Aluminum Exhaust Manifolds and Saltwater...

[JimG]

How long are they going to last?

Ok, guys... no theory, no metallurgical discussions, no "dissimilar metals" talk. I've searched this board thoroughly and you guys have made me well-versed in the theory.

The questions are this: How long did YOURS last? How did they fail? Did you cut them apart, and look inside?

I have a H/M 351W with Edelbrock log manifolds and H/M risers. I flush thoroughly with fresh water on muffs within 30 minutes of pulling the boat out of the water. Every single time.

We will use the boat every weekend from now until November, sometimes Friday/Saturday/Sunday.

Let's just consider my manifolds new, as of today. How long before they crater?

Thanks!! :)

JimG

[Dredgeking]

i would think they would last quite a while. years. how many i don't know. i never had problems with my aluminum exhaust manifolds on my fountain with 4 years use on them.

[JimG]

Thanks Dredgeking! That put's them about on par with cast iron for longevity (as long as you flush them), at a fraction of the weight. Look cool, too! :)

JimG

[Dredgeking]

i'm dying to get rid of the damn log manifolds i have in the 16. damn logs.

[BigGrizzly]

My H&M on my 16 lasrted 3 years. But that was 36 years ago and todays manifolds are better. Most seem to last same as Iron ones in salt enviorament and much longer the stock in a fresh water area,The ones on my Criterion have ben on the boat since 1985 in a fresh and some salt water weekends. Mine have an inspection plate and they look good still,

[boatnut]

I have a '69 18' with a H/M 302 all original.
The aluminum manifolds are still in use. I have used the boat approx 50 times in salt water over 10 years (SF Bay, Pacific Ocean) but only lake usage now. I have had the boat since '73. Lower end of engine has never been apart, during one of two valve jobs (about 15 years ago) I noticed significant erosion of the aluminum in the bottom of the exhaust passage of the manifold (near head port). I had these areas built up with a heliarc. This boat has been used every year (about 100 hrs/yr) at least since '73 and the manifolds are hanging in there. Salt will not be a problem if you flush the engine. Boat is immaculate, all H/M decals are intact but one is soon to be replaced.
The Volvo drive is original also (one seal replaced) amazingly bullet proof drive as we do not baby the boat as far as running it.

[MOP]

I've seen quite a few over the years as a boat mech, they do a lot better than you would think. One I remember was a pilot can't remember the boat, but it had a Ford with nice looking tapered jobs with high risers the whole Biz polished. That boat stayed in all the time behind his house.

[BillG]

I had a pair of Edelbrock logs on my 351 for 11 years, always in salt water. They corroded from the exhaust side into the water jacket. You would think it would the other way around. Looking inside the water jacket they looked almost new.
Bill G

[knots2u]

Check the manufacturers warranty. I was director of mfg at Barr Marine for 12 years and we offered no warranty on alum manifolds/risers for salt water or high performance applications, even though they could be used in both applications within reason. Buyer beware!

[JimG]

Thanks guys! I think I have my answer... It appears that my old Edelbrock manifolds are going to do just fine! As a matter of fact, I'm going to keep my eye on eBay for another spare set. I saw some go for less than $100 a few weeks ago.

This board is the best!!

JimG :)