Impossible to install spark plugs!

-
L

LovetheA's

Well-Known Member
Joined
Aug 26, 2010
Messages
827
Reaction score
117
Location
Fairfield, CT
So I’m thinking wow things are going so great on the reassembly of my car. Something has to go wrong this is too good. Then bam what I expected happens. So I’m about to put the new champion plugs in my 383 in which I just installed edelbrock rpm aluminum heads and finally got my tti headers back in. What a pain in the *** getting those in. Then I realize that you can’t install spark plugs in the aluminum heads with the the tti header flanges bolted to the engine. WTF? The bottom of the header flange plus the bump out on the bottom edge of the head combine to make it impossible to install the plugs. Sure they use a standard 13/16 inch socket and it fits over the plug but the material that is in the way only allows you to get the plug in a small amount. The flange and bottom raised edge of the aluminum head get in the way and prevent the plug from seating. Has anyone had experience with this? If so was the solution to take a carbide Metal cutting/sanding bit put it in my drill and carefully grind away the area on the head and at the bottom of the header flange to open up the area around the plug hole? Did this work for anyone? I’m so frustrated. I never heard of this issue before when installing tti headers on the aluminum heads in an a body. Please help!
 
LovetheA's said:
So I’m thinking wow things are going so great on the reassembly of my car. Something has to go wrong this is too good. Then bam what I expected happens. So I’m about to put the new champion plugs in my 383 in which I just installed edelbrock rpm aluminum heads and finally got my tti headers back in. What a pain in the *** getting those in. Then I realize that you can’t install spark plugs in the aluminum heads with the the tti header flanges bolted to the engine. WTF? The bottom of the header flange plus the bump out on the bottom edge of the head combine to make it impossible to install the plugs. Sure they use a standard 13/16 inch socket and it fits over the plug but the material that is in the way only allows you to get the plug in a small amount. The flange and bottom raised edge of the aluminum head get in the way and prevent the plug from seating. Has anyone had experience with this? If so was the solution to take a carbide Metal cutting/sanding bit put it in my drill and carefully grind away the area on the head and at the bottom of the header flange to open up the area around the plug hole? Did this work for anyone? I’m so frustrated. I never heard of this issue before when installing tti headers on the aluminum heads in an a body. Please help!
Click to expand...

Hello LovetheA's,
Truly sorry that you are having a terrible time with your build.
Can you please post some pictures of the issues you have so we can give the best possible advice.
Thanks in advance,
Stay Safe.......
Happy Mopar :)
Arron.
 
Not sure if small block and big block Edelbrock heads are the same but the small block heads require 5/8" hex. The spark plug recess is only big enough for a 5/8" hex.

What plugs are you using?
 
IDK about 383s but the right plugs for SBMs are the ones that take a 5/8 thinwall plug socket. I think they are coded RN12YC/not sure; but they are 14mm,3/4 reach,copper,5/8s hex-drives.

Hah treed by 66fyssh
Edit;
RN12YC is wrong as noted below; the correct number being
RC12YC.
Now that I'm seeing it; I think my plug code had a J in it.
 
Last edited:
66fyssh said:
Not sure if small block and big block Edelbrock heads are the same but the small block heads require 5/8" hex. The spark plug recess is only big enough for a 5/8" hex.

What plugs are you using?
Click to expand...


This^^^^^^^^^. Those heads weren’t designed for that giant assed 13/16 hex. You need the Champion RC12YC or equivalent. The heat range depends on your combination.

Ditch that 13/16 stuff and you shouldn’t have too much trouble getting the plugs in.
 
AJ/FormS said:
IDK about 383s but the right plugs for SBMs are the ones that take a 5/8 thinwall plug socket. I think they are coded RN12YC/not sure; but they are 14mm,3/4 reach,copper,5/8s hex-drives.

Hah treed by 66fyssh
Click to expand...

N is the 13/16 hex and C is the 5/8 hex.
 
Maybe an old trick will help- instead of a socket, try using a short piece of rubber hose to start plug. I would be inclined to grind away excess header/head material now so that future maintenance will be easier.
 
The rubber hose may get it started but then he probably couldn't tighten it up with the socket.
 
Wow thank you so much everyone from the abody community. If it’s as easy as putting a smaller plug in that would be awesome. I know the mechanic that previously changed my plugs years back put 13/16” AC delco’s in the old iron heads. The car hasn't run in two years so I wasn’t sure if that size was the correct plugs. Am I fine using the RC12YC champions and what is the approx set gab for the Edelbrock’ s? Would you just say .030 or .035? Thanks again everyone. I’ll keep you all updated.
 
LovetheA's said:
Would you just say .030 or .035?
Click to expand...
That would depend on your ignition system; you can't go wrong with .035

I run the Accell Square-Top Super Coil which has mega power, and has no problem jumping big gaps from idle to 7200. I run mine at ~.045/.050, in a Tight-Q aluminum chamber
 
66fyssh said:
You'll be fine running RC12YC. That's the plug I use.
Click to expand...
yur not kidding,
I bought a new set to install the day before the annual airport drags. When I took the 4year old plugs out, they looked too good to change, so I screwed them back in.
That was 2004. The next morning they went 93 in the Eighth, and have been in there ever since........ so they were new in Fall of 1999. That was over ~100,000 miles ago.
 
You must log in or register to reply here.
-

Back
Top