How To: Restoration of Ford M8 armoured car US Ordnance number 7373

[Big D]

More photos.

[Big D]

Hi all,

Here are a few photos now that I have the pistons out of the block. I’m glad that the pistons were not reuseable as it was a real battle getting them out and as expected, the pistons are now a sad sight! Four out of the 6 bores are not too bad. As you can see cylinder 5 has quite a hole in the cylinder wall. You can probably make out in the photos that the cylinder wall is actually quite thin there and as I said in my last post, I wonder if .060 thousand oversize is pushing it on these blocks. Cylinder 6 has a bit of damage from where the rings and the bore had become one. Structurally though, this cylinder and all cylinders bar cylinder 5 are sound.

I guess the reconditioner will determine whether the condition of that cylinder makes it a viable option for sleeving. I can’t see any reason why not providing the sleeve seals around that hole in the wall, but then I am no expert. Hopefully I haven’t wasted about 2 days work in getting it apart so far!

I am almost inclined to get the reconditioner to assess the block first before I try to get the valves out as I can see these are going to be a battle as well. All are stuck in the guides and I suspect there will be plenty of pitting around the valve seats once I get the valves out. I doubt whether any of these valves will be reuseable and I will be replacing the guides and springs anyway, providing the block can be rebuilt. Does anyone have any bright ideas on the most time effective way of getting the valves out?

The engine sump holds oil but is a bit of an eyesore and I am debating whether to repair it or not. It has several internal baffles so getting access to the dents is impossible without cutting the bottom off the sump, panel-beating it and then welding the bottom on again. I am a little hesitant to go that route though, as cutting through the sump without seeing what is behind the sump wall might be risky. Alternatively I guess I could drop it off to a panelbeater and get them to try pull out the main dents.

I have seen worse sumps than this though and I’m confident that the majority of the oil would drain during engine change. However, it does look ugly. Thoughts anyone? Has anyone done such a repair?

That's it for today.

[Big D]

More photos.

[Big D]

Hi all,

A bit more progress on the engine block side of things. We had a close look at the spare block from the Scout Car rebuild now that all the pistons are out of that.

The crankshaft from this block has some wear on it and the crank I took out of the M8 block I was working on will be a better option.

The good news is that the bores in this block are STD size and are all intact. The bores actually don’t look too bad, and may be good enough with just a hone, but if not they will be bored out to 0.20” oversize.

Like the other block, the valves in this block are all stuck as well. There is some pitting around the valve seats but from what I can see, it is a lot less than the M8 block.

Overall this block appears to be a better rebuild option than the M8 block I have been working on. I will finish stripping it and then get it back to the reconditioner for a crack test etc, just to be sure, but I'm fairly sure this will be the one.

As an aside, here are some pictures of the manifolds for the Scout Car and the M8 which shows the differences between them. The pictures of the M8 block and the scout car block show the two studs missing at each end for the different manifold that the M8 uses. If I use this block, I will need to drill and tap the ends and fit some studs to mount the M8 manifold.

I’ve completed the gearshift and linkage assemblies. I had an original of the shorter rod for the linkage but didn't have the longer one. I’d seen NOS rods for sale but the freight cost of getting what was basically just a length of 7/8” solid rod sent here versus making one just didn’t warrant the expense, so I ended up fabricating the longer rod. In the end, I didn’t even use a solid rod, and went with a hollow pipe with heavy walls on it instead.

I stamped my data tags and fitted the ones to the gun side plate. One of the letters I stamped is not flash but overall not too bad.

That is all for this week.

[Big D]

More photos.

[David Dunlop]

Hi Darryl.

Sorry I am backtracking here a bit, but I forgot to ask when you posted photos of your disassembled main gun.

Is the damage to the barrel deliberate de mil work, range damage, or a combination of both?

David

[Big D]

Hi David

I think it is range damage. I don’t believe this gun was ever fitted to the turret I have, which was certainly a range target at some point. However, the damage on the tube of the gun suggests to me that it was done on the range as well.

I’d say the damage done to the tube happened some time ago, as the sleigh and the recoil system fitted to it had been on it for some time, and that sleigh actually covered up the damage quite nicely, so I didn’t see how bad it was until I got the sleigh off.