Otter LRC CM4647296 comes home

[Jordan Baker]

Last of the front hatches finished up. The only thing that needed replacement were a few badly corroded nuts.

Next was the removal of the door vision hatches. In some of my pictures you may have noticed some text. I am really enjoying the text feature my iPhone and iPad have. It is super simple to add some captions right after taking a picture. Such as noting which shim went where or the location of specific bolts. Yes I’m doing my best to put the same bolt back in the same spot.

[Grant Bowker]

Originally Posted by Jordan Baker

Yes I’m doing my best to put the same bolt back in the same spot.

Putting them where they came from beats mixing them up and discovering they are either too short to do the job at their new location or that they are too long and interfere with another part you've spent hours getting "just right"....

[Jordan Baker]

Many of the boss head bolts called for in the manual are all very close in length. Varies by 1/8” sometimes.


The one door hatch after needle scaling revealed what I believe to be a Hamilton Bridge Company number. Hand painted on the metal prior to the KG#3 layer.

[David Dunlop]

Hi Jordan.

That number find is interesting. Very possibly a form of 'Production Control Number' applied by Hamilton bridge to track their work flow and allow them to identify the scope of any manufacturing problems that came to light on the line.

Be interesting to find a similar applied number on the core, armoured body assembly of your Otter and see how far off it might be from the actual Serial Number assigned to the completed vehicle.

Marconi was using a similar number system on all the chassis units for the various main 52-Set components, and similar number systems also showed up on major sub-assemblies they had contracted out to other manufacturers.

Keep up the good work!


David

[Jordan Baker]

Hi David.

Hamilton Bridge’s part number for that assembly was A42 and B42. So I’m guessing it’s related to that. I did find a hand stamped number of 223 on the bottom right inside edge of the driver’s visor. I’ve also found a hand stamped number on the turret ring.

If only this was 40-50 years ago, I would have been able to track down some Hamilton Bridge employees.

[Jordan Baker]

Door vision hatches all taken apart, sandblasted and repainted and put aside.

Next up was the cover plates in the armoured body. These plates gave access to points on the frame for the rear spring mounts and steering arm. It was neat to see more hand applied assembly markings from Hamilton Bridge.

[Jordan Baker]

One of the plates needed to be fixed up as the weld had totally cracked. A new side plate was made as the original had the bolt holes torch cut out. I was going to weld them up and redrill but then realized the plate had been ground down and was too narrow. So I made up a new one with some scrap that happened to be the correct dimensions. The holes were punched using the punch press. I have to say it it much nicer the drilling them. A quick countersink was done and the part was ready to be welded to the original piece. Everything bolted into place on the hull to ensure perfect alignment. It then got tack welded to hold it in position. It was then properly welded up on the bench once off the hull. A quick sandblast was done and it was painted up along with the other plates last night.


One day the rest of the hull will look as nice as this little plate.

[David Dunlop]

Did they use armoured screws and bolts anywhere on the hull, Jordan, or are they all mild steel?


David

[Jordan Baker]

The bolts on the hull for pretty much everything are the boss head style. The same as found on Universal Carriers with the round dome headed and also countersunk. The only difference is these are all 3/8-16 NC thread. The nuts are the heavy hex size so require an 11/16th wrench. They are all slotted too. So it can make for a challenge in removing them.

[Jordan Baker]

The front engine mount had been bent and ripped into a couple of pieces when the vehicle had been rolled onto its side. The assembly is a standard GM inline six front engine mount used from the mid 1930’s up into the 1950’s. NOS ones were available but what fun would there be in that. The parts were bent back into shape using the shop press and welded up. Are they perfect?….close…. but they are the original ones that were holding the original engine in place.

[Grant Bowker]

I think you are better off with your repaired originals. The repro oil shields (top in your finished photo) generally have much squarer corners than the original. The heavy support cup (bottom in the finished photo) isn't that readily available, just because it is built of heavy gauge material... the middle part aslo isn't nearly as readily available as the tin top cover, again it lasts better due to thicker material (unless abused like yours was...)

[Jordan Baker]

Hi Grant.

Excellent points. I did buy one of the reproductions of the top cover years ago when I was working on my C15A. I was quite disappointed with how different it was to the originals. It is still sitting on the shelf.

