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View Full Version : cracked exhaust manifold- 86 prostar


milehigh970
05-23-2010, 08:06 PM
So after yesterdays adventure... I spent the day cleaning up around our property, and tinkering with the boat. I found my first issue that needs immediate attention. A neighbor was checkin out the boat and was trying to remember how the electric choke worked(which by the way is question#2) and I fired it up and shut it off 5 seconds later. When I looked back I noticed water dripping slowly from the drivers side exhaust manifold. Looked and its the manifold itself, has a small crack on the bottom side. So can I prep and clean this spot really good with some wire brush and sandpaper and jb weld this as a temporary fix till I can find another manifold? in now way do I want a 5 year fix out of the jb... just a couple weeks maybe a month. thanks in advance!
Ps.. anyone got a right bank exhaust manifold? 86 prostar with a pleasurecraft 351

Laurel_Lake_Skier
05-23-2010, 08:56 PM
More than likely, yes, you will be able to patch up the manifold. I fixed a crack in the top of mine 3 years ago and have not have any problems with it. Rather than JB Weld, I used PC-7 which is a bit thicker. Prior to putting in the epoxy, I ground out the crack to create a v-groove with a Dremel tool, and drilled holes at each end to prevent the crack from spreading. I tapped the holes and put set screws in to fill the holes. Once the epoxy was set, I sanded and painted the manifold and it looks better than the "good" side.

thatsmrmastercraft
05-23-2010, 09:05 PM
More than likely, yes, you will be able to patch up the manifold. I fixed a crack in the top of mine 3 years ago and have not have any problems with it. Rather than JB Weld, I used PC-7 which is a bit thicker. Prior to putting in the epoxy, I ground out the crack to create a v-groove with a Dremel tool, and drilled holes at each end to prevent the crack from spreading. I tapped the holes and put set screws in to fill the holes. Once the epoxy was set, I sanded and painted the manifold and it looks better than the "good" side.

Great tip with the set screws. That would make a huge difference in how long it would last.

milehigh970
05-23-2010, 11:21 PM
That is a awsome tip! I was planning to clean out and grind a bit.. so I will try that aswell and see if we can't atleast get through the summer.. my season is already short enough here in colorado! What size hole/set screw did you use? I'm picturing a lil 1/4 in or so allen type set screw... we on the same page?