What should I worry about changing my exhust manifolds and hear risers?

Ka1oxd

Ka1oxd

New Member
Nov 19, 2009
1,071
Connecticut River at Portland Riverside Marina
Boat Info
1988 Sea Ray 340 Sundancer
Engines
7.4l inboards
I have never done this before, but it does look like a strait forward process. But because of my nature, I am always playing the role of devil's advocate. I sprayed the bolts down with PB Buster this past weekend. They are the original ones from 1988 by guessing.

Anyone have any tricks or warnings before I start this weekend?
 
Lets see...........
Drain the coolant first. This will keep coolant out of the cylinders.
Take the risers off separately. Its too heavy if you try to take the manifolds off with them attached.
Have all of your sockets available SAE and metric. The bolts sometimes need a smaller size hammered on to remove, due to corrosion.
Plan on using all new iron bolts and torque to speck. i have been advised the stainless bolts wont hold the torque do to the uneven heating of the different metals....(never challenged that one).
Get a length of threaded rod to thread into the block to create studs to hang the new manifolds on the block and line up the gaskets.
Ensure the fridge is full of beer. This just helps you work through the pain that is inevitable with any engine project.
When the engines are stripped. Look around the E/R, is this a good time to change some other system parts??
Water heater, vac pump, ect. You might have better access.
Take your time and good luck!
Mark.
 
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Great time to change plugs, plug wires, oil filter. Much easier without the manifolds in the way.
 
Areonautical, Excellent idea with the threaded rod manifold hangers !
 
Thanks all. Yup I was planning to do the spark plugs on both engines while the manifold was off between the two. Threaded rods is a good idea. Refer not on right now, but I think a cooler with ice and beer sounds like a good idea so that when I smack my fingers I can sink them in the ice after opening the beer.
 
I could not believe it. not one bolt snapped, not one head rounded, they came off. The hardest job was getting the rubber house of the exhaust. I am glad that I put some long boats in the manifold as I was taking them off. well tomorrow I put the new ones on.!
 
Try a heat gun on the hose's when reinstalling them. I tapped the threads in the head before installing new bolts. Just to clean the rust out of them. Great idea on the threaded rod!!!
 
Put a large washer and nut on a stud for the riser. Tie a rope around the washer and loop it over the radar arch. Makes for better control lowering them back in.

If the new manifolds are OEM replace all the bolts so they are the same length equal to the original longer ones.

If you have the correct size tap run it in the holes. The cleaner they are the better the torque.

If you put the long studs in temporarily put them at the far ends. Cut out a little bit of the gasket for these holes so the gasket can slip in
once the manifold is in place. If you hang the gasket on the studs first you might damage it lowering the manifold in. Damn those things
are heavy working in the hole, especially the inboard ones.

Once the engine is warmed up retorque the bolts
 
I got down to the last bolt on the manifold and I saw it starting to back away from the block. So I reach up and got 2 of the elbow bolts that was long with a head, so I screwed them in just so it would not drop on me and break my hand / arm.

Well while I was inside the engine before I put the manifolds back on, I took an old bolt and cut a deep vee down the length of the thread on a pedestal grinder. That has the same effect as running a tap down the hole and more accessible at the marina. I did notice the hose running form the water pump to the heat exchanger had a nice bubble in it. so the manifolds are not installed yet. Ordered new hoses since there is more room to work right now. I did find the raw water pump, again better without the manifolds on. I never took one of those apart yet. I will be doing that on Friday since I took my birthday off for a long weekend and to work on the boat.

On the raw water pump, I know I will have to loosen the belt, but to get at the pump, Should I take the pulley off then unbolt it from the frame to pull it out to change the impeller? Or once I loosen the belt and undo those two bolts that co through the bracket, does the pump pull apart?
 
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Ka1oxd said:
On the raw water pump, I know I will have to loosen the belt, but to get at the pump, Should I take the pulley off then unbolt it from the frame to pull it out to change the impeller? Or once I loosen the belt and undo those two bolts that co through the bracket, does the pump pull apart?
Click to expand...

I don't think that you will have room for a pulley puller to take the pulley off, much less an impact to do the work for you. but I am not familiar with the bigger engines. It's just as well to take the whole assembly off and then pull the pulley. Although you shouldn't need to pull it unless you are replacing that front seal.
 
No need to take the pulley out. Unless, as mentioned, you are doing something with the front seal or bearings.

Do you guys recomend using some type of dressing, silicone, etc for the gaskets? This questions applys to manifolds and the riser gaskets.
 
Agreed the pulley stays put..
Take the whole pump assemble off the motor.
Work like a gentleman standing upright with the pump on deck.

If you have a mechanical fuel pump attached to the same bracket change the oil in it's little drive cam housing.
You will see a large straight screw driver slot that is the fill / drain hole.
Fill with outdrive gear oil to be level with the bottom of fill hole when upright.
 
I am so happy I did pull the raw water pump. most of the vanes broke off, parts were in the hose that I could retrieve. Going back down with a snake since both ends of the hose is open. I came home and took apart the heat exchanger and found other parts of the vanes in there. Tomorrow I am doing the other engine since I have the parts now. I think I will do the genset as well. What a mess! Better now than later in the season.
 
Ka1oxd said:
I am so happy I did pull the raw water pump. most of the vanes broke off, parts were in the hose that I could retrieve. Going back down with a snake since both ends of the hose is open. I came home and took apart the heat exchanger and found other parts of the vanes in there. Tomorrow I am doing the other engine since I have the parts now. I think I will do the genset as well. What a mess! Better now than later in the season.
Click to expand...

You can back flush the system with fresh water to flush out the smaller pieces.
Fun,fun.
 
Looks like your job is turning into a can of worms. Great post to let folks know that the initial repair is rearly the only thing that needs attention. Good luck putting her back together.
 
I had to order a full blown kit for the raw water pump. Pulled the other one off and both were scored real bad in the housing. Showed it to the maria mechanic and he said it would be better to replace the housing as well, not just the impeller. I agree so he ordered the whole kit x 2. If I am going to do this much work, I rather make sure I do not ahve to do this again for a while.
 
And I found the problem that started this whole project. The hear exchanger had a crack in it which allowed the raw water to exchange with the antifreeze. Part of it was because of proper water flow through the raw water pump, but made the heat exchanger hot. The repair cost 189 for the heat exchanger, but that was far less than a new one. So if you ever see steam coming out your exhaust, start looking around before it cost you an engine!
 
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