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| | | | Joined: Jun 2015 Posts: 201 Shop Shark | | Shop Shark Joined: Jun 2015 Posts: 201 | Hey,
I was doin check up on my 41 which has a 47 216 in it, all this work and haven't checked spark plugs till now.
While they arnt terrible they are worn and really old, even have some rust.
What is a good replacement? The ones in there are autolite 85s. I read my manual and it said gap .040.
Last edited by Ian Ring; 10/11/2017 1:37 PM.
| | | | | Joined: Jul 2008 Posts: 1,321 'Bolter | | 'Bolter Joined: Jul 2008 Posts: 1,321 | Stock plugs used in the early days were AC-44 with .035 gap The AC44 has been discontinued but occasionally shows up on eBay.
Delco plug numbers de-code as follows: R=resistor type, 4=14 mm thread, next digit (4 or 5)=heat range (higher number is a hotter plug), S=extended tip. The R45S plugs are middle of the road heat range & should work fine if your engine is in good condition. Heat range is simply how fast heat is carried away from the plug. I believe the AC R45S (gap .040) is the correct modern plug for our “unmodified” 216 motors.
Harold
Harold
Is a restoration ever finished? | | | | | Joined: Jun 2015 Posts: 201 Shop Shark | | Shop Shark Joined: Jun 2015 Posts: 201 | | | | | | Joined: Feb 2004 Posts: 29,778 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,778 | Doesn't the 47 216 run a 10MM spark plug thread? I've got a 46 engine that does- - - -not sure what year they made the switch to a 14 MM thread.
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
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| | | | | Joined: Jun 2015 Posts: 201 Shop Shark | | Shop Shark Joined: Jun 2015 Posts: 201 | What plug do you suggest if it's a 10mm? | | | | | Joined: Jun 2015 Posts: 201 Shop Shark | | Shop Shark Joined: Jun 2015 Posts: 201 | Got r45s and they went in good so guess it's a 14mm | | | | | Joined: Aug 2005 Posts: 6,377 Ex Hall Monitor | | Ex Hall Monitor Joined: Aug 2005 Posts: 6,377 | I use AC45s in my '38 with no issues.
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| | | | | Joined: Jan 2000 Posts: 2,074 'Bolter | | 'Bolter Joined: Jan 2000 Posts: 2,074 | Jerry is correct 10mm plugs, think ACs were M 8 (I think) also used Champion UY-6 | | | | | Joined: Feb 2004 Posts: 29,778 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,778 | Of course, it's possible the engine has had a different head installed at some time in the past. I believe there were only a few years the 10 MM plugs were used. I'm also wondering if the 10 MM head could be drilled and tapped for 14 MM plugs?
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!
| | | | | Joined: Sep 2001 Posts: 29,269 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,269 | The 10mm plugs were used up through 1948. 14mm from 1949 onwards. Post your head and block casting codes. | | |
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