Exhaust Manifold Replacement

[Joe Luciano]

I have a 1987 Universal 25XP on a Catalina 30 that I've just noticed a slight exhaust leak in the area near the engine exhaust flange. I suspect a piece of pipe that's near the end of it's useful life. I've only owned the boat a couple of years, so I don't know the last time it was replaced. My question has to do with options for replacement, cost, and any how-to advice for doing the job myself. I've heard that you can purchase a complete replacement piece from engine flange to aqua-lift muffler, insulated and ready to go, (how much?). Also, I've heard about folks replacing the pipe with brass or stainless themselves from the local hardware store, and then re-insulating. In terms of how-to, I would assume breaking the bolts with a warm engine after a good soaking with penetrating oil would be a good bet. Probably get the gasket from my local universal dealer. Would appreciate any advice you may be able to provide before jumping into this one.

 

[Gordon Torresen]

Universal exhaust leak

The leak you describe could be from a loose piece of pipe but an attempt at tightening it could prove disasterous. all that is under the wrap is black pipe. Replacing it with brass or stainless probably would not result in longer life. We generally replace these exhaust pipes with schedule 80, black pipe and fittings. Sometimes the wrap can be removed and reused, but we generally replace it with new, fiberglass insulation. (gotta have it) I think you will find that the bolts holding the exhaust flange to the manifold are actually studs with nuts. If the nuts are too badly corroded to be "wrenched" off, they can be split with judicious use of a cold chisel. Either way, plan on new nuts and possibly new studs plus the flange gasket. Remove the whole assembly and use it as a pattern for building your new one. Tighten each joint as much as you possibly can. A little lubricant on the threads can help. Pipe compound or teflon tape will just burn away, leaving potential looseness. You will probably have to remanufacture the mixing elbow but any self respecting welder can handle that job. I have not heard of a complete assembly being offered. It sounds like a good idea. There are lots of M25's floating around in Catalina 30's. Good luck. Keep in mind that there are qualified mechanics out there.

 

[Steve W]

I just did this job myself....

and it is very easy. Unwrap the fiberglass insulation. Disconnect the exhaust at the flange and where it clamps to the large black exhaust hose. Disconnect the small heat exchanger to exhaust hose. Remove the exhaust pipe. Don't even bother trying to reuse the old elbows and parts. Use them for a template and buy the 1.25" pipe and elbows at Home Depot or any hardware store. Put it togther, then take to a welder to have the heat exhanger hose nipple welded on. Install and re wrap and you are set. My costs were about $20.00 from Home Depot and the welder charged me $15.00. Gordon is right, you will need a new gasket at the flange from Universal. That takes about a week to get. Order 2 and keep one as a spare ($2.00 each) Hope this helps.

 

[Gordon Torresen]

Faster service

Thank you, Steve. But if we can't beat one week delivery on that gasket I'd like to know it. We pride ourselves on speedy delivery from Diesel Direct.