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Just noticed that I have 2 different heads...? |
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CrazyCanuck 
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Joined: July-21-2013 Location: Vancouver B.C. Status: Offline Points: 254 |
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 Topic: Just noticed that I have 2 different heads...?Posted: April-18-2021 at 6:57pm |
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Hi all. Been a long time since my last post. I hope that everyone is well. I was just looking into changing the spark plugs on my 351 (78 Ski Nautique), and noticed that the heads are not the same. On the drivers side, I have 13/16 plus, (NGK WR5), under a PCM exhaust manifold, but on the port side, the plugs are 5/8 under a commander manifold. I cannot check the type of plug, as I need a swivel socket to get the plug out with the commander manifold being in the way. I was planning on putting a new set of Autolite plugs in, so I guess I need 4 24's and 4 124's. Does anyone see any issue with having mis-matched heads? The engine runs great as it is. Thanks. Corey.
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KENO
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Joined: June-06-2004 Location: United States Status: Offline Points: 10662 |
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Posted: April-18-2021 at 7:19pm |
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Strange as it may sound, on the side with the Commander manifold with the 5/8ths plugs, use the box end of a 5/8 combination wrench and you can remove and reinstall the plugs with that wrench.
Just loosen the plug and unscrew it the rest of the way by hand, and screw it in by hand and tighten with the box end. As far as the mismatch, read this quote 3 times
If you're using 24's on one side, you might want to use 44's instead of 124's. The 24 and 44 are both power tip resistor plugs. The 124 is a standard tip resistor plug. |
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CrazyCanuck
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Joined: July-21-2013 Location: Vancouver B.C. Status: Offline Points: 254 |
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Posted: April-18-2021 at 7:33pm |
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Lol. I figured I might get that poke in the ribs,.. I ordered a swivel socket to pull the plug under the commander manifold. I will post what plug is in there. Just want to make sure I replace with the right plugs.... Thanks for the reply.
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KENO
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Posted: April-18-2021 at 7:43pm |
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It's easier with the box end wrench..............really
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CrazyCanuck
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Joined: July-21-2013 Location: Vancouver B.C. Status: Offline Points: 254 |
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Posted: April-20-2021 at 8:31pm |
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Okay, so I pulled out the port side plug and its an NGK UR4GP. That matches up with an Autolite AP25. The WR5's match to an Autolite 45. Platinum on one side, copper on the other. I spoke to a tech at Autolite cust service and he said that the 25 and 45 have the same heat range and will match. He also said that they were only 1 level colder than the 24's, but I thought the bigger that last number the hotter??? He must have been confused. So since my boat has been running fine on the 25/45 equivalent, I figured that I would stay with those. KENO, I cannot find 44's on the Autolite website, are they discontinued? Does anyone out there run 25's or 45's? Thanks, Corey.
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KENO
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Joined: June-06-2004 Location: United States Status: Offline Points: 10662 |
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Posted: April-21-2021 at 6:08am |
They might be discontinued I have a boat with 25's and another with 45's..............you get to do it all on one boat. Since it looks like you've had the boat for somewhere around 8 years of running great, slap em' in and you'll be good till who knows when, but check them a little more often than every 8 years or so
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CrazyCanuck wrote: