SOHC Gear Drive

[Autoholic]

I forgot to add scans of the article, that can be read easily. So forgive the thread resurrection, I'm sure many will like to see the whole article.

[turbohunter]

Connie get under your skin Joe.

[Autoholic]

A little, how can anyone who knows the SOHC be that ignorant to say that chain stretch doesn't exist? The tiny chain on your regular OHV will stretch a little, a 6 ft timing chain most definitely will.

Then again, I have an engineering degree and Connie only graduated HS. He knows business, but engineering problems? I bet he thinks steel doesn't stretch, or know that there is elastic and plastic deformation.

[66FAIRLANE]

I did extensive experiments on that back in about 2006

Bloody hell! Seems like yesterday!!

[Barry_R]

The most recent stretch info Jay has is intuitive in that the stretch is load over the unsupported link count on the chains.  The "lead" chain and cam are carrying the full load from both heads, while straight shot from the driver side to the passenger side only carry one head's spring load.  They should be different.  I degree the driver side first, then once that's locked in I go and degree the passenger side - treat it like two four cylinders.  I do not have the tuning history Jay does, so I target the cam card data for setup.

I would be willing to wager that old Conrad has dealt with an engineer or two over his 50 years of drag racing at the highest level.  I would be pretty leery of getting into an argument with a self made millionaire with literally hundreds of fuel wins.   He absolutely knows about chain stretch, he also enjoys ripping on old competitors every chance he gets.

[Autoholic]

Then he should know better than to lie in an interview that would be published, just to lash out at someone who actually builds engines for a living.

[Barry_R]

At this point in his career Connie can do and say anything he wants.  To anyone he wants to.  Actually he never had a problem doing that.  In person.  His reputation for being a brawler exceeds his reputation as a businessman and a drag racer.  He knows exactly what he's doing and who he is talking to.  You do not have to like the man (few do) but you probably should respect him.  I bet Pinkie reads that interview and says something along the lines of "that #$%^&*^!er"...

He probably has a few dozen degreed engineers working for him at any given time.

Despite the positive attributes I do not believe that either the belt drive nor the gear drive notched any wins....

[Autoholic]

The gear drive I think came a little late in the game and Sneaky Pete died not too long after creating it. It most likely is one development on the Cammer that didn't get to show its full potential. Improved and more reliable timing will always provide better, more consistent power.

[jayb]

After running my initial tests back in 2006, I've learned a lot more about the chain stretch phenomenon.  Better chains, like the 0.250" pin full roller chains (like the ones Munro and Robert Pond sell), don't stretch anywhere near as much as the factory type, 0.222" pin non-roller chain that I tested in 2006.  On the other hand, bigger valve springs will make the chain stretch more.  Kind of makes sense.  Also, there is an initial stretch to the chain after the first run-in, and then the stretching starts to decrease somewhat, so that you don't have to monitor the chain tension as often.  After I replaced the cams at Drag Week in September I ran the engine another 400 miles to finish the event, then checked the chain tension at home, and hardly had to adjust it at all. 

One thing I like about the chain stretch at speed is that the cams retard.  At high RPM, this is what you want.  I normally time the cams way advanced, and with my springs see the right cam retarding about 6-8 degrees by 7000 RPM, and the left cam retarding about 3 degrees less (assuming I can trust the log data from my cam sensors).  So, by about 7000 RPM the cams are timed straight up, but with less RPM they are advanced, which is good of course for mid range torque.  Right now, I don't think I'd run a gear drive if I could; I'll stick with my variable valve timing due to chain stretch 

[cjshaker]

Trying to put this as politely as possible, I'll take experience over a degree sitting behind a desk any day. Being someone who works on equipment day in and day out, you quickly learn the shortcomings of engineers who have no field experience.

Connie Kallita knew a thing or two about a thing or two. His propensity for 'stretching' the truth, or outright lieing, is pretty common among top racers.

[Autoholic]

No offense taken, and you have to be an engineer that thinks about how something would be operated and maintained, to be a good engineer. One of the funniest memes I've ever seen about this...



I get it. What makes the perfect spot to put something can also be the worst place to put it in order to service the device. You have to be an engineer with common sense and have grown up using your hands, as I did. Whenever I designed something, I'd think about how it has to be constructed, used and maintained. Often KISS was the method used. German engineers have a reputation of designing nightmares.


As for Connie, I figured you'd have to have some gall to say that. I'll take a difficult engineer over an asshole trying to one up everyone all the time.

[Leny Mason]

If this long chain is such an issue why not put two short chains on it , it looks like it would be a lot less headache than gear drive, the gear drive gear mesh from the head to the idler gear looks to me like a problem the gasket thickness would be critical, if you plain the head to straiten it the gear mesh will change, maybe I am missing something here. Leny Mason

[cammerfe]

One of the problems we have to deal with---highlighted here---is the propensity for taking anecdotal information from fifty years ago and acting as if it were equally true today.

For today, gear drive for the cams on an SOHC Ford engine are a solution looking for a problem.

Go back and read carefully what Jay said just above.

Better chains and the experience that now exists have zeroed-out what was once a real problem. Which doesn't mean you put-'em-in-and-forget-'em. But it does move such things solidly into the realm of routine maintenance.

KS

[My427stang]

One of the problems we have to deal with---highlighted here---is the propensity for taking anecdotal information from fifty years ago and acting as if it were equally true today.

For today, gear drive for the cams on an SOHC Ford engine are a solution looking for a problem.

Go back and read carefully what Jay said just above.

Better chains and the experience that now exists have zeroed-out what was once a real problem. Which doesn't mean you put-'em-in-and-forget-'em. But it does move such things solidly into the realm of routine maintenance.

KS

Fair enough, and often hammers mistakenly try to find nails without a reason, but you don't have to have a failure to want an improvement. 

Although power per $ is why I don't spend on a cammer, (better way to say it is I am a cheapo LOL) the other reason is that I think the front of the engine is overly complicated and rockers still seem to be more of an issue than I ever would expect)  Keep in mind this is from what I read, not experience, I have never laid a hand on a cammer.  But, I do think the design could be improved.  I'll also add that it likely would be improved if it was a mainstream engine, but even with the incredible (and welcome and WAY cool)  new interest, I wouldn't think the demand warrants any significant engineering cost unless guys like Jay personally want to improve it.

I think the dynamic cam retard is good, but remember, harmonics do funny things, you may find that chain does a lot of different things as the rpm rises and does different things based on cam and spring design.

That being said, the engines are still cool as cool can be, and I respect anyone who is willing to spend the time and money to play. 

[machoneman]

My 2 cents says.....Jay hit on the #1 limitation of the SOHC engine. It's the rocker/cam design that severely limits the lift one can achieve. Heck, many all-out pushrod race engines are at, near or over 1" of lift, a number the OEM stock cammer can't even approach. Fix that and then maybe the gear drive is #2 on the list. JMO!