Designing NG Engine Exhaust Manifold

[wehber]

Hi all we are putting together some equipment packages that run off of NG Engines. We are currently not satisfied with the design of the cast iron ones currently provided to us. In I am designing a new flange/manifold for the engines. I am just curious about a few concerns. We are currently using a Vortec 4.3L GM engine.

1. Is there recommended steel used for these type of applications? It's been a while since material science. I don't want to use SS because of the difficulty welding/machining.

2. If anyone is familiar with the 4.3L GM Vortec have you seen the difficulty fitting a pipe between the two flange bolts? I currently have no room for a socket head cap screw and for a weld to be used around the pipe. Anyone had to deal with situation before?

If anyone has any recommendations please feel free to post. Thanks a lot!

 

[MechanicalChef]

The 4.3 is a pretty common engine. What have you found in your searches for the an off-the-shelf aftermarket part?

 

[wehber]

To my suprise not too much. There are a few aftermarket options for marine applications and automotive but I am creating a custom collector with short runners to then exit straight up off the collector. After talking to a materials guy here I decided to go with 14 GA Rect. ASTM A 513 Flash In Tube for the runners. The rect. shape will just allow a weld and space for socket head screws.

If anyone has any expierience building these and can verify the 14 GA will hold please let me know. FYI this engine is not exposed to the elements it is enclosed.

THX

 

[turbocohen]

GM makes several gen set manifolds that shoule work fine on the 4.3. Are you experiencing problems on cng?

 

[IceStationZebra]

As far as material goes, anything that works on a SBC will work with the 4.3L.

And I dito Turbochen - what is your actual problem? I used to work for Hyster/Yale and I believe that they had their own cast iron manifold made up for the 4.3l (and the majority are LPG).

ISZ