Timing Chain Proposal

[imp]

The engine below is a Caterpillar Diesel, Double-Overhead Camshaft experimental engine (back then, about 1967), which we had lent to us at Victor Manufacturing & Gasket Co., set up on one of our dynamometers. Cat was developing the engine as a possible entry into the long-haul trucking scene. Wish I had taken pics of the engine disassembled, though. The heads were extremely wide, it was a V-8, the camshafts were mounted in a "box" attached to the top of the heads. Victor's intent was to develop the best possible sealing products for it, especially head gaskets. Too bad, I transferred out of Gaskets to the Oil seal Division, and never got to find out how the program wound up. Wish I had taken pics of the engine disassembled, though.

Cat was well-known to spare no expense in development of it's engines, aiming for million-mile longevity. So, how did they drive those overhead camshafts? Gears, of course! The front of the engine was a maze of gears, encased within a huge alloy cover. That engine ran 500-hour tests consisting of idle-speed to run-up at full power output, cycling thusly every 10 minutes or so. During the year or so that I witnessed it, that engine never experienced a single hiccup. Just ran and ran.

What's the point of all this? Do any of you think a market might exist for a kit for our beloved Explorers having those troublesome, difficult to service 4.0L timing chains which would provide gear-driven camshafts? This would be a juicy technical challenge! imp

 

[Rick]

If it weren't too expensive it would be a great option for SOHC owners.

 

[Josh P]

I wonder if a company like Milodon could be sweet talked into making it happen.

 

[CDW6212R]

There are two issues with the chain system on the SOHC. The main timing chain called the jackshaft chain, it has two guides which control the chain and lengthen it. A normal OHV engine(the 4.0 OHV) has no guides or a tensioner, on the one timing chain. That chain may swap to the OHC, but I'll bet it needs better control of the chain, thus the OHC different parts.

The main problem is the connection of the main chain to each head's cam, through the driving chain. Those cassettes are what create the problem. Those along with the external tensioners are intended to control the chain, but they don't do it for a long enough time. They do fine for 50k miles, given quality clean oil. Under ideal conditions they have gone 100k, 150k, or more miles.

Look at the space for each head's timing chain. It would be tough to install gears along that path, both front and back. It's an interesting idea, and if done right might be the best answer. My first thought was the DOHC heads, which with some work can be adapted. But nobody is going to do that, or how many out of the countless SOHC's owners will. The other thought I had was the 4.6 tensioners; I wondered if those could be fitted in there, and eliminate the cassette guides and external tensioners, completely. That might be the most feasible, but I had given up on the idea of the V6 ten years ago. I'm aiming at a 306 swap next year.

This picture is of the back of a DOHC 2.9 Cosworth Ford engine. I had a front picture too, but can't find it now. A member here had a thread where he got those on his 4.0, but it was in Europe and he didn't tune/finish it.

 

[Josh P]

http://www.explorerforum.com/forums/index.php?threads/4-0-ohv-into-4-0-24v-cosworth.176114/
Problem with the Cosworth 2.9L dohc heads is you create a mail order engine if anything breaks on it.

 

[CDW6212R]

http://www.explorerforum.com/forums/index.php?threads/4-0-ohv-into-4-0-24v-cosworth.176114/
Problem with the Cosworth 2.9L dohc heads is you create a mail order engine if anything breaks on it.

Definitely, I'm not suggesting it, I just mentioned all possibilities. I am very aware of what my custom alterations will do to my vehicles, should they ever need worked on, or sold. I create a book/manual for any car that I alter significantly. My 95 Crown Vic for example has lots of wiring changes for my past work, an added ABS, plus 1998-2002 front brakes. That stuff is easy for me to remember, but a new owner would have a hell of a time getting things worked on. Example, I swapped 97 Town Car seats into it also, using factory wiring from a Grand Marquis for the seat controls etc. A good mechanic could figure it out, but a manual created with the non stock parts is wise/best.

 

[Josh P]

I'm a diehard fan of the cologne engines. At some point is the return on the investment going to be worth it?

 

[96firephoenix]

I'm a diehard fan of the cologne engines. At some point is the return on the investment going to be worth it?

Sell anything you own related to cologne engines, invest in index funds. That is when it will be worth it.

 

[Josh P]

Sell anything you own related to cologne engines, invest in index funds. That is when it will be worth it.

I've always invested in beer and women....

 

[CDW6212R]

I've always invested in beer and women....

Poor man, but happy.

 

[shucker1]

I've always invested in beer and women....

At the time those options always seem like a good option but you wind up just as poor in the end.

@imp

Nice bit of information about the 1967 Cat.

