The Stovebolt Site Forums The Shop Area Engine Shop Spark plugs on GMC 54, 56 and Chevrolet 51 and 59 engines

Would anybody may help me regarding the right spark plug and gap for it on these engines?. They all are on pick ups I am restoring. Does it make any sense to use an extension to the spark plug when heavy blue smoke shows up at the tail pipe?

Hey man whats up, well that sucks a little doesnt it.First off what truck do you have and secondly what engine is on it?

This blue smoke "shows up" under what circumstances? How much smoke are we talking about here; a puff on takeoff or a James Bond accessory? Has this truck been sitting for the past decade or has it just started doing this after years of use/abuse?

Common "blue smoke" culprits are valve stem seals and rings. If that's where the problem lies, nothing you do to the plugs is going to help much.

Lazy: They have an extension that is called "foulers" that screw in and then you screw your sparkplug into that. The only thing it does is help with not changing plugs so often. They work I have one in a cylinder on my 88 350. Sound like the above post: rings or seals. Nothing will help until you do that. popcorn The Truth is Out There (Good Luck)

AC-44 or 46. Gap= .035"

The only reason I'd try non-foulers is if the engine were fouling-up a plug very quickly.

I'd try a higher heat-range plug first.
If the hotter plugs foul, then the engine is probably using so much oil that it needs to be overhauled.
That's been my experience anyhow, with 216s and 235s.

You'll find GMC engine tune up specs on my website under "technical stuff", then click on Tune Up Specs

http://www.oldgmctrucks.com/photos/EngineTuneUp_Pg3G.gif

Thanks a lot folks for your answers. I am a new comer (You may have already figured out by now)on this field so I would try to have some rational answers for you:
BIGGY.-GMC 54 Pick up half ton. no idea reagrding engine size.
HEDGEHOG.-The smoke comes from the GMC 54, just recently purchased after being sited for at least eight years. Smoke came out when I started after those eight years. I changed oil previously. After some time running, about 20 minutes the engine died after a fowl. I could not restart it.
POPCORN.- It has already a fowler on every spark plug.
If in need of rings/ seals, where can I get them?
FRANK54.- GMC54 currently has Champion J18C, no idea on the others. Somebody also told me to use Autolite 333 or so. I may use AC44 or 46 as per your comment. What may be be a hotter number?.
OLDCARKOOK.- Thanks a lot for the manual copies, it solves some of my current questions. I will spend some time reading it.

If it's a GMC engine, the first 3 digits of the serial number should reveal the engine. Serial number is on a machined boss just aft of the distributor. Should start with 228, 248, 270 or 302.
On AC plugs, the higher the number, the hotter the plug. Plug foulers are made to be used only on the plugs that are fouling, the can reduce fouling, but cost you some power from incomplete combustion.