Technical Help - Cast Iron v.s. Aluminum Risers

[LI_Sailor]

I have a 1986 Liberator. I need to change my risers. I've been looking at a few online but I am not sure whether to go with an aluminum riser or a iron riser.

I have done some research and really didn't come to a conclusion.

If anyone has any input as to which type will last longer in salt water please let me know.

 

[HT32BSX115]

Re: Technical Help - Cast Iron v.s. Aluminum Risers

Howdy,




Hmm...Another Liberator....they actually made more than one of those things?.



I don't think I would use aluminum in salt water. Aluminum corrodes very quickly.


What engine/drive is it?

 

[Alpheus]

Re: Technical Help - Cast Iron v.s. Aluminum Risers

You shouldn't use aluminum on saltwater...

But this is what GLM says:

We would like to answer a question that we keep getting asked.
Q: Are aluminum manifolds ok to use in saltwater?
A: Aluminum manifolds are OK to use in salt water! Just as the aluminum
sterndrive you have on your boat, these manifolds need zinc too. (included with manifolds)
With proper care, the aluminum manifolds will provide years of trouble free service.

 

[wire2]

Re: Technical Help - Cast Iron v.s. Aluminum Risers

If you can find them, stainless would be ideal. If you can't find manufactured ones, can take your cast ones to a weld fab shop. They can weld an inner and outer ss shell on ss plate flanges, cut with a water jet.

It probably won't cost much more than premium commercially made iron ones.
I made a set for a friend years ago, they're still working perfectly.

 

[nofuss]

Re: Technical Help - Cast Iron v.s. Aluminum Risers

i did some research on this topic some time ago as i needed manifolds and it would have been cheaper to ship the aluminum home. It seems that the iron lasts longer in salt water and the Stainless steel is the best.
GLM says that the aluminum should last as long, however they dont offer the same waranty. 2yrs for al and 3 for cast. i wont trust that.
there is however a company that makes a coated aluminum that was way to costly for me at the time, however they warrantied them for 5 years. this to me would be the best bet, and then the cast iron. or if u could really afford them the stainless they look very good.
the only fresh water my boat will see comes from the tap.

 

[zbnutcase]

Re: Technical Help - Cast Iron v.s. Aluminum Risers

Stick with iron. Cheap and effective!

 

[LI_Sailor]

Re: Technical Help - Cast Iron v.s. Aluminum Risers

The engine I have in my liberator is 260hp mercruiser. Its a good motor, just time to change the risers because one side is getting a little too hot for my liking.

Im not to sure if there are metal shops in my area that will be able to cut the ss plates. If not I guess i should just stick with the cast iron

 

[HT32BSX115]

Re: Technical Help - Cast Iron v.s. Aluminum Risers

I'm guessing you have thru-hull exhaust?


You can get stainless steel jacketed elbows like these

But they're not gonna be cheap! The ones above are on ebay starting at about $1700!!


Your best bet is going to be new cast iron and you'll just have to flush with fresh water when you can and inspect on a regular basis.....

 

[LI_Sailor]

Re: Technical Help - Cast Iron v.s. Aluminum Risers

ya ill probally stick to the cast iron. Seems like the most economic way to go. I cant afford the ss and aluminum is no good.

Thanks for all your help. I have another thread with a question I need help with