Starting new thread for my hot section rebuild guidance on final approach..

[TimBSmith]

Update on hot section replacement...questions regarding doping/tightening pipes..


Al, John, others that have replied here or DM on longer thread, restarting here to focus. And to the long lineage of thread contributors on exhaust and hot side rebuilds. Thank you.

Regular monitoring of riser hot section and injection point seems important. Touchless temperature checks/inspection and the role of back pressure as a diagnostic tool is interesting, and I will take more time with it when less critical issues are in front of me.

Again thank you all for assist so far.....newbie help on final approach please...

I have read above and elsewhere here no thread dope on pipes, if anything some high temp anti seize...reconfirming this is the best practice. I tested some high temp pipe dope. Strangely all of the thick dope seems to scrape right out of the threads and end up out of the thread interface all together.

Guidance for tightening pipe assembly... I have read that others here simply snug the pipes hand tight. In other posts the tightening process is not covered. Is there a good rule of thumb?

Technician at the pipe and plumbing supply advised snug by hand then get 180 turn with pipe wrench. When I dry fit, this does not result in the pipe alignment I need. Proposing approach where I snug then turn straight connects then snug and tighten my street L and regular L at flange for the angular alignment I need.

Moyer Flange torque requirements? I have seen warnings about using too much force and pulling threads. Thought I read 35lb somewhere but cannot find thread.

Has anyone used 316/316L stainless nipple with the Moyer flange or SS nipple or connector to Moyer water injector? Have you noticed accelerated galvanic corrosion? Seems like all conditions met especially with the flange and environment. I have both.

I am planning to provide some additional surface rust protection using high temperature primer. For those that have used BBQ paint or other high temp surface protection 1) did you prepare the surface of the pipe or just spray, 2) did you notice any smell in the boat after curing? Wife very chemical sensitive. 3) any other pointers? I have high temperature header spray paint and will cure by baking twice at 400F for 30 min.

I have been reviewing many threads...further thread list to be compiled.

Progress slow/steady here link below, is where I am at now... about to do final fitting and tightening welcome any helpful hints or lessons learned, favorite threads. I will do all tightening at bench then install and fine tune before seating flange/hoses. My Moyer water injection is 1 5/8 my waterlift intake is 1 1/2" using 1 5/8" hose (as did PO) and adding double clamping.

Hot Section and Injection Point Old/New
https://photos.app.goo.gl/xEEeLfoF9gK4ZMkG6

Here is what schedule 80 connector looks like compared to schedule 40 my PO used. The mass and dimensions are dramatically different...

https://photos.app.goo.gl/zhrN3nsmcqxxnbWM6

Reflected a lot on schedule 40 and schedule 80 as well as black pipe vs. SS 316/316L. Using schedule 40 black pipe to re-create PO 10 year old build. Bought 316 SS flange gap nipple and gap nipple for water injector connector (my/common failure points), resolving sealing and galvanic corrosion questions may still use them. Making time to revisit long term solution. That discussion another post.

Here is the before and after of the flange seating area. I learned a great deal about importance of preparing the seating area. I have come to believe that part of the flange leak problem was a gasket buildup on the seating area that led to several high and hard to seal hot spots. I believe the PO or his technician passed on the opportunity to clean the flange seat where most difficult, where the gasket seems carbonized and fused.

Part of earlier generation gasket fused solid to seating area, last gasket laid over this...pleased with cleanup result thanks to ball peen hammer, picking tools, and Dremel wire brush lowest setting/gentle..between actual work and outreach..way..more..time..than I could imagine. Very confident with seating area and manifold material available for seating and operation.
Before
https://photos.app.goo.gl/3X4iRgPYA5eGkYeC6

After
https://photos.app.goo.gl/4XN1jwepzWx3qDYe7

Hot Spot and seating pattern seems to match these high spots. Gasket before removal. Note high spots and sealing trouble areas addressed with liquid gasket.
https://photos.app.goo.gl/totv6jCan5Qk481TA

Grateful. Stay well. Tim


p.s. Boston MA area members..
The folks at Metro Pipe in Watertown are outstanding. They have black pipe and 316 stainless.