Riser/Manifold Inspection

[gnealon]

Hello!! I searched high and low and found bits and pieces to my questions so I am very sorry if this is repetitive.

I have a 2005 280 DA w/ twin 5.0L Merc. I'd like to inspect the elbows and manifolds for corrosion and use the opportunity while the manifolds are off to replace the plugs. So... few questions...

1. Read a decent amount about just pulling elbows (no risers )and looking down into manifolds is good enough. That true?

2. Should I replace all the bolts I take off as well?

3. I sent my wife (with a part number) to my local Marine Max to get some gaskets for me today. The elbow gasket is metal?!?! I was a little surprised by that. I double checked mercurypartsexpress and its shows 2 different gaskets. One a block off, one a restrictor where the latter is for standard cooling and the block off for closed cooling. I suspect they gave me the block off gasket. But is the restrictor gasket still going to be metal? I was just surprised by that.

4. Any ideas of the torque specs for the elbow bolts? I read snug fit the bolts and torque from center out. Does that make sense?

5. Am I just being foolish to check the elbows and manifolds of a 100% salt water boat (year 2005) as opposed to just replacing them? I have very low hours ~300.

Also, any other advice would be great regarding placement of gasket... watch out for this type stuff etc. This will be my first time doing this so dont hold back w/ the advice.

As always, much appreciated!!:grin:

 

[gnealon]

Sorry, just to clarify #4. I meant to ask for the torque specs for the elbow bolts and clarify the tightening procedure for the manifold (aka center out). I assume the torque specs for the manifold would be the same?

Thanks again.

 

[northern]

What I do is take the elbows off. If the mating surfaces were in good condition I took the elbows to a rad shop and had them cleaned if they looked good I put them back on. Torque on a 454 was under 30#. I used old elbow bolt. I would not reuse old manifold bolts.
When cleaning the mating surface on the manifold where the elbows goes plug all the openings so you do not get material into the engine or the cooling system.

 

[gnealon]

Thanks a lot for the advice!

When cleaning the mating surface on the manifold where the elbows goes plug all the openings so you do not get material into the engine or the cooling system.

Its funny you mentioned that because i was going to ask. Thanks! Do you know if there could be residual water in the exhaust passage that could get into the engine when removing the elbow? Should i pull all drain plugs first?

Thanks again.

 

[masilobes]

i just had my risers and manifolds done. i have the 4.3"s so it may not be the same clearance but i watched them do it and they couldent pull just the risers because in order to lift them off the studs you have to lift them about 5-6 inches and would hit the floor. they tried to double nut the bolts so they could remove the whole stud to get the risers off . that was working but was taking forever and was asking to break off a stud. they ended up pulling the whole riser , manifold and spacer off in one piece. my luck, they saw some rust. not much at all. i mean specks of rust. but when he pulled the drain from the bottom of the manifold, out came a handfull of rust and scale. so $3200 later all new. hours dont really matter because mine only has 40 hours and still needed them.

 

[Ididntdoit]

The riser/elbow gaskets are metal with a graphite coating and silicone sealing rings for the water passages and yes FWC are blocked and RWC are open in the back and restricted in the front, also the "lip" is marked to face up - if you have the 3 inch risers you will need the gasket set as you will probably break both seals when pulling the riser as they use one long bolt - the 6 inch blocks use separate bolts so you do not necessasarily need to remove them. The proper torque is 45 foot pounds - the manifolds take less torque (i belive 32 lbs) as the gasket is different and yes you tighten the inside first. Remember to retorque everything after the first heat cycle. I just had a riser off my '05 to gain access during my generator install and it appeared as new (no pitting or scale) we did my buddies '03 3 weeks ago and his were negligably worse (just starting to pit/scale) I'm not saying not to check them but if it were me and there was no signs of major external seepage I would just remove the intermediate pipe to gain access to the "snout" and if all went well and looked good I wouldn't go any further - remember the gaskets are $30-$40 each - I definately would not remove the manifolds themselves as there is nothing you can see with them off that you can't see with them on. Of course all of the above only applies to the dry joint system (2001 and up) as the procedures and inspection intervals are much different for the earlier systems. Also, I'm speaking as a northeast boater (as I see you are too) - experience in warmer water with higer salt content and a longer season may be different.

