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454XL Exhaust Elbow/Riser

Ply

Ply

Contributing Member
Hey all!! That time of year again...

Got a pair of 94, carb'd, 454 XL engines. Time to replace risers..

I see 2 options. Barr makes the original design BUT I see that Crusader also has their own that stand 1 1/2 taller than the originals to reduce the chance of her ingesting water??

I have a blackfin 29 and not even sure I can tolerate that extra inch and a half BUT if I can is this the best way to go?

I honestly don't know which I have on there now, I'll have to check.. never knew they offered the higher rise elbow exhaust.

THANKS GUYS!!!
 
Crusader has installation specs that will help to determine appropriate part selection....if there hasn't been an issue since the boat was built, what you have is likely adequate....and will minimize the need for additional parts and labor.

FWIW, there are several different RISER heights to ensure adequate ELBOW height .....
 
Ply, What you are calling a riser may be what most of us call an elbow. The riser is the part that raises the height of the elbow and goes between the elbow and the manifold and as Mark says come is various heights.
 
Mark I thank you!!! I almost PM'd you as I knew you would have solid input but I believe in archiving these answers for all to learn from. Mark I love the whole MerCrusader thing you got going on there...lol... I have also adopted a few of their parts, or approaches... For instance I prefer their Heat Exchanger drain plug made from that thermo blue plastic verse brass.. I know I know... metal has to be better right?? well in this case I'm not sold ;-)

Yes I was using the term Riser incorrectly... I did say elbow/riser ;-)

And that's a great point if I needed that extra height a riser would accomplish same darn thing...
 
You're welcome.....when I worked at the shop, it was a no-brainer decision on what was best value.....I'm not against plastic, as long as the grade is appropriate.

If you are worried, you can find the crusader installation manual on the www - just search L510023-07
 
Thanks, Mark!! Turns out, I do have the slightly taller elbows, but without the riser block.

Mark is it safe to re-use the block off plate since my girls are FWC?
 
if you have the separate gaskets and block off plates, reusing the plates with new gaskets shouldn't be a problem....if the gasket is integrated (bonded) to the plates, new ones would be standard practice....
 
Sometimes the wing, or the turned up section, on the newer style Crusader block-off plates rust or corrode away. For the relatively cheap price, why not replace with new? The gaskets can't be reused.
 
I have plenty of room, and actually have the tall ones on there now. Interesting. Mullet what year is your 29? I'm a 95.. wonder if my engine covers are a smidge higher? I had the laser level down there today and I have easily another 4 inches even with the taller ones now before I come close to engine covers.

Mullet what year engines you have? Any secrets to replacing these? Never done these particular ones, but plenty of room... ONLY issue is that circuit breaker plastic housing that's scewed into the side of the elbows.. appears just to be screwed on there right? Do you have MSTS? I've gotten rid of mine but that box is still there... LONG story there.
 
Ply,
My BF is a 1988 with 1992 era 454s (MSTS). Not sure but the challenge my be getting the outboard units mounted due to lack of overhead space. Following is a paste of my experience. HTH

The first and biggest challenge is removing the old units. I would strongly recommend first cutting off the exhaust tubes attached to the outer elbows (assuming the outer tubes terminate to a 45 degree fiberglass fitting). Wireless tubes can simply be cut off with a utility knife. Wire tubes will require a Dremel tool to cut the coils to simplify removal. If the boat is in the water the exhaust outlets at the transom must be plugged or expect to be terrified when a deluge flows in as soon as the outer exhaust tube is removed. I found a rubber cap used for PVC tubing that had an OD exactly correct to plug the exhaust at the transom. To minimize water/coolant intrusion into the exhaust manifolds during removal, attempt to drain any residual raw water from the elbows by removing the brass plugs from the base of the elbows, and disconnect the coolant hose from the manifold and drain as much coolant as possible to get the level below the elbow mating surface.
Unbolting the elbows would seem to be straight forward – eight long bolts and eight nuts on studs. My problem was one bolt that was seriously stalled due to corrosion between the bolt and the mounting bore. A sheared bolt would have been a major setback. A few minutes with the blue tip wrench on the lower boss and the bolt backed out fine. One nut was heavily rusted to the stud and sheared at the bearing surface – no big deal since I was replacing all the hardware. After removing the bolts and nuts is when it gets a little crude. It is very common for rust to form between the stud shanks and the associated mounting bores of the elbows. You cannot merely lift the elbows off the studs ! Women and kids should not be present for the next phase of the operation. The school solution is to employ a four-pound plus sledge and whack the elbows from side to side to rock the units up the studs. A heavy sledge is essential since low velocity impacts still carry much energy (KE=1/2MV**2 for the Dilbert types). The studs were heavily corroded in my case, however, numerous whacks and much Deep Creep later the old Blackfin finally yielded all four elbows.
The studs were easily unscrewed from the manifold using a stud puller. The old gaskets were scrapped off and the surfaces on the manifold and block-off plate were cleaned with acetone. All the threads were chased and new studs were installed dry and tightened in place with the stud puller. Marine grease was smeared around the shanks of the studs in hope of avoiding the Thor routine next time. I researched the issue of sealer on the gaskets on the internet and did not find any reliable direction. Many recommended installing gaskets dry while others recommended Permatex. One troop went dry but later regretted it when leaks developed. I elected to use a light film of Permatex around all openings.
Low profile OEM elbows are no longer available so I researched aftermarket options. The wrench-benders at my local marina were down on the elbows made offshore. Their biggest dissatisfaction was a high degree of porosity which limited longevity. I went with Barr units (CR20-98126) ordered from Boaters Plus. They appear to be perfect replacements – already painted Crusader blue, great fit, include new gaskets and a complete hardware kit, and made in the USA. I also ordered four additional gaskets since two are required per elbow (FWC manifolds). Service from Boaters Plus was excellent – ordered Sunday night and had them in hand to do the job the following Saturday.
With the gaskets gooped and in position, I maneuvered the elbows into the exhaust tubes while slipping the elbows on to the studs. I elected to put anti-seize on the bolt threads which some do not recommend. I also greased the bolt shanks. After tightening the hardware in sequence, the job was pretty much over. The final issue was the 1.0 inch water hose fittings on the elbows (CRU97911). The only way to remove the fittings is with a pipe wrench. I managed to remove all four but cracked three of them when they collapsed slightly under the load of the wrench. OEM units are available but cost $25 plus. I went with Mercury Part Number: 22-807155 which is compatible and only cost $7. It also has a hex fitting which simplifies removal/installation.
Hope anyone taking on this challenge finds this helpful. Every three years or so the elbows need to be changed and patience and planning will make the job just a little easier and predictable. Everything considered, it was not that bad. Not looking forward to doing it again any time soon !!
 
