exhaust header

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mdidomenico

i've been back and forth during my refit on whether to pull the engine.  looks like my decision to pull it paid off.  i believe these should be connected...

1989 Cat34 #856, original m-25xp

Jon W

Congratulations. What a nightmare that could've been.
Jon W.
s/v Della Jean
Hull #493, 1987 MK 1, M25XP, 35# Mantus, Std Rig
San Diego, Ca

Noah

Not a mechanic, but pull the engine to repace exhaust riser?
1990 hull #1014, San Diego, CA,  Fin Keel,
Standard Rig

mdidomenico

Quote from: Noah on September 22, 2018, 05:38:51 PM
Not a mechanic, but pull the engine to repace exhaust riser?

no no, i'm doing more then that.  i'm putting in a coupler/shaft/hoses/electrical (found some gummy bears), it needs a repaint and new engine mounts.  i was going to leave it be, trying not to open a can of worms.  but i guess it's good i did.

oh and the bolts on the damn riser are in such an awkward position, it might have been easier to pull it out.  ugh, i'm getting too old to contort in these positions
1989 Cat34 #856, original m-25xp

Ron Hill

mdid : If you are going to do all that work (new mounts /new riser/repaint/ etc) it might be best to pull the engine.  Look in WiKi and the Mainsheet tech notes and you'll find my write up on removing the engine.  also think about new insolation for the engine compartment and maybe moving the oil drain to the back of the oil pan etc. etc.

You'll also find that you can forget the replacement of the "gummy Bear" connectors and just hard wire the engine and do the same at the engine instrument panel unless you are going to replace that panel in the future. 

Long story but I had the misfortune of having to pull the old XP twice and then replace it with a XPB.

A few thoughts.  Good Luck  :thumb:
Ron, Apache #788

KWKloeber

md

Not a problem, you need the wye connected ONLY if you actually want cooling sea water to get to the muffler. 🙃

So long as you're doing all that work you might consider the water cooled riser as Bill Shreeves did. http://c34.org/wiki/index.php?title=C34_Exhaust_with_Water_Cooled_Riser

Bill:  a thousand apologies for noticating that roundtuit and reviewing the article as I said I would 🤥. 
If I see anything I'll add it as a note. Good job, but I would "sign" it 😀. 
And add it to the boat/owner project list
http://c34.org/wiki/index.php?title=Owner_Projects_by_Boat/Author

cheers
ken
Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain

Stu Jackson

Quote from: mdidomenico on September 23, 2018, 12:21:31 PM>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

oh and the bolts on the damn riser are in such an awkward position, it might have been easier to pull it out.  ugh, i'm getting too old to contort in these positions

I've included some handy tips & tricks for just that here:

http://c34.org/muffler-exhaust-riser-replacement-2015/
Stu Jackson, C34 IA Secretary, #224 1986, "Aquavite"  Cowichan Bay, BC  Maple Bay Marina  SR/FK, M25, Rocna 10 (22#) (NZ model)

"There is no problem so great that it can't be solved."

mdidomenico

any thoughts on replacing the header studs?  i'm gathering the list of parts to order from Catalina Direct for the engine and i see they sell new exhaust bolts.  mine came off surprisingly easy and i don't see any corrosion on them.  just wondering whether it's necessary, i might do it anyway given the low cost, but i've never changed an engine stud before, so i'm not sure whether that's another can of worms or not.
1989 Cat34 #856, original m-25xp

KWKloeber

If you are speaking of the exhaust flange studs, if they are in pristine condition there's no need to replace them. You could replace the nuts if they are at all worn.

Be SURE to install the exhaust flange gasket the correct side out. If not, you will dump all your engine coolant out your exhaust hose.

-k
Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain

Stu Jackson

Don't mess with the studs unless absolutely necessary, that means absolutely.  Get new nuts, that's easy.
Stu Jackson, C34 IA Secretary, #224 1986, "Aquavite"  Cowichan Bay, BC  Maple Bay Marina  SR/FK, M25, Rocna 10 (22#) (NZ model)

"There is no problem so great that it can't be solved."

Ron Hill

mdid : I agree with Stu - don't screw with the studs.  Even if you need to split the 3 nuts go to Fastenal and get new hard Stainless nuts to replace the old ones.

The main problem with replacing that new flange and new gasket is to make absolutely sure that the  flange side on the engine is CLEAN of the old gasket.  I've said it before that you need to clean and then clean again before you install the new gasket and flange.                                                               Also make sure that your new flange is not over wrapped with insulation and rides on the top of the HX!!  Use my "Dollar bill" test -  make sure you can slide a dollar bill between the riser and the HX!!

A few thoughts


Ron, Apache #788

KWKloeber

IINM, the studs are oddballs, different thread on either end. Doubt Fasenal would have em. At least that's what I recall from the last time I ordered them?
Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain

mdidomenico

Quote from: Stu Jackson on September 27, 2018, 11:28:28 AM
Don't mess with the studs unless absolutely necessary, that means absolutely.  Get new nuts, that's easy.

message received...  glad i asked...

1989 Cat34 #856, original m-25xp

mdidomenico

finally got around to pulling the fiberglass insulation off the exhaust header...  good thing I pulled it all apart for replacement.  I would suggest anyone with a vintage boat check their exhaust system
1989 Cat34 #856, original m-25xp

Stu Jackson

#14
Quote from: mdidomenico on October 17, 2018, 03:12:08 PM
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>
I would suggest anyone with a vintage boat check their exhaust system

Uhm, by now we ALL have vintage boats!  :D

Years ago one of our skippers suggested starting an info base on how long the risers last.  Results came in ALL OVER THE PLACE, due to different materials being used and different "situations."  We abandoned the effort to record hours.  IIRC, my first one went at 1350 hours.  Seemed about 1000 to 1500 hours based on input.  I did another one later, both in Mainsheet.
Stu Jackson, C34 IA Secretary, #224 1986, "Aquavite"  Cowichan Bay, BC  Maple Bay Marina  SR/FK, M25, Rocna 10 (22#) (NZ model)

"There is no problem so great that it can't be solved."