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I just bought a 1947 tonner flat bed - fully restored. I tried to drive it from PA to CT this weekend but the vibration above 2000 rpm was so intense that I was worried it would rattle the rebuilt 226H flathead six apart so I had it towed after about 100 miles. It has original 6v system with spark plug wires that are metal clipped to the plugs. The clips seem like maybe there is a possible reason for vibration - cross fires on the cloth covered wires or ?
Last edited by flatsoface; Nov 8, 2021 at 09:40 AM.
Reason: adding photos
What would the wrong flywheel be? From a V8? Hard to believe it would bolt on. That's a beautiful truck. The engine, while they are expensive items, are way cheaper and easier to replace than rusty panels and frames and chopped tops and other Ills that befall these old trucks. Let's figure out the vibration and be done with it. VERY nice truck btw. I'm betting on front U joint.
At home now in CT 7.50X17 Tornell 10 ply tire Could these wires be cross-firing at high speed? The carb was leaking gas down at the flange when I stopped halfway - about after 50 miles. New center u-joint New front u-joint
I too suspect a u joint. I’ve had bad u joints show themselves only at certain rpms. Maybe check out the center carrier for good measure. Driveline shop can help you. Did it vibrate when you took your foot off the gas and coasted? Or all the time? GB is right though these old flatheads are cheap and easy. Also those straight sixes are tough mills, nice to see one in a restored truck like that.
That sure is a beauty though. Very tasteful! Do you know what rear gears you have in it? Would love to see more and more details.
The final drive is quite steep - I was pushing 50 on the freeway but the vibration was so rough I had to back off. It seemed to be rpm induced, not speed induced? When I put it in neutral it went away.
the previous owner did a great job - unfortunately he passed before he could enjoy the fruits of his labor - he never was able to drive it after he became ill. I was blessed to be able to start taking care of his ride and will do my best to honor his fine work.
I stand CORRECTED on my tonner wheel comment. Was perhaps thrown by no hubcaps. I like having the correct caps on my tonner Panel and pickup, but as a flatbed I might be prone to running without. I love seeing the Full floating rear axle. The truck is gorgeous!
Thanks - I thought it was a tonner and glad to confirm with your kind observations. I am new to the pre-48 Fords and have a lot to learn.
Going to continue the vibration diagnosis with checking the spark plug wires next to see if there is proper fitment during higher rpms. They look period correct but not sure if the quality is good enough to prevent crossfire? Also, it looks like I need to torque the head down as there is a little seeping along the gasket - probably not re-torqued as the flatbed has not been run since the previous owner passed. I wish I could have talked to him about his restoration and next steps...
I'm still a bit confused if we're talking about an actual mechanical chassis/drivetrain defect-caused vibration, or an electrical induced misfire type engine shake? OP seems to keep referencing a misfire while also mentioning the word vibration, a condition most commonly considered caused by something mechanical.
One would think a miss fire or mixed plug wires would cause shaking or vibration at low speed in higher gears, I mentioned flywheel cause that truck should have the G engine, and it's an H, and ford changed flywheels almost with every engine.
