Spark Plug gap and torque 239

Reply Subscribe

Thread Tools

Search this Thread

Jan 18, 2007 | 01:37 PM

galaxie641

Thread Starter

Postmaster

Joined: Nov 2006

Posts: 4,517

Likes: 3

From: SE Wyoming

Spark Plug gap and torque 239

As the title says what are the gap settings and the torque on the plugs for my '51 Flat8?

I pulled one plug and it was not very tight.

Jan 18, 2007 | 06:20 PM

kotzy

Elder User

Joined: Apr 2004

Posts: 970

Likes: 3

Per 49/50 truck manual old H10 plugs were .025 to 028. Plugs were tightened to a torque reading as follows with a new gasket, 24-30 ft. lbs.

Jan 18, 2007 | 06:55 PM

galaxie641

Thread Starter

Postmaster

Joined: Nov 2006

Posts: 4,517

Likes: 3

From: SE Wyoming

More torque than I would have figured thank you.

Jan 20, 2007 | 10:55 AM

dffay

Elder User

Joined: Dec 2003

Posts: 531

Likes: 1

From: New Mexico

Could that be INCH pounds?

Jan 20, 2007 | 11:00 AM

dffay

Elder User

Joined: Dec 2003

Posts: 531

Likes: 1

From: New Mexico

Bishop's book cites 24-28 foot lbs in cast iron heads. If you have aluminum heads it would be less. Both should get some anti-seize lube on the threads.

Jan 20, 2007 | 02:42 PM

kotzy

Elder User

Joined: Apr 2004

Posts: 970

Likes: 3

My info comes from a Ford service manual by Ford dated May 1 1950. You have to remember you are crushing a copper and asbestos gasket which had a direct influence on the heat transfer from the sparkplug shell to to the head. That is what people don't think about even today with the tapered seat plugs, if they are not tight enough the plug becomes a hotter plug then someone thought they installed. I don't know what they have substitued for the asbestos today,
I'm sure someone jumped on the plug makers to get it out of there.
Kotzy

Jan 20, 2007 | 04:13 PM

galaxie641

Thread Starter

Postmaster

Joined: Nov 2006

Posts: 4,517

Likes: 3

From: SE Wyoming

I was surprised, the plugs in it seemed really loose. The plug box said something about tightening to either a 1/4 or 1/2 turn. Anyway got the new ones in and the engine runs even better now that it has new plugs and the original wires, yes I said original, are gone. All but 1 plug were still within spec, one was under .020, probably close to .010 rest were around 025.