5411 Exhaust Flange

[tomlang63]

Looking for some advice on a 1981 Catalina 27 with a Universal 5411. The exhaust broke right at the flange, and the from what I can tell, except for the first 8 or 10 inches of pipe, the rest of the exhaust is in okay shape. What's the best way to either a) remove the remaining pipe material from the flange and try to clean up the threads, or b) should I be removing/replacing the flange and replacing all the pipe. From what I can tell, the exhaust and flange are original to the boat, so that flange has been bolted in place for 30 years, and I suspect it's not going to come off easily. Any suggestions are appreciated.

If any posters are in the Noank, CT area and would be willing to take a look, please send me a note.

Thanks.

 

[Stu Jackson]

You need to take the flange off to get the riser off. PB Blaster, don't be in a hurry. Don't get the PB Blaster anywhere near the seals on the transmission down below.

My top two bolts came right off the studs, the bottom one took a week.

You might, could, maybe get the old pipe out of the flange, but then how would you install a new riser? If the new riser was in pieces, perhaps, but most of the risers I've seen have been pre-assembled. Install riser in flange, install flange & riser onto engine, use hump hose to attach other end of riser onto muffler lip.

Use muffler patch paste on the flange threads to avoid blow-by.

 

[tomlang63]

Stu- thanks for the quick reply. The exhaust is nothing more than some sections of black pipe threaded together. I get what you're saying about assemble everything to the flange and then attach the flange to the engine. From what I can see, two bolts on the top of the flange, one on the bottom. There is no fabricated riser that is part of the exhaust from what I can tell. My biggest quandry is the boat is in the water, and 90 minutes from my house, so working on it requires alot of prep time. My original intent was to have the boat shipped to my house and fix the exhaust and a few other issues(bulkheads, windows, mast, etc), but I keep debating with myself that I can salvage something out of this season by getting this all fixed in the next few weeks.

 

[Stu Jackson]

I understand your travel time issues, but have no idea what your other time constraints are. Can you get someone trustworthy to go down and spray carefully withe PB Blaster? Have you tried to get the nuts off the flange yet? Sometimes there are GOOD surprises...

 

[tomlang63]

Stu - my only opportunity to get down to the boat is weekends, and while I could probably get someone to spray for me during the week, working on the boat out on the mooring presents challenges as well. I may give it a shot this weekend, but would like to get some pb on it prior to then.

 

[Stu Jackson]

I hear ya. When ours broke, I realized we were gonna be "out of it" for a while. Same thing when I had to redo the blow-by issue. If it were my boat, I'd head out early Saturday or late Friday night, and just get started. Bring a list of other things to do, and I'm sure you'll get to some of them, unless your bottom nut comes off easily. Good luck. Sometimes there's just no hurrying... Once you're on the boat, it doesn't matter whether you're on a mooring, at a dock or on the hard.

 

[tomlang63]

Stu - latest update. I had the boat brought home last week. After looking at everything I needed to do (windows, bulkheads, exhaust, mast), and things I would like to do(brightwork, update electric, etc), and the fact that we have long winters here in the north east, I bit the bullet on the remainder of the season and decided that sacrificing this year was better in the long run. I now have the boat right out back, and easy access to tools, electric, water, and local mechanical expertise. I have been spraying the bolts on the exhaust for a few days now, with the occasional tap of the hammer to try and get the pb blaster to work it's way in. I have not tried to loosen yet, will probably wait at least a week before I attempt that.

One quick observation, the flange has two bolts, upper left, lower right as you look at the flange. They do not appear to be studs and nuts, just a bolt (1/2"). Do you know if that's the way they were originally done, or may that be the work of some previous owner? I will attempt to get a picture of this uploaded...