MTFCA Forum

I have what I believe is an original condition 1921 Touring. There is an extra wire in the right side wire loom which is not connected at the generator or the 5 terminal firewall block, as it has a single wire running from the single terminal on the generator cutout to the ammeter, through it's own hole in the firewall, parallel to the right side loom. Is this original?

Doesn't look like a correct cut-out (aftermarket?) and the extra wire on the generator is a ground. I see a pulley can't tell if is from the outlet water neck or a water pump on the side of the engine.

Correct early style rectangular cutout, you can faintly see the Ford script stamped into the cover in the posted photo by Sarvert's.



Please correct me if I am wrong, but I do believe that the single wire going from the cutout to the ammeter is correct, for the early F.A. electrical system (rectangular cutout, firewall or generator mounted). The wiring harness is later with the wire for the cutout in the loom and going to the terminal block. Could this be a case of a faulty generator that was replaced with an earlier "working" one at some point? A 1921 should have the round cutout and utilize the wire in the harness.

Thanks for the assistance. Here is a photo of the other side. Where would the loose yellow wire from the cutout, tie into the 5 terminal block?

SarverT's wrote: ↑

Mon Dec 07, 2020 10:50 pm

Where would the loose yellow wire from the cutout,DSC_0136.JPG tie into the 5 terminal block?

You say it is a 1921, I think it is earlier and wired correctly. The wiring harness with the loose/unconnected wire is a "later" style harness (more than likely a replacement) with the wire for the cutout to terminal block woven into the loom. The loose wire was not "used" because it was not needed. The loose wire should go from the cutout to the number 1 terminal on the block, but with that being said, leave it as it is. The single wire from the cutout to the ammeter (which is where I believe it goes to after it passes through the firewall), was eliminated sometime in 1920. Here is a wiring diagram with the early rectangular cutout:



And then the later wiring diagram:

While unlikely it was replaced, my September 1921 had the 5 terminal block on the firewall. I don't recall now if the wire from the generator was part of the loom or separate wire that bypassed the terminal block and went to the meter.

Found wiring diagrams for 5 post terminal block and rectangular cut-out. https://www.modeltcentral.com/Model-T-F ... erial.html
rectangular cut-out on generator rectangular cut-out on firewall

Frank,

That extra pulley, you mentioned, appears to be a Nims water pump. The Nims water pumps were an aftermarket engine outlet elbow water pump/flow assist device. Being as small as they were/are, I don't don't know how much good they actually did. But, with an impeller as small as they have/had, they would not impede the thermo-siphon effect much if they were disconnected as this one is.

This photo shows a very early generator car. Its rectangular cutout is correctly mounted on the firewall. There is a hole in the firewall (just inboard of the carb adjustment rod) where the wire from the cutout passes through. I assume it is going to the ammeter.

I've had problems with the current reproduction wire looms. What I did was using original factory used looms, I took them to Y and Z's wiring in Redlands, California. They did it right, and even wove in the original Ford tags just like original. Of course, it took twice and much money to do this, but I'm satisfied.

On the original wiring, does anyone what was used as an insulator between the wire and the terminal? Now I mostly see black rubber or those bright-colored plastic ones.

Tadpole wrote: ↑

Thu Dec 01, 2022 7:02 am

On the original wiring, does anyone what was used as an insulator between the wire and the terminal? Now I mostly see black rubber or those bright-colored plastic ones.

There was no insulator on the wiring to the terminal block or the coil box or spark plug wires.

The only loom with insulators is the switch wires, the ones that fit to back of the combination ignition and light switch at the dash panel.

Hard rubber insulator used at switch components.

Here are some pictures of a NOS 4 wire dash harness showing the hard rubber on the terminals. Also the Ford tag.

Well, the "extra wire" isn't a ground...it is the generator wire contained within a later wiring loom and left unused. Hard to tell if the generator is a very early FA generator even after blowing up the picture, but I'd love to see which ammeter is on the dash, as early ones are beautifully made and the light switch is a cast and not stamped item.

Mark Nunn: who cares about where the cutout is mounted...look at that head!!! What's going on there??

Scott_Conger wrote: ↑

Thu Dec 01, 2022 10:31 am

...look at that head!!! What's going on there??

DITTO !

Sleeve valve conversion?

I was wondering too. The intake valves appear to be spring-loaded and not connected to the cam. Downward piston movement (pressure differential) would open valves. My understanding is that some period motorcycle engines had valves like these.

Save that old Ford script wiring. That is what I use to have perfect reproduction looms made. My guy even puts in the Ford tag.

Original colors? I don't think so.

"Automatic" or "atmospheric" intake valves were in wide use on low speed stationary engines and some very early cars. They quickly fell out of favor for automotive use due to their limited speed range and throttling effect and limitations on valve size/weight and valve timing options. The atmospheric intake valve had to have a very light spring in order to function, and that would not allow for engine speeds much beyond 400 RPM, if that. Volumetric efficiency was also limited. The ability to time the intake valve opening and closing points was very limited. I can't think of a reason to convert a T engine to such a system, especially if it involved significant expense. A stock T engine would run within a limited speed range if you removed the intake valve lifters and put low pressure intake valve springs in it. But if you increased RPM very much above slow idle, the intake valves would begin to bounce and float, and valve timing would be come erratic.

I'd like to know more about that cylinder head.