Go Back   The Ford Barn > General Discussion > Early V8 (1932-53)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Display Modes
Old 12-02-2015, 01:09 PM   #1
bluardun
Senior Member
 
bluardun's Avatar
 
Join Date: May 2010
Location: Tucson, Az.
Posts: 321
Default Spark plugs

I have a 59A stock engine, 6 volts. My question is: Has anyone use a Chevy spark plugs. They both are 18mm threads. The Ford (Champion)
H-10 threads are 11mm long. The Chevy (Champion) J-12 threads are 9mm long. The H-10 porcelain is receded in the head, as the ignitor is flat with the surface of the combustion area. The J-12 the threads are short of bein flush with the combustion surface about 3/32", but the porcelain and ignitor protrude into the combustion chamber about 3/16 of and inch. Seems the J-12 plugs would burn cleaner at slower speeds.

The reason I ask is, the plugs always look black, like the are not firing hot enough, or long enough.
Thanks
Bill Herbert
bluardun is offline   Reply With Quote
Old 12-02-2015, 01:31 PM   #2
rotorwrench
Senior Member
 
rotorwrench's Avatar
 
Join Date: Jun 2010
Location: San Antonio, Texas
Posts: 16,346
Default Re: Spark plugs

Most plugs are designed per the manufacturers specs for length of reach, type of sealing surface between head and plug, and the desired heat range. If you want a colder plug or a hotter plug, there are designations for that. If the reach it too long, it can lead to detonation or after fire dieseling. If the gasket surface isn't the same it may not seal well or damage the faying surface. Almost every plug ever made has at least one step up or down for heat range which is reflected by the part number.

Champion H-10 is only one usable brand. Autolite, NGK, and Bosch all make equivalent plugs for the flatheads. Some are better than others. Fuel system problems or piston ring problems can also be the cause of sooty plugs.
rotorwrench is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 12-02-2015, 01:52 PM   #3
bluardun
Senior Member
 
bluardun's Avatar
 
Join Date: May 2010
Location: Tucson, Az.
Posts: 321
Default Re: Spark plugs

I'm aware the manufactures design and make a spark plug for each engine. Thanks.
I was just asking if anyone has adventured into using a different plug as described.
You advice about detonation is something to consider.
Probably will re-use the H-10. Doesn't hurt to inquire about peoples experiences.
Thanks for the reply
bluardun is offline   Reply With Quote
Old 12-02-2015, 02:07 PM   #4
tubman
Senior Member
 
tubman's Avatar
 
Join Date: Dec 2013
Location: Minnesota, Florida Keys
Posts: 10,247
Default Re: Spark plugs

Just to stir the pot, I had a '51 276" Merc all built up in a '36 3-Window. I had an MSD ignition and Offenhauser heads. I found some surface gap plugs from a 2 cycle outboard motor that were perfectly flush with the inside surface of the head. They worked perfectly. I don't think I would have tried them with a stock ignition. I am currently building a 258" 8BA that I am going to run Edmunds heads on. According to "Ol' Ron", Edmunds moved the spark plug just enough to allow the use of an extended tip plug. We'll see how it works out.
tubman is offline   Reply With Quote
Old 12-02-2015, 02:09 PM   #5
adileo
Senior Member
 
adileo's Avatar
 
Join Date: Jun 2014
Location: New Jersey
Posts: 1,772
Default Re: Spark plugs

I've read many posts on here regarding plugs and based on that bought NGK. I am very happy with their performance, as is a good friend with a 40.
adileo is offline   Reply With Quote
Old 12-02-2015, 02:48 PM   #6
BillM
Senior Member
 
BillM's Avatar
 
Join Date: May 2010
Location: Everett, WA
Posts: 504
Default Re: Spark plugs

Sponsored Links (Register now to hide all advertisements)
I made a drawing of various plugs fitted to an Offenhauser head to help in picking something that would fit best. Can't help with heat range.
Attached Images
File Type: jpg Flathead plugs.jpg (48.8 KB, 210 views)
__________________
My web page:
http://myplace.frontier.com/~wgmumaw/
BillM is offline   Reply With Quote
Old 12-02-2015, 03:55 PM   #7
JSeery
Member Emeritus
 