[Jordan Baker]

Rear axle convoy light removed from the Otter. Came apart and still had a light bulb. Even the filament looks good. One of the things I have loved with this vehicle was just how original it still was in the small details. One of them was the internal star washer under between the nut and the frame for the convoy lamp mounting bracket. I know it is just a washer but it’s cool to see these little bits.

[Jordan Baker]

Managed to get the internal fuel tank cover removed tonight. Only 30 round head slot screws to cut through. My original plan was to try and reuse them. However pretty much everyone was heavily rusted in place or I was unable to get a wrench on the nuts on the back side. As for the fuel tanks, the one tank end has been blown out, I suspect during the fire. Otherwise the tanks look pretty solid. I’m hopeful it can be worked back into shape and sealed up. It’s also great to see the detail on how the fuel lines and gauge sender wiring was run.

[Jordan Baker]

Convoy light restoration completed. New green wire with proper cloth covering. The metallic shielding is a repurposed NOS Otter fuel tank wire. I cut it down to match the original which was no longer usable.

[Hanno Spoelstra]

Really enjoying this thread, Jordan. Excellent work and a pleasure to read/ see your progress and eye for detail!

[Ed Storey]

I also enjoy reading about the progress you are making and the detailed work that you are doing.

[Jordan Baker]

Thanks guys for the feedback.

Well tonight I managed to finally remove the fuel tank. But first I took a bunch of pictures to capture how everything with the fuel lines and electrical went together.

[Jordan Baker]

Last batch of pictures for now

[Jordan Baker]

Detail pictures of the fuel tank. It’s pretty solid but did rupture during the fire. My thoughts are to repair this tank vs making a new one.

[Jordan Baker]

Some more pictures

[David Dunlop]

That is an interesting arrangement, Jordan. Two tanks sharing a common end wall?

Did the two halves feed to a common selector valve, and I assume that would also mean a selector switch as well at the dash to be able to read both tanks as required.


David

[Jordan Baker]

Hi David.

Yes it’s one tank construction but divided in the middle. There is also a baffle on each side. Two drains and two fill ports. Two fuel senders as well. Two fuel lines run in the frame rail up to a standard CMP type 3 way fuel selector valve. On the dash there is one fuel gauge with a tank selector switch.

[Grant Bowker]

I think I'd be willing to give it a go for repair.
The obvious caution is to be at least 100% sure any gas fumes are gone before applying heat/flame to restore the solder joint(s) that opened up (or for any other reason). When I was doing my CMP tanks, I put a shop-vac to blow into the tanks for a couple of days out in the sun to warm and ventilate. I used the mark 1 nose as fume detector, do you know anyone who has access to combustible fume detectors? (Occupational safety, fire investigator, police/military bomb section etc.) There don't seem to be sharp creases - good news - gentle persuasion can work instead of needing brute force. If you aren't sure of safe soldering in your shop, you might be able to do the straightening and joint preparation and farm out the soldering to a radiator shop. One of the challenges will be to get to the corners of the tank to apply outward pressure if needed. One end looks as if it is enough de-soldered that it might be worth considering finishing removing the end cap to make it easier to restore the end cap and tank body and then reinstall the refurbished end.

[David Herbert]

Since it has already been in a fire and exploded I doubt that there are any combustable fumes in it ! I think it will straighten out quite well once you remove the damaged end plate which will probably be the hardest part. I assume it is spot welded or crimped on prior to soldering to seal it ?

David

[David Dunlop]

Based solely on your photos, Jordan, that tank looks a lot shorter than a pair of 15-cwt tanks would be, sitting end to end, but it looks a lot chubbier. It must have been fun to fill in the field.


David

[Jordan Baker]

I took another quick look at the tank tonight. Both ends are ruptured so I’ll have to remove the end pieces and figure out how to undo the crimping. I suspect both baffles have popped looking at how the parts of the tank are more “round” than other parts. Removing the end caps will also be good for getting the inside completely clean.

As for lingering fumes. The fire would have burned off anything that was still there.

The double tank is 41” long, 18” high and 12” wide. It works out to about 30 imperial gallons. The filling spot definitely isn’t handy.