Ply,
Did some measuring today. The distance from the top of the outboard elbow to the vertical edge of the engine box is about 2.25 inches. BTW- removing the electronics backing plate from the elbow is a no-brainer. Removing the plastic cover will provide immediate access to the mounting bolts.
 
Hey I wrestled so the same thing on a 31 tiara. ‘94 454’s with short elbows. My shop quoted the taller and when I asked the difference it came down to whatever fits. I think I could have gone with tall and was wondering what the advantage was if anything. I decided to go with the same short as price difference was minimal and then I wouldn’t have to worry about refitting something else.

I will say my mechanic planned a lot of time to take them apart but only took a few hours. They had to cut bolts on my firiends,etc. but then I had an issue with the surfaces on 3 parts. My shop had them swapped by crusader within a week so despite Being disappointed because we couldn’t have done both motors in one day, I was happy they stood by the parts.
 
The Taller version, is supposedly to simply reduce the risk of ingestion of water I believe. Correct me if I'm wrong. A riser block can serve same purpose. My boat currently has the taller versions, and since I have the room I'd likely stay with that level of comfort. Having said that, I also trust Mullet's opinion on these matters, and he chose to go the USA made Barrs that are an inch and a half shorter. Mullet, Ed, does his homework and has helped me immensely in the past ;-)

So after a conversation with a childhood friend, and very well respected marine mechanic in the area.. He genuinely believes that I'm changing these out prematurely. I have 4 season on them, and he's of the opinion I'm throwing away time and money a year early.

So what's the consensus here guys? Mullet how old were yours when removed? how were the passages?

Any input is as usual always appreciated... This is by far the best service oriented forum going.

Thanks,

Lou
 
Ply,
If you can comfortably keep a hand on the top of an elbowafter running at elevated RPM, and there is not an excessive amount of vaporcoming out the exhaust at speed, you are probably still good to go. Really no reliable rule of thumb for changingsince there are many variables, i.e. degree of use/disuse, fresh/brackish/saltwater etc. When I first got my boat theelbows were 19 years old but the boat had been used very little during thattime and was kept in brackish water. I had one engine running about 190 degreeswhile the other stayed at 160. Changedout the elbows only to discover the problem was not corrected. The problem turned out to be a clogged U-Tubecooler, so the elbows could have gone on even longer. My current elbows are four years old andstill work fine. I will change them outwhen they feel hot and/or I see elevated vapor and I know the U-Tube is clearand the impeller is good. Best advice isprobably to monitor temps/vapor and expect a change may be needed sometimeafter four or five years. BTW – High marksfor your mechanic !!

 
So, Ed, you are reading my ever curious mind.. you mentioned U Coolers ;-) So may I ask how they were clogged? old Zinc remnants? What did you do for that fix? Full replacement obviously I'd assume. Though they are basically a Heat Exchanger right? Do tell me how this turned out...

My mechanic is a solid friend. I drive him nuts because I'm eager to keep up with PM, but sometimes he subscribes to the old "if it ain't broken...."
 
Lou,
U-Tubes tend to clog with zinc slime, sea weed, impeller pieces, and crust. I get mine cleaned by a radiator shop. They desolder the caps, rod out the tubes, recap and pressure test. Cost about $140. New OEM units go for $400-$700; aftermarket units about $275. HTH
Ed
 
Mulletwagon said:
Lou,
U-Tubes tend to clog with zinc slime, sea weed, impeller pieces, and crust. I get mine cleaned by a radiator shop. They desolder the caps, rod out the tubes, recap and pressure test. Cost about $140. New OEM units go for $400-$700; aftermarket units about $275. HTH
Ed
Click to expand...

Ed, did you pick up any pearls of wisdom while removing those u-coolers that you may not have expected? Those oil lines seem super straight forward... but just checking.
 
Lou,
About a ten minute job. Recommend putting down some newspaper to catch the residual oil/transfluid to keep it out of the bilge. Careful not to overtighten the flarefittings.

 
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