JSeery's Avatar
 
Join Date: Nov 2012
Location: Wichita KS
Posts: 16,132
Default Re: Spark plugs

Quote:
Originally Posted by BillM View Post
I made a drawing of various plugs fitted to an Offenhauser head to help in picking something that would fit best. Can't help with heat range.
Very interesting!
JSeery is offline   Reply With Quote
Old 12-02-2015, 04:21 PM   #8
bluardun
Senior Member
 
bluardun's Avatar
 
Join Date: May 2010
Location: Tucson, Az.
Posts: 321
Default Re: Spark plugs

Thanks for the input. One of the reasons I'm interested in information and experiences is because the H-10 plugs were engineered for the needs of a Flathead and the "GASOLINE" we use to have. With todays "formulated fuel" I don't think the H-10 is totally efficient.
Thanks
bluardun is offline   Reply With Quote
Old 12-02-2015, 04:32 PM   #9
Ronnieroadster
Senior Member
 
Ronnieroadster's Avatar
 
Join Date: Dec 2010
Location: East Coast in CT
Posts: 1,503
Default Re: Spark plugs

Quote:
Originally Posted by bluardun View Post
Thanks for the input. One of the reasons I'm interested in information and experiences is because the H-10 plugs were engineered for the needs of a Flathead and the "GASOLINE" we use to have. With todays "formulated fuel" I don't think the H-10 is totally efficient.
Thanks
My experiance has shown the best plug to be the NGK which offers two heat ranges. Any Champion plugs I have treid in the past which come from Mexico were easily fouled even on a stock flathead.
Ronnieroadster is offline   Reply With Quote
Old 12-02-2015, 04:36 PM   #10
flathead 53
Senior Member
 
Join Date: Jul 2011
Location: central nj
Posts: 717
Default Re: Spark plugs

I am with adlieo, the ngks are great,car never ran better
flathead 53 is offline   Reply With Quote
Old 12-02-2015, 04:43 PM   #11
Ronnie
Senior Member
 
Ronnie's Avatar
 
Join Date: May 2010
Location: Canada Where it snows
Posts: 2,058
Default Re: Spark plugs

Quote:
Originally Posted by bluardun View Post
I have a 59A stock engine, 6 volts. My question is: Has anyone use a Chevy spark plugs. They both are 18mm threads. The Ford (Champion)
H-10 threads are 11mm long. The Chevy (Champion) J-12 threads are 9mm long. The H-10 porcelain is receded in the head, as the ignitor is flat with the surface of the combustion area. The J-12 the threads are short of bein flush with the combustion surface about 3/32", but the porcelain and ignitor protrude into the combustion chamber about 3/16 of and inch. Seems the J-12 plugs would burn cleaner at slower speeds.

The reason I ask is, the plugs always look black, like the are not firing hot enough, or long enough.
Thanks
Bill Herbert
18mm thread ??

R
Ronnie is offline   Reply With Quote
Old 12-03-2015, 03:15 PM   #12
hotrodcbx
Senior Member
 
Join Date: Jul 2010
Posts: 136
Default Re: Spark plugs

I didn't want to admit it, but after seeing Tubmans response to using Mercury surface gap plugs, I too have to admit doing the same thing. The plugs were spares out of a 2000 Mercury 90HP two stroke. The engine is 286", B&M supercharger with MSD ignition. It ran great on these plugs but I got concerned about long term effects and removed them for Autolite 216s.
hotrodcbx is offline   Reply With Quote
Old 12-03-2015, 04:35 PM   #13
supereal
Senior Member
 
supereal's Avatar
 
Join Date: Jul 2014
Location: Iowa
Posts: 1,634
Default Re: Spark plugs

I've used Champion RJ14YC plugs for years in my flatheads. The longer snout stays cleaner, even in loose engines.
supereal is offline   Reply With Quote
Old 12-03-2015, 06:08 PM   #14
tubman
Senior Member
 
tubman's Avatar
 
Join Date: Dec 2013
Location: Minnesota, Florida Keys
Posts: 10,247
Default Re: Spark plugs

Yep, it's interesting that "hotrodcbx" was kinda reluctant to admit he used surface gap plugs. My lifelong desire was to have a '36 3-Window with a "3/4 race" Merc and hydraulic brakes. I drove the car as a "daily" for about five years until a local "rich guy" made me an "offer I couldn't refuse". I never replaced any plugs, and it ran as good when I sold it as when I built it. He later sold it to some guy in New Zealand for a lot more than he paid me. Any of you "Kiwis" know about a "Vineyard Green" '36 3-Window that came in about 10 years ago?
tubman is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 11:53 PM.