Assembling a black iron hot section

[marginal]

Hi everyone,
I'm assembling the parts to replace the hot section on my C&C30 A4, and have a couple of questions:

1. On the black iron nipples and elbows, do I put some type of sealant compound on the threads, or just dry fit them?

2. How do I make sure everything is facing the right way when it is tight? In other words, once tight enough, can I get another half to full turn on the threads to align things?

3. How tight is tight enough on 1.25" black iron?

So far things are going well, but surprisingly, the part I'm having the hardest time sourcing is the 1-5/8" pipe to go from the Moyer water mixer fitting to the water lift. If anyone has a tip for where to get that near Ottawa I'm all ears!

Thanks very much
Simon

[joe_db]

I just tighten mine as much as I can, no sealant. Any NPT pipe assembly has the issue of too loose at the desired position plus not able to get one more full turn. I use pipe wrenches and crank the crap out if it sometimes, YMMV. McMaster has all kinds of pipe if you can't find it locally. I made my own water injection fitting and did it all with 1.25"

[JOHN COOKSON]

Hi everyone,
1. On the black iron nipples and elbows, do I put some type of sealant compound on the threads, or just dry fit them?
2. How do I make sure everything is facing the right way when it is tight? In other words, once tight enough, can I get another half to full turn on the threads to align things?
3. How tight is tight enough on 1.25" black iron?
So far things are going well, but surprisingly, the part I'm having the hardest time sourcing is the 1-5/8" pipe to go from the Moyer water mixer fitting to the water lift. If anyone has a tip for where to get that near Ottawa I'm all ears!
Simon

1.No sealant is necessary. Just tighten 'em down. Tight.
2. Getting all the pieces lined up is a bit of a trick if you never have replaced a hot section on a C&C 30 before. When I replaced the hot section on my Catalina 27 I lined the pieces up as good as I could, secured the new hot section in place to check, then removed it and made adjustments as necessary. I have a union just after the flange which made it easy to place and remove the new hot section and do the adjustments. I don't have access to get the wrenches near the engine on my boat so I needed to make the adjustments in the cockpit. It was labor intensive.
If you have access on your boat to get the wrenches around the engine area just start building the new hot from the manifold back.
3. See #1

TRUE GRIT

[joe_db]

If you just can't get it tight you can always weld all the junctions. I did this once, but last time saved the $$$ and just cranked it.

[BunnyPlanet169]

If you're going to McMasterCarr (or a good plumbing supply store), pay the up charge and go with schedule 80. The thicker wall will last longer, especially at the threads.

[Antibes]

The black pipe threads basically corrode themselves shut very quickly, why sealant is unnecessary.

[Peter]

i recently re-did my hot section and there were really only one or two spots where getting the angles correct were critical. For the others I tightened the hell out of them.

One of the tricky ones was the section going from the engine to a 90 degree elbow and then out of the engine compartment. The PO had done this with two nipples and a coupler from the exhaust flange to the elbow instead of a single nipple. This put four threads in the section instead of two. I repeated this because I felt it would give me more play to get that final turn. Seemed to work out nicely.

Wrap - tried a cheap "titanium" - smoked, stank like hell, and was getting "crispy" - I think it was some curing process. Go for the good stuff. MMI has it and it is also readily available at performance car shops and bike shops.

Threads - from Don Moyer - " I replaced the hot section on each of our three sail boats over the past years and all I ever used was Never-Seize simply as a lubricant to be sure the tapered pipe threaded fittings were tight, and I never had any leakage. Having said that, I do hear of a heat resistant dope that some folks have been using, but I can't recall the brand or where they got it."

Needless to say, I used Never-Seize on my threads

Peter

[marginal]

Thanks for the help everyone!
Simon

[Bruce Macdonald]

Simon
Fellow NSC member, just replaced all the black pipe exhaust system, all piping was purchased from Boone Plumbing.

[marginal]

Thanks Bruce. I got all the pipe at Boone as well, the mixer and flange from Moyer, and the 1-5/8 exhaust hose ordered in by The Chandlery.

It all went together today fairly easily and I'm back in action

Simon

[sastanley]

Simon, thanks for the update!