Rotten Bat Wings; Water Injected Headers?

[Lou C]

Dennis @ Moore Performance referred me to GLM directly for warranty. I sent them some pics, and they are going to send me another manifold, and throw in the one rubber coupler (elbow to U-pipe) that I need also. I think it's about a $25 part. I guess that'll work. Just ready to get it done and out on the water again.

I found out something I didn't know about the V6 during this too - the exhaust ports aren't evenly spaced, but the manifold fits either side because the heads aren't mirror imaged. I thought they were left and right specific.

That is true the cyl heads are identical and so are the Volvo style exhaust manifolds. The manifolds have water ports on both ends to allow for that. What GM did when they created the V6 was remove one center cyl on each side from the 350 (5.7) V8. So the bore and stroke is identical to the 5.7 but obviously the crankshaft and cams are different. The later model 4.3s have a balance shaft to reduce vibrations caused by the 90* included angle of the cyls. A balanced V6 will have a 60* angle but doing it this way allowed them to use the same tooling used for the V8.

 

[PITBoat]

Good to hear that GLM was responsive and helpful. I'm debating going with the GLM kit, or piecing together Barr /Volvo stuff like Lou did. The price difference is significant. But reworking due to ill fitting parts is frustrating.

Didn't have any trouble getting through to their customer service, and talked to the same live person every time.

The fitup of everything was good, didn't have any trouble there. The machining on the exhaust ports was a little iffy, but I didn't hear any leaks, even before I torqued them down more. The other part was better, at the elbow joint.

I like the 2-piece design. The batwings were kinda hard to get off since there wasn't much give in the rubber couplers (and they were stuck on) and getting the manifolds all the way off of the studs required some force. Getting the new manifold started is a little harder w/o studs since you have to hold it and start a couple of the bolts (I think Lou has a method that eliminates that), but it's easy to fit up the rest.

I liked being able to buy it all together too.

 

[PITBoat]

If you use the GLMs what I’d advise is after the install, run it warm it up and re torque the fasteners. Then disable the ignition. Next let it sit for a while and then remove the plugs. Crank it over and make sure no water comes out of plug holes. It’s a good idea to make sure there are no leaks from those manifold to elbow gaskets. No matter who makes them that is the Achilles heel of the wet joint design. The Merc dry joint design is superior in this regard and I looked into trying to adapt it to the OMC but the downslope angle of the Merc elbows is different from the Barr/Volvo style and I wasn’t sure the parts would match up properly (Barr/Volvo is 10*, Merc is either 5* or 15*) depending on the elbow used.
The Merc dry joint is also considerably more expensive than the wet joint for both OE Merc or aftermarket.

I didn't have them torqued as tightly as I thought when I first started it Sunday evening, and there was a little leaking there on one, but after I went around it several more times (before even getting to 20 lb-ft), there was none. "Around", like crisscrossing and so forth...

I started it again Monday or Tuesday night to get a pic with the drip happening, but I pulled the closest plug first, for what that was worth, and it was dry. Hadn't thought about checking them all just in case, but that would buy me some confidence that all is gonna be well.

It sure looks nice compared to the original setup.

 

[Lou C]

I’ve been pleased with the fit and performance. And for us salt water boaters who have to replace exhaust every 5-7 years no more worrying about NLA parts; I can just pick up another set of Barr manifolds and elbows...

 

[Lou C]

Didn't have any trouble getting through to their customer service, and talked to the same live person every time.

The fitup of everything was good, didn't have any trouble there. The machining on the exhaust ports was a little iffy, but I didn't hear any leaks, even before I torqued them down more. The other part was better, at the elbow joint.

I like the 2-piece design. The batwings were kinda hard to get off since there wasn't much give in the rubber couplers (and they were stuck on) and getting the manifolds all the way off of the studs required some force. Getting the new manifold started is a little harder w/o studs since you have to hold it and start a couple of the bolts (I think Lou has a method that eliminates that), but it's easy to fit up the rest.

I liked being able to buy it all together too.

See post # 3 for the easy install method pic. Longer bolts same thread pitch and you cut off the heads and cut a slot in the end for easy removal with a screwdriver.

 

[Lou C]