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South America Jeep Tornado SOHC engine

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pdq67
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South America Jeep Tornado SOHC engine

Post by pdq67 »

I have to say that I am fascinated by this engine's SOHC design!

Hopefully the link will work?

http://wildaboutcarsonline.com/members/ ... ix_1-4.pdf

I thought back a while ago when I posted about it somewhere that somebody said that it was sorta, "modernized", down in South America after it was obsoleted up here. I think maybe about a, "12-lobe", cam head??

Anybody able to tell m ore about it or hopefully post a link??

Thanks in advance.

pdq67
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Re: South America Jeep Tornado SOHC engine

Post by Ken_Parkman »

That engine originated in 1935 as a Graham flathead 169 cu in engine, grew to 217, got taken over by Continental as a 226, back to Graham which became Frazer, then Kaiser, then Willys, and they did a SOHC conversion with slight overbore in 62. The SOHC definitely had some early design issues that caused problems. Kaiser fixed some of the issues, then shipped the engine to Argentina when no one would buy it in North America, where they continued to improve the engine. They changed the mounting from plate to conventional block (which the M715 had) fixed up some of the timing chain problems and oil leaks, added optional IR heads and intakes with Webbers, nice dual exhaust manifolds, and so on. IKA had taken over the 64 Rambler and did a facelift and called it a Torino; one of the places the engine went. Continued upgrades happened until a fairly major redesign in 73 where they went to a 7 main crank and a 12 lobe cam with followers. It stayed in production til 82, at which point was owned by Renault. So in 82 you could buy a RWD Renault that was actually a 64 Rambler with an engine that started in a 1935 Graham.

https://www.oldwillysforum.com/forum/in ... ead.15575/

In Argentina they raced them and loved them. The engine was way ahead of the competition for power, and was outlawed in some road race classes. Here are couple of pretty cool video's from South America. It does seem they can make a lot of power:

https://www.youtube.com/watch?v=CjyegvBoq5g

https://www.youtube.com/watch?time_cont ... e=emb_logo
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Re: South America Jeep Tornado SOHC engine

Post by pdq67 »

How did the South American Jeep Tornado engine become a 12-lobe head?

Do you have a picture of it or a link to it so that I can see how it is designed?

Thanks, ^^^^^^^ great post!

pdq67
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Re: South America Jeep Tornado SOHC engine

Post by Ken_Parkman »

Here is another one of the Dodero car running 6.23 in the 1/8th. There are various YouTubes you can find, some claiming 1000 hp which seems a little hard to stomach. But no question some of them make big power.

https://youtu.be/r-nky2Itvw0


Torino head.jpg
Torino cam deck.png
Torino cam.jpg
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Re: South America Jeep Tornado SOHC engine

Post by pdq67 »

Thanks Ken!

Is this the more modern top-end South American 12-lobe cam design or just pictures of the older OEM 6-lobe cam design?

pdq67
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Re: South America Jeep Tornado SOHC engine

Post by Ken_Parkman »

That's the 12 lobe - you can count the lobes. They dropped the cam down with 1/2 bearings in the head, and the top 1/2 bearings and a cam follower set in an aluminum carrier. The follower and rocker studs must be at the same angle as the valves as the rockers are now angled to allow lobe offset with the valves almost across from each other.

The earlier setup has the cam mounted up higher in the carrier, with the rockers straight and running directly on the cam. There is a slight offset between valves, but the rockers run on the same lobe. The equivalent of the LSA is built into the valve geometry, and measures about 104.

There was a lot of changes on this thing in Argentina. They seemed to be constantly upgrading the thing. I think a lot of stuff can be interchanged, but you need a degree in Tornado parts interchange first.
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Re: South America Jeep Tornado SOHC engine

Post by pdq67 »

Do you Ken or anybody else have pictures of their combustion chambers? All SOHC heads chambers???

If so, then please put it/them up.

Thanks,

pdq67
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Re: South America Jeep Tornado SOHC engine

Post by Ken_Parkman »

Here is the chamber. I've found 3 of 4 have the wrong reach plugs; short reach from a flathead.
Combustion Chamber.jpg
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Re: South America Jeep Tornado SOHC engine

Post by pdq67 »

^^^^^^^^^^^^^^^^^^^^^^^

Thanks Ken!

That's what I wanted to see.

I find it so hard to believe that NO American car maker didn't follow up with this SOHC Jeep Tornado design.

Link here..

https://news.pickuptrucks.com/2012/06/c ... t-six.html

Imho, it makes the old MOPAR hemi obsolete, what with its two rocker shafts and p/r's!!

I guess the old, "We didn't think of it, so fu*k it", run's deep!!!

They could have investment cast the cam tower and rolled right on!! Sure, the (4)-bolt head bolt pattern might hold some back, but when the (5) and (6) bolt head molds wore out then go!! And the same deal with the block head bolt deck bosses!!

Drop the timing chain and go with a belt that will last 250,000/300,000 miles! No front end timing chain lube problems.

What am I missing??

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Re: South America Jeep Tornado SOHC engine

Post by GLHS60 »

Great History story Ken!

