[DeTomaso] NPC: DOHC or Pushrod holy war.....Was: New CorvetteEngine

corey price coreyjprice at gmail.com
Sat Jun 4 18:38:49 EDT 2011 

The modulars were designed to run transverse, just like the Northstar.  I just saw a transverse 4.6 DOHC in a Lincoln today at the junkyard while picking up some Taurus window motors.  That's why they share a crappy bore spacing, which spilled over to the new 5.0 Coyote, in order to avoid major retooling.  It also dictated what Ford could do with the 5.4 in the GT and found it easier to supercharge than get the rpm range up due to the long stroke (or something like that).  I bet it seemed like a great thing at the time, but it really hurt the engine in the long run since not many cars have transverse-mounted modulars.

The new DOHC 5.0 Coyote weighs 440 lbs complete, and makes 440+ hp in the Boss variant.  Reported to be stable to 8400 rpm, the Boss motor is very alluring to me, but I'm probably going to stick with the Cleveland.

The new 6.2 liter SOHC truck motor has a wider bore spacing (115 mm), variable valve timing, double spark plugs, and only two valves per cylinder.

Just my two cents again.




On Jun 4, 2011, at 3:50 PM, Dave Londry wrote:

> Some good points here.....
> - VVT yes. Simple advance is OK with SOHC, but anything more complex 
> than that is just stupid difficult.
> 
> - 2 cam pushrod makes sense if you have a rule-book to bend; otherwise????
> 
> - I really don't get why Ford went to 3.937" bore centers for the 
> modular engines.
>   It's too small, and going to 4.25' would have cost them a whole inch 
> of block length.
>    Must have been a marketing decision.
>    GM made the same decision with the North Star (4.00") so it was  was 
> contagious.
> 
>    The AMG 6.3 engine has 4.29" centers  which is a little less than a 
> Cleveland
>     but it's pretty good and it's the only one of the new, new engines 
> in that range.
> 
> dave
> 
> 
> 
> On 6/4/2011 7:12 AM, Will Kooiman wrote:
>> I think it really boils down to this...
>> 
>> DOHC has many advantages - rev higher, more hp per cubic inch, etc. - but it
>> comes at the cost of more complexity.
>> 
>> The biggest problem with DOHC engines is they tend to be smaller
>> displacement.
>> 
>> The other problem is the complexity doesn't seem to be worth it.  DOHC has
>> lots of small improvements over pushrod.  The only one I consider a big
>> improvement is the ability to rev 8,000 without mongo springs.
>> 
>> -----Original Message-----
>> From: detomaso-bounces at realbig.com [mailto:detomaso-bounces at realbig.com] On
>> Behalf Of Sean Korb
>> Sent: Saturday, June 04, 2011 8:39 AM
>> To: List Pantera
>> Subject: Re: [DeTomaso] NPC: DOHC or Pushrod holy war.....Was: New
>> CorvetteEngine
>> 
>> I would very much like a pushrod engine with two camshafts.  The lower
>> for exhaust and the upper camshaft for intakes.  Then you could have
>> independent and variable movement of intake and exhaust in the same
>> small lightweight package.
>> 
>> Not a new idea.  Ford was going to try this on their big block can-am
>> cars, but they quickly changed the rules.
>> 
>> sean
>> 
>> On Sat, Jun 4, 2011 at 8:58 AM, corey price<coreyjprice at gmail.com>  wrote:
>>> Okay, I just have one comment:
>>> 
>>> DOHC makes it much easier and cheaper to implement independent
>> intake/exhaust variable valve timing.
>>> Just my two cents.
>>> 
>>> 
>>> 
>>> 
>>> On Jun 3, 2011, at 1:43 PM, Dave Londry wrote:
>>> 
>>>> Now if you said:
