Log style exhaust conversion question

Dogdave

Seaman
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Jul 31, 2011
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I have a '79 260 merc, I'm going to convert to center rise this fall. I have seen kits from GLM , BARR and Sierra all at diffract prices. I have read lots of bad on GLM . Is this true ?? Any real world experience ? The boat has a closed cooling system and lives in the salt. I do not want to install future work.
 

achris

More fish than mountain goat
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May 19, 2004
Messages
27,468
Re: Log style exhaust conversion question

Manifolds and elbows are very much items where you get what you pay for. And yes, the GLM ones are pretty thin... Best value for money are OEM, and if you're buying new, why not go to' dry-joint'.... Especially if you plan on keeping the boat for a while....

Chris.....
 

Volphin

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Re: Log style exhaust conversion question

I ditched my GLMs. Not worth the $$ OR the hassle trying to true them up.
 

HT32BSX115

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Dec 8, 2005
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10,083
Re: Log style exhaust conversion question

Manifolds and elbows are very much items where you get what you pay for. And yes, the GLM ones are pretty thin... Best value for money are OEM, and if you're buying new, why not go to' dry-joint'.... Especially if you plan on keeping the boat for a while....

Chris.....

I would ABSOLUTELY go to "Dry-Joint" if it were me. With a closed cooling system, the manifolds would outlast you!

You would still need to inspect your risers every few years or so.
 

geneseo1911

Petty Officer 2nd Class
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Jul 3, 2011
Messages
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Re: Log style exhaust conversion question

Has anyone seen this kit from Dana?
Mercruiser 260 Retrofit Exhaust Kit - Dana Marine Products
I like the idea of aluminum to save a bunch of weight, and the polished finish would look...NICE. I worry a bit about how they would hold up, though.

ETA:
Oops....just noticed the OP said he was in salt....I suppose that rules out aluminum, then?
 
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Volphin

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Re: Log style exhaust conversion question

Has anyone seen this kit from Dana?
Mercruiser 260 Retrofit Exhaust Kit - Dana Marine Products
I like the idea of aluminum to save a bunch of weight, and the polished finish would look...NICE. I worry a bit about how they would hold up, though.

ETA:
Oops....just noticed the OP said he was in salt....I suppose that rules out aluminum, then?

For that much cash, I'd chip in a few hundred more and get stainless manifolds:
CP Performance - Small Block Chevy

I run them on my V6 and they weigh in at 14lbs each. Change the zincs and keep them flushed and you are good to go. Have a buddy that has been running them for 4 years on his offshore boat. They are as good as new.
 
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achris

More fish than mountain goat
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May 19, 2004
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Re: Log style exhaust conversion question

I'd be a little wary of stainless steel manifolds. As much as I love the idea, it was tried here in Australia about 15 years ago, and abandon. The problem was that when the drive ran out of water, for whatever reason, the internal tubes got very hot very quickly, then when water flow was restored, the cold water shock on the stainless cracked the welds. Water in exhaust system, you know how the rest of the story goes.....

Chris...
 

geneseo1911

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Jul 3, 2011
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Re: Log style exhaust conversion question

Thanks for that link...I hadn't seen those yet, and I thought I had looked at all the options. I like the idea of headers, but I'm also lazy and want a kit that gives me the new t-stat housing, elbows, hoses, etc. all in one shot. I reckon all that stuff would add up to several hundred more dollars.
 

Dogdave

Seaman
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Jul 31, 2011
Messages
65
Re: Log style exhaust conversion question

Thanks everyone for the input . I will see if the dry joint manifolds will fit . I thought I read that they were a bit taller and I'm tight as it is . I'll save a bit more for Mercruiser parts
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: Log style exhaust conversion question

The newer 15? elbows are 1.7" taller, but the older 7? elbows are the same height as the 'wet joint' elbows (and still easily available)...

Chris.......
 

HT32BSX115

Supreme Mariner
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Dec 8, 2005
Messages
10,083
Re: Log style exhaust conversion question

I'd be a little wary of stainless steel manifolds. As much as I love the idea, it was tried here in Australia about 15 years ago, and abandon.

Didn't Mercruiser discontinue (cast) stainless steel risers some years ago too?
 

Volphin

Lieutenant
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Re: Log style exhaust conversion question

I'd be a little wary of stainless steel manifolds. As much as I love the idea, it was tried here in Australia about 15 years ago, and abandon. The problem was that when the drive ran out of water, for whatever reason, the internal tubes got very hot very quickly, then when water flow was restored, the cold water shock on the stainless cracked the welds. Water in exhaust system, you know how the rest of the story goes.....

Chris...

Funny you should mention that Chris, Hi-Tek's welding process and materials are top grade. The composition of the manifold is a polished stainless grade that is not as brittle as some stainless steels. As you know, there are many grades, and sub grades of SS, some more brittle than others depending upon the amount of chromium, nickel, moly, copper and titanium. Today, you can basically spec your own grade as well, if you are buying enough of it.

I'm just guessing here, but after working with so many OEMs, here is what I think happened: Merc tried to use the cheapest stainless they could, and tried to use substandard welding not suited to the product base material... Soooo it blew chunks and was too expensive to manufacture to fit projected margins. Chat with Allen @ HT. He's based down under, too. He backs his manis up with a 5 year warranty and has for many many years. If there were lots of problems out there with them, you can bet they would be all over the offshore forums and forums like iboats. Personally, I'd put them on my mom's boat. ;)
 
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