60 bird with hopping fenders

[Royce Richmond]

I have two questions. I have a 60 conv. which used to be a 430 now a 390. Any ideas about the cause of a pretty severe wheel hop at 40 to 50 MPH. It is smooth up to 40 and smooths out after 50mph. Its driving me nuts. the fenders bounce up and down, no shimmy. I have replaced upper and lower ball joints, wheels and tires, and coil springs.
Second question, what would cause turning in the air/fuel mixture screws on the carb makes the engine run faster. The engine idles smooth with the screws turned out only 3/4 turn.
Thanks Royce

[RAVEN]

Royce, I"m not an active reader of the 58/60 section, but I do take time every so often to view. With regards to your second question about engine speed vs needle settings. In your post you state that the rpm s climb as you ajust the screws, from this I assume in a closing fashion, or a "leaning out" of the air/fuel ratio. By "leaning out" the engine the speed will increase to the point of eventual no fuel and motor stalling. In a simple way think of it as an acetylean torch, the flame, in a non cut state is yellow/blue and semi quiet, but when you squeeze the trigger the flame turns a semi clear colour and begins to roar. This is a leaning out of the flame and begins to cut/blow the material being cut. Increased oxygen is being introduced allowing a more active burn rate of the fuel and more effective power so to speak or increased rpm s. Your carb just maybe happy providing the air/fuel ratio at 3/4 turns vs the old "rough" setting of 1 1/2 turns. In my past, every good carb man I found would set up a unit by trial and error (sound of motor,vs exhaust smell and smoke colour vs engine rpm vs rad temps vs all or any variables.) In todays world of injection, our motors have sensors which read all these perameters and adjust themselves, for combusion/fuel ratios. And tailpipe tests for NOX to see if everything is working right. Hope I have given you some things to think about, and answered your question.

[Walt711]

My '57 has that same wheel hop. It feels like the car will shake apart. I never found the cause. The only thing I could think of was to make sure the wheels were in balance, which they are. I have new shocks but I don't know how old my joints and bushings are. I'm looking forward to hearing some ideas on the cause of the wheel hop.

[Royce Richmond]

Hello all, My wheel hop is no more. I measured the ride height at 29 inches and the correct height is 26 to 26 1/2 inches. I removed the springs and cut a coil off which lowered the front down to 26 inches and now I have no wheel hop. I do have new coker radials that are not too round and have to be sent back. Now without the fender hop I can feel in the seat and steering wheel a small amount of vibration.
Royce (a happy man)