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Joined: Apr 2010
Posts: 173
Shade Tree Mechanic
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OP
Shade Tree Mechanic
Joined: Apr 2010
Posts: 173 |
Hi Guys and Girl., What octane gas do you use in your 1934 Master engines. Also what plugs do you run. I am having problems with my coupe Spark plugs blackening and causing car to miss -fire. if I replace plugs engine runs sweet for a few miles then the same problem happens again I have changed Coils points condensers distributor caps and rotors complete distributors and Carburetors,High tension leads but can not find the cause of my problem. (Engine is not using any Oil, no black or blue exhaust smoke from tail pipe)
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Joined: Jul 2008
Posts: 1,896 Likes: 28
ChatMaster - 1,500
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ChatMaster - 1,500
Joined: Jul 2008
Posts: 1,896 Likes: 28 |
Paul,
What brand and part number are you running? What gap do you have them at?
Dave
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Joined: Dec 2016
Posts: 656 Likes: 3
Oil Can Mechanic
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Oil Can Mechanic
Joined: Dec 2016
Posts: 656 Likes: 3 |
There is a very strong possibility you are having carburetor trouble. Black fouled plugs in an otherwise healthy engine are usually an indication of too much fuel.
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Joined: Feb 2004
Posts: 424 Likes: 6
Backyard Mechanic
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Backyard Mechanic
Joined: Feb 2004
Posts: 424 Likes: 6 |
What fuel pressure do you have at the carburetor?
Jon.
Good carburetion is fuelish hot air
Owner, The Carburetor Shop (in Missouri)
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Joined: Jan 2002
Posts: 30,701 Likes: 141
ChatMaster - 25,000
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ChatMaster - 25,000
Joined: Jan 2002
Posts: 30,701 Likes: 141 |
Use the lowest octane gas available. The engine was designed to run on 65 octane.
I ran AC45 plugs in my 1934. If you do a lot of low speed driving with a cold engine you could us a slightly hotter #46.
A too rich fuel mixtuer could cause the problem as well as over use of the choke. Could be caburetor float or metering rod adjustment. Also extended periods of engine idling can foul plugs Taking the car out and driving at higher speeds can clan the spark plugs.
Last edited by Chev Nut; 10/26/19 09:53 AM.
Gene Schneider
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Joined: Nov 2002
Posts: 7,472 Likes: 26
ChatMaster - 7,000
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ChatMaster - 7,000
Joined: Nov 2002
Posts: 7,472 Likes: 26 |
Check the air cleaner for restriction.
Steve D
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Joined: Apr 2010
Posts: 173
Shade Tree Mechanic
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OP
Shade Tree Mechanic
Joined: Apr 2010
Posts: 173 |
Thanks for Information and answers / questions. I am running the car on 91 octane that is the lowest grade here in New Zealand I have tried running it on 98 and found that made the car run terrible could hardly drive it home. I have tried different brands of plugs AC 44S Champion J-12Y Champion J12YC and Bosch R6.
Delco AC plugs are not available here in NZ. All the plug set have been NOS or new.
I have not checked fuel pump pressure but will do. What pressure is correct ?
I do not have a carburetor flooding problem that I have noticed. The car needs choke on initial cold start ( momentarily ) I have tried 2 different Rochester Carbs one old carb one rebuilt Both appeared to run the same. To day I will change Carburetor for a rebuilt Carter W1 and see if this improves the coupes performance.
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Joined: May 2005
Posts: 1,295 Likes: 2
ChatMaster - 1,000
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ChatMaster - 1,000
Joined: May 2005
Posts: 1,295 Likes: 2 |
Paul on my 39 m.d. I run between 3 & 4 pounds of fuel pressure with no problems ! I also run a/c R-45 spark plugs. Good Luck 
p.k.
1956 BEL AIR 2 DOOR HARDTOP
I've spent most of my money on Booze,Women and mechanical things. The rest I just Wasted........
Remember , I'm not Always Right. But I'm Never Wrong !
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Joined: Jul 2008
Posts: 1,896 Likes: 28
ChatMaster - 1,500
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ChatMaster - 1,500
Joined: Jul 2008
Posts: 1,896 Likes: 28 |
J12Y and 44s are rather cold plugs. Unless you are doing a lot of high speed highway driving I would follow Gene's recommendation of 46/R46 AC or their equivalent you can find in NZ.
Good luck
Dave
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Joined: Jan 2002
Posts: 30,701 Likes: 141
ChatMaster - 25,000
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ChatMaster - 25,000
Joined: Jan 2002
Posts: 30,701 Likes: 141 |
would be a Champion J18Y.
But that and the AC that ends with an "S" are extend tip plugs. I would say a hotter plug with no extended insulator and eletrode.
Gene Schneider
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Joined: Mar 2017
Posts: 201 Likes: 2
Backyard Mechanic
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Backyard Mechanic
Joined: Mar 2017
Posts: 201 Likes: 2 |
Am I correct in assuming that it is okay to run the AC "S" series plugs in the 216s and not the 235s due to possible piston damage from the extended tip? My understanding is that the 216 piston and head configuration doesn't have the clearance issues. I'm currently running AC 45S type in a 1950 model 216.
Last edited by Rusty_Heaps; 10/30/19 12:17 PM.
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Joined: Jan 2002
Posts: 30,701 Likes: 141
ChatMaster - 25,000
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ChatMaster - 25,000
Joined: Jan 2002
Posts: 30,701 Likes: 141 |
The "S" extended tip spark plugs can burn a hole in the top of a 235 with aluminum pistons.
The extended tip spark plugs were dsigned back in the mid 1950s. The extended tip was supposed to melt off the lead deposits from leaded gas. The lead would from on the insulator and short out the spark plug under high speed load. My experiance back then is it helped but was not perfect. That is why I was happy to see lead removed from gas.
Gene Schneider
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Joined: Mar 2017
Posts: 201 Likes: 2
Backyard Mechanic
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Backyard Mechanic
Joined: Mar 2017
Posts: 201 Likes: 2 |
Thanks Gene.As long as its safe for the 216 .
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