Saw a post on here somwhere a while back stating you should not run stainless or brass hose fittings when using an aluminum intake manifold. Something to do with the two different types of metal having different heat expansion characteristics........any truth to this or just BS ?? :confused:

If true than I would assume aluminum fittings would be the only choice??

Any ideas or experiences would be appreciated.


Thanks

Jeff

I've never had an issue using stainless, brass, or aluminum fittings. When I HAVE run into problems is when someone used steel fittings without an antisieze compound on the fitting.

When using steel in aluminum, the metals are dissimilar and cause a reaction that will cause the steel fitting to become nearly impossible to get out later. Antisieze solves this.

This goes anytime you thread a steel bolt, plug, spark plug, etc into any aluminum part or an aluminum plug into a steel part. ALWAYS use antisieze compound in those applications.

Randy

I used a steel plug in an Edelbrock manifold. corrosion or electrolysis ate a trough into the roof of the water passage between the plug and the t-stat. one day I smelled anti-freeze, opened the hood and there was a nice little green fountain squirting up about 16" from a pinhole in the manifold. Took 9 years to do it. I use brass now.

I like brass because it's softer and conforms to the threads better.

Very Interesting...this is all news to me. Keep the replies coming guys!

Look at a galvanic chart and compare the properties of the metals and alloys. I do a lot of marine work on and around aluminum hull boats. The first thing a Marine surveyor will look for below the water line is brass or bronze fittings coupled to aluminum. It is always recommended to use stainless to aluminum first.

Look at a galvanic chart and compare the properties of the metals and alloys. I do a lot of marine work on and around aluminum hull boats. The first thing a Marine surveyor will look for below the water line is brass or bronze fittings coupled to aluminum. It is always recommended to use stainless to aluminum first.

So your recommendation would be to use stainless or aluminum manifold hose fittings?

I use brass fittings and have never had any problems. Brass fittings in NPT are commonly available at a good hardware store. Stainless is harder find. Try a pool store if you want stainless fittings.

I always buy brass (Weatherhead brand) fittings from NAPA and have never had any problems. I recently got a Weatherhead catalog and have noticed that they have a few stainless fittings listed.

OPGI sells a nice selection of stainless steel coolant and vacuum line fittings. The ones I got were very nicely made and look great.

Thanks for the responses everyone. I went down to the local hardware store and picked up some brass 1/2 npt 90s, 1/2 npt to 5/8 barb, and 1/2 npt plugs fittings. I also decided to try and not run bypass. I've read where others have not run bypass and supposedly had no issues. Hope they are right on that one.

I'm going to run two 5/8 heater hoses to heater core, one from intake manifold (front horizontal port where bypass normally goes) and one from water pump. Using the front horizontal port with a 90 degree fitting seems to make a nice clean install for routing the hose downward and hiding it behind my pass side alternater and brackets. And same with 90 coming off water pump...actually they both lay side by side nicely and can both be routed downward and behind. Plan on then routing up the pass side behind the pass fender to a hidden bulkhead fitting installed where the old circular heater motor used to set under the fender on the firewall. Then to underdash heater.

Opinions on this setup and opinions on just running just the two 5/8 heater hoses and not running bypass hose would be appreciated???

Thanks ahead of time guys! :thumbsup:

I think one heater hose is 5/8 and one is 3/4... maybe different on a 66?

Jmeek, My choice would be stainless. The cost should not be that bad as you only need a few small fittings as Rich said. Plus they will never go bad and may save the manifold from being damaged later in life.

Jmeek, My choice would be stainless. The cost should not be that bad as you only need a few small fittings as Rich said. Plus they will never go bad and may save the manifold from being damaged later in life.

I know the stainless maybe looks a bit better PCB, as far as saving the manifold, this is where opinions differ I guess. I've read, based on the galvanic table, that brass is closer to aluminum than stainless and therefore less corrosive down the road. Again, just what I've read and partly what prompted me to go brass instead of stainless in an aluminum mnifold. Actually, the brass fitting polish up pretty trick on a wire wheel or emery cloth.

Anyone else care to enter the frey on the metal corrosive debat?? LOL