In the DOHC thread i mentioned in posting a Motor Trend article about a DOHC Mopar,this is a pic of it..anyone ever seen this thing?
Wow Just what a hemi needs, bigger valve covers and more heavy complicated stuff up top! Seriously though, that's cool
Had never heard of this until a week or so ago when this was posted on another hotrod forum. Follow the link to post #35. http://www.nz-hotrod.com/vbulletin/showthread.php?p=27824#post27824
Man, just plain amazing, and I love the Doomsday Machine name on that picture, totally fits that thing...glad to see it's still around...
Please tell us the rest of the story, the article sort of leaves us hanging. Did it ever dyno 500 or see use in a car? Certainly looks like an amazing piece of engineering and machining skill.
There was a write-up about it in Musclecar Review mag about ten or twelve years ago. Amazed me, too. Seems the engineers had problems with a magnesium girdle that was supposed to keep the lifters/followers steady in the head, and gave up the idea due to not being able to design something strong enough for it. With today's materials, the guy that had the one that was written about had planned to have a girdle made out of ***anium, and plant it in a period correct AWB clone. I never did hear anything more about it, so I'd be interested in hearing the rest of the story, also. Roger
They (Chrysler) gave up up not because of the girdle breakage, but because the engine was being developed to compete with the Ford SOHC that was slated to be used for NASCAR......NASCAR wouldn't allow the Ford SOHC, therefore Chrysler saw no need to go further with it's DOHC, since the Race 426 could "hang" with Ford's current NASCAR engine......Stock car racing was big business back then.....it sold cars.... Had Ford been allowed to use it's SOHC, I'm sure Chyrsler would have continued with it's DOHC development and worked out it's breakage issues.....what an engine that would have been......may have had a big impact, not only in NASCAR, but drag racing as well.....then again, maybe not.....kinda cool to think about what "might have been"....
Whether it develops more power will still be answered by the same factors as the original: how good is the head, and how much development time did you spend. All that hardware was originally intended to increase the safe operating speed of an excellent engine with very heavy valve gear (a hemi exhaust rocker can also serve as a tire iron) by removing as much weight as possible. The extra power still requires flow + development. Considering the springs available today, it's not needed. What would be helpful is, of course, what's already been done to modern engines - 4 valves, which releases the port from the lock-step of long duration for power - but it's much more difficult to develop because you're starting from square 1 (rather than bolting new bits onto the existing).
Thats why I posted this up,it does mention some big revs through the gears.. I wonder if Ryndboys' Family has any more info than what is in the mag?
sinistercustom, you are mistaking the engine in this thread with the later "Elephant" 426 hemi which Mopar was indeed preparing for Nascar. This motor is long before Ford was working on the SOHC Nascar engine; it's based on the old 392 hemis with the distributor in the rear.
************************************** Oops! That applies to me, too. The writeup I saw was centered around the "late" Hemi. Sorry. Roger
Hey, we're all here together! Every now and again I get one where I've got my head pulled out and can contribute!
Just as a side bar to this...someone made a set of four valve heads for the Donovan 417 Hemi and runs it in a dragster. It's on youtube. I too would love to see more photos and info on Mr. Gillelan engine.
Then there was this Australian built 511 CID all aluminium quad cam four valves per cylinder drag race engine. A real killer, but the NHRA banned it, it was just too good. http://www.mcgeecams.com/history.html
Old post, I know, but I just happened to this site while researching something else. Gilly (Bob) is my Dad, so of course I've seen it, along with most engines he built or tweaked. I grew up surrounded by stock cars, dragsters, motors, and crankshafts (and worked in the business he bought over in '66). I was probably the only infant taken to the racetracks back then. Hey! Who the heck is the "step-son" "ryndboys"??? I'm an only child, with only one half-brother (Mother's side and older than me) living in Michigan. By the way, Dad was inducted into the MMSHOF in 2008 after declining the honor for years. Go, Dad! I still have his land speed record certificates (sands of Daytona Beach) from the very early 1950's, signed by Bill France. If anyone is still interested in the history or particulars of this motor, let me know and I'll ask Dad.
not ohc/not mopar/4valve has lots miles on a dyno see/hear it run at bangshift.com burbank car show..... it's in a competive blown gas car.........
Hi to lgh0777. "lg____" for L___a G, of course. I remember you learning to drive and working in the office. Now that I'm reading it, I think he mumbled something about being in Singapore one time, too. Hope all is well with you, and of course the motor. Sorry to hear about his recent p***ing, though. He gave me a great start in life. And I never laughed so hard in my life as when working on stuff with him, treasured every minute, he was simply the greatest. Of course, there are a few pics of the motor in the MotorTrend mag from Aug '57 and copies can be had on ebay, etc.
These are two different deals, the "Doomsday" is late hemi based, the first engine on this post is early hemi based. The "Doomsday" motors are common knowledge, but the early hemi conversion is new to me. Both are cool, just not the same deal. Oops, I see I am late to the party, as usual...
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