Perhaps Another "Dumb" Question
 

I've blocked off the heat risers on my 59AB and love the "rapping" sound out the tail pipes. I have Red's Headers and Smithy mufflers.

Does blocking the heat risers also cause a chugging type sound under load...almost like an exhaust leak.

I've checked for leaks and can't find anything abnormal in the exhaust plumbing.

Has anyone else experienced this or do I need to dig deeper??:rolleyes::rolleyes:

Re: Perhaps Another "Dumb" Question
 

Done a compression test lately?

Re: Perhaps Another "Dumb" Question
 

The short answer is no, unless something else lead to a leak in the process. How did you block them?

Re: Perhaps Another "Dumb" Question
 

Wheatstalk pennies in the heat riser holes in the block. Wheatstalk for the alloy metal.

Re: Perhaps Another "Dumb" Question
 

My exhaust sounds different with the heat risers blocked too. I have been driving it that way a few years.

Re: Perhaps Another "Dumb" Question
 

I blocked them with a piece of thin stainless on each side, held in place by the intake manifold gasket.

Re: Perhaps Another "Dumb" Question
 

I would check to make sure there are no leaks around that area on the intake manifold, but it should be fine.

I like to old Hot Rod wheat penny method, it should be your birth year.

Re: Perhaps Another "Dumb" Question
 

Thanks to all who replied....and I could have used two 1943 pennies...they are steel and are now "collector's items"!!

After checking intake manifold and header flange gaskets, turns out it was a small exhaust leak where the left connector pipe attached to the header....just a pin hole I couldn't see until I took the old pipe off. A new left connector pipe and a new Smithy muffler, installed with JB Weld muffler cement cured the noise.

As someone said here on another thread in the last few days, taking these things off once installed is a real "bear"

Great service from Victor and Liz at Red's!!! Much appreciated!!!

Re: Perhaps Another "Dumb" Question
 

I have totally forgot what the benefit of the pennies was and does it need to steel pennies ?

Re: Perhaps Another "Dumb" Question
 

Cool coupe, long story here. Heat risers help vaporize the fuel when the engine is cold. Makes for a quicker warmup. A side effect of these heat risers is that they connect the two exhaust systems directly, going through the intake manifold, thereby buffering each other’s noise level. Pennies are sized perfectly to tap into the holes in the block under the manifold, and don’t interfere with the gasket, as is possible if shim stock is used. Wheatstalk pennies are of a good alloy for the purpose, not causing electrolysis. Guys used to select pennies from the year of their birth for the heck of it, and the 1943 steel pennies should work as well. Modern pennies not so well, not a good alloy. Two reasons for blocking heat risers. One, the flathead exhaust rap is accentuated, which brings a smile to my face, and two, blocking these ports helps dump heat directly to the exhaust rather than saturating the manifold with excess heat.

Re: Perhaps Another "Dumb" Question
 

I like "Dumb Questions"; they seem to be the only kind I can answer.

Re: Perhaps Another "Dumb" Question
 

Sorry, but personally I would not do that to my engine.

Re: Perhaps Another "Dumb" Question
 

Thanks Alan, I had heard of this years ago but thought someone was just joking with me.
Flatjack. Is there a reason you wouldn't do that to your engine ? Just wondering what the downside is. Moe

Re: Perhaps Another "Dumb" Question
 

I don't recommend this either, probably runs rich in cruise?? Flatheads sound great!

Re: Perhaps Another "Dumb" Question
 

I’d like to keep the intake cool, but don’t need a raspy sound from the exhaust. Maybe I’ll try some pennies though and see how it goes.


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Re: Perhaps Another "Dumb" Question
 

The heat helps to keep the fuel atomized for better fuel distribution and makes for a better running, more efficient engine.

Re: Perhaps Another "Dumb" Question
 

That's true in cold weather, but in hot weather the intake charge does well when cooled. I don't drive in cold weather.