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| | | | Joined: Jan 2011 Posts: 144 Shop Shark | | Shop Shark Joined: Jan 2011 Posts: 144 | '51 216:
In my search for new spark plugs my research has shown the original to be AC 46-5. What I took out of the engine were AC R43. NAPA tells me they show the correct plug to be R45XLS. The R45XLS has a much longer threaded section than the R43's I took out (3/4" vs. 3/8"). Last thing I want to do is punch a hole in a piston. Is the 3/4" too long and what should I be using?
Dave www.fallenherosdreamride.orgall give some MY SON GAVE ALL The fallen hero's dream ride is a 1951 Chevrolet 3100 with original 216 In memory of LCpl Phillip Vinnedge USMC KIA 10/13/2010 Afghanistan
| | | | | Joined: Sep 2001 Posts: 29,269 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,269 |
NAPA online shows 3/8" for all plugs listed for your year. Did you get NAPA info from online or from a local store?
I have several excellent NAPA dealers who have people who can and will look into catalogs for old parts. Nonetheless, I check out parts in NAPA online before I call or visit a local NAPA store.
Maybe someone will post informaton about the longer plug being OK. I'd go with 3/8".
| | | | | Joined: Jun 2004 Posts: 8,597 Riding in the Passing Lane | | Riding in the Passing Lane Joined: Jun 2004 Posts: 8,597 | The long thread fits the later engines. 63 up to about 71. I would put the extended tip plug in. R45S.
They say money can't buy happiness. It can buy old Chevy trucks though. Same thing. 1972 Chevy c10 Cheyenne SuperIn the Gallery Forum | | | | | Joined: Jan 2011 Posts: 144 Shop Shark | | Shop Shark Joined: Jan 2011 Posts: 144 | Thanks. I'm going to exchange the plugs for R45S
Dave www.fallenherosdreamride.orgall give some MY SON GAVE ALL The fallen hero's dream ride is a 1951 Chevrolet 3100 with original 216 In memory of LCpl Phillip Vinnedge USMC KIA 10/13/2010 Afghanistan
| | | | | Joined: Oct 2006 Posts: 9,671 'Bolter | | 'Bolter Joined: Oct 2006 Posts: 9,671 | Here are a couple of poor pictures of the most commonly used AC Delco R45 plugs being use in the AD trucks now days. Second one shows the reach of the R45 plug and as you can clearly see, you’ve got a long way to go to reach the piston: http://www.pbase.com/dennygraham/image/136038165 http://www.pbase.com/dennygraham/image/136038174 Here it is with a long reach plug installed. I would think that you would have one 'ell of a time getting that plug out with the threads loaded up with deposits, which is inevitable: http://www.pbase.com/dennygraham/image/136038755 Denny Graham Sandwich, IL
Last edited by Denny Graham; 07/01/2011 2:14 PM.
Denny G
Sandwich, IL
| | | | | Joined: Jan 2011 Posts: 144 Shop Shark | | Shop Shark Joined: Jan 2011 Posts: 144 | Denny,
Great photos. Thanks for posting.
I ended up with the R45S. Not sure what the "S" stands for but it has a 3/8" thread length. The "xls" were 3/4".
Dave www.fallenherosdreamride.orgall give some MY SON GAVE ALL The fallen hero's dream ride is a 1951 Chevrolet 3100 with original 216 In memory of LCpl Phillip Vinnedge USMC KIA 10/13/2010 Afghanistan
| | | | | Joined: Oct 2006 Posts: 9,671 'Bolter | | 'Bolter Joined: Oct 2006 Posts: 9,671 | The ‘R’ as you know Dave, indicates a resistor plug, the ‘4’ is the thread size 14mm in this case, the ‘5’ is the Heat Range and the ‘S’ is an extended tip.
Denny Graham
Sandwich, IL
Denny G
Sandwich, IL
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