new guy with two flathead questions, if I'm allowed

[danny1940]

Justpassinthru, I decided to do the thread cut and unshroud the plug area. My thinking is that at 7/16 thread length, there might be a better selection of plugs to use. Of course I have not researched this just a gut feeling. I currently use NGK B6-L, thinking of going a little cooler with the B4-L's at 7/16 length. I really don't know what the best method is but I feel good about getting back into the motor after a lot of years of running it with very little work other than tune ups and oil changes. I'm anxious to see how it all goes together. Dan

[KGS]

Dan, I believe the NGK B4L is a hotter plug than the
B6L. I don't know if there is a cooler plug than the B6L.
Good looking '40 BTW. Ken(ex Malvernite)

[28jalopy]

Hi Dan! I also had a problem with the thread leingth on the plugs being to short on my 48 Weiand FullRace heads on my flatty. Some Great-verry seasoned gentalmen I met told me to use a Bosch W8AC plug for street and a W7AC for race with the help of indexing washers from summit racing to fine tune the exact depth and position of the electrode at .03 gap for my elevation of near 1 mile. Its goofy that the plugs are origonaly for a VW bug and Bus, But if you think about it they are industrial air cooled motors and a flatty isnt the coolest running motor around. It helped me maybe it might work for you also.

[Mike in AZ]

it's a flathead...lol...therefore, this forum works....doesn't have to be a stock flathead, etc....good luck with your fixes....Mike

[George/Maine]

I have alway heard pinging is from cheap gas.
Well i,m cheap.I,m running a 1951 Mecury .060 over with EAC heads and when going up hill ping bad just let off and live with it.Save your money for gas.I'm running a c4 with 2.78 gears when hitting the hills i,m below 2k stock dist. 2k = 55 mph.

[ford38v8]

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George, No flathead having less than 7 1/2 x 1 compression ratio should ping on regular gas. Your distributor is seriously retarded. Even if your vacuum brake is non functional, it should not ping.

The difference between regular and high octane gas is that the high octane contains a flame retardant, to allow combustion to continue through the full combustion stroke. A high compression engine will require high octane, but your Ford shoiuld not. In fact, the result of using high octane in a flat motor is likely to raise the operating temperature a bit, which is of course a no-no for flatties!

[flatjack9]

I doubt the distributor is seriously retarded if the engine pings. In fact it could be overadvanced. Also the late model Merc does not have a vacuum brake. I would be leary of an engine that pings a lot. Detonation can lead to pre ignition which can lead to a burned piston. I think I'd spring for a higher octane fuel if the engine is timed properly.

[danny1940]

I though I posted about the results of my engine/head work, guess I did not. I did the relief around the plugs, put in my re-curved distributor by Bubba buttoned it up and drove it to York. Seat of pants the 40 ran great. Best it's ever been. The ping was not apparent. I think due to the engine being more efficient, I'm hearing more noise at the headers and plan to change out the header gaskets as I might have a small leak. Otherwise the car is great. All the advice given was well taken and very helpful. I've got a set of Porters to put on and I still have not installed the heat spacers I got at York. These are the aluminum/fiber type D. Spadaro is selling.

I've been away from this group for a few weeks. I recently picked up a 56 Ford 2dr Ranch Wagon in very good original condition. Only 61,000 miles, auto, 292. I've been trying to learn the Y block. I wanted the 56 as a family type cruiser that I could also put my dogs in. I'm in Ford heaven at the moment. Between the 40 and the 56, I personally am more than satisfied. So I'll be jumping between two forums. Thanks again for the advice. See you on the street. Dan