Hemi Challenger

Page 7 of 7  
wrote:


Good point. AFAIK, there are no multiple-valve OHV engines (yet). However, 2 valves per cylinder is certainly not the death knell that some make it out to be. Witness current offerings by Chrysler and GM.

I basically agree with everything you've said, but keep in mind that I only said that the OHC design doesn't have a _clear_ advantage. It can be argued that the DOHC is more complex and has more moving parts to wear out and/or break, thereby possibly negating the advantages of the extra valves per cylinder.
All things considered, current technology enables OHV and OHC engines to be on par with each other. I believe it all comes down to preference.
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Joe wrote:

The two valve engines make for good low end torque numbers. They can't hang with the high end breathing and high rpm redline potential of an OHC engine without some very expensive machining and/or compromises in low end performance. Matching VVT with a multi-valve OHC engine makes for some very potent potential regarding hp/torque across the entire rpm range to well over 7,000 rpm. IMO, Ford is getting hp from their modular motors very easily where GM and Chrysler can only get high hp numbers from their OHV engines by increasing displacement. Making hp through sheer displacement isn't that difficult or impressive, IMO. Saying that, don't forget I plan to put a 427W in the old Mustang. ;)

This is where I have to disagree. I think the OHC engines are less complex and are more reliable due to their design. Look at the complexity of the VVT on the OHV engines. If they ever get multi-valve technology then they will be even more complex. Whether these OHV engines with VVT are durable remains to be seen. We know for certain VVT is durable on OHC motors. One of the major problems for any OHV engine is the frailty of push rods, lifters and rocker arms. This is a lot of moving mass to account for, especially in the upper rpm range. The OHC engines don't have this issue. Although they may be percieved as more complex I think they are actually simpler. We perceive them as complex because we think it is new technology. It really isn't. All you have to do is look at the track record of the OHC engines in the cars that use them. It is stellar. The 4.6L is proving to be even more durable than the 302 and that is saying something.

I agree. The one big advantage I see with OHV engines is their smaller size. Take that away and, IMO, there isn't much of a reason for their existence in today's automobile world.
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wrote:

There's hope yet! ;)

Michael, in a warped kind of way way you are making my point by going with the 427 in your LX. :)

Then why are you planning on that 427??? ;)
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Joe wrote:

If I had my druthers I would LOVE to stuff an '03/'04 Cobra motor with a Kenne Bell blower on top into the engine bay. The 427W is easier and less expensive but, make no mistake, the Cobra motor would bitch slap it with ease.
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wrote:

this
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Well, of course it would! And that brings us back to the SN65. Remember that thing? Awesome...
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Joe wrote:

That engine would make a Yugo sweet.
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Mike,
HP/liter means absolutely nothing. There isn't any tax for using extra displacement. Weight and external size of the motor is what's important.
Patrick
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snipped-for-privacy@aol.com wrote:

HP/liter means something when talking about an engine's power production efficiency. A Viper engine weighs in at about 650 lbs. and a Z06 at about 460 lbs. The 4.6L weighs in at around 440 lbs. The Ford Triton V-10 weighs in at 635 lbs. fully dressed. I will give you that the external size of OHC engines are greater than OHV engines. The weight looks to be nearly equal.
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Joe wrote:

" Here is the latest info... 5500 produced in 2008, they will be SRT8's only w the 6.1L hemi and AutoStick Transmission. 2009 they will have a 3.5L V6, 5.7L Hemi, and 6.1L Hemi w/ Optional 6-Speed Manual. Looks like it will be very close to the concept. Different wheels and a few small changes but overall it is pretty close."
Pictures and conjecture at: http://www.bmcforums.com/showthread.php?t9341
--
Frank ess


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Les Benn wrote:

Can I get one with a manual tranny? If not I'm not interested.
Bob
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