The Ford Barn

howie123 · 05-13-2012, 01:36 PM

I have been working on this for awhile. I have a Model A speedster with a stock 1928 engine, Zenith carburetor, fuel tank in the rear with electric fuel pump back by the tank. When driving under power above about 15 mph, I hear a noise which I think is coming from the exhaust. It is more like a spitting noise than a backfire and occurs every few seconds. The engine starts good, runs well at a slow, smooth idle with the GAV about 1/4 turn open after warm-up. The fuel pump was connected to the ignition switch but I changed that by running a wire from the fuse block to a switch and then to the pump without any change. I am not sure where to look next. Any help would be appreciated. Thanks. Howie

TK in LA · 05-13-2012, 04:42 PM

Sounds like you have a slight exhaust leak? Possibly from unburned gas in the pipe. Is the tail pipe original or did you make your own?

Clem Clement · 05-13-2012, 06:24 PM

How about a loose baffle inside the muffler?

howie123 · 05-13-2012, 07:28 PM

The exhaust system is a reproduction Model A unit. It bolted on without problems. Howie

1931 flamingo · 05-13-2012, 08:53 PM

What Clem said.....................

Paul in CT

40 Deluxe · 05-14-2012, 12:34 AM

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Long shot: Is the fuel pump mounted in rubber or solid to the frame or body? Is it a pulse-type pump that 'rattles' when it is pumping? Maybe you're hearing the pump as it fills the float bowl, then stops for a brief time and pumps agian when the carb needle valve opens. Try switching the pump off to see if the noise stops.

23hack · 05-14-2012, 05:12 AM

Kind of a Putter Put Put ? Yup, That's a Model A, all right !

howie123 · 05-14-2012, 07:31 PM

No, more like a ftt, ftt, ftt. Thanks for the suggestions. I will keep looking. Howie

lindy williams · 05-15-2012, 07:48 AM

Look for black soot spots around the connection between the maniford and the pipe. Drive it far enough for the soot spots to appear. If you find any soot spots(black) you have a small leak. Use muffler seal or high temp. silicone to seal the joint but be sure to follow the directions and don't start the engine for overtnight. Worked good for me.

Jim Brierley · 05-16-2012, 11:24 AM

Speedsters are supposed to make noise from the exhaust! :-)

howie123 · 06-07-2012, 07:33 PM

Well, now I'm not sure it's an exhaust noise. I checked the exhaust pipe to manifold connection which did appear to be leaking. I replaced the brass gasket with Permatex exhaust system sealer. I also reworked the rear clamp which was pulling down on the rear of the pipe. I also retorqued the manifold. The noise persists. If deffinitely sounds like it is coming from the rear but it's hard to tell which side. It could be a squeak or creak but I can't pin it down. It doesn't seem to happen under 15 mph which has me stumped. The fuel pump and lines are all secure. I have greased all major lube points. Any ideas would be appreciate. On the bright side, the car starts easily, runs smoothly and has never left me stranded. I will keep driving until I figure it out. Thanks again. Howie

Bob Johnson · 06-07-2012, 08:10 PM

I use my shop-vac to find the leaks. Connect the shop-vac hose to the outlet, exhaust, of the shop-vac. Connect the other end of the shop-vac hose to the tail pipe. Get a spray bottle with soapy water. Turn on the shop-vac and spray the suspected area with the soapy water. You should find the leak if there is one.

Bob

howie123 · 06-10-2012, 05:31 PM

Well, I definitely have a leak around the manifold. Thanks Bob for the suggestion. It was a quick and easy test. The manifold is now off the engine. I will take it to the machine shop for resurfacing. Does anyone have suggestions on the best gasket to use. The gasket that was in it was two peice with gland rings. It didn't look like there was a metal layer but hard to tell. I put it in so long ago I can't remember. Any suggestions on reassembly would be appreciated. Thanks for all the help. Howie

05-13-2012, 01:36 PM	#1
howie123 Senior Member Join Date: Jul 2010 Location: Eau Claire, WI Posts: 113	Noise from exhaust I have been working on this for awhile. I have a Model A speedster with a stock 1928 engine, Zenith carburetor, fuel tank in the rear with electric fuel pump back by the tank. When driving under power above about 15 mph, I hear a noise which I think is coming from the exhaust. It is more like a spitting noise than a backfire and occurs every few seconds. The engine starts good, runs well at a slow, smooth idle with the GAV about 1/4 turn open after warm-up. The fuel pump was connected to the ignition switch but I changed that by running a wire from the fuse block to a switch and then to the pump without any change. I am not sure where to look next. Any help would be appreciated. Thanks. Howie

05-13-2012, 04:42 PM	#2
TK in LA Senior Member Join Date: May 2010 Location: La Verne, Ca. Posts: 827	Re: Noise from exhaust Sounds like you have a slight exhaust leak? Possibly from unburned gas in the pipe. Is the tail pipe original or did you make your own?

