MTFCA Forum

What's everybody's personal experience with Autolite 3095 spark plugs for a "Driver" T ? What's your experience if you've ever used Older Firestone E-40-F plugs in your T ? Also Champion A25's ? (not the take apart type).

I'm using Champion A-25s and get good results. Engine is near stock and has good oil control. Ignition is stock except for a New Day Timer.

Motorcraft Model T spark plugs are a good aftermarket plug. They work fine.

I use Autolite 3095 plugs.
I drive between six and ten miles once a week exercising low gear up a long hill on one of my regular routes.
I’ve had plugs go bad on me so I change them once a year and clean them pretty regularly.
My motor is currently using a distributor.
I like that I can find them in a few of the auto parts in my area.

I've been using the Champion A25 (aka 525) plugs with good results and no problems. Rajo head, Stromberg RF carb, bored 0.030".

I just found a set of 3095 plugs I bought at Chickasha a few years ago. When I read this post I thought I had some somewhere. The older guy I got them from had them on his table and he couldn’t sell them. Brand new in the boxes for a dollar each. He told me they weren’t original and I was the first that asked about them. He came down on the price .50 each and they were mine for a dollar each! I guess times have changed!

I know nothing about these air gap plugs other than a stash of them came in a Model T parts lot, so I presume the PO was running them. I have not installed them in my T but may do so to test them. NOS Champion 6 com 62. What little verbage I can find them is they are commercial plugs designed for engines that run hot, a cooler running plug.
I've got a little roughness in my T engine right now and connecting everything up after gas tank cleaning and lining. If it still runs a little rough, I'll replace the plugs with something and see if that helps. Then I'll move to the coils.

Anyone heard of these AC plugs?

From the internet for AC 6-COM-62 plugs

6COM-62, 18mm plugs were listed as for "Ford and pre 1926 Harley." by spark plug dealer Donald McKinsey in 1994
from a discussion on aaca.org
My pre-war Champion catalog shows this 18mm plug as mainly intended for commercial vehicles and motorcycles. It's a "severe service" plug and is recommended for engines that run hot. (It's a colder type plug.) There were no specific vehicle recommendations in the catalog but there is a note that it can be used in some Studebakers, but it is indicated as a plug that can be used to help correct rapid gap growth, pre-ignition, ping, overheating and core fracture caused by hot running motors, high speed usage, heavy loads and long highway upgrades in hot climates.

If that's a gasket on there - it won't fit a T - they're 1/2 pipe !

RajoRacer wrote: ↑

Thu May 16, 2024 12:31 pm

If that's a gasket on there - it won't fit a T - they're 1/2 pipe !

18MM is not the same as 1/2" pipe thread.

Would a early Ford and Harley plug really be 18mm? I haven't tried to thread one in yet, but certainly don't want to mess up a head.

signsup wrote: ↑

Thu May 16, 2024 1:17 pm

Would a early Ford and Harley plug really be 18mm? I haven't tried to thread one in yet, but certainly don't want to mess up a head.

Good question. All depends on what one means by "Early"
Spark Plug (18mm Champion);
1933-37 Ford V8
1929-1952 Harley-Davidson WL
1936-1940 Harley-Davidson EL
1937-1947 Harley-Davidson UL
1941-1947 Harley-Davidson FL