The Ford Barn - View Single Post - 1941 convertible backfire to carb, with video

Mart · 10-09-2020, 04:09 AM

Do you think you might have a lazy valve spring, or intermittently sticking valve? Swapping all the parts from a known good car eliminates all of those parts. All that is left is the base engine unit.

It drives ok if driven slowly or accelerating gently.

The only thing I can think of would be to put as many gentle miles as possible on it and see if it improves. You could try adding something to the fuel or directly down the carb, a locally available version of Marvel Mystery Oil. (I'd try auto trans fluid straight down the carb. be prepared for lots of smoke.)

If it is a sticking valve it will free up with use. It may have gone tight during the time taken during shipping and may have been ok when the previous owner had it. He may have only ever driven it gently and slowly.

Other than that I'm completely stumped.

Mart.

10-09-2020, 04:09 AM	#17
Mart Senior Member Join Date: May 2010 Location: Solihull, England. Posts: 8,754	Re: 1941 convertible backfire to carb, with video Do you think you might have a lazy valve spring, or intermittently sticking valve? Swapping all the parts from a known good car eliminates all of those parts. All that is left is the base engine unit. It drives ok if driven slowly or accelerating gently. The only thing I can think of would be to put as many gentle miles as possible on it and see if it improves. You could try adding something to the fuel or directly down the carb, a locally available version of Marvel Mystery Oil. (I'd try auto trans fluid straight down the carb. be prepared for lots of smoke.) If it is a sticking valve it will free up with use. It may have gone tight during the time taken during shipping and may have been ok when the previous owner had it. He may have only ever driven it gently and slowly. Other than that I'm completely stumped. Mart.