Les - Need Your Help

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Les,

Order No. 120771, Sierra Supply Port Side Exhaust Manifold for 1987 OMC 5.7L, OMC Part Number 912442, BoatFix Part Number 47-1903.

Received today. Upon inspection, the passages in the manifold to riser mating surface do not line up with the passages in either the OEM riser nor the gasket supplied with the manifold. The Sierra gasket matches the OEM riser and old manifold perfectly. However there is less than a 50% overlap on the passages between the surfaces on the OEM riser and the gasket with the surfaces on the new manifold. This is going to facilitate corrosion on the exposed faces, and quite possibly allow water intrusion into the exhaust passage. The manifold appears to be poorly cast in this area. Perhaps it is just a bad part. I would like to replace this unit, however I need someone to do a visual inspection prior to shipping to verify that the casting matches and aligns with the gasket. If that's not possible, or if all the available parts exhibit the same misalignment, I'll need to return the part.

Photos follow:

Manifold1.JPG


Manifold2.JPG


Manifold3.JPG


I have filed a help desk ticket. Any help appreciated.

Edit: Noticed you also carry the Barr Manifold (109-OMC1912442 MANIFOLD-OMC V8 PORT
Barr Manifolds). If it could be inspected to avoid the same problem, I'd be inclined to purchase the Barr.

Thanks,
 
Flip that gasket over and you'll be fine. :)
I'd be more worried about the rust you have in there !!
 
Unfortunately, the gasket is symetrical, doesn't matter which way it's on, same problem. And that's not rust, it's reflection from the flash (that photo is the new manifold, painted black). But thanks for the reply...
 
From looking at the photos I'm not sure that replacement manifold mating surface is cast well enough to be worth a porting job. I'd replace it, too.
 
Gaskets never match perfectly but this is a poor example IMO. There is poor surface finishing, pits, in some areas and two narrow areas. Lets see what Charlie says but that doesent look like a good casting to me.
 
I don't know much about marine stuffs but I wouldn't use it, very poor surface matting.
 
Thanks all, nice to know I'm not the only one who sees a problem here. The purpose of showing the gasket alignment was more to illustrate the misalignment between the riser and manifold as opposed to how "perfectly" the gasket fit. Whereas the wall thickness of the passage walls is about 5/16" on both parts, by the time you put them together there is less than 1/8" common bearing surface, and that is the only portion that creates the seal and seperation between the passages, essentially reducing the life expectancy of the connection by more than half. There is a 2003 5.7L sitting on an engine stand next to mine at the shop. Suffered a riser/manifold seal problem similar to this discussion. Not a pretty sight!

BTW, please don't take this as a knock on BoatFix. This is a Sierra problem. I buy all my parts from BF when possible, and have been very pleased with customer service in the past. Figured they'd be my best chance for getting this resolved.
 
Looks like flashing on the casting - we'll get it resolved for you monday.
 
Once again, BoatFix to the rescue!

No response to me from Sierra/Teleflex customer service, however talked to Mike at BoatFix customer service this morning. Sending pre-paid shipping for the return and sending advanced replacement (Barr) for defective Sierra manifold. Again, many thanks to Les and his folks at BoatFix.
 
Got here a bit late, but yeah, that is a bad casting. Excessive porosity in the casting is showing up in the machined surface.

I've never seen a bad Sierra casting before so I guess it's a 'made in china' or worse.
 
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