Who read the Car/Driver acticle on pushrod engines?

95Viper

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Latest Car/Driver has an EXCELLENT article on pushrod engines. Everyone thinks so much about how great the DOHC engines are and how so advanced they are, that's crap. Sure, they might get more valve coverage but at what cost? Size, complexity, weight, cost!

Some people better jump back on the pushrod bandwagon, and buy Vipers.
 

JGK95

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I haven't read the article yet but always felt that the Oldsmobile Aurora DOHC motor was a MAJOR step upwards for GM. Prior to the C5 I believe there was even talk of going to a DOHC setup. My subjective logic was: If the Ferrari's got it, why don't we(American Mnfrs.)? However, you must agree that being able to Rev a car several thousand RPM's higher garners alot of respect vs. the standard Pushrod 6K RPM. Of course there will be plenty of examples of non production Pushrods going over 6K RPM; however, until recent these were the exception and not the rule.

Great Topic,

Jay K.
 

FE 065

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Umm, that flies in the face of just about every max hp/litre engine out there doesn't it? Crotch rockets, 10 sec or faster ricers, F1, etc etc.

Somehow I can't see C&D dissin 4/5 valve heads, or over head cams - but I won't be able to read the article until I get back in the USA next week.

The flathead isn't coming back.
 

Tom F&L GoR

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Haven't read C&D yet, but recollect that Penske won Indy one year with a new design pushrod engine over the OHC engines that were the norm?
 
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95Viper

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In my opinion the biggest thing everyone misses is exactly what was said above. "max hp/litre engine "

Why don't you measure what really counts? max HP per exterior engine size. A DOHC takes up more space under a hood per liter (a lot more). This is room needed for components and hood clearance.

Let's exclude high performance for a second and talk mass production sedans for the everyday family. DOHC's are more complex with multi cams, chains and valves, they cost more to produce, they take up more space, etc.

The article was totally not about slamming the DOHC. It just gave credibility to the pushrod and questioned the myth everyone has that DOHC's are so advanced and superior.
 

JGK95

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Why does this sound like a 'feelgood' article for the pushrod. When I read re: mass production claim and engine size I had to reevaluate the entire purpose of the article that you have read. Forgive me for being rude, buuuut "What the **** are they thinking??" If I cared about engine/engine bay size I'd go RETRO to a 1957 Bel-Air BUCKET!! and stuff a BIG Block under the hood with the worlds BIGGEST Blower!!


...then again it couldn't be mass produced for the fam o lee.
 
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95Viper

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Most people who think DOHC's are so advanced do so because they picked up on a new technology (not actually new though) and suddenly claimed pushrods stink and were old and outdated. Maybe true for a Ferrari but what gets me is they push their theories into the mass sedan markets. This is where engine size, cost, weight, complexity, etc. account for everything.
 

Bill B

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Max hp per liter. Lets see I have a 1.3 liter with no valves making about 390 hp per liter. And you could fit 3 1/2 of them in the space of a V-10 :headbang:
 

Guibo

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Here's the article (props to SilverFenix for the scan).

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Imagine how good the design would be today if companies invested the time and effort even remotely similar to what they've been spending on other types. The pushrod 300C Hemi has a "displacement on demand" system, like Cadillac. Caddie's V16 prototype had some kind of variable valve timing (which may show up later on some Corvettes). Bentley's turbocharged Arnage is supposedly going to be good for Euro emissions through 2008...
 

jcaspar1

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HP/liter means about as much as HP/wiper fluid volume to me. Never have seen any value in that measure. What is important is HP/lb of engine weight or HP/total engine volume. What would you rather have: a 300 hp 2 liter motor that weighs 400 lbs or a 300 hp 4 liter motor that weighs 300 lbs???
 

Fiorano

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In one of the current issues of a car mag (maybe C&D), some schmuck wrote in to discuss the new Ford Mustang. Basically, he said "when is Ford going to learn not to stick some old technology crappy pushrod engine into a shoebox and try to sell it." The idiot does not obviously read as the Mustang doesn't have a pushrod engine.
 

Chuck 98 RT/10

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HP/liter means about as much as HP/wiper fluid volume to me.