05-13-2012, 06:24 PM	#3
Clem Clement Senior Member Join Date: May 2010 Location: Fairfax, VA Posts: 3,393	Re: Noise from exhaust How about a loose baffle inside the muffler?

05-13-2012, 07:28 PM	#4
howie123 Senior Member Join Date: Jul 2010 Location: Eau Claire, WI Posts: 113	Re: Noise from exhaust The exhaust system is a reproduction Model A unit. It bolted on without problems. Howie

05-13-2012, 08:53 PM	#5
1931 flamingo Senior Member Join Date: May 2010 Location: new britain,ct 06052 Posts: 9,390	Re: Noise from exhaust What Clem said..................... Paul in CT

05-14-2012, 12:34 AM	#6
40 Deluxe Senior Member Join Date: May 2010 Location: now Kuna, Idaho Posts: 3,779	Re: Noise from exhaust Sponsored Links (Register now to hide all advertisements) Long shot: Is the fuel pump mounted in rubber or solid to the frame or body? Is it a pulse-type pump that 'rattles' when it is pumping? Maybe you're hearing the pump as it fills the float bowl, then stops for a brief time and pumps agian when the carb needle valve opens. Try switching the pump off to see if the noise stops.

05-14-2012, 05:12 AM	#7
23hack Member Join Date: Oct 2010 Posts: 52	Re: Noise from exhaust Kind of a Putter Put Put ? Yup, That's a Model A, all right !

05-14-2012, 07:31 PM	#8
howie123 Senior Member Join Date: Jul 2010 Location: Eau Claire, WI Posts: 113	Re: Noise from exhaust No, more like a ftt, ftt, ftt. Thanks for the suggestions. I will keep looking. Howie

05-15-2012, 07:48 AM	#9
lindy williams Senior Member Join Date: May 2010 Posts: 335	Re: Noise from exhaust Look for black soot spots around the connection between the maniford and the pipe. Drive it far enough for the soot spots to appear. If you find any soot spots(black) you have a small leak. Use muffler seal or high temp. silicone to seal the joint but be sure to follow the directions and don't start the engine for overtnight. Worked good for me.

05-16-2012, 11:24 AM	#10
Jim Brierley Senior Member Join Date: Jun 2010 Location: Temecula, CA Posts: 4,088	Re: Noise from exhaust Speedsters are supposed to make noise from the exhaust! :-)

06-07-2012, 07:33 PM	#11
howie123 Senior Member Join Date: Jul 2010 Location: Eau Claire, WI Posts: 113	Re: Noise from exhaust Well, now I'm not sure it's an exhaust noise. I checked the exhaust pipe to manifold connection which did appear to be leaking. I replaced the brass gasket with Permatex exhaust system sealer. I also reworked the rear clamp which was pulling down on the rear of the pipe. I also retorqued the manifold. The noise persists. If deffinitely sounds like it is coming from the rear but it's hard to tell which side. It could be a squeak or creak but I can't pin it down. It doesn't seem to happen under 15 mph which has me stumped. The fuel pump and lines are all secure. I have greased all major lube points. Any ideas would be appreciate. On the bright side, the car starts easily, runs smoothly and has never left me stranded. I will keep driving until I figure it out. Thanks again. Howie

06-07-2012, 08:10 PM	#12
Bob Johnson Senior Member Join Date: May 2010 Location: California Posts: 979	Re: Noise from exhaust I use my shop-vac to find the leaks. Connect the shop-vac hose to the outlet, exhaust, of the shop-vac. Connect the other end of the shop-vac hose to the tail pipe. Get a spray bottle with soapy water. Turn on the shop-vac and spray the suspected area with the soapy water. You should find the leak if there is one. Bob

06-10-2012, 05:31 PM	#13
howie123 Senior Member Join Date: Jul 2010 Location: Eau Claire, WI Posts: 113	Re: Noise from exhaust Well, I definitely have a leak around the manifold. Thanks Bob for the suggestion. It was a quick and easy test. The manifold is now off the engine. I will take it to the machine shop for resurfacing. Does anyone have suggestions on the best gasket to use. The gasket that was in it was two peice with gland rings. It didn't look like there was a metal layer but hard to tell. I put it in so long ago I can't remember. Any suggestions on reassembly would be appreciated. Thanks for all the help. Howie