The Fairbanks Morse OP Model 38 8 1\8 was actually completely gear driven on both cranks, Upper and Lower. (2 Stroker so no cam needed)

Enterprise Diesel was actually doing gear driven cams as a production units on the DSRV or the DMRV Series units back in the earily 70's

DS = Diesel Stationary

DM= Diesel Marine

RV was the series of engine.

A lot may have to do with production cost and the longevity of the engine.

A gear driven cam engine would more than likely outlast the body of the vehicle it was put in.

 

[96firephoenix]

Model A Fords had cam gears...

 

[shucker1]

Lots of them did.

Chevy "Iron Duke" (4 Cylinder)

British Leyland B Series (4 Cylinder)

Chevy, Ford, Chrysler Inline 6 (Chrysler 225 slant 6 was a good engine)

It all has to do with engine geometry.

As a lot of us know there are kits out there to convert almost any 8 cylinder made to a gear drive cam set up.

 

[Josh P]

The 427 sohc ran better with gears than the mile of chain.

 

[imp]

I'm a diehard fan of the cologne engines. At some point is the return on the investment going to be worth it?

@Josh P
No, probably not. Cost of the parts initially, not terribly high, IF the stock front cover could be retained, modified as needed. Gearing to the jackshaft looks fairly do-able, but with somewhat different ratio. the view above seems right offhand to say two idler gears would be needed between the camshaft gear, and jackshaft gear. Supporting those idlers might require, if not demand, slicing off the end of the head, and making up a cover plate to support the gears' bearings. That would allow support on a shaft held at both ends, cover and head, instead of cantilevering the mount.

The jackshaft would require extensive rework, possibly complete replacement. Without ever having worked on a 4.0, I can't say for certain, but think mounting of the crankshaft gear and jackshaft gear would pose little difficulty.
If memory serves correctly, that Cat engine had quite a bunch of gears. Necessary because of the distances between shafts involved; ya can't have 2 giant gears hanging out!. Same would have to apply to the "customized" 4.0. And, mounting driving mechanism other than clutch or converter between the transmission and engine, in the back, seems totally insane, to me! Yeah, I understand that allowed them to not have to make mirror image heads, AND, if they had used GEARS instead of blanket-blank chains, I'd almost have to buy it.

Gears ain't perfect, though. They gotta have a certain amount of "lash", tooth clearance. The more gears, the more cumulative total lash between driving and driven gear. That could be worked around with proper timing. These damned chains present headaches by design alone, not to mention the R.H. placement in the back. Long ago, when I was dirtying my hands early-on, all the guys talked about chains "stretching"; they couldn't have actually believed that, could they? Chains have a zillion wear-points, the wear shows up as length-change of the chain. That's what all these "squeezers" are supposed to cover. Push the running chain against a spring-loaded trough, and the chain, kept tight, maintains constant length along it's tension run, no matter how much the chain wears. Unless the squeezer runs out of available travel. Wonder if that can happen on these 4.0s? imp

 

[imp]

The 427 sohc ran better with gears than the mile of chain.

@Josh P
Gotta LOVE that engine! I saw one stuffed into a Mustang in Cicero, Illinois, maybe around 1970 or so. How badly I wanted one! Rumor had it that Ford red-lined it somewhere like 8,000, but some of the boys were pulling closer to 10!

 

[Josh P]

A mighty oak started out as a lone nut that stood it's ground, I'm sure someone might find parts from another engine to help cut costs to make this a reality. All my cars are old enough that I'd swap a newer engine in first. More power and better fuel economy also reliability seems to be better than the old days.

 

[shucker1]

Rumor had it that Ford red-lined it somewhere like 8,000, but some of the boys were pulling closer to 10!

Look at NASCAR.

Rousch Yates engines pulling 9K RPM all day long easy. Pushrod at that.

Kieth Black Marine Big Block Chevy, Pushrod Engine 8K no problems.

It can be done. How much money do you have?

 

[CDW6212R]

Ooh, the Cammer. I loved that engine, more after I saw a real head in person, in the machine shop where my first Cleveland was done. In the early 80's I saw a 427 SOHC shop manual in a books magazine I had. I bought it for about $40 just to learn more about it. It's cool manual, lots of pictures and detailed build instructions. It's a shame NASCAR banned it before it could get in a car. They let the 426 Hemi run but the Ford was too much to let it compete against the other Hemi. The Cammer had a hemi chamber too. That was a ten foot chain though, that would have taken a lot of gears to replace those.

 

[shucker1]

Started web surfing and drinking scotch. Blame @imp.

Found this.

Gear Drive Crammer.

About 1\2 way down.

https://macsmotorcitygarage.com/cammer-the-real-story-of-the-legendary-ford-427-sohc-v8/