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 01-21-2016, 02:28 PM   #1
Kray_Z-1
Junior Member
 
Join Date: Jan 2016
Posts: 17
Default Spark plug shims

I've built a flatty based on a 51 merc block. During the machine shop phase, my machinist shaved the decks a "little" (I don't really know how much).
I'm running the Edelbrock 74cc heads and a Potvin Super 3/8 cam. I also m sing Edelbrock's recommended spark plugs, Champion rc12yc. The problem I'm having is the valves are closing all but one of the gaps on the passenger side bank. It doesn't seem to be smashing the electrode, nor does it leave and real damage on the valve. It just seems to close the gaps. I don't want to use a shorter plug because they are MUCH shorter and the heads are aluminum. I know of several manufacturers of "indexing washer" that vary in thickness, the thickest being .064" . I believe that should be enough of a shim to keep from closing them. I have run the engine a bit (not knowing at first) and it sounded real lumpy and randomly spit fire from the pipes. After finding the problem, I re-gapped the plugs then installed them hand tight, then backed them off about 2-3 threads and fired it up again, now both banks are running but I don't think well enough to get any real tune. Has anyone dealt with these indexing washers before? or had similar problems? I guess what I really need to know is...do I remove the "gasket" from the plug before using the washer, or just leave it on?

Here's a link to it running...

https://youtu.be/rJsxl5MS4PY
Kray_Z-1 is offline   Reply With Quote
Old 01-21-2016, 04:53 PM   #2
JWL
Senior Member
 
Join Date: May 2010
Location: Fitzgerald, Georgia
Posts: 2,033
Default Re: Spark plug shims

The indexing "washers" replace the original plug gasket for the purpose of aligning the plug ground strap to the desired location. The variety of thickness options allows for differing thread calibrations so most rotational locations can be accommodated.
JWL is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 01-21-2016, 05:18 PM   #3
BUBBAS IGNITION
Senior Member
 
BUBBAS IGNITION's Avatar
 
Join Date: May 2010
Location: SPEEDWAY INDIANA
Posts: 3,999
Default Re: Spark plug shims

I do have a box of champion plug gaskets . I coud send you a few and you could just doble them up????
__________________
If it Makes Spark, we do it !!!!
www.bubbasignition.com
jimlinder@juno.com
BUBBAS IGNITION is offline   Reply With Quote
Old 01-21-2016, 05:22 PM   #4
Ronnie
Senior Member
 
Ronnie's Avatar
 
Join Date: May 2010
Location: Canada Where it snows
Posts: 1,996
Default Re: Spark plug shims

http://www.speedmartinc.com/shop/item.asp?itemid=124

R
Ronnie is offline   Reply With Quote
Old 01-21-2016, 05:23 PM   #5
petehoovie
Senior Member
 
petehoovie's Avatar
 
Join Date: May 2015
Posts: 2,882
Default Re: Spark plug shims

Way to go, Ronnie!....Thank you for that link....
__________________
The only thing nice about being imperfect is the joy it brings to others....

"Silver rings, your butt! Them's washers!"
"We shot our way out of that town for a dollar's worth of steel holes." - from 'The Wild Bunch' - 1969

https://www.youtube.com/watch?v=7NReUd2_0u0

Last edited by petehoovie; 01-21-2016 at 06:09 PM.
petehoovie is offline   Reply With Quote
Old 01-21-2016, 06:17 PM   #6
Pete
Senior Member
 
Pete's Avatar
 
Join Date: May 2010
Location: Wa.
Posts: 3,849
Default Re: Spark plug shims

In addition to the indexing washers, I think it was Tony Baron used to have 1/8 inch thick solid copper plug washers.
Pete is offline   Reply With Quote
Old 01-21-2016, 06:43 PM   #7
Bored&Stroked
Senior Member
 
Bored&Stroked's Avatar
 
Join Date: Jan 2011
Location: Central Ohio
Posts: 2,705
Default Re: Spark plug shims

Another option might be NGK Surface Gap spark plugs - they make one in 3/4" reach that might be worth checking out. A lot of boat engines use them. What I don't know is how much energy it takes to fire them and if there are any issues with fowling. I bought a set of 7/16 surface gap plugs to try in my 42 Merc 284 cube flathead (just for shits and giggles) - they are NGK BU8H. Regular plugs work fine in this engine, just wanted to try these for the heck of it. (I am running a Vertex Mag).

