|01-18-2003 03:07 AM|
no offence was ever taken kultuz, just wanted to know if i had somehow stepped on your toes.. anyway. to contribute to the topic:
pushrod engines have the advantage of being able to run rocker armes that multiply the lift and as such yield a faster lift than is possible with a flattappet pushing dirrectly on the valve as is the case in many new OHC heads,
On japanese motorcycles the cam pushes on a roller mounted on a roller rocker which gives the best of both worlds so to say, but the head becomes very tall and would be 7-8 inches tall if you were to make and mount such a head scaled to a chevy sb. The price on 4 steel cams, 48 roller rockers, and so on would be very much more expensive than the OEM iron or alloy head.
so the difference comes down to engineering choice, price and space confines.But a pushrod engine is not nessecarily obsolete, take Panoz that still to this day runs ford small blocks in their Le Mans challenge (or did till they went bust)
|01-17-2003 09:31 PM|
|email@example.com||Don't forget 6000hp from a 450 hemi!|
|01-17-2003 08:25 PM|
there you have it... thanks for the corrections, all.
|01-17-2003 04:47 PM|
I saw a show about this on the speed channel. Top fuel drag racing has reached a peak. Rules and safety issues are what is keeping them from going any faster. Sure they can be faster, there is so much more technology out there that can be put onto them to make then possibly run in the low 4s. Buts its not really safe, and nhra doesn't allow it. For instance, they can have onboard computers but the air/fuel cannot be adjusted and delivered by a computer. They can't run i believe more than 90% nitromethane because its unsafe. And they have to have pushrod engines in NHRA. The question is, would they make more power if they have multiple valves, variable valve timing, and overhead camshafts? I believe they would.
Another thing is that nascar is also using 60s technology in their engines. I bet if Honda got together and build up their VTEC V6 thats in the NSXs they could probably keep up with the nascars.
I think OHC engines are better than pushrod engines. If you compare the two, indy vs nhra, the indy winds out to 18,000rpm and makes up to 800hp from a 3 liter V10, and nascar makes 750hp from a 5.8 liter V8. I think its obvious which is better. But then again, those indy engines cost like millions of dollars.
|01-17-2003 04:28 PM|
|firstname.lastname@example.org||Depends what you consider 'better'. At Indy, all you see is OHC hemis. In Top Fuel drag racing, argueably the most powerful piston engines on earth, all you see is push rod hemis. The hemi is a constant so is better no matter what the valve train looks like. Jury is still out on push rod vs. OHC.|
|01-17-2003 11:43 AM|
I believe the ZR-1 corvette engines were made by Mercury (marine engine company). It was suppposed to be state of the art at the time. I heard on car and driver that the redline was like 7000rpm, but thats only becasue the accessories on the front of the enigne couldn't handle any more rpm.
The Ford Modular engines are all V8s and are all OHC. They have DOHC and SOHC 4.6L and 5.4L. Supposedly the V10 in the pickups are modular also.
|01-17-2003 08:08 AM|
I have a '93 Lincoln MK VIII,It has a 4.6 litre V8 with 4 OHC, rated @ 280 HP. I was sceptical about these engines till I drove this car. This oversized Fox body eats 5.0 ponies. And it revs into oblivion. It's clocked for 140mph and goes well past that. I would never have test drove the car but the wife wanted it.
Bad thing is when it's time for service I'll have to get a loan. Same with the air bag susp. and 4 wheel disc. Still a really cool ride tho.
|01-17-2003 04:56 AM|
|nicefrog||Steppenwolf I think there should be stacks of OHC V8's in Europe, I don't really know but I can't imagine BMW or Mercedes making a pushrod V8 anytime since well ever: )? plus all the sports car makers should have made one or a dozen each. There was a OHC Corvette back in the 90's I remember it from a magazine the ZR-1? What's the go with that anyway? was it based on the small block? with bolt on OHC heads kind of like the Cosworth Ford 4cyl? or a whole new engine?, if it was a bolt on job then how come those heads arn't the gun item to have?|
|01-17-2003 04:18 AM|
[quote]KULTULZ posted January 15, 2003 05:01 PM
Now we await the mechanical engineers and factory certified responses...<hr></blockquote>
[quote]deuce_454 posted January 16, 2003 09:54 AM
say kultuz what is the deal with you and my education, i keep finding small sarcastic remarks on the topic..?<hr></blockquote>
Uh...My sarcastic remark(s) was/were not directed at you personally. If you have noticed recently, there have been a few minor disagreements over theory and such, and as the disagreements escalate, it seems like everyone is waiving PHD's, ASE and factory training certifications.
I was merely trying to be humorous.
[ January 17, 2003: Message edited by: KULTULZ ]</p>
|01-16-2003 10:02 PM|
|4 Jaw Chuck||One thing for sure overhead valve engines are always heavier, all those extra valves and cams and gears and chains weigh a lot more. My Dad's 94 Taurus SHO's Yamaha 3.2 Litre V6 DOHC engine weighs 465 pds, a 302 Ford engine weighs 460. Hardly seems worthwhile when you consider the tradeoff and the durability question. Besides wedge chamber engines make more low end torque than a pentroof chamber which makes it ideal for passenger car use.|
|01-16-2003 09:46 PM|
|crazy larry||money ain't cheap? hell it don't cost nothin'. but the bill man shore likes it. OK dumb question time. the ford modular engine. is a v6 and/or a v8 right? 4.6l or 5.4l ohc or pushrod?|
|01-16-2003 09:43 PM|
|mustang66maniac||its only money. if you can't spend it, what good is it for? Its not worth the effort you go through to get it if you can't spend it. thats my philosophy. Ford Modulars are stupendous in my opinion|
|01-16-2003 09:40 PM|
|dk01_99||money not cheap....not unless you do this!!!! <img src="graemlins/crash.gif" border="0" alt="[crash]" />|
|01-16-2003 09:35 PM|
|stonedchihuahua||well yeah 2 cams per head... anyhow... MONEY IS NOT CHEAP!!!! if you get what I mean|
|01-16-2003 09:28 PM|
|crazy larry||actually, you'd need 4 and "whats the problem?" its only money. and your talking about more power. damn boy, whats gotten into you. you dipping them doob's in formaldehyde?|
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