>>>> "There is no reason to build a DOHC engine instead of a SOHC engine"
>>>>  - I could get that. Twin cams are just more shit to keep spinning and
>>>> the width is ugly,
>>>>     So long as you manage to place big valves, across a hemi chamber, a
>>>> single cam is fine.
>>>> 
>>>> But a pushrod with in-line valves - that's just still more heavy shit to
>>>> keep moving and to no benefit.
>>>> 
>>>> Now the direct injection system in the new LS is very fine - keep that
>> part.
>>>> dave
>>>> 
>>>> (duckin' and weavin')
>>>> 
>>>> 
>>>> 
>>>> On 6/3/2011 12:28 PM, michael frazier wrote:
>>>>> Weak...very weak.  If you want to start a holy war, well then:
>>>>> 
>>>>> I hope the new Vette doesn't go to a OHC engine more like the high-end
>> Euro competition.  That would be a step
>>>>> backwards in performance if it ran like a F-car or Lambo.  Ford now
>> builds engines bigger on the outside that an old Hemi,
>>>>> smaller on the inside than a 289, and just overly complicated.  I think
>> you're now required to put your testicles in your
>>>>> purse when you buy a new (plastic magnet) Mustang.
>>>>> 
>>>>> On an only slightly more serious note...I don't think they would gain
>> anything over the LS engines.  Those are beautiful
>>>>> engines capable of much much more than they than come off the assembly
>> line with.  Pushrods, overhead cams,
>>>>> in the real world one's not "better", they're just different.
>>>>> 
>>>>> Michael Frazier
>>>>> Gruppo Rompiculi Corsa
>>>>> Pushrods are better.
>>>>> 
>>>>> 
>>>>> 
>>>>>> Date: Fri, 3 Jun 2011 15:07:01 -0400
>>>>>> From: rob at dumoulins.net
>>>>>> To: detomaso at realbig.com
>>>>>> Subject: [DeTomaso] NPC: DOHC or Pushrod holy war.....Was: New Corvette
>> Engine
>>>>>> Personally, I believe a Dual Overhead Cam design is superior and
>> wondered
>>>>>> why it took so long for US manufacturers to adopt it in their high-end
>>>>>> motors.
>>>>>> 
>>>>>> Flame On
>>>>>> _______________________________________________
>>>>>> 
>>>>>> Detomaso Forum Managed by POCA
>>>>>> 
>>>>>> Archive Search Engine Now Available at http://www.realbig.com/detomaso/
>>>>>> 
>>>>>> DeTomaso mailing list
>>>>>> DeTomaso at list.realbig.com
>>>>>> http://list.realbig.com/mailman/listinfo/detomaso
>>>>> _______________________________________________
>>>>> 
>>>>> Detomaso Forum Managed by POCA
>>>>> 
>>>>> Archive Search Engine Now Available at http://www.realbig.com/detomaso/
>>>>> 
>>>>> DeTomaso mailing list
>>>>> DeTomaso at list.realbig.com
>>>>> http://list.realbig.com/mailman/listinfo/detomaso
>>>>> 
>>>>> 
>>>> _______________________________________________
>>>> 
>>>> Detomaso Forum Managed by POCA
>>>> 
>>>> Archive Search Engine Now Available at http://www.realbig.com/detomaso/
>>>> 
>>>> DeTomaso mailing list
>>>> DeTomaso at list.realbig.com
>>>> http://list.realbig.com/mailman/listinfo/detomaso
>>> _______________________________________________
>>> 
>>> Detomaso Forum Managed by POCA
>>> 
>>> Archive Search Engine Now Available at http://www.realbig.com/detomaso/
>>> 
>>> DeTomaso mailing list
>>> DeTomaso at list.realbig.com
>>> http://list.realbig.com/mailman/listinfo/detomaso
>>> 
>> 
>> 
> _______________________________________________
> 
> Detomaso Forum Managed by POCA
> 
> Archive Search Engine Now Available at http://www.realbig.com/detomaso/
> 
> DeTomaso mailing list
> DeTomaso at list.realbig.com
> http://list.realbig.com/mailman/listinfo/detomaso

More information about the DeTomaso mailing list