 

[gnealon]

The riser/elbow gaskets are metal with a graphite coating and silicone sealing rings for the water passages and yes FWC are blocked and RWC are open in the back and restricted in the front, also the "lip" is marked to face up - if you have the 3 inch risers you will need the gasket set as you will probably break both seals when pulling the riser as they use one long bolt - the 6 inch blocks use separate bolts so you do not necessasarily need to remove them. The proper torque is 45 foot pounds - the manifolds take less torque (i belive 32 lbs) as the gasket is different and yes you tighten the inside first. Remember to retorque everything after the first heat cycle. I just had a riser off my '05 to gain access during my generator install and it appeared as new (no pitting or scale) we did my buddies '03 3 weeks ago and his were negligably worse (just starting to pit/scale) I'm not saying not to check them but if it were me and there was no signs of major external seepage I would just remove the intermediate pipe to gain access to the "snout" and if all went well and looked good I wouldn't go any further - remember the gaskets are $30-$40 each - I definately would not remove the manifolds themselves as there is nothing you can see with them off that you can't see with them on. Of course all of the above only applies to the dry joint system (2001 and up) as the procedures and inspection intervals are much different for the earlier systems. Also, I'm speaking as a northeast boater (as I see you are too) - experience in warmer water with higer salt content and a longer season may be different.

Awesome, I really appreciate the feedback. I wasn't sure if I had the "dry joint" system but after reading about it (and your confirmation) i believe I do. After doing more research on this site, I agree with your suggestion on NOT removing the manifolds. My main motivation for removing them was to replace plugs, but i can do that w/ them on obviously. Just more of a PIA. This way i don't have to worry about the gasket placement and nonsense w/ putting the manifolds back on. I'm 95% sure I do not have risers (haven't taken a close look), just the elbow/manifold gasket is needed.

What is your opinion on scale/pitting in regards to when to replace elbows and manifold? I mean, if I saw a ton of rust/flaking it would be obvious to me. But what if I take it all apart and see "some" or minor rust/pitting?!?! Just clean mating surface, replace gaskets and check every year from now on type thing? I am confident in the fact that I can do this work, its more of the trained eye on what to look for that scares me. Thanks again for the help. :smt100

 

[Ididntdoit]

Looking at the "snout" (the part that the hose is attached to) no part of it should be "missing" ie corroded away - this will be obvious when you take it apart. the paint will be missing but you will be looking for enlargened holes, missing/corroded grooves, etc - as far as the coolant passages are concerned there will be a significant amount of "build up" in the front restricted passage but the "holes" should not be significantly bigger, deformed, or sealed off from corrosion. of course the thing you cant see is the condition of the water jacket inside the manifold.....With the elbow off look for teltale rust stains running down the inside of the manifold towrds the exhaust ports in the heads. I have never worked on a 280 with 5.0s - I know the 4.3s have the 3inch riser - if you have em it is a bit tricky lining up the holes in the manifold with the 2 gaskets, riser, and elbow - I slid the elbow into the hose/intermediate pipe first then inserted the block, next I slid in the gaskets and threaded the bolts through. If your set up uses studs instead of bolts that simplifies this process (once you release the hatch supports to tip it further back and get the necessary clearance) As for when to change.....based on what I saw on my buddies boat and subsequently mine - I plan on changing them in 2-3 years - I have been told the wear is not linear and once they start to go, they can go quick.

