How To: Ford CMP "Blitz" miscellany

[Jacques Reed]

Good Day,

I am presently trying to sort out my speedo cable on my F-15A equipped with a late war round speedo.

I bought a NOS cable years ago which is 119" long. I remember reading on MLU the cable length should be 84" so mine is extra long. I also have a F-15 cable which is 74" long, so 84" sounds the correct length allowing for the extra distance to the xfer case on a F-15A instead of the rear of the transmission.

Searched all my Ford publications and could find nothing about the routing other than perhaps the image attached which seems to show what looks like a speedo cable going behind the handbrake bracket at the transmission. When I tried the F-15 cable going that way there is a long run out in the open above the engine before it gets to the cowl opening. And that is leaving it 10" short of the speedo.

Another interesting thing I discovered is that Ford changed the design of the front idler bearing cap to re-orient the cable more nearly horizontal. Earlier caps had the cable entering vertically which resulted in a sharp bend at the xfer case crossmember. C01Q 19818 is the vertical one and C29Q 19818 is the horizontal one.

I am thinking maybe I should run the long cable through the same opening as the wiring to the rear chassis to use up some of the length. No publication show a speedo cable there however.

Also shown is the different ends at the speedometer. Round gauge at top and Ford type below. Not interchangeable.

Anyone have experience with the cable routing on a late war speedo?

Cheers,

[Lynn Eades]

Jacques, my 41 to 47 Canadian commercial parts book lists casings at:
60.8"
103"
54"
92"
68"
and lastly at 61" long
How any of these match up to CMPs, I have no idea.
The LP2 and LP2A Australian carrier used a 51F-17261 case and a 51F- 17262 shaft. I can't find a length.
Any part numbers on your cable?
Not sure this helps you in any way, but I wondered.

[Jacques Reed]

Originally Posted by Lynn Eades

Jacques, my 41 to 47 Canadian commercial parts book lists casings at:
60.8"
103"
54"
92"
68"
and lastly at 61" long
How any of these match up to CMPs, I have no idea.
The LP2 and LP2A Australian carrier used a 51F-17261 case and a 51F- 17262 shaft. I can't find a length.
Any part numbers on your cable?
Not sure this helps you in any way, but I wondered.

Hi Lynn,

Thanks for that information. Will have a look at the cable today for a part number.
Parts Manual list the casing as *C29Q 17261 for late model cabs. Another part unique to CMP's

Of interest: The cable was purchased from a dealer who's father bought up tons of surplus items after the war from the Ford factory in Geelong Vic.
I had thought it possibly was from another wartime Ford truck but not sure if any were fitted with the round gauges other than the CMP's.
If it was a carrier cable the length seems more likely, but the speedometer end would not fit a Ford instrument cluster. Perhaps Lynn you can answer if any carriers were fitted with the round military speedometers and gauges.
I really don't want to shorten it but it is excessively long for a F-15A. To use it, I have to run it along the right chassis rail, past the radiator, back to the cowl opening for the harness and then to the speedo. Running it along the handbrake bracket, like in the sketch, I wind up with about a metre of cable inside the cowl!

Thanks Grant also for that info and link.

Cheers,

[Keith Webb]

Jacques as far as I'm aware all Australian built carriers used the Ford commercial type dash.
Interesting story about the dealer who bought the Ford spares!

[Mike Cecil]

Ford, like many other companies, were contracted to assemble other imported models as well, such as Ford GPA, Ford GPW, etc, and other US military pattern types which had round gauges. So a stack of parts disposed of from Ford Geelong may well have had other models and even makes mixed in amongst them.

Then there were the boats, landing craft and other equipment that Ford were involved with that also used a speedo type drive for measuring rpm, etc. Lots of possibilities.

Mike

[Jacques Reed]

Originally Posted by Lynn Eades

Any part numbers on your cable?

Hi Lynn,

Just has a good look. No part numbers on the cable. As Mike said, Ford assembled many other vehicles during the war so it could be for anything. Wonder how standard the fittings at xfer cases and transmissions were between manufacturers? We know it fits Fords but are others the same?

I am of the belief now just to us it as is and route it with large radiii through the chassis and clip it to keep it off wires etc. It was obviously designed to work at that length on some vehicle so no need to shorten it to make it work any better.

Yes, Keith, it was a great place, an "Aladdin's Cave" back in the 90's. I made three-monthly pilgrimages there between times at sea for many years. It closed over 15 years ago. I got NOS transmission gears, spring pins and bushings, crankcase breather filter, head gaskets, and front shock absorbers, just to name a few. He had a bin of rear spring pins still wrapped in grease paper and when he needed some round stock to turn up he would use them. Enough to make this grown man cry! Luckily I got some when the bin was still half full.