True that. One time some dork commented "450HP? That's not even one hp per cube." I told him I'd wait for him at the finish line to remind me.
 

Torquemonster

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Some very valid points - the pushrod engine is defintely not dead for street applications as they are well suited to making great power and torque over sensible street rpm ranges.

In addition it is a great point about looking at PHYSICAL size and WEIGHT compared to Cubic Capacity.

My friend just bought a new Aussie Ford 5.4 cammer V8 Ute. It might be 5.4 litre capacity but that thing is seriously as big as a 426, 572 or 604 Hemi! It is MASSIVE.

Overhead cams are bulky

Multi-valves would be nice - they have huge advantages, but the overhead cams are not needed on street engines or even racing engines under 9000rpm.

even better would be F1 electronic valves - no cams at all... but I don't guess they'l want our sticky little fingers on that tech for a while yet....

mutter mutter mutter

:p
 

jcaspar1

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Pneumatic or electric valves seem almost unbelievable! Could you imagine being able to essentially changes cams with the flick of a switch!
 

Tom F&L GoR

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I think BMW has a system that electronically drives the valve lift and there is no throttle. (A drive by wire system, obviously.) That always made me go back to that argument about larger TB's... if there isn't one at all, (keeping the same runner sizes) what does that mean? ;)
 

GTS Bruce

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Ferrari 575M.Same HP as Viper but no torque.You have to rev it to WHAT to get the car to move?How often does it need a major tune up?How many passes on a drag strip can it make?Could it ever out drag a Viper?As far as usable torque is concerned there is no substitute for diaplacement NA.No one in the world builds big torque motors like us.Not euro or *** peaky but flat as a table top.Boats demand torque.Ever see a *** or euro inboard? Bruce
 

Cobra4B

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I read that article and it was great to see some recoginition of the advantages of the pushrod 2v design. There was an in-depth analysis of this over on Z06Vette.com

http://www.z06vette.com/forums/showthread.php?t=56736

If you read some of that thread the guy does a good comparo of the ls6 to the Farrari V12 and the Bimmer M5 motor. HP/Liter is stupid as f'ck. You need to look at outer dimensions, weight, number of parts etc. Take the ls6 for instance it only weighs like 430 lbs and it's really quite small. Also, the moder 2v head flows almost as much as a 4v head and doesn't need to rev as high to accomplish the same goals (torque baby)

I especially like the m5 comparo. The ls6 is smaller (dimensionally) uses less parts, less costly parts, makes more torque, and gets much better fuel economy. Also, the size allows it to be positioned low and rearward in the car for optimal weight distribution. Technically a C5 is a mid engine car, no part of the motor goes in front of the front axels.

Anyway... so many people thing that dohc is "high tech" and is "better" but they're ignorant and only know what the marketers tell them.

For instance, I had dinner on Easter at my College ex's house. Her dad was asking me all about the car and was literlly shocked and put off when I told him that the car was OHV w/ 2V/cylinder. I explained all the advantages of the powerplant and he did come around.

BTW my 4.6 DOHC in my old cobra is bigger than a 429 BOSS BB and they're over 600 lbs for an aluminum motor.

Cheers Viperdudes...
 

Torquemonster

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Great points guys

and Cobra4B - is the 4.6 really 600lb? wow that's disgusting!

You can build a 572 or 600+ cubic inch Mopar wedge that is 460lb ringing wet using alloy - and guess which one will go better between that and the 4.6?

even a twin turbo street 4.6 wouldn't make the power of a well set up naturally aspirated 572 indy wedge that was 140lb lighter and smaller dimensionally.... so much for technology then.... :D

Those cammer motors do rpm and sound nice tho....

But then - ever heard a mountain motor roar to 8000 pulling 1000hp on a single carb? :D

its enough to send the 4.6 cammer back into the shed with a sqeaky voice
 

FE 065

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I give... so 9 sec fatory motorcycles using multi valve and multi cam technology are a step in the wrong direction? Aren't they in a smaller package than 4 cylinder bike engines 20 years ago? And lighter too?
'
Four valve heads would be worse because there'd be more weight, complexity, and cost?' Sounds like the same banter a young GM engineer I talked to 6 years ago in Clarkston, MI was tossing at me. There's nothign to prove the pint except for SS Hemis or other specialized drag vehicles overall

Two valve heads don't need to rev as high??? You mean can't rev as high as a multi-valve don't you?

