1946 ford with one dead cylinder

moose83

moose83

Junior Member
Need advise on ford flat head I have a cylinder that has a constant miss.I have checked the compression on all 8 cylinders.1@110 2@110 3@95 4@115 5@120 6@120 7@115 8 @110. 3 is the one causing issues I can pull the plug wire off with it running and no change in sound or how it runs. I have put a vacum gauge on it and it reads at 25 with a constant flutter of the needle. I know the valves are free because I have hade the head off and intake the bores did not look bad did have a ridge on the top of the cylinder but other than that looked fine don’t know if a valve is just not sealing or weak valve spring or just bad piston ring. The engine other than running on 7 cylinders does not run bad does not smoke when running.
 
IMHO it should run ok and on all cylinders with #3 being a bit weaker, but it should fire. Have you checked for spark on #3? Or maybe #3 spark plug is oil fouled or has a bad plug wire.
 
If you are getting good spark TO the plug, I'd suggest you change the plug.
If you are not getting good spark, then wire, inner cap, rotor???
 
I agree, when I was young, compression figures like that were a good reason to buy the car. I think that if you can find and fix what's actually causing it to run sourly, it may come back.
 
I'll never forget this. Way back in high school we had a flathead that had the same problem you have. Teacher said 'lets play detective' . Us kids smoked our brains finding nothing wrong its impossible. After all said and done, teacher said the problem is right in front of your nose -open your eyes! We all gave up. The teacher made lines inside the dist. cap with a lead pencil!! gotta be kidding Now thats real teaching.
 
Thanks for all the comments I am going to take the crab cap off and look at it for cracks and carbon. I hope it is something simple like that.
 
The issue is solved I think it was carbon in the cap took it off blew it out cleaned plug and wire. The tone of the engine is better and runs a lot smoother something simple.
 
Tubman has it right. A little flame in the chamber will help burn off the unburnt oil and fuel around the compression ring and things should get even better. Tim
 
Yes the compression came up a little sure sounds a lot better.I did add a little MMO to the gas. I am just glad the issue was solved. Now to move on to the body work.
 
And while you're at it, dump some MMO in the oil too. After sitting a long time this stuff really gets things moving again. Sounds like you have a real nice project!
 
You must log in or register to reply here.
Back
Top