Here is a link to Summit, with a .750 reach NGK plug (#2322) . . . maybe be something that works, won't know until yah try it!

http://www.summitracing.com/parts/ngk-2322

Also, here are spark plug index washers at Summit:

http://www.summitracing.com/parts/mor-71910/overview/
Bored&Stroked is offline   Reply With Quote
Old 01-21-2016, 06:57 PM   #8
tubman
Senior Member
 
tubman's Avatar
 
Join Date: Dec 2013
Location: Minnesota, Florida Keys
Posts: 6,614
Default Re: Spark plug shims

So I am not the only one that used surface gap plugs in a flathead. I had a "hot" 276" Merc with an MSD igition which fired the surface gaps just fine. After 6 years and 14,000 miles of trouble-free driving (except for axles) I sold it too a guy who told me they flat out wouldn't work!
tubman is offline   Reply With Quote
Old 01-21-2016, 07:15 PM   #9
Jack E/NJ
Senior Member
 
Jack E/NJ's Avatar
 
Join Date: May 2010
Posts: 1,712
Default Re: Spark plug shims

>>>I re-gapped the plugs then installed them hand tight, then backed them off about 2-3 threads and fired it up again>>>

Prolly not a good idea to run it too much with loose plugs. Aluminum threads can get buggered up and/or fouled with super-hot combustion leaks.

Jack E/NJ
Jack E/NJ is offline   Reply With Quote
Old 01-21-2016, 10:48 PM   #10
Bill S
Senior Member
 
Join Date: May 2010
Location: H.B. So. Calif
Posts: 411
Default Re: Spark plug shims

Back in 1970 I had a Kawasaki 500 two stroke. It had surface gap plugs. Did not have any problems with fouling. I still have some of the plugs.
Bill S is offline   Reply With Quote
Old 01-21-2016, 11:21 PM   #11
Kray_Z-1
Junior Member
 
Join Date: Jan 2016
Posts: 17
Default Re: Spark plug shims

Quote:
Originally Posted by Jack E/NJ View Post
>>>I re-gapped the plugs then installed them hand tight, then backed them off about 2-3 threads and fired it up again>>>

Prolly not a good idea to run it too much with loose plugs. Aluminum threads can get buggered up and/or fouled with super-hot combustion leaks.

Jack E/NJ

Yeah I know...It was just a warm up run.
Kray_Z-1 is offline   Reply With Quote
Old 01-21-2016, 11:24 PM   #12
Kray_Z-1
Junior Member
 
Join Date: Jan 2016
Posts: 17
Default Re: Spark plug shims

Quote:
Originally Posted by JWL View Post
The indexing "washers" replace the original plug gasket for the purpose of aligning the plug ground strap to the desired location. The variety of thickness options allows for differing thread calibrations so most rotational locations can be accommodated.
Yes I understand the true purpose of the indexing washer. I did ask Speedway about the use of them, they say to use them WITH the gasket.
Kray_Z-1 is offline   Reply With Quote
Old 01-21-2016, 11:27 PM   #13
Kray_Z-1
Junior Member
 
Join Date: Jan 2016
Posts: 17
Default Re: Spark plug shims

Quote:
Originally Posted by Bored&Stroked View Post
Another option might be NGK Surface Gap spark plugs - they make one in 3/4" reach that might be worth checking out. A lot of boat engines use them. What I don't know is how much energy it takes to fire them and if there are any issues with fowling. I bought a set of 7/16 surface gap plugs to try in my 42 Merc 284 cube flathead (just for shits and giggles) - they are NGK BU8H. Regular plugs work fine in this engine, just wanted to try these for the heck of it. (I am running a Vertex Mag).

Here is a link to Summit, with a .750 reach NGK plug (#2322) . . . maybe be something that works, won't know until yah try it!

http://www.summitracing.com/parts/ngk-2322

Also, here are spark plug index washers at Summit:

http://www.summitracing.com/parts/mor-71910/overview/


Whoa hey now!!!! that plug may be the ticket as I am running an MSD. I like that better than "double gasketing" another plug.
Kray_Z-1 is offline   Reply With Quote
Old 01-21-2016, 11:34 PM   #14
Kray_Z-1
Junior Member
 
Join Date: Jan 2016
Posts: 17
Default Re: Spark plug shims

Quote:
Originally Posted by BUBBAS IGNITION View Post
I do have a box of champion plug gaskets . I coud send you a few and you could just doble them up????
Hey thanks for the offer there Bubba!! .... I have a bag of these indexing washers on the way already,but I think I may try these surface gap plugs mentioned here.
Kray_Z-1 is offline   Reply With Quote
Old 01-22-2016, 12:11 AM   #15
tubman
Senior Member
 
tubman's Avatar
 
Join Date: Dec 2013
Location: Minnesota, Florida Keys
Posts: 6,614
Default Re: Spark plug shims

If you screw one into a head before it is on the engine, you can see that they produce an almost absolutely flush surface on the inside of the head. The ones I used were Champions, but I believe that most plug manufacturers make them. I never changed plugs in the 6 years I had the car. (It was a '36 3-window coupe, BTW.) Like B&S, I got the idea from the plugs that were used in a Johnson O/B motor I had at the time. You really should try a set. The cost will be minimal, and there is no electrode to break off and drop into the engine. The worst thing that could happen is that they wouldn't work very well, but I doubt it.

