Otter chassis question

Jim Burrill · #1 21-03-13, 05:25

Just what are the differences between the Otter chassis and a C-15 Chassis? I have heard it said that they are the same. Are they?

James Gosling · #2 21-03-13, 09:58

Hi Jim,

I think the basic chassis frame is the same, it is the standard 101 inch chassis.
James

Grant Bowker · #3 21-03-13, 20:30

Based on the parts books, the Otter and C15A frames are not the same. There are a few parts in common but that's it.
There is more in common with the C15TA (after all the Otter and C15TA both used the 270 rather than 216 engine) but even these frames are not identical.

Jim Burrill · #4 21-03-13, 22:09

Thanks for the responses!

Ok, reason I asked Is that I am exploring the feasability of making a mild steel replica for living history uses. ( and never sold as a "restoration"!!) and thought a 15 cwt chassis and drive line would be a logical starting point.

While any such project has its share of challenges, does any one see any significant ones for using a CMP C-15 chassis and driveline?

All thoughts welcome!

chris vickery · #5 21-03-13, 23:19

Hi Jim

I would suggest that if a C15 chassis is even "close" it would make an excellent starting point;
It has the right "look", it is cmp afterall. Probably easier to make convincing rather than using anything else.
A 270 will fit right in.
I think the Otter used larger wheels but then again the 10.50-16 tires available from Wallace again look the part.
I have often thought about a project like this one myself to see if it was feasible.

Grant Bowker · #6 21-03-13, 23:28

Sence you are doing a cosmetic recreation, you have greater liberty while staying close to the spirit of the original.
Although much harder to find the chassis for a C15TA or another armoured version (either Fox or Otter) might be your best starting point as they are already set up for the 270 engine that the original used to allow for the greater weight (and the chassis will be re-inforced for the weight).
If original chassis are not available, you could use the chassis from the Gun tractor (also reinforced but they originally 20" wheels instead of the 16" used on the Otter). The gun tractor also had a 2 speed transfer case rather than the Otter's one speed. This is an advantage for slow parade work, but less originl, your choice.
On the other hand, the C15A had 16" wheels, single speed transfer case, correct wheelbase, no winch and is relatively plentiful. All positives for recreating an Otter replica for your project. To add power without having to modify the C15A frame to fit a different engine you have the option of a later 235 or 261 that would match or exceed the HP of the 270 (and probably be better on torque too).

Jim Burrill · #7 21-03-13, 23:46

Hey Chris,
If this project does move forward, I will be happy to share my findings.
I will say I am thinking to build a couple and sell them to pay for my own, but certainly not getting into the new car business!

If I get framing jigs made to weld the hull panels, it may make more sense to come to me to get a hull made than to just use my drawings and try to weld the hull locally. On the other hand, I would be fine with sending you the measurements for you to do it yourself.

If I can get the first one built as a proof of concept and then tally the cost and then see what that comes to, I would be surprised if f there were more than 5 solid orders world wide. A lot of inquiries and dreaming, but I just don't think that many folks would want a "fake" Otter except for a few reeanctment clubs that think the freak-out factor on the Germans is worth the cost of a replica. <g>

Bruce Parker (RIP) · #8 22-03-13, 01:05

Use a 12 cab Chev 15 cwt chassis, axles and all.

Bob Carriere · #9 22-03-13, 03:52

HI Bruce

Just curious ......... I have 11, 12 and 13 frames in 15cwt and they all look very similar. Did I miss something.

Bob C.

maple_leaf_eh · #10 23-03-13, 01:20

The truck chassis might have trouble carrying the weight of an armoured body. I suggest you might want to box weld steel panels on the insides of the C-channels the way hotrod and custom off-road truck builders do.

Jim Burrill · #11 23-03-13, 04:09

Terry,
Good idea! I have to explore what weight savings I can get using mild steel. I want the correct thickness though. As this develops, need to see what engine can mate up and still fit. Not going to shoehorn a modern V8 with auto tranny! Will keep the straight 6 and intend to keep the same tranny.

So many questions yet... <g>

Jack Innes · #12 23-03-13, 05:16

Jim,

Sounds like a viable project.

As a point of reference 3/8 thick mild steel weighs 0.06 lb. less per sq. ft. than stainless steel. The difference between mild steel & armour plate would likely be less. ( 10 to 15 Lb. weight saving on the whole machine )

Most Chevrolet 6 cylinder engines up to about 1961 will bolt up to the earlier transmission. I have several CMP lift truck conversions with newer engines. The advantage with a later engine is full pressure lubrication & insert bearings.

Jim Burrill · #13 23-03-13, 15:40

Thanks Jack! I fully expect this to be an educational experiance!

When the original 216 threw a piston out the side of the block on my first road trip with the C15A, I was educated on the differences between a wartime "splash-oil" system and post war pressure systems. I found a 1954 230 block to put in. Did a full rebuild on the block and yes, it bolted right in.

Seems the 54 and 55 230s used the water pump in the same location, so I had no clearance issues with the fan blades, but that was dumb luck... That was the only 230 block inthe local junk yard.

I later learned how lucky I was when i read about the need to buy an adapter for the water pump if replacing the engine from a vintage Chev site.

No idea at this point just what could be found and fitted inside the space of the Otter. While I want to try to get it street legal, I fully expect tot trailer it to events like I do the Humber Armoured Car.

Thanks for the info on the steel weight. Not near as much a benefit as I had previously heard from "conventional wisdom"!

Cheers,
Jim