[David Dunlop]

I have been thinking about the fuel tank situation with your Otter, Jordan, and wanted to offer some observations and ideas on the topic.

Essentially, you have one large fuel tank, sealed and divided at the centre-line, mirror imaged outwards from that point, and it needs a bit of TLC.

If it were my tank, Jordan, the first thing I would do is study the hell out of it to learn as much as possible before attempting any disassembly. It should be able to tell you a lot about itself. You already know the tank was in a fire with enough volatiles still inside it to cause it to explode. If both tanks were expanding under pressure at the same rate during the fire, then the internal pressures on either side of the centre dividing plate would be equal and that plate would stay in place and should be OK. As pressures built within the tank, the external sheet steel would start to stretch and expand and the end plates begin to stretch and bulge out until one, or both ends ruptured to release the internal pressure. Did both ends eventually rupture, or just one? Also look at the amount of stretching evident on the sheet metal of both sides of the tank. Do they both look equally bulged out, or is one side more pronounced than the other? The side with more stretched sheet metal was likely the tank with the most volatiles in it during the fire. As an aside on this point, and bearing in mind potential years of fiddling may have happened, but did the fuel tank selector valve still point to the tank showing the greatest expansion/rupture? That would show the valve was still it its point of last use when you obtained the Otter, still set as left.

Then take a close look at the centreline of the tank, where the dividing wall is fitted. What you would like to see here, is that the dividing wall survived the stretch and rupture process of the tank in the fire. If you have a large roofing square handy, it will help in the analysis. If the dividing wall held its ground, visually, you should see something of a wasp-waist effect on the sides of the tank at the centreline. The centreline will reflect the factory shape and dimensions of the tank with things getting bigger as you move away, either side. All four sides at the centreline should also be very close to square and flat, versus other cross-sections moving towards the ends of the tank.

At this point, you might want to jury rig a small inspection lamp from an automotive lamp socket and bulb with enough leads you can lower it into one side of the tank through the filler and cover the filler with a rag in a dark room. What you don’t want to see when looking into the other filler tube is any sign of the light being visible from the other tank. You may want to use a flex mirror to have a better look. If all looks dark, the dividing wall is likely in good shape. If you do see some light, see if you can determine if it matches up to the most bulged side of the tank. The dividing wall may just have been pulled away from the one side and it may be an easy fix once you access it.

The baffles should have been immune from any pressure imbalances during the fire and rupture, but it is possible one, or both might have been torn free from a side of the tank that suffered a lot of expansion stretch. I am not sure how the baffle plates are designed or mounted, but if the edges were folded to 90 degrees for spot welding to the sides, it is possible that as the sides expanded, they may have pulled some of these tabs beyond 90 degrees, opening some up enough they might break free.

The stretched sides of the tank can be shrunk back to normal with a little time and patience, a blow torch, or heat gun, cold water and rags, but you will need to have a good look inside the tank to fully assess the amount of work involved. Both end plates will need to be studied to see how they were put together. Not an impossible task overall, but certainly an interesting one.There are likely not many original Otter fuel tanks out there today. Don’t rule out restoring this one until you absolutely have to, Jordan.

Best regards,


David

[maple_leaf_eh]

^^^ I am fundamentally lazy, and always try to be respectful of the craftsmen who designed and built machines long before my birth. They knew what they were doing. So, repairing the tank would be my first encouragement. And how you do it is a matter of applying old-style skills, which seems to be exactly how you are approaching all the steps of this build.

As the others have said already, keep up the good work and thank you for sharing the journey.

[Jordan Baker]

Great observations David.

The tank was held down by three substantial metal straps so that kept most of the tank in shape and forced the weaker end plates to pop. Both ends are popped. I can tell the interior baffles have come loose on one of their four sides. This goes for both baffles.

Plan is to remove the end plate and then further inspect and see what’s going on. Right now I’m working on removing the senders. Got some screws backed out. Working on the others.

I firmly believe this tank is repairable. The steel is in great shape with next to no rust. Most of the tank still has its exterior KG#3 paint.

Ultimately the tank will not be visible except for a small part at the top where the fill ports are. The rest is all behind and inside a plate steel box.