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Manifolds and risers and elbows

R

rmm

Regular Contributor
Boat is a 1988 Tiara 31 with Crusader 454s FWC, with approx 1500hrs used on Chesapeake Bay. Bought boat used with about 1100 hrs in 2006 and replaced elbows and risers in 2006.

Should I be looking at replacing them again as it is 5 years later? Started noticing a little more steam so thinking may be getting clogged.

Also how do I detemrine if I need to replace the manifolds? They look OK but I have no idea as to age.

Thanks
 
Ditto dave. That's my practice. I have 91 tiara 3100 with 09 elbows and risers. I'm due next summer even though she is cool and runs fine. I think you can use IR gun to see bad things with heat, but even if heat readings are good you could be near an internal breach.I guess that's called "false negative" diagnosis
 
When I changed my elbows 5 seasons ago, I really thought they would get more than the 5 years they lasted...However, I started to see the cruising temps rise and with the simple stuff ruled out like low coolant, lack of raw water volume, heat exchangers etc. It was the new elbows that did the trick. Understand that I only went from 160 to 175...but since we are out there, I needn't risk it so I made the change and it was the answer for our situation
 
As noted before, the manifolds shouldn't be an issue as long as the coolant they contain was maintained.

You may get 7-8 years off the elbows; depends upon where you are in the bay. For all the effort required to remove them, replacement (vs cleaning) makes a lot of sense. Another factor is use - more is much better as the corrosion due to the exhaust gases is minimized when the engine isn't sitting dormant.
 
Given a fixed set of circumstances such as ...same operation year to year, time , water exposure etc. : how would an extreme cleaning compare to replacement in terms of longevity? If my risers only started to cause temps to rise 10% when replaced after 5 years, would a thorough cleaning given them "X" number of years more and if so, what is "X" ...approximately ?
 
A clooged riser or elbow is not your only worry. When the wall rusts through and water is ingested into the cylinder is your biggest unseen worry. It happens without warning. Just an FYI, I replaced my 1986 Crusader 454 manifolds this year because of the rust scaling / deterioration on the underside of them. I was doing risers and manifolds and went for the whole deal. A lot of work but great piece of mind.
 
knuckle - based on what i have seen, cleaning won't buy you more than another year. when the corrosion has occurred long enough to flake off enough material to restrict the water flow, the original structure (cast iron) is reduced a good bit and has little life.

If you are talking about a preventive maintenance program....don't have any experience there. maybe we have a good chemist or a seasones metallurgist that reads and could provide their views???
 
Manifold.jpg

So anyway to tell the age of the manifolds or what is best way to know if they should be replaced. For all I know they could be the originals.Here is a shot of the underside.
 
I was young and dumb 2.5 years ago when I bought my boat and replaced the manifolds, risesr and elbows. I'm pretty sure I threw out perfectly good manifolds :)

'88 with about 800 hrs. They looked about the same as yours. maybe a little less rusty.

Bob
 
Life of exhaust components exposed to rw water depends on where on the Chessie you boat: up north, expect 20 years, but down near Norfolk, 5 years is pushing it.

Jeff
 
For what it's worth: Many years (25+) ago, I had a FWC Kohler generator whose riser would plug every 2 years. An old mechanic suggested that I find some way to flush the raw water side. I rigged up a garden hose connector with a series of valves and tees so that, by opening valves, I could run fresh water from the hose through the salt water side of the generator and the main engines. The generator never plugged up again & I got 35 years out of it. The main engines, Crusaders that I installed in 1993, still have 3 of the original 4 risers.

System also comes in handy for winterizing--can suck anti-freeze mix from a bucket into the engines' raw water sides.
 
Whether you decide to change or not. That photo of the rusty bolt brings back some awful memories. When I changed ours 6-7 years ago, those rusty bolts had corroded down from 9/16 to around 13mm . Some came out easily, some just stripped, some we had a cutoff wheel to slice the head off and the rest to a 16 lb "BF" sledge hammer, horrid job. PB Blaster and numerous other penetrating oils became my dinner guests for a few weeks. Good Luck.
 
For what it's worth, here's an idea: Many decades ago, after struggling with manifold bolts on a Graymarine, I replaced the bolts with studs and used brass nuts, which can be easily split.
 
rjrva said:
For what it's worth, here's an idea: Many decades ago, after struggling with manifold bolts on a Graymarine, I replaced the bolts with studs and used brass nuts, which can be easily split.
Click to expand...
That's a good idea. Even using just two studs on the ends makes the reassembly with gasket much easier. Against Osco's advice, I'm using 6 stainless hex bolts and 2 hi carbon studs at the ends, which has been working well.
 
diver_dave said:
That's a good idea. Even using just two studs on the ends makes the reassembly with gasket much easier. Against Osco's advice, I'm using 6 stainless hex bolts and 2 hi carbon studs at the ends, which has been working well.
Click to expand...

I used stainless steel bolts, liberally coated with anti-seize, when I replaced an elbow on one of my 1994 Crusader 350ci's. Did Osco say why they recommend against SS?
 
Has anyone had any experience with quality difference between osco and barr products for the exhaust systems ? My 1990 454 looks as if it's about ready for the whole works. Every gasket joint has about 3/4 of an inch of rust on either side of the joint,manifold,risers and elbows. They all look original except for the starboard engine , it has osco risers on it, but those joints are rusted too. The temps are a little high on the port engine(runs around 180 at 3100), the starboard runs at 140 according to the gauge, I have real doubts about the accuracy of that reading. I'll take the IR gun on the next run and check it for real. Also, the bottoms of the manifolds are scaling badly, I always find rusted metal on the tops of the stringers and if this is happening on the inside as bad as outside I'm already in trouble. I've used osco's before on previous boats and have had my share of problems with them and I'm considering using barr this time,just trying to not make some of the same mistakes that I've already been through. Hoping to get some feelings from the guys on the site that seem to have dealt with this many times. Thanks in advance....Lee
 
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I can tell you that Osco vs OEM/Crusader is very little life difference, if any. Not sure about Barr. Rust on joints after a couple years is pretty normal in salt, one of the joys...
I'll be trying a 2 part epoxy primer on my next round of elbow replacements. I'm NOT impressed with Rust oleom primer/industrial top coats now.
 
Dave ...I have a friend that lives up in ct.,he's a coatings chemist and we used to keep in touch a lot on one of the Pacemaker sites, I'll drop him a line and see what he suggests to use for a coating. He completed a top to bottom rebuild just a couple of years ago and I'm sure he would have used the best.....Lee
 
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