 

[Gunn]

Good luck with those spark plugs. I'll be changing mine too shortly, and I don't think it's going to be fun. I mean...I can't even visually see any of them! But I have 4 less to change than you. :smt001

 

[Ididntdoit]

Good luck with those spark plugs. I'll be changing mine too shortly, and I don't think it's going to be fun. I mean...I can't even visually see any of them! But I have 4 less to change than you. :smt001

Ya - the are A LOT easier to do with the manifols off - we did my buddies with the manifold replacement and the ones we took out looked perfect light tan (original to the boat too)

 

[gnealon]

Looking at the "snout" (the part that the hose is attached to) no part of it should be "missing" ie corroded away - this will be obvious when you take it apart. the paint will be missing but you will be looking for enlargened holes, missing/corroded grooves, etc - as far as the coolant passages are concerned there will be a significant amount of "build up" in the front restricted passage but the "holes" should not be significantly bigger, deformed, or sealed off from corrosion. of course the thing you cant see is the condition of the water jacket inside the manifold.....With the elbow off look for teltale rust stains running down the inside of the manifold towrds the exhaust ports in the heads. I have never worked on a 280 with 5.0s - I know the 4.3s have the 3inch riser - if you have em it is a bit tricky lining up the holes in the manifold with the 2 gaskets, riser, and elbow - I slid the elbow into the hose/intermediate pipe first then inserted the block, next I slid in the gaskets and threaded the bolts through. If your set up uses studs instead of bolts that simplifies this process (once you release the hatch supports to tip it further back and get the necessary clearance) As for when to change.....based on what I saw on my buddies boat and subsequently mine - I plan on changing them in 2-3 years - I have been told the wear is not linear and once they start to go, they can go quick.

Sweet, thx! Sorry, for the million questions, but what did you mean by "once you release the hatch supports to tip it further back and get the necessary clearance". Are you saying you needed to release the hydrolic pistons for the ER hatch for clearance?

Also, do I need to drain anything (freeze plugs, hex style manifold plugs) before i remove the elbow? I dont want to risk water getting into the exhaust.

Thanks again!

 

[gnealon]

Good luck with those spark plugs. I'll be changing mine too shortly, and I don't think it's going to be fun. I mean...I can't even visually see any of them! But I have 4 less to change than you. :smt001

Thanks, and good luck to yourself. They are not easy to do, and with the 5.0's there is even less space. Last season I replaced the water pump impeller, engine mounted on lower port side! OMG, i think i was on 4 motrin a day for a good week. haha

 

[Ididntdoit]

Sweet, thx! Sorry, for the million questions, but what did you mean by "once you release the hatch supports to tip it further back and get the necessary clearance". Are you saying you needed to release the hydrolic pistons for the ER hatch for clearance?

Also, do I need to drain anything (freeze plugs, hex style manifold plugs) before i remove the elbow? I dont want to risk water getting into the exhaust.

Thanks again!

We did no have to as his was put together with bolts - i understand some use studs and there would not be enough clearence if that was the case - I have not done this job on a FWC boat -I assume you will have to drain the system - I would further assume that since the gaskets are "blocked off" the manifolds are FWC and the risers are RWC - if thats the case I would think you have even less to worry about with the manifolds......Hopefully someone with real experience/knowledge in this area will jump in here to advise you

 

[gnealon]

We did no have to as his was put together with bolts - i understand some use studs and there would not be enough clearence if that was the case - I have not done this job on a FWC boat -I assume you will have to drain the system - I would further assume that since the gaskets are "blocked off" the manifolds are FWC and the risers are RWC - if thats the case I would think you have even less to worry about with the manifolds......Hopefully someone with real experience/knowledge in this area will jump in here to advise you

Sorry if there was any confusion, my boat is RWC. When I refereed to draining, I was just talking about getting any residual raw water out of the engine before taking the elbow's off.

 

[Ididntdoit]

Sorry if there was any confusion, my boat is RWC. When I refereed to draining, I was just talking about getting any residual raw water out of the engine before taking the elbow's off.

Oh - thats easy then - yes, drain the motors via the single point drain as long as nothing is clogged it will do the job.

 

[gnealon]

Oh - thats easy then - yes, drain the motors via the single point drain as long as nothing is clogged it will do the job.

Sweet, thanks!!!