Advice on A4 exhaust problem

[contagous]

So yesterday when I was about to go out sailing, after about 5 mins of running, my Exhaust blew out... stop engine right a way, and rinse off the salt water with fresh to make sure no salt stayed on engine...

ok

Im not 100 Sure on the part name, but I try to explain the prob.


The U Bend pipe that leave the exhaust manifold and goes up around and down, and then connects to the rest of the exhaust where the water and air meet, is what looks like broke... (see photo)

I have been quoted around $400-$500 for a new pip to be crafted and put in...

What I was wondering is this about the right price? and also is there anyway I could maybe get the pipe crafted out of galvanized steel instead of Brass or anyways to bring the cost down a bit? Just wondering....

Or is there another way of running it, Or does anyone in the Seattle Area, have a Dead A4 they might wanna sell that part if its the same or anything.


I have a photo of the break, but doesn't really show you the exact part I need so I drew a quick picture to explain it.







Any info would b awesome, need the boat up and running for my parents arrival from england on the 22nd


Thanks in advance.


Dave

[sawingknots]

yup they're proud of those elbows,i fabricated one for my yanmar from stainless steel,i joined the water hose a couple of inches down on the downward side,these mixing elbows are usually made of cast iron but the stainless has worked well for several years[make sure to join the water pipe far enought down so you don't get a runback into the engine.

[contagous]

Originally Posted by sawingknots

yup they're proud of those elbows,i fabricated one for my yanmar from stainless steel,i joined the water hose a couple of inches down on the downward side,these mixing elbows are usually made of cast iron but the stainless has worked well for several years[make sure to join the water pipe far enought down so you don't get a runback into the engine.

Thanks for the info

[MARC2012]

Is this the exhaust elbow,exhaust passes into it or the antisiphon,mounted high up,water probably from oil cooler in and exhaust elbow out?marc

[RichH]

From your pic. what you have there is called a 'dry stack'. A dry stack is made from simple threaded black iron pipe (typically 1-1/2" dia.) and black iron elbows, 'nipples' - all stuff you get from a plumbing supply or hardware store. The 'fabric/insulation' is called 'lagging' and can be obtained from most marine engine distributors.
Once you pull off the lagging, you'll probably find that all the pipe is all cut to 'standard lengths' (increments of 3 inches).

The only problem that you will probably have is the outlet flange of the exhaust manifold - just a flange with internal threads to accept the pipe. This 'adapter' flange will probably be 'corroded'/rusted to the piping and usually cracks/breaks when you try to remove it. I'd try to get a new adapter flange (and a new injection elbow, if used) from a source such as Moyer Marine Atomic 4 Engine Rebuilding and Parts When assembling a replacement dry stack madce from black iron pipe, its usually best to seal all the threads with automotive 'muffler cement' to seal all the threads from leaking exhaust gases.

Be sure to soak all the bolts into the engine with rust/penetrating compounds before removing .... so you dont break off a bolt in the engine's manifold casting --- a good one is "PB Blaster", auto supply store stuff.

;-)

[jaschrumpf]

If you have any mechanical skills at all and access to the area is decent, you can do this fix yourself for far less than $4-500. As others have said, the pipe is simple black iron from Home Depot. Some people use galvanized pipe, but that stuff generates a lot of stink when it heats up, so black iron is better, I think.

The flange can be bought at Moyer Marine, as others have said. The exhaust flange is $60, and is tapped for a pressure gauge for testing back pressure in the system. The cooling water insertion fitting is $40. The exhaust wrap kit is $21. So, for $121 plus another $20-$30 of pipe from Home Depot you can build your own replacement, saving a good $250-350 in the process. Plus you will know so much more about your engine, which is always a good thing.

Hop over to the MMI forums -- you'll find a wealth of A4-specific knowledge over there.

[downeast450]

I just replaced the hot pipe on my A-4. Along with the Moyer fittings, I used standard ss that I purchased on the web. It was twice the price of black iron but not a lot of money for the difference of eliminating the repair for good and reducing any rust staining on the transom.

Down

[QuickMick]

Hmm... thats interesting... i just yanked my whole manifold/exhaust and dont think i have one of those... however mine has an all copper 'tube in a tube' for hot exhaust/h20 which is routed to an elbow joint at a 90 that goes up to a muffler well above water line, then out ye ole booty.... just guessing/wondering if the part of which you speak is effectively replaced my my muff set up..... in anycase, the advice these guys give you is golden more oft than not. good luck

[contagous]

*Update*

So had a guy try to get off my exhaust flange today so the broken pipe can be removed....

He says its so corroded and rusty that he would have to cut off the bolts and their is a big risk that some would drop inside the exhaust manifold, and that would have to be replaced as well...
and that would be spendy, I just don't have alot of money at this point in time, and we decided not to go ahead with cutting them off for now.

Any ideas?


will post photo later if possible


1st photo broken pipe/part




2nd photo exhaust flange bolts, he couldn't remove, and said he might need to saw off....

[wheelhouse]

my $0.02, is to remove the manifold from the engine block, (AND off the boat!) and flame those 2 bolts with a torch. repeated heating and cooling cycles frequently persuades rusted bolts to loosen. Another option, if you unwrap the lagging, you may find some other pipe joints which could be undone without disconnecting that flange.