The Stovebolt Site Forums The Shop Area Engine Shop Fenton headers and exhaust pipes ?

I have an urge to go to Fenton headers but am wondering about the pipes. I see that Patricks sells a set of Stainless pipes and muffler for a fancy price but I'm not that interested in paying that much. Questions:

Does anyone sell pre-bent reg'lar steel pipes w/o muffler ... I wanna use twin glass packs

Can you use the original exhaust pipe and just add a second one ? Don't see why not.

Is there really a need to provide exhaust or water heat to the intake since it sits right over the headers ?

Yeah the heat is best set up. I'm lucky as a local muffler guy here in Central Cal still splits stock exhaust and has been at it for 40 plus years. So that's the cheapest and also good way to go IF you can find the experienced welder. Also this way you can use the original pipe and then add the second one.

I have Fentons on a 55 1st series 3100 with the original 235. I am also lucky to have a good muffler shop close that bent both new pipes back from the headers. I wanted to hear the exhaust so I had them use some pretty much straight through small glass packs. I love the sound until it hits around 2500 rpm, then it takes on an unplesent rattling sound. No big deal since I usually keep it under 2500 rpm anyway. I have been told that an X pipe would solve this problem. Just a thought. I am sure different mufflers would also help.

Yeah, I had planned on an X pipe. I like glass packs too.

I know where Turlock is...I'm in grass valley. Do you mean that this guy made dual headers out of the original exhaust manifold ? Might be worth a drive down for a couple days

About using hot water to warm up the intake, i am confused also. I read article from Tom from the stovebolt engine company and he says yes. I talked to Patrick from Patricks antique cars and trucks and he says no. Maybe its because of where i live. I live in Las Vegas where it gets hot but in the winter sometimes it gets cold believe it or not. Where you live might be a factor to consider. My 2 cents

You need to heat the intake with either coolant-water or exhaust heat (my preference - I have used both methods) - no matter where you live.

The vaporization of gasoline in the carburetor causes cooling (caused by the latent heat of vaporization). This cooling in/near the intake manifold will result is condensation of the vaporized gasoline.

a general discussion about latent heat of vaporization

put the mufflers further back rather than closer to the engine, The fella that did mine put them quite close to the engine, and it was horribly obnoxious. I eventually put a second set of magnaflows after the rearend, now it is just about too quiet with it being loudest at low speeds, and as I increase rpm's it seems to acutally quiet down. It was loud enough however to set off the car alarm in the car next to me when I started it. My theory is if you place the mufflers further back they knock the sound waves down just before they exit. Keep in mind this is just my theory, I would have to take the first set out to make sure and I just ain't that concerned. One other note, the kid across the street did the welding for me, on the second set of mufflers, and brand new out of the box he had to weld up the magnaflows where they missed in the factory, and they weren't exactly cheap. He did the work for a very reasonable cost and was about the only thing I have had done on the truck that I was happy with the first time around.

Very nice article Professor, thanks for posting that. Hope that will quill the flow of
naysayers the next time the subject comes up as to the importance of maintaining a
working exhaust manifold heat control valve.

Denny Graham
Sandwich, IL

The only other clear on-line explanations for that necessity are in reference to airplane engines (same principle, but I thought people would not understand that physics is physics).

Along that same line of thought, Denny:

What is your opinion regarding the thought of removing the entire exhaust-manifold heat control valve from the standard manifold combination? That topic/suggestion has arisen recently.

GM article from 1954 regarding the
235 Corvette Exhaust Manifold Heat Control Valve.

The basic exhaust manifold design consists of two outlets instead of one,divided by an internal wall at the rear of the heat box.

When using the manifold heat control valve, the exhaust gases from the front three cylinders are directed to the heat valve in the heat box.

Part of these gases are then directed by the valve to the intake manifold to preheat the incoming charge during warm-up. This portion of the gases then rejoins the original stream to be expelled through the front exhaust pipe, right hand muffer and tail pipe. The exhaust gases from the rear three cylinders are carried away by the rear outlet and expelled through the left hand tail pipe.

However, it has been determined that manifold heat control valve operation is neither necessary nor desirable under normal temperature and operating conditions encountered with the Corvette.

Consequently a manifold heat shield has been installed between the exhaust and intake manifolds to direct exhaust gases from the front three cylinders away from the intake manifold, thus eliminating preheating of the incoming charge.

Also, the heat control valve spring has been reversed so as to hold the valve continuosly in a "heat-off" position.

If preheating of the incoming charge is desired for extreme cold weather operation, it will be necessary to remove the heat shield and reverse the heat control valve spring.

"Also, the heat control valve spring has been reversed so as to hold the valve continuosly in a "heat-off" position."

So, do you think the valve should ever be completely removed from the exhaust manifold on a standard vehicle (because that would always be "heat-on")?