Bah humbug. Since when did underhood space outweigh horsepower?
 

joe117

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Back in the 60s, pushrod chevy V8s turned up more than 6k rpm. I believe a 61 Vette 283/315 stock engine had a factory redline at over 7k rpm.

A big downside to OHC today is drive belt replacement. It needs to be done at very short intervals for normal cars that will probably last through five changes.

Replacing the drive belts on OHC engines is a serious expense on some cars.

Didn't I read that it's an engine out job in a Ferrari?
$$$don't ask$$$

There are other ways to do valves in a four stroke. Sleeve valves.
 
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95Viper

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We need to get off the motorcycle comparison, just read the article and understand that no one is slamming the DOHC. Just understand if you are a car builder, you need to consider size, weight, cost, complexity, etc. Otherwise you'll end up in one of those orphan car shows.
 

GraphiteGTS

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When the Honda S2000 came out the mags were raving about being able to rev above 9000 in a car. Would they rave more at 11000 or 13000, like some bikes?
I want good old American low-end torque.
 

Fast Freddy

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i own just about all of these motors being discussed here, including the ohc inline 4's that reside in my drag bikes. one drag bike has a 929 cc fuel injected engine wtih dry nitrous kit that makes 170 crank horse with just a 25 shot of juice. i shift it at 11,500 rpm's. pretty trick engine i think. my other drag bike engine has a displacement of 1052 cc's and i turbocharged it with a aerodyne aerocharger variable vane turbo pushin 8 lbs. of boost and that engine is making 190 crankshaft horsepower with no intercooler. i blow thru the rejetted stock carbs and shift that engine at 10,500 rpms. that engine has 125 crank torque. it is one bad *** engine for sure. a 8.1 litre viper engine would have to make aproximately 1500 horsepower to equal that kind of volumetric efficiency. the suzuki hayabusa engine that resides in my 800 lb. mini superlite sandbullet sand rail is one way wicked race engine that displaces 1300 cc and revs to 10,500 rpm's. it makes 175 n/a crankshaft horsepower and 120 crank torque. the mini bullet muffler i run on my rail makes that engine sound like some kinda f1 race engine. it is the most killer sound on the planet.

as far as my car and truck engines are concerned the 6.8 litre ohc v-10 engine that is in my ford superduty truck is a pretty cool engine with its "y block" and all. but like a viper engine it is big and heavy. i will probably end up putting a centrifugal supercharger with aftercooler on it thanx to vortech. the ohc engine in my ford lightning that is currently making 530 crankshaft horsepower thanx to the 15 lbs. of boost that i am runnin thru it is the coolest automotive engine that i have ever had the pleasure of owning and operating. that boost coupled with that 5.4 litre stroker engine is one of the most addictive torque rushes i have ever felt in a automotive application. the bore on the engine is only 3.55 inches yet the stroke is a massive hemi like 4.15 inches. i am making 600+ ft lbs. of torque at the crankshaft with this setup. the v-10 engine in my super duty has the same bore and stroke with just 2 more cylinders. the updated version of this engine that will reside in the new ford gt-44 will be the baddest thing to ever hit the street. last but not least my old 1971 datsun 240-Z race car that i put a 1981 280-ZX turbocharged ohc straight 6 engine into made some killer torque too. i ran 10 lbs. of intecooled boost thru my triple mikuni side draft carburetors and dyno'd 300 crankshaft horsepower and 350 crankshaft torque with only 2.8 litres (175 cubic inches) of displacement. a small block chevy with 350 cubic inches would have to make 700 horsepower to equal that kind of volumetric efficiency.

with that said, i still like my pushrod engines too and the ls6 that is in my Z06 is one silky smooth high revvin little demon. but the 454 engine in my drag boat that i bored .030 over and bumped the compression ratio to 10.25:1 is bad to the bone. i have a weiand tunnel ram with 2 holley 650 carbs and open headers. it dyno'd 750 crank hp with a 200 shot of nitrous. i throw one hell of a rooster tail at the lake thanx to my dominator jet drive.

