Information on exhaust manifolds !!!

[Brits-RV]

Hi,

Can anyone give me some information on exhaust manifolds?

I have a 2000 Chevy 7.4 Vortec engine in my Damon Motorhome, I have a fine hairline crack on the drivers side of the exhaust manifold.  Can anyone tell me if its possible to have it welded or is that false economy?  Is it better to replace the manifold?  If so can you tell me whom I can contact to get a replacement part that will ship to the UK.

Many thanks,  Mick

 

[Gary RV_Wizard]

Stress cracks are a fairly common problem in this engine's manifolds.  I suspect it can be welded but likely will re-appear after awhile. Don't know whether "awhile" is months or years, though. You have to weigh labor costs to remove, weld &  and re-install the manifold for a possibly short term fix versus the cost of a new manifold.  The labor to remove/replac eis the same in either case and may be the major cost involved. 

In the US, any Chevrolet dealer can get you replacement parts and there must be one somewhere who ships parts to the UK. There are also aftermarket parts suppliers.  But if replacing a manifold I would be inclined to get tuned headers instead, for a probably perfromance and maybe fuel economy boost.  Companies like Banks, Thorley & Gibson produce some fine exhaust header (manifold) products for the 7.4L (454 cubic inch) engine.  You can probably buy a pair of headers for about the price of one factory-replacement manifold.

Here's a link to a place that handles new and re-conditioned manifolds. Don't know if they could ship to the UK, but you could email and ask.  http://www.stevensparts.com/INDEX.htm

 

[JohnSandyWhite]

Hi Brits-RV (Mike). As has been mentioned. Hot exhausts are a regular problem on Chevy's and on Ford's, causing Manifold leaks and exhaust cracks. You should be able to get them repaired, much cheaper than having to buy New. I am considering having some New Stainless Steel one's made to measure that would be a cheaper solution than importing from the USA. 

 

[Brits-RV]

Hi RV Roamer,

Just phoned the dealer of the website you gave me, he had an exhaust manifold but does not ship to the UK.  Till I find a supplier that can ship one to the UK I'm going to have this one welded.

THanks for your help Mick

 

[Scoundrel]

Hi,

Can anyone give me some information on exhaust manifolds?

I have a 2000 Chevy 7.4 Vortec engine in my Damon Motorhome, I have a fine hairline crack on the drivers side of the exhaust manifold.? Can anyone tell me if its possible to have it welded or is that false economy?? Is it better to replace the manifold?? If so can you tell me whom I can contact to get a replacement part that will ship to the UK.

Many thanks,? Mick

I just had mine resurfaced because they were leaking but not cracked. I found a guy on e-bay of all places that sold them for around $69.00 (American) That beats the price and a dealer by far.

Check this Item number: 8033591417 on e-bay. I suggest you contact him via e-mail for the cost of replacing both including shipping. If you are going to the trouble to replace one side you might as well replace both.

 

 

[JohnSandyWhite]

Thanks for that Scoundrel. Wish I had kdnown about this while I was in the USA. I was quoted $1300 to change the passenger side Manifold. 

 

[John From Detroit]

Can it be welded,,,, YES, there is a company that makes welding rods specially for welding cast iron engine parts, they are expensive, it has been nearly 30 years since I heard their name (Somethign like Tec-Tek or Tec-Tic please don't quote me)

Finding a welding shop to do it may be an issue

Better option for many reasons is a company called BANKS, there should be a Banks power kit for your engine, (I know there is for my 8.1 Vortec) which though expensive, will make a serious dent in the income of the folks down at the gas station (that is it will increase your engine's performance, and thus reduce your fuel consumption) since you got to do most of the labor of instalation anyway, why not upgrade at the same time?

 

[Scoundrel]

Thanks for that Scoundrel. Wish I had known about this while I was in the USA. I was quoted $1300 to change the passenger side Manifold.?

If you have the aptitude you may want to purchase the manifolds and put them in yourself.....Should save yourself about $1000.

When I had mine resurfaced it cost me $867.00 and the vast majority was labor!

The Banks system was quoted at $3000 installed. It would take allot of gas savings to make the change cost effective IMO. 

 

[Brits-RV]

Hi,

Have located manifold @ stevensparts.com, part no 1728L,Casting no 12550881. Which is exactually the same casting no on my manifold @$119. but do not ship to the UK. Have also located one at Directauto.com, the part no is the same but the casting no is different 12553149. @$80. and will ship, to the Uk. Both these parts have been advertised for Surburban truck. Both these suppliers seem to think that they will fit, do we go by the part number or the casting no.  Going by the pictures they both look the same as mine. Does anyone know any other supplier I could get in touch with?

Mick.

 

[Gary RV_Wizard]

Same part number indicates a part that fits and is interchangeable. A different casting number indicates it was cast from a different mold and implies a different design. How different, is the question, and what is the significance of the difference, if any? 

The casting numbers refer to a blank casting prior to machining, so even parts with the same casting number can still be different because of differences in machining after the casting is made.  There probably isn't much machining on an exhaust manifold, though - just some smoothing/polishing on the gasket surfaces.

There is a website called the American Auto Casting Number Club (no kidding!) that might be able to help. See http://www.aacncclub.com/

As an alternative you can have a US vendor ship your part to a shipping agent in the US and then the agent ships to you in the UK.  I have no idea if the agent fees would make this unreasonable or not.

 

[dsl4us]

How have the manifolds been holding up on the 8.1L GM gas engines?
Those manifolds were supposed to be made of a cast stainless/iron mix of some form to help with warping and cracking under heavy use.

If they are holding up better than the standard cast units that would be another option. Those would have a different casting # but might have the same exhaust flange locations.