Thanks
Randy

PS: We love history!
Ken_Parkman wrote: Thu Aug 13, 2020 10:00 am That engine originated in 1935 as a Graham flathead 169 cu in engine, grew to 217, got taken over by Continental as a 226, back to Graham which became Frazer, then Kaiser, then Willys, and they did a SOHC conversion with slight overbore in 62. The SOHC definitely had some early design issues that caused problems. Kaiser fixed some of the issues, then shipped the engine to Argentina when no one would buy it in North America, where they continued to improve the engine. They changed the mounting from plate to conventional block (which the M715 had) fixed up some of the timing chain problems and oil leaks, added optional IR heads and intakes with Webbers, nice dual exhaust manifolds, and so on. IKA had taken over the 64 Rambler and did a facelift and called it a Torino; one of the places the engine went. Continued upgrades happened until a fairly major redesign in 73 where they went to a 7 main crank and a 12 lobe cam with followers. It stayed in production til 82, at which point was owned by Renault. So in 82 you could buy a RWD Renault that was actually a 64 Rambler with an engine that started in a 1935 Graham.

https://www.oldwillysforum.com/forum/in ... ead.15575/

In Argentina they raced them and loved them. The engine was way ahead of the competition for power, and was outlawed in some road race classes. Here are couple of pretty cool video's from South America. It does seem they can make a lot of power:

https://www.youtube.com/watch?v=CjyegvBoq5g

https://www.youtube.com/watch?time_cont ... e=emb_logo
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Re: South America Jeep Tornado SOHC engine

Post by BCjohnny »

GLHS60 wrote:PS: We love history!
Sure do

Not trying to steal anyone's thunder, but always intrigued by old designs, so dug up some online stuff about the earlier 6 lobe version ......


Kaiser_Tornado_engine.jpg
Kaisersohc.jpg
Kaisersohccam.jpg



As said, LSA taken care of by obtuse stud separation angle and wide lobe cams to take up the valve offset
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Re: South America Jeep Tornado SOHC engine

Post by Truckedup »

I was in the Army assigned to a vehicle issue yard when the first M715's with the Tornado engines were first delivered. This was at Ft Carson Colorado. The trucks were driven from St Louis I believe, they were hooked up in tandem,one flat towing another one. Almost everyone of them dropped a cylinder when the SOHC lost a lobe. Some were switched out on the road from towing to being towed and still had trouble.I bet some heads rolled over that problem....
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Re: South America Jeep Tornado SOHC engine

Post by Ken_Parkman »

I've taken 4 of them apart and found damaged cams in 3. The lobes were still there, some with a little nose damage, but the bigger issue seems to be the overlapping rockers cut little grooves in the lobes. Interestingly they changed rockers, cam, and springs very quickly. The early cams were actually pretty big at ~207 @ .050", where the later measures 183. They also put better springs. But both early and later single lobe cam setups had issues. My one good cam is an early "big" cam.

There was a LOT of changes in these things as they learned what they designed wrong, and a lot of improvements were cranked in quickly. But too late as they had a bad reputation, so they sold them to the army and went to the AMC 6 in civilian Jeeps. The oil leakage and burning was biblical in the early stuff. The later engines really seemed decent, hear of lots of guys with no issues who really love them.

One example of really bad design is the #1 cylinder exhaust spring seat on the head casting blends into the side wall, and there is no oil drainage. The only way out for the oil is through the guide! The engineer on that job pooched it! The later heads had the casting relieved to make a drain passage.

People like them for the huge power improvement over the previous engines. There was so much more power they took gear ratio out of the old Willys pickups and wagons and these things would actually go a decent highway speed. Which then created the next problem as the steering in those things was horrific and it had to be redesigned to keep the Willys on the road.
Tornado with paint.jpg
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Re: South America Jeep Tornado SOHC engine

Post by BCjohnny »

Ken_Parkman wrote:...... but the bigger issue seems to be the overlapping rockers cut little grooves in the lobes ......
Yes, that's the 'problem' that jumps out from just looking at the design

Two ball stud mounted rocker followers running on the same lobe, with the clearance necessary in a non-hydraulic set up ..... it's not difficulty to imagine the okey-cokey going on, edge loading and subsequent inevitable wear

The only alignment valve guided rocker tips ? You can't quite see from the pics, but looks likely

Probable materials incompatibility of steel rocker on cast cam ?

In the six lobe set up maybe sled fulcrums might have been less disastrous, assuming they could have held the alignment in production, although it's difficult to see how it could have been adequately crutched

It's little wonder it subsequently went to a lobe per valve ...... a compromise design too far
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Re: South America Jeep Tornado SOHC engine

Post by Ken_Parkman »

BCjohnny wrote: Mon Oct 19, 2020 5:16 am
The only alignment valve guided rocker tips ? You can't quite see from the pics, but looks likely
There is a sheet metal alignment retainer the goes on over the cam deck studs and tabs go into the upper ends of the rockers. Not exact, only gets you in the ballpark. There is a welded machined foot on the rocker that does the actual lobe contact. The Argentineans did a second retainer design, and it looks like the 12 lobe cam engine went to valve guided rocker tips.
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