If you try some, let us know. I would be interested to see if I am not the only one who got away with this.
tubman is offline   Reply With Quote
Old 01-22-2016, 10:46 AM   #16
Kray_Z-1
Junior Member
 
Join Date: Jan 2016
Posts: 17
Default Re: Spark plug shims

Quote:
Originally Posted by tubman View Post
If you screw one into a head before it is on the engine, you can see that they produce an almost absolutely flush surface on the inside of the head. The ones I used were Champions, but I believe that most plug manufacturers make them. I never changed plugs in the 6 years I had the car. (It was a '36 3-window coupe, BTW.) Like B&S, I got the idea from the plugs that were used in a Johnson O/B motor I had at the time. You really should try a set. The cost will be minimal, and there is no electrode to break off and drop into the engine. The worst thing that could happen is that they wouldn't work very well, but I doubt it.

If you try some, let us know. I would be interested to see if I am not the only one who got away with this.
I'll keep ya updated, man these things re hard to find in stores! I know I can ebay them and find plenty, but I've had bad experience with that. Local stores don't have them and when they order them...they get one from KC, and 2 from Springfield and 1 from blah blah blah.... I got some on order thru NAPA, it'll be next weekend before I hear anything from them

But I do believe this is my best option.
Kray_Z-1 is offline   Reply With Quote
Old 01-22-2016, 12:06 PM   #17
Jack E/NJ
Senior Member
 
Jack E/NJ's Avatar
 
Join Date: May 2010
Posts: 1,712
Default Re: Spark plug shims

Got my Champion L76V marine plugs at Tractor Supply. Run them in my Case SC.

Jack E/NJ
Jack E/NJ is offline   Reply With Quote
Old 07-10-2020, 02:13 PM   #18
russcc
Senior Member
 
Join Date: May 2010
Posts: 2,388
Default Re: Spark plug shims

What is the reach, less gasket on the L76V champ plug ? Thank you.
russcc is offline   Reply With Quote
Old 07-10-2020, 02:19 PM   #19
GOSFAST
Senior Member
 
GOSFAST's Avatar
 
Join Date: May 2010
Location: Long Island, NY
Posts: 1,039
Default Re: Spark plug shims

Quote:
Originally Posted by Kray_Z-1 View Post
I've built a flatty based on a 51 merc block. During the machine shop phase, my machinist shaved the decks a "little" (I don't really know how much).
I'm running the Edelbrock 74cc heads and a Potvin Super 3/8 cam. I also m sing Edelbrock's recommended spark plugs, Champion rc12yc. The problem I'm having is the valves are closing all but one of the gaps on the passenger side bank. It doesn't seem to be smashing the electrode, nor does it leave and real damage on the valve. It just seems to close the gaps. I don't want to use a shorter plug because they are MUCH shorter and the heads are aluminum. I know of several manufacturers of "indexing washer" that vary in thickness, the thickest being .064" . I believe that should be enough of a shim to keep from closing them. I have run the engine a bit (not knowing at first) and it sounded real lumpy and randomly spit fire from the pipes. After finding the problem, I re-gapped the plugs then installed them hand tight, then backed them off about 2-3 threads and fired it up again, now both banks are running but I don't think well enough to get any real tune. Has anyone dealt with these indexing washers before? or had similar problems? I guess what I really need to know is...do I remove the "gasket" from the plug before using the washer, or just leave it on?

Here's a link to it running...

https://youtu.be/rJsxl5MS4PY

Wrong plugs, no matter what Edelbrock "recommends"??

(Add) Just realized the date of this thread, missed that. Also, today there always seems to be plug length issues, more than normal for these Flatheads with aftermarket heads?

Thanks, Gary in N.Y.

P.S. We never use "extended-tip" plugs in any of our Flatheads, and we don't particularly care for that brand any longer! We use "Autolite" pump-gas plugs on almost all our builds!

Last edited by GOSFAST; 07-10-2020 at 02:37 PM. Reason: Add
GOSFAST is online now   Reply With Quote
Old 07-10-2020, 02:28 PM   #20
tubman
Senior Member
 
tubman's Avatar
 
Join Date: Dec 2013
Location: Minnesota, Florida Keys
Posts: 6,614
Default Re: Spark plug shims

Quote:
Originally Posted by GOSFAST View Post
Wrong plugs, no matter what Edelbrock "recommends"??

Thanks, Gary in N.Y.

P.S. We never use "extended-tip" plugs in any of our Flatheads, and we don't particularly care for that brand any longer! We use "Autolite" pump-gas plugs on almost all our builds!
I run extended tip plugs in my car, but I have Edmunds heads where the spark plug has been relocated just enough to get it away from over the valve. Two years and 3000 miles with no problems. I wouldn't try it with "regular" heads, though.
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 12:11 PM.