OMC Batwing replacent

[Khembree1]

Hello all,

I know there are a lot of topics covering this however I haven't found exactly what I'm looking for yet and maybe someone has done what I'm wanting to do. So question is, I want to get rid of my batwings. They're working fine but I don't like chances. It's a 1989 omc 4.3 in an 89 alumacraft trophy. So what I'm gathering is the main issue is the 4" to 3.5" y pipe from updated two piece risers. I understand there are conversion kits out there but if I can purchase a two piece risers set for Volvo or OMC for half the price, what keeps me from be able to use that? All that would need to be don't is the correct connection between the new riser and old 3.5" y pipe correct? I know they have the elbows you can purchase as well, part # 913583. I'm assuming this would work. But if I can machine one why would that not work as well? Just making sure there is nothing I'm missing if I were to just purchase any ole manifold and riser set for the 4.3 and go with it.

Thanks for the help!
Kyle

 

[Bondo]

Ayuh,....... Welcome Aboard,...... Lou C has done what yer lookin' to do, with Barr manifolds,.......

I'll let Lou C fill in the details,......

 

[Scott Danforth]

Hey Lou C

 

[Khembree1]

Awesome, thanks Bondo!

 

[Lou C]

Yep I did it, not the cheapest way but it worked great. I used Barr aftermarket V6 manifolds and elbows and then used Volvo Penta 90* exhaust pipes that adapt the 4" elbow outlet to the 3.5" OMC Y pipe. The expensive part is the Volvo parts, the exhaust pipes alone are $200 each plus the hoses. I used the VP stuff because I am in salt water, and want something to fit right and work right, which all of this did, fit like factory. However, GLM does make an aftermarket version of that VP exhaust pipe, that I'm sure is much cheaper. However, the 2 marine parts supply places where I am won't even order GLM stuff! Not saying it would not work though, and you can find them on line. If they fit right and don't leak, fine. I actually thought of switching to the Merc Dry Joint system, but the angle of the exhaust elbows is off by just enough that it might not work or might leak. So I went with what I know was used on these engines from '91 on up.

http://www.volvopentastore.com/Exha...on_id.215036255--store_id.366--view_id.791178

this shows what you need. If you have a pre-vortec engine which I'm guessing is the case, you don't really need the check valves that Volvo and OMC added in the exhaust elbows to keep water from getting pulled back in (this seemed to be more of an issue after the switch to the Vortec engines) which is part #5 in the diagram. Its a simple one way valve that allows air in the exhaust elbow, when a vacuum develops in the exhaust flow, to prevent water from getting sucked back in. If you repowered to a Vortec V6 you might want these, however, I have not had any trouble with that on the old pre Vortec design.

 

[Lou C]

PS I see the price of these went up since I did mine, I paid about 200 each, but might have gotten a discount from the dealer where I got mine....
sometimes they can be found on ebay used or from places that sell used parts....
This shows the GLM part numbers, that way if you want to source these you know what you are looking for, but I know people who have had trouble with GLM manifolds, when I checked my Barr manifolds and sealing surfaces they were perfect when checked with a straight edge and feeler gauges.

 

[Khembree1]

Thanks Lou C. I looked the 90 degree up looks like I can find them used in good shape for around $50-70 which I would be fine with if they're not all rusted out. I know the barr manifolds will work, did you get those for Volvo or OMC or did it matter? Looking at this set here on e basic power, I'm sure it may be a lesser quality. But shows three different heights for the risers. I think the standard it comes with are 7 3/4" tall so any idea if that will work or if it matters for this? The photos are posted of what I found. Then I know I'll need the bellows/boots for the Volvo setup correct? Im just looking for ways to save some money on it but just depends what I end up with wether is be better off going with a kit with everything. I have heard guys having quality issues with the GLM kit which is the most reasonable priced.

 

[Lou C]

The Barr manifolds for Volvo and OMC are identical, same parts number. I used the standard height elbows and all the Volvo rubber hoses fit perfect. If you didn't have water ingestion issues with the batwings then the standard height will work fine, if you go higher you will need longer hoses from the 90* exhaust pipe to the Y pipe to make up the difference.
PS I got the Barr kit from a local parts house who ordered them from a distributor here in Long Island (Lighthouse Marine in Riverhead NY) and the kit cost about $720. So that HGE kit is a good deal cheaper, so is GLM or Sierra but they are all made in China vs Barr made in USA. Now if you had a good set of batwings like I did (actually 3 good sets, none ever leaked but in salt water we have to change them approx. every 5-7 years or risk rust through), you might not realize that the gasket in between the manifold and elbow, is a weak spot of all wet style exhaust systems. Merc (before the dry joint) and Volvo both have had issues with them. I used the gaskets supplied with the kit, and coated the surfaces with Permatex Aviation. You can also use the Volvo Penta gaskets which take a copper based sealant. Some pix:

 

[Khembree1]

Good deal. I've had no issues with water ingestion and in all honesty the batwings look pretty good from as much as you can see anyways. They've always been in fresh water but I'm sure they're original. It's just one of those things in the back of your mind ya know? The engine was refreshed a couple seasons ago and I serviced the outdrive this winter with new bellows, shift cable all that good stuff so I'm at the point of peace of mind more than anything on keeping the engine running good for a long time. We will be taking the boat to Erie and Lake Huron this spring so I've been thinking the worst of the batwings giving out on me lol. Which may not happen but who knows.