Cheers,

[Jacques Reed]

Good Day,

While working on sorting out my speedo cable I had an idea that perhaps a Ford commercial truck speedometer driven gear might work in the single speed transfer case despite the Parts Manual identifying it as unique to CMP's.

I had recently sold an F-15 transmission and took photos of the speedometer gear used at the back of the transmission for the buyer. See first photo. If I could use a similar commercial gear then the drive cable end at the transfer case would be a simple formed square in the cable instead of a keyhole fitting which would make shortening the cable simpler.

The F-15 uses a 20 tooth driven gear but I could find no info on the number of teeth on a F-15A. So I removed the gear sleeve and driven gear to see what it looked like. See second photo. Surprisingly it is only a 15 tooth gear so it sure is unique to CMP's! Most Ford commercial truck speedometer gears are 18, 19, or 20 tooth. The F-15A gear is very different in other aspects also.
I then wondered why the big discrepancy in the number of teeth as an F-15 has a 6.66:1 diff and the F-15A a 6.50:1 diff. Very similar ratios and both use 16" wheels. Probably caused by the difference of number of teeth on the speedometer drive gear in the two vehicle types but I didn't have the number for a F-15.

I found a good device to determine number of teeth required for a speedometer gear on the Summit Racing website.
Inputting 4 teeth for drive gear- known from Parts Manual.
6.27 for diff ratio- (27/28 x 6.50 to allow for 27 teeth on driven gears in transfer case and 28 teeth on the idler where the speedometer gears are).
34"- for the tyre diameter as measured.

And Bingo 14.86 teeth!

Hope this is of some interest.

Cheers

[Ganmain Tony]

Fantastic information Jacques.

I must say I have never gone to this much trouble to document this information and I am finding it very useful.

Have you looked into Oil filters for the original system on an F15/F15A? I'm keen to learn what you may already know.

[Jacques Reed]

Hi Tony,

I have attached a link to a post I made in 2017 on Lynx42 thread.
Think all is still relevant especially for procuring parts in Australia.

Couple extra points: They are bypass and not full flow filters.
I have heard of people drilling out the orifice in the input side of the filter cannister in some misguided belief of better oil flow. A real no, no, as that restriction allows the oil pressure to build up to the designed amount. Drill it out and the pressure drops in the system.

Thanks Tony I document everything for whoever has the truck after me and to hopefully assist others now.

Cheers,

http://www.mapleleafup.net/forums/sh...7&postcount=17

[Mike Cecil]

Instruction sheet that came with a Ford oil filter set. I remember the bracket shown did not suit a CMP, but there was a pressed steel bracket that mounted on two of the top line of engine head bolts that did fit. When I installed the oil filter on my CMP, I used an outlet connection into the side of the sump, rather than into the oil filler/engine breather.

The block I used had a tapped hole with a plug in it below the oil pressure gauge boss. If a block doesn't have that (and many don't), it would be easier to install a 'T' below the oil pressure gauge than to drill and tap a hole into the gallery.

Mike

[Jacques Reed]

Originally Posted by Lynn Eades

Jacques, my 41 to 47 Canadian commercial parts book lists casings at:
60.8"
103"
54"
92"
68"
and lastly at 61" long
How any of these match up to CMPs, I have no idea.
The LP2 and LP2A Australian carrier used a 51F-17261 case and a 51F- 17262 shaft. I can't find a length.
Any part numbers on your cable?
Not sure this helps you in any way, but I wondered.

Hi Lynn et al,

Just jumping back to getting a speedometer cable length and route for my F-15A I think I may have a solution:

I tried running the longer cable through various parts of the chassis and along the chassis rail. Nothing seemed satisfactory. Either the bends were too sharp or it ran very close to clutch, brake, or handbrake rods and levers. I went back to the idea from the sketch of running it along the handbrake to transmission bracket.

I found only one unused hole in the transmission crossmember was large enough to allow the speedometer end nut to pass through and it was the one closest to the handbrake bracket. It allowed a sweeping bend from the transfer case to it and well cleared the handbrake rod that runs above the transfer case.

I noticed holes in the same place on three floor assemblies and thought there must be a reason they were factory drilled there. Putting a chassis clip there held the cable well away from any rods and allowed a gradual bend along the cab floor rails. The cable now passes well above the rods.

On a spare cab I bought were the two clips on the back of the engine cover clips. I carefully repositioned them on this truck at the time not knowing what they were for. Assumed it was for the wiring. They work out well to guide the cable to where it penetrates the cowl.

