Advice on Hedman Headers?

[Clyde9]

From: firstonthebadlist1  (Original Message)    
Sent: 2/12/2006 9:06 PM

Has anyone experience with heavy duty headers listed for class A and C motor homes from Hedman. I'm interested if this solved the exhaust leaks long term and any other experiences you had with them. Thanks



From: Member_Administrator   
Sent: 2/14/2006 9:55 AM

I don't think the headers in themselves are a cure to the exhaust manifold leaks.  You can cure that without having to go to headers and the additional complications they create (see Headers in the Message Search).  What has been proven to cure the leaks, at much less expense and additional considerations, are copper gaskets (see "copper" and "Exhaust Manifold" in the Message Search).  Read these posts thoroughly before deciding on getting headers and what you are expecting from them, there's a lot of good info in these posts!  They may be worth it... or a waste of money, depending on your application, the specific qualities of the headers, and the safety/mechanical issues presented.

- Sob



From: 911rs1   
Sent: 4/18/2006 4:31 AM

There is a company on ebay that sells heavy duty stainless steel shorty headers for under or at $200 delivered with thick flanges and all gaskets and hardware. I think their company is called SS something I have installed two pairs on vehicles I have using permatex orange high heat sealer. Don't recall the number. One pair I added lock washers on the header bolts since they where not recessed. The exhaust pipe bolts just like the factory with no gasket or donut required. I am currently looking to buy a Winnie with a 440 and will be retro fitting a set for it. They are polished finish and look real good in the engine bay. Check and make sure you have proper clearances to fit. Shorties are usually easier to fit since they don't take up any room down low. FYI



From: PhÃ¥rÃ¥oh   
Sent: 4/18/2006 5:05 AM

Also, a bit of advice before deciding to install headers on the 440 in a Class A:

Members have fried wires, vaporized fuel, melted brake lines, and suffered other nightmarish problems due to the immense heat given off by headers and their very close proximity to these items.

Remember, we are talking RVs rather than cars.  Not to say it can't be done, but there must be major consideration given to providing adequate heat shielding.

Headers on a Class C mini seem to be a pretty straight forward add-on since it's the same as putting them on a van.



From: 911rs1   
Sent: 4/18/2006 6:53 AM

I agree. I will either install heat shields or just wrap the headers. If there is a will there is a way.



From: denisondc   
Sent: 4/18/2006 7:46 AM

To avoid vapor lock I installed simple heat shields in locations where the exhaust manifolds, exhaust pipes, and muffler were radiating heat into the fuel lines, and auxillary fuel tank. If you look in my picture album:
denisons73d22tindian, you can see where I put the shields on my 413-1 engine.
I bought my Winnie in 1991 with a cracked drivers side exhaust manifold, and replaced it with a new one. That was at almost 50,000 miles. Last fall I noticed a very slight exhaust gasket leak from the drivers side when I first started it, though the sound went away in less than a minute. I would not have heard a leak that small except that when the RV has been unused for a few weeks, I ALWAYS remove the engine cover to start it.
Sometime in the new thousand miles I will remove the manifold and install a new gasket, and probably do the other side for assurance. I used the regular gaskets - metal skin with mineral fibers in the middle. Changing them every 15 years is okay with me.
And since that manifold was new when I put it in, and has probably warped a few -mils-, I will measure it and maybe have it milled flat.



From: denisondc   
Sent: 4/18/2006 7:52 AM

My Winnie now has 103,000 miles on it. The curbside exh. manifold is original, but I had it milled flat after it warped in 1993 and the gasket burned out. Still, I think the OEM type manifolds hold up well.



From: Im-still-Lefty   
Sent: 4/18/2006 11:12 AM

I have an '83 Chevy C-10 pick-up that I rebuilt the engine in back in '99. At the time, I bored it out .030" and put in a 400 crank, making a 383 stroker. Mine was built strictly for heavy-duty towing as we had a travel trailer then that weighed about 7,500lbs.. I put Hedman Hedders on it, and I have not had to remove them since. The flange gaskets have never leaked, although I have had to replace the collector gaskets about 4 times. Mine are not wrapped, and I have always used special extreme-heat boots on my plug wires. I have only burned one wire, when one fell out of the wire holder. And a heat-shield on the starter. Also, the stock fuel line ran underneath the manifolds, and had to be re-routed away. I cannot tell that they added any additional under hood heat, but again, mine is a pick-up, and has plenty of airflow and room. Wrapping headers will keep the heat in the headers, and also can help mileage due to the higher exhaust energy, at the expense of the life expectancy of the headers. The higher heat causes the headers to burn out quicker, and can cause warpage problems. I think another issue with a big-block & Class A would be the close proximity of the master cyl. on the drivers side. The additional heat could cause the master cyl. to get so hot, the fluid could boil.
The stock cast manifolds are very durable, and any warpage usually is the result of other problems. The most common being: Lean carb. from vacuum leaks, restricted exhaust from collapsed mufflers or damaged pipes. incorrect timing, or cooling problems causing over-heating. replacing the manifolds without fixing the underlying cause, will not make the problem go away. The warped manifolds are only a symptom, not the disease. Warped manifolds can usually be milled to ensure flatness after other repairs have been made.
As for quality, Hedman Headers are top-notch. but, I wouldn't recommend using them in a Class A due to the closed-in nature of the engine bay. and as mentioned, the very close proximity of several critical components (such as brakes).



From: denisondc   
Sent: 4/18/2006 11:45 AM

The dodge motor home chassis always came with a heat shield between the drivers side exhaust manifold and the master cylinder, at least the 413s and 440s did.
Mine came without one, and from the ones I saw in salvage yards, I could see that it would be a bear to remove and replace. I made up my own heat shield for that area, that slides on in two sections. The master cylinder and brakes lines, a wiring harness, the speedometer cable, and possibly the handbrake cable, all are protected by that heat shield. But don't be surprised if its missing.



From: ClydesdaleKevin   
Sent: 6/24/2006 7:26 PM

I think the Ark has a cracked or slightly warped exhaust manifold on the driver's side.  I had a sizable leak on the driver's side where the manifold met the down pipe (4 hole flange) since a stud was busted...exhaust pressure blew out the gasket at the flange, and it was making a lot of noise.  I drilled it out and tapped the manifold...I had to do the same for another stud that broke when I removed the down-pipe...and used through-bolts with a new gasket.

Most of the noise, probably 90% of it, went away...but there is still a cough and sputter from the driver's side...its nothing I can feel with my fingers (no hot wind...lol), and I can't find any tell-tale signs (no white marks, etc), and the bolts are all properly torqued holding the manifold to the head...but the noise is still there, though now in the background.  If I ever have to remove the heads to do a head gasket, etc., I'll take it to a machine shop, have it milled/checked for cracks, and replace the gasket...for now its just a slight annoyance, since I can't hear it anymore with the engine cover in place.

Kev