 

[Lou C]

Here's a pic of what my last set of batwings looked like after 5 1/2 seasons here in Long Island....you can see why any inboard that is used in salt water your exhaust is a maintenance item, you can push it to 7 years but after that you are at a high probability of failure. If you look closely you can see one of the outlets is totally plugged. I cleaned these up and they looked good but, I found that the corrosion was extending up into the elbow section, and I was concerned that engine vibration would allow rust flakes to drop down and perhaps get into a cyl via an open exhaust valve, not likely but by the time they were due for replacement, I was doing a top end overhaul on the engine (another story) and didn't want to chance messing up the reman cyl heads I just installed. So while the cyl heads and gaskets only cost about $600 or so, the new exhaust (which I would have needed anyway) added about $1200 onto to that, but all the Volvo stuff was a one time expense only, if I do future replacements it will still be the Barr aftermarket manifolds/elbows....

 

[Khembree1]

Mine don't look that bad but I know salt water is harsh on things. Mine may last a long time honestly but who knows. I figure I won't be selling this boat anytime soon and we use the heck out of it so I don't mind to make it better. Although everyone says ditch OMC all the way lol. Ive had mercruisers as well and honestly I like this omc outdrive better than the others as long as the adjustments are kept up. Bellows and water pump are easy to replace as well. I appreciate all your info, it's exactly what I was needing to know and the parts I was hoping to find. Thanks!!

 

[Lou C]

You're welcome! I'm going to keep running the Cobra as long as I can get parts. Its held up extremely well in salt water, and I taught myself how to do the shift cable adjustment some years back so that's not a problem if I had to change the cable, etc.

 

[nutnboltguy]

i am so glad i stumbled upon this thread.

while un-winterizeing my boat yesterday i came upon a small h2o drip leak near the drain plug on my OMC batwing manifolds. thinking it was a simple thread leak i realized upon further inspection it was not. there was a hairline crack about an inch from the drain plug... having heard the batwings were potential ticking time bombs and the fact that the boat came to me with a cracked block because the pervious owner did not remove the water from the engine in the winter, i think its safe to assume i need to replace em asap!

so here i am scouring the web for information, and my biggest question being, what is the best brand to replace em with? clearly so far from your posts Lou C, Barr is your favorite, while GLM and Sierra are made in China and are not as well made as the US made. which i get.

im in the Nor Cal Sierra foothills and will only be in fresh water as long as i own this boat. my question is, are there any other brands out there that are of better quality or exhaust flow that i should be looking for? the other is which of these are as low profile as possible so i don't have to make a new engine cover, as the bat wings seemed very narrow and low profile?

thanks to the both of you for all the info, pics and links of where to buy.

oh and by the way, my 89 4.3L is a vortec.

 

[Lou C]

Well I have only had experience with Barr, never heard a bad story about them, if you have an '89 4.3 did you put Vortec heads on it? Because that would have been the older style pre-vortec engine with the roller cam, no balance shaft, and still has the hole to mount the mechanical fuel pump (like mine). If you do have Vortec heads (does your intake have 8 bolts? that's a vortec, if 12 bolts its the pre-vortec)….then there are a few things to think about...
1) Volvo Penta and OMC used the same style exhaust, and when they went to the Vortec engines in '96, they had to make some changes because the Vortecs are more likely to pull back water up the exhaust (reversion) than the pre-vortec. So they changed the 90* exhaust pipes that fit between the elbows and the Y pipe to a sharper angle, and added a pair of check valves to prevent vacuum from developing in the exhaust system. V/P used these on the 4.3 Vortecs all the way till they changed to cat converter exhaust. Look at a V/P parts catalog, you will see what I mean.

So first question, how many bolts does your intake have?
Then you go from there.

 

[Lou C]

http://www.volvopentastore.com/Exha...*****.215036255--store_id.366--view_id.791178

take a look at this and read what I wrote in post #5 above

 

[Lou C]

part # 5 is the check valve part # 19 is the 90* exhaust pipe. BTW, GLM makes a much cheaper copy of this part, that may work fine for you in freshwater. I am in a harsh salt water environment so I have to use the best stuff I can find. V/P parts are very expensive.