Finally measured up the long cable up and it is about 14" too long. I have teed it up to have it shortened to 105" by Flexible Drive. I have read 84" was the length of a F-15A cable but I cannot see how it can be done without very tight bends and straight runs between points.
This may or not be all correct but it seems like the best solution unless some other info is forthcoming.

Hope this is of some interest.

Cheers,

[Hanno Spoelstra]

Originally Posted by Jacques Reed

This may or not be all correct but it seems like the best solution unless some other info is forthcoming.

Jacques, I was trying to catch up with your tread, so only just read this otherwise I would have responded earlier.

If it is of any use to you, I would glady make some pictures of the speedometer cable routing on my 1943 F15A. I has the civilian instrument cluster, but I'd say the routing for the later speedometer would be the same.

[Jacques Reed]

Originally Posted by Hanno Spoelstra

Jacques, I was trying to catch up with your tread, so only just read this otherwise I would have responded earlier.

If it is of any use to you, I would glady make some pictures of the speedometer cable routing on my 1943 F15A. I has the civilian instrument cluster, but I'd say the routing for the later speedometer would be the same.

Hi Hanno,

That would be great! I've been trying to find the original routing for a long time now. Never found an existing one on any paddock vehicle I have looked at or found anything in a publication. The route I took was the best I could make to clear transfer case linkages, handbrake rods, clutch rods, brake master cylinder rods, and electrical items like the battery cable and chassis wiring.

I haven't taken it to be shortened yet so that information would help greatly to get the length right. Still cannot see how it can be done in 84" but always willing to keep an open mind.

Many thanks in advance.

Cheers,

[Jacques Reed]

Good Day Hanno,

I may have answered my own question. Revisiting my various publications and studying the diagrams I noticed what could be the speedometer cable passing over the engine. See attached.
I am now thinking 84" may be the correct length but will wait until later today to check it out. Seems unusual to have it go above the engine, but when I was researching speedometer cables I read they should be kept away from hot exhaust manifolds. My route in the previous post puts it very close to the right exhaust manifold. A photo on the engine and transmission colours thread shows an open engine bay from above on a Polish CMP truck but I could not see any speedometer cable. As the truck was under maintenance perhaps it was removed for access.
The other thing I noticed was the clips on the ignition wire conduits. I saved them off some other conduits but don't really know where they are used. Perhaps they are to clip the speedometer cable to the conduit? They have the right diameter opening for the cable. Would make sense not to have it flapping around on the engine.
Anyway we are back to Covid19 lockdown in Melbourne so more time to go back over things like this. I cannot legally go to a different area so going to get the cable shortened will just have to wait 6 more weeks.
I will still be interested to see how your cable is routed Hanno.

Cheers,

[Hanno Spoelstra]

Originally Posted by Jacques Reed

I will still be interested to see how your cable is routed Hanno.

Jacques sorry to keep you waiting, hope to take the necessary pics this week. Remind me after the weekend if you don't see anythng posted here!

[Hanno Spoelstra]

Originally Posted by Jacques Reed

I may have answered my own question. Revisiting my various publications and studying the diagrams I noticed what could be the speedometer cable passing over the engine. See attached.

Your manual diagram indeed shows the speedometer cable.

Originally Posted by Jacques Reed

I will still be interested to see how your cable is routed Hanno.

Well Jacques, I finally took to time to crawl under my 1943 F15A. I can't vouch for the routing to be the orginal one, but this is how it has been routed for the past decades and it works.

Behind the speedometer:

P1040007_resized.jpg P1040011_resized.jpg

Coming through the engine cowling it dives straight down past the engine in between the 2nd and 3rd cylinder.

P1040016_resized.jpg P1040038_resized.jpg

And then dives past the cylinder head into the chassis:

P1040041_resized.jpg

[Grant Bowker]

Originally Posted by Jacques Reed

Another interesting thing I discovered is that Ford changed the design of the front idler bearing cap to re-orient the cable more nearly horizontal. Earlier caps had the cable entering vertically which resulted in a sharp bend at the xfer case crossmember.

A simiilar change from vertical entry to horizontal entry took place on Chevrolet CMPs (in 1942 based on serial numbers given). There is a service bulletin covering adding a curved guide to the vertical style on Chevrolets to reduce the chances of kinking. I've no idea whether a similar kit existed for Fords.

The same service bulletin gives lengths of speedometer casing as 95" and cable or shaft as 96" to 96-1/4".


For more on Chevrolet speedometer cables see Phil Waterman's site https://www.canadianmilitarypattern....ge%20Notes.htm which includes a photo of the cable guide.