OHC as well. IMHO they are just delaying the inevitable and losing mileage and durability in the mean time.

Reply to
WindsorFox

Meet George Jetson, Jane his wife, daughter Judy, his boy Elroy... LMAO

Reply to
My Name Is Nobody

Much of what we have in the cars of today are based in racing's roots. I have no doubt that if turbines were allowed to run at Indy and the rest of the cars would have to conform and also run turbines or be perpetual loosers. Had the Indy cars gone turbine back then the fans would be open to them in production cars and actually demand them to be built. Chrysler went down that road briefly but interest never developed. Had Indy let the turbines run things would probably have turned out differently.

Reply to
Michael Johnson

The conspiracy theorists of course say that the car companies couldn't have it because they last too long.

Reply to
WindsorFox

And of course, people who know what they're talking about would say that turbines are great for specific tasks but not suitable for passenger cars.

Reply to
Tony D

That could be said about most suitable power plants, early in their development stages... It may be true now, but that doesn't mean it will be later...

Reply to
My Name Is Nobody

I'm not so sure about that. You know there was a guy on one of those cable shows a few years back who drove a turbine powered Vette. He drove it normally in traffic. And then there's the GM/Jay Leno thing. Here is an interesting article on the Chrysler turbine

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Heh, 130HP and 425 lb/ft

Reply to
WindsorFox

...and just what do you know that makes your statement more truthful than mine? Chrysler had a turbine engine in a passenger vehicle back in the 1960s. It worked. Imagine what another 40-50 years of development might have brought. Do you realize how durable a turbine engine would be in a production car considering how long they last in airplanes? The fuel turbines burn is less expensive that gasoline. Just because the piston engine is the most common in automobiles today doesn't necessarily make it the best design.

Reply to
Michael Johnson

And HORRENDOUS fuel consumption. Even a turbine chopper uses more fuel than a piston engined one - just cheaper fuel. Not sure it ballances out.

Reply to
clare at snyder.on.ca

Jay Leno's proto burns biodiesel.

Reply to
WindsorFox

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