in the end the pushrod v-10 engine that resides in my viper has the most potential of all the engines i own. 488 cubic inches with 10 cylinders. ahhh................. there is just no replacement for displacement!

not!!

ohc and pushrod engines? its all good for me! just like chevy, dodge and ford. at the end of the day the only thing that matters to me is did that ride put a smile on my face :laugh: and as long as it spends more time runnin at wide open throttle than bein torn down to be fixed at the shop then it is worth it to me. :2tu: and so with that said of all these high performance engines that i own and operate i would have to say that the viper engine is probably the most reliable as a result of relying upon it displacement to get the job done. it doesn't have to be built as high strung as other engines to make torque. and that is just fine with me because............. 5,000 horsepower will never do u any good if u can't get the thing started. :usa:
 

Russ M

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Haven't read C&D yet, but recollect that Penske won Indy one year with a new design pushrod engine over the OHC engines that were the norm?

Yes he did but it was not for the reason you think.

He used the illmore(Spelling?) engine, which was a pushrod design. There was a rule in CART that allowed a motor with pushrods to use more boost, and maybe even more displacement. They quickly changed that rule when Penske had slapped the entire field in the face with it.
 

formula1

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Russ is correct. The OHV did not have an advantage, it was allowed more boost and they built a special motor to take advantage of it.

OHV and OHC engines both have their place. Obviously the Viper is a great example of an OHV engine application in a street car. It's less complex, easier to manufacture, etc. In all out, no holds barred competition where there is a displacment limitation, then high revs is one of the best ways to make hp and OHC engines allows high revs with sufficient valve area to fill the cylinders and make that happen (as in most open wheel race cars of advanced design).
 

FE 065

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OK, I'll stick to cars.

I've had alot of Mercury Sable wagons. My latest is a 2001 with the 3.0 litre DOHC 24 valve engine.

This car runs liked a ***** ape, and would just destroy any of the other 3.0 litre 2 valve wagons I had before in a race.

It's a monster. Passing more than one car at a time is no problem.

Complex? I do the same maintenance on it as the 2 valve cars...

Same body, same engine compartment, same reliability.. win, win, win

You don't need a specialized race car to reap the benefits.


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FE 065

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Now that I'm in a cheaper internet cafe (I'm overseas) I've read the C&D article. All I see is GM's Winegarden making excuses for not stepping into the 21st century with DOHC.

"Performance requirements were met by adding displacement" he says? Must have been some pretty low requirements. They sell all the Vettes they make; they're in no hurry to invest any more than necessary to make the new model an inch better than the previous year. Maybe they needed some print in C&D to appease disappointed Vette owners...

And that sniveling about how much heavier the Northstar engine is!

I worked in GMs test area for 10yrs, and drove the ZR-1, C5, and Northstar during development, those kind of weak-kneed excuses are typical.
 

Guibo

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Whoa, did you guys check that link posted by Cobra4B?

"LS6
Crated Shipping Weight: 497 lbs

LT5
Crated Shipping Weight: 741 lbs" (?!)

Brand new LT5 crate engines are something like $12-15K, depending on where you look. Heard on another forum that the heads alone used to be like $5400 each from the dealer. What's a whole crate LS6 w/ECU cost, ~$7K? Of course, the LT5 is exceedingly rare, but still. Wonder if the $65K price of the car (in the late '80s) had anything to do with engine production and development costs.

The weight difference for the Northstar vs LS6 seems like a valid point. In a sportscar like the Z06, you sure wouldn't want the extra pounds at the front (even if the entire engine is behind the front axle line). I've heard that one of the reasons why Cadillac went with the LS6 in the CTS-V is that, besides cost and weight issues, the Northstar simply wouldn't fit without clearance problems.

Here's another recent article on pushrods:
http://www.autoweek.com/search/search_display.mv?port_code=autoweek&cat_code=carnews&content_code=01028000&Search_Type=STD&Search_ID=2061786&record=1

Apparently, that's a savings of about $2.7 billion.

Read in an R&T article that RUF gets Turbo engines (415 hp) from Porsche, at $37K per. That's also similar to the cost Jet Motorsports paid BMW for the 400-hp M5 engine to be used in their M3 GTR a few seasons back. How much is a 450-hp Gen II crate engine again?
 

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