S spark plugs debate

rstreet

Well Known Member
Supporting Member 12
#1
Ok an opinion question for you guys and Pontiac SD guys.
A "friend" has a 62 SD that is hard to start and runs terrible. I told him to stick a set of hot plugs in it as it is a show car and never comes off idle. I have experience with the exact problem as my 62 409/409/ is only driven from the trailer to the show field as it has to be running when passing by the dignitaries showfield entrance tent to judging area. Mine got so bad a couple of years ago I stuck a set of 45 or 46 heat series long reach plugs in it but as many are aware all new plugs are S series plugs that extend the tip a mini amount into the combustion chamber. The 409 runs like a new one and the racing fuel I use has very minimal build up on the plugs when I checked compared to the massive build up on the cold correct spec plugs.
Now, back to the story. The SD owner is in a panic as his car's plugs are also only found with S series AC plugs. He is convinced that the S series plugs will hit the pistons in a SD! The plugs in it are very fouled and are not S AC's.
Opinions?
Robert
 

Don Jacks

Well Known Member
Supporting Member 2
#2
Hide an MSD 6 unit under the dash somewhere,problem solved.I doubt that the extended tip plugs that you mentioned will cause a problem unless the engine was built pushing the blue print spec's pretty hard. I would suggest properly indexing the new plugs as well.
 

rstreet

Well Known Member
Supporting Member 12
#3
Hide an MSD 6 unit under the dash somewhere,problem solved.I doubt that the extended tip plugs that you mentioned will cause a problem unless the engine was built pushing the blue print spec's pretty hard.
Don I recall many many years ago I had a deep V offshore Donzi and had Flagship Marine do the engines when they were located on Long Island. Pretty stout big blocks and I was very impressed when the MSD unit went on. I am a MSD believer!
Robert
 

wristpin

Well Known Member
#8
Check what factory plug length was. Then get NGK plugs one heat range hotter than factory plugs and with correct length threads. Then have him set timing and carb correctly.
 

Don Jacks

Well Known Member
Supporting Member 2
#12
That's just what the owners of this type of car have to put up with.Warming them up discolors the expensive coating on the manifolds,,,,,,,,,,points deduction.They never get any hotter than is necessary to get them from the trailer to the floor and back.I wouldn't want to try to put one of these cars back as a cruiser,drive to and from a local show and cruise type of car without having the budget to completely go through the engine.
 

rstreet

Well Known Member
Supporting Member 12
#13
That's just what the owners of this type of car have to put up with.Warming them up discolors the expensive coating on the manifolds,,,,,,,,,,points deduction.They never get any hotter than is necessary to get them from the trailer to the floor and back.I wouldn't want to try to put one of these cars back as a cruiser,drive to and from a local show and cruise type of car without having the budget to completely go through the engine.
Yep Don you got it! I might have 10 miles on the 62 SS since I have owned it and about a 1/4 of that on the 61 real SS car. Our trailers are set up usually beside the showfield at a national event but of course sort of hidden to the general public. The cars have to be driven past the dignitaries tent and running not towed to place them on the showfield. If there is a line of a couple of cars for what ever reason I will start and stop the engine to only move the car when necessary as can't have heat in the engine as you noted(points loss). And you are correct that 409's came with black AC plugs BUT the heat ranges are never looked at so I just use the hottest AC I can find and have fantastic luck with that approach using leaded racing gas that seems to foul colder spec plugs. The cars aren't tagged of course either as aren't used at a local drive to show. Weird world but fun when someone looks and comments at the cars as they appear as delivered by the dealer in 1961 and 1962.
The only local "drive to" show was this summer as there is an area chapter of the Late Great Chevy that apparently never got the memo that the association is no more. Anyway they have an annual event at a large area Farmer's market helping to benefit area veterans and one of the officers knows about my two cars and "strong armed" me to take them and show them. They had adjacent showfield trailer parking for those fascinating restored old tractors and farm trucks so there I was.
I was swarmed with folks at this event. I wish Tommy Nolen was able to bring a couple of his!
Robert
 
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Don Jacks

Well Known Member
Supporting Member 2
#14
My concern is that all of this cold running,short operating time is going to KILL the cylinder walls due to fuel wash.I did a HEMI several years ago that had been a show car for about 12 years.When the car was built,they had installed a new Mopar performance stroker Hemi in it.They had put maybe 500 miles on it prior to selling it.When it got too me,it smoked profusely from the tail pipes[blue smoke],you could smell the burning oil.It had massive blow by,and was way down on power.After it was torn down,the taper in the walls was so bad that it took an 040 overbore just to get the walls in shape.The owner of the car didn't believe me about the wear and taper until I showed him.When he got it back,he looped it in front of the station,very nearly wrecking the thing! I couldn't resist asking him"Where did you get the idea that you could handle 550 horsepower"?:fear2
 

rstreet

Well Known Member
Supporting Member 12
#15
Don you have caused me to possibly rethink something. No I hadn't considered oil dilution. I use 30W racing oil after all we all learned in the early 60's that was the best as our racing heros used it(Don Nicholson, Dave Strickler,Ronnie Sox,Pat Lobb and Tommy Nolen down in NASCAR) I must admit on these cars I change oil as frequently as I do Antique Battery show cars batteries. I guess I should change oil annually at end of season and probably use 30W conventional oil.
Oh you don't have to worry about me doing what your Hemi customer did. I guess the most rpms I've seen is about 2,000.
Robert
 

Don Jacks

Well Known Member
Supporting Member 2
#16
Yes,at least annually,but use a multi wt.synthetic. Synthetic oils are a lot better for staying on parts,and there by reducing the wear from fuel wash.The reason for multi wt oil is that being thinner when cold,it gets up to the needed areas faster,reducing wear as well.The guy sold that Cuda about 2 months later,it had scared him so bad.:thudSome people just can't handle good old American torque.:dunno2
 

303Radar

Well Known Member
Supporting Member 2
#17
You can also get your oil analyzed to see fuel and metal content. They cannot pin point all metal content (rockers versus cylinders versus rings) but seeing annual changes is better than nothing.
 

61BUBBLE348

Well Known Member
Supporting Member 8
#18
I am not a 100 points sort of guy, and my stuff will never be that good.
But surely the judges should either ignore heat related changes or better still add points for heat related changes, this clearly shows the engine actually works to operating temperature.
just my 2 cents worth