Riser material - latest wisdom

[joe_db]

I was so happy my engine fired right up last weekend. This weekend I leaned on the exhaust pipe and the end of the riser broke right off - rusted to pieces
I can make another one from Home Depot black iron, but I am getting the idea that the quality of said iron goes down every time I do this exercise
So besides for the tried, true, and cheap way out, I have:
1. Brass. Seems to violate some USCG/ABYC standard. Nut sure about longevity.
2. Stainless. This will cost a bit more. It might last forever and then again I think someone got 5 years out of stainless before it corroded apart. Any ideas on 304 vs. 316?

[67c&ccorv]

There are many, many posts in this website on making a new exhaust system - AFAIAC this is a place where it's penny wise-pound foolish.

MMI has a number of cost effective solutions to the exhaust rebuild issue...I would use them if I were you.

[edwardc]

I did mine out of stainless. McMaster-Carr (www.mcmaster.com) has the pipe and fittings at the best price I've found for stainless. And since they're in NJ, here on the east coast we get very rapid delivery times.

[Ajax]

That sucks, Joe.

How many years have you been getting out of black iron pipe?
What is the typical lifespan among A-4 enthusiasts?

I've owned my boat for closing in on 4 years. I'm sure the exhaust is many years older, but the boat was also on the hard, winterized with fresh water for some years before I bought it.

[joe_db]

I think I am running around 4-5 years.

That sucks, Joe.

How many years have you been getting out of black iron pipe?
What is the typical lifespan among A-4 enthusiasts?

I've owned my boat for closing in on 4 years. I'm sure the exhaust is many years older, but the boat was also on the hard, winterized with fresh water for some years before I bought it.

[Dave Neptune]

FWIW, I am on my 4th exhaust now at 31 years. That is the one it came with and the 3 I have cobbled. One galvanized and 2 black pipe. The one running is on it's third year now.

Dave Neptune

[Ajax]

Ok, thanks. This will help me to not be too surprised when mine fails.

I don't have the vertical standpipe that you guys seem to have.
I just have a short, black iron elbow bolted to the exhaust manifold.

I *think* I get away with this, because the exhaust manifold is above the waterline (and the exhaust port on the transom is definitely above the water.)

[joe_db]

If MM made something that fit my boat, I would buy it

There are many, many posts in this website on making a new exhaust system - AFAIAC this is a place where it's penny wise-pound foolish.

MMI has a number of cost effective solutions to the exhaust rebuild issue...I would use them if I were you.

[joe_db]

Traditionally the risers were failing on the downside where the water teed in. The water hitting the far side of the pipe would eventually eat it away. I redesigned the riser to inject at the top with an internal pipe aiming down and that seemed to fix that. Now what died was the very bottom where the hose connects. The part of the pipe the hose clamped to rusted away. If I actually could get that part to unscrew I could do a $3 repair, but I doubt it will come apart. The factory original exhaust lasted from 1973 to about 1985, so the iron seems to be getting worse.
I actually was thinking I migght take the riser off this spring anyway and remake it just as preventitive maintenance.

FWIW, I am on my 4th exhaust now at 31 years. That is the one it came with and the 3 I have cobbled. One galvanized and 2 black pipe. The one running is on it's third year now.

Dave Neptune

[HOTFLASH]

A vote for SS Schedule 80

Mine are McMaster-Carr SS Schedule 80 (thick walls) for both hot section and for approx 2 feet post water-injection, paired with the MM SS "Tartan" standpipe. Took me a couple of years! to figure this out. Worth it. Beautiful.

I recommend this setup with the MM standpipe for post 1974 Tartan 27's. (These have the redesigned cockpit and a mounting area on engine room side of forward cockpit bulkhead). May work for other T27's too. It better last a while.
Mary

[Mo]

How long will it last?..black iron.

I did a little search here on this sight and figured out that I actually rebuilt the hot exhaust in
- September 2010...used black iron and had it done start to finish in 3 hrs...boat back operational.

- November 2014 ... used black iron again and it took the better part of a day because I was having trouble finding black iron. I ended up going to EMCO, a plumbing supplier, and got some. After that it took no time and she was all back together.

The first black iron hot exhaust I made lasted 4 yrs and 2 month (I had thought previously it was 5 yrs and 2 months).

Keep in mind my boat, for seven months of the year, is started and used almost every day. So the pipe heats up and cools etc almost daily...in a salt environment I'm not sure if that is a factor in longevity. Hopefully, the pipe I've gotten this time is of better quality...or it could be more of the same, who knows.

There was no SS or Brass available or it would have been made of that. Keep in mind that I keep the boat operational and had the rusted/ leaking exhaust off, rebuilt and replaced in less than a day both times.

[romantic comedy]

Two years ago I rebuilt my exhaust from black iron. I checked online, think I ordered it there too. Pluming dot com, maybe.
I got 10 years out of my last rebuild.

The prices for brass pipe were more then for SS. BTW

[joe_db]

I got my riser off today. It seems in good shape except the end.

[hanleyclifford]

A close nipple is always the weak link in a hot section. If possible try using a street 90 on the new one.

[Administrator]

A close nipple is always the weak link...

That has been my experience as well.

Bill