DIY Exhaust
 

Hi,

More on the Continuing Saga of Far Cove's Engine...

My engine dealer tells me one difference between the M25 (what I have)
and the M25XPB (what I'm getting) is the exhaust: it's a hose-clamp
fitting rather than a screw-in, and he suggested that the "typical"
exhaust for the M25 is smaller in diameter than for the XPB.

Which means I'll probably have to replace the custom exhaust "riser" in
Far Cove. (donno if "riser" is the right word: it's the pipe from the
manifold to the cast-iron elbow where the cooling water is injected)

I was thinking: I used a flexible stainless-steel "hose" wrapped in
hi-temp insulation for my diesel furnace exhaust: Can I use this for a
26hp diesel engine? Any pros/cons? Seems to me it would be cheaper than
the $1000 I spent to replace the exhaust last time, and it would be
flexible so it would be easier to install/align/etc. the engine.

Lloyd Sumpter
"Far Cove" Catalina 36

DIY Exhaust
 

The engine exhaust temperature can get very hot - much hotter than the
heater; a diesel mech or possibly (this subject doesn't usually concern
most buyers) the manufacturer could tell you _how_ hot. If the cheap
flex stuff sprouts a hole, very bad things can happen - CO poisoning
and/or fire.

I haven't done any hotrodding in 20 years, but I think I recall gas
engine exhaust in the area of 1400-1800 F. at the port. I don't know if
diesels run hotter or cooler, but you'd have to get a _long_ way cooler
before I'd consider using flex hose for engine exhaust.

Back pressure may also be an issue for the flex.

Rufus


Lloyd Sumpter wrote:

Hi,

More on the Continuing Saga of Far Cove's Engine...

My engine dealer tells me one difference between the M25 (what I have)
and the M25XPB (what I'm getting) is the exhaust: it's a hose-clamp
fitting rather than a screw-in, and he suggested that the "typical"
exhaust for the M25 is smaller in diameter than for the XPB.

Which means I'll probably have to replace the custom exhaust "riser" in
Far Cove. (donno if "riser" is the right word: it's the pipe from the
manifold to the cast-iron elbow where the cooling water is injected)

I was thinking: I used a flexible stainless-steel "hose" wrapped in
hi-temp insulation for my diesel furnace exhaust: Can I use this for a
26hp diesel engine? Any pros/cons? Seems to me it would be cheaper than
the $1000 I spent to replace the exhaust last time, and it would be
flexible so it would be easier to install/align/etc. the engine.

Lloyd Sumpter
"Far Cove" Catalina 36

DIY Exhaust
 

Take it to an exhaust shop. have them bend and fit the piece out of
regular exhaust steel tube, then send it to HPC coatings and have them
thermal coat it (header coating). It will last for ever, look nice, be
heat resistant and should not cost too much.

Kevin

DIY Exhaust
 

On my Wifes 38' sloop, The diesel had a 14" piece of stainless flex pipe, going
straight up from the manifold, to the muffler. It developed a few leaks.
I ended up taking it to a place in NW Portland, OR, called Petersons. They sell
hosing, etc.
They cut off the 2 end fittings, and welded a new section of flex pipe on, for
a total of $20! And had it done the next day!
I usually can't find a welder to do anything for less than $30.
The flex pipe was in the orig design, and works fine. But like "Danforth" type
anchors, all are not created equal!
Good luck, Cliff, S/V Lightnin'

DIY Exhaust
 

On Wed, 31 Dec 2003 21:17:06 +0000, Kevin wrote:

Take it to an exhaust shop. have them bend and fit the piece out of regular
exhaust steel tube, then send it to HPC coatings and have them thermal coat it
(header coating). It will last for ever, look nice, be heat resistant and should
not cost too much.

Kevin

That's basically what I did last time, and it cost me about $1000 (SS pipe, of
course!) The exhaust is still fine 10 yrs later, but the new engine has a
different attachment (hose-clamp vs screw threads) and may need larger diameter.

Lloyd Sumpter
"Far Cove" Catalina 36

DIY Exhaust
 

On Wed, 31 Dec 2003 21:44:21 +0000, Rufus wrote:

The engine exhaust temperature can get very hot - much hotter than the heater; a
diesel mech or possibly (this subject doesn't usually concern most buyers) the
manufacturer could tell you _how_ hot. If the cheap flex stuff sprouts a hole,
very bad things can happen - CO poisoning and/or fire.


The flex tubing I'm looking at is usually fitted on diesel trucks, and
although mine is "dry" at this point, it goes through the water-jacketed
manifold first, so I suspect it's cooler than a truck's exhaust.

I AM concerned that since it's "indoors" it will require more
"leak-proof-ness" than for the external exhaust on a truck.

Lloyd Sumpter
"Far Cove" Catalina 36

DIY Exhaust
 

Exhaust work should be much cheaper than that for a small part even in
stainless. If you can trailer it you may want to take it down to the
local muffler shop and see what kind of rates they quote you. I have a
lot of custom exhaust work done on various hot rod and 4x4 projects
and have never spent anywhere near that much.... As one of the other
posters said, you may be able to re-use your existing piece by just
having the proper ends welded on it if the dimensions are correct.
Even welding the correct ends onto the existing piece of tube
(assuming its dimensions are correct) shouldn't run more than about
$60.00 (an hour of shop time), and a good shop can expand or shrink
the tube down the correct diameter.


Kevin

DIY Exhaust
 

On Thu, 01 Jan 2004 16:20:36 +0000, Kevin wrote:

Exhaust work should be much cheaper than that for a small part even in
stainless. If you can trailer it you may want to take it down to the local
muffler shop and see what kind of rates they quote you. I have a lot of custom
exhaust work done on various hot rod and 4x4 projects and have never spent
anywhere near that much.... As one of the other posters said, you may be able to
re-use your existing piece by just having the proper ends welded on it if the
dimensions are correct. Even welding the correct ends onto the existing piece of
tube (assuming its dimensions are correct) shouldn't run more than about $60.00
(an hour of shop time), and a good shop can expand or shrink the tube down the
correct diameter.


Yeah...the more I find out about the guys I used to do this (and many other
projects, usually costing about a Boat Buck each...) the less I like them. Just
had a Real Look at it - the pipe is about 2 ft long altogther, with 3 bends in
it and a "injection site" on the last bend to inject the cooling water. As you
say, any competent steel fabricator should be able to make this up for a few
hundred dollars, tops.

Lloyd Sumpter
"Far Cove" Catalina 36