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Crusader manifolds

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bob_on_this

Regular Contributor
"We have a 1989 28' Carver

"We have a 1989 28' Carver with two 305 GM Crusaders.
Anyone done much with the Crusader manifolds?
I would really like to replace all the exhaust on my 89, but that's a couple grand for new. So I have a couple questions.

1. What is the best way to clean and inspect the manifolds and can you really predict their remaining life?

2. Do they deteriorate at the same rate, if you wanted to replace them a few items at a time, which one would you do first? (Raw water cooled, used in fresh water only)

3. Has anyone used a different set of manifolds on their inboard Carver, or does the design of the others not lend itself well on these boats?
In other words, could you use Mercruiser stern drive manifold for the same small block GM?

We have both engines out and at the rebuild shop
We did find one bent rod on the Port engine, and I think the manifolds are original, so there maybe one that's leaking....and their 20 years old! So I know what I should do, just don't have the cash right now.

Thanks
Bob"
 
"Thanks Rich, but your still t

"Thanks Rich, but your still talking over 2 grand for both engines
uhoh.gif

Ouch"
 
"Bob,

I tend to believe tha

"Bob,

I tend to believe that even if fresh water cooled you are at the end of their useful life regarding reliabiltiy. My were about 15 when due to water intrusion, I had to replace the entire cooling system on each engine except for heat exchangers. The cast iron was breaking down internally creating more problems. Needed to re-do all 4 cyl heads, pushrods, etc and it got expensive quickly.

Since you are raw water cooled,and you think they are original, you are due."
 
"Bob,
Mercruiser parts will n

"Bob,
Mercruiser parts will not work and besides they may be more expensive. Al is right, now is the time to replace them especially since you are rebuilding the engines. Look on www.ebasicpower.com for the parts. I figured the price to be around $1775.00 for 4" exhaust (including 4" risers). About $1180.00 for 4" exhaust w/o risers. If your exhaust is a 3" version then it is slightly less. I know that that is not that much less than the $2000.00 you stated but $225.00 is still $225.00. Check it out."
 
"Bob the best way to clean the

"Bob the best way to clean them is the "hot tank", just like a cylinder head. I can't say i've ever seen a detailed, comprehensive inspection method. Probably the best test is the pressure test the manifolds (Thanks to FastJeff). The risers and elbows are typically 'disposable items'. Their expected lifetime will vary, mostly by the water quality and the frequency of use.

The deterioration rate, in my experience, increases with age, expontentially and linearly with closeness to the actual water -exhaust gas mixing point. This means your manifolds get replaced with your second or third set of elbows.

Regarding different parts, I can't speak to the small block directly but can on the big blocks. (I see NO reason why the two would differ in this aspect, either). I switched from the older "log" style crusader exhaust to the Mercruiser styled center riser type. Besides changing the hose barbed adapters, I needed about a foot more exhaust hose on each side. Greg's right on the 'expensive' part; we opted for Barr's version. The best part of the swap was the stainless steel exhaust elbows. they haven't clogged in over 15 years and, internally, looks just like they did when they came out of the shipping cartons. Probably why they went NLA."
 
"Usually, water leaking in fro

"Usually, water leaking in from corroded manifolds/ risers/ elbows will cause bent rods. You may have waited too long.

Note to all: When you crank up an inboard motor that has sat overnight or more, LISTEN carefully to the starter motor. If it goes RRRRRRR--that's fine, but if it goes RRR--hesitate---RRRR, then STOP! You have water in a cylinder.

Jeff"
 
"Mark, Are you saying you can

"Mark, Are you saying you can use the newer manifolds on an older cylinder head? I like that center riser setup. I only replaced the ones I had since it was what was on there and I did not know they were interchangeable... shoot!

That would have given me more room for a different type of muffler set up that Rick had been talking about and I would have been better able to mount the generator in a center rather than port side

Bob, Jeff is SO right...Of course your engines are out of the boat now so the rest will be discovered as you dismantle it"
 
"Both engines are done, transm

"Both engines are done, transmissions are still in FL getting overhauled.
We had one bent rod, two cracked heads, and two broken pistons.
Engines had very high hours, but still ran strong, and had good compression.
Trans and Vee drives also worked good, but I wanted to get everything back to "new" as I do a two year major restoration.

The reason I mentioned the other type manifolds is two fold, one, you can get "kits" with everything for around 800 per engine, and two, I think the old log type manifolds are ugly.
Mostly the money.
My only worry is the height of the riser.
This component needs to be higher than, or above the exhaust outlet on the stern, so the water and exhaust will flow out. My setup had 8" risers and I would need to maintain that height.

Bob"
 
"..."e had one bent rod, t

"..."e had one bent rod, two cracked heads, and two broken pistons. "

Whoa! Definitely sucking water.

You can get spacers that raise the risers even higher. Assuming you have the overhead clearance, that would be a good idea.

Jeff"
 
"Most of the water-into-the-en

"Most of the water-into-the-engine from the exhaust I've seen are due to the elbows rotting thru allowing the water to enter the exhaust passage 'early' which lets it flow back into the manifolds. This makes it very easy for water to enter the cylinders during the overlap period.

Al- The eight holes straddling the four exhaust ports haven't changed from the Mark IV stuff to the new stuff. Many of the bolt-on parts swap as well.

Like Bob, I was cost conscious when I did it. Working at a boat shop and getting dealer pricing helped a lot. Saving a few pounds made it win-win. Only 'drawback' was giving up that proven Crusader designed manifold to riser joint. It's got to have 3 or 4X the surface area which has to last longer than the Merc style. So far, it hasn't been an issue."
 
Good info. I stand corrected

Good info. I stand corrected on the Mercruiser parts not working on a Crusader. I was thinking more about it all actually fitting into the engine compartment rather than just to the engine itself. On my Carver I am pretty sure that the Mercruiser manifolds wouldn't fit into my engine bay area. I agree with Mark that the manifold to riser joint gasket is a common failure point for that style.
 
"Thanks guys,
I am looking at

"Thanks guys,
I am looking at a couple options here, as I still don't know what I want to do.
I am headed down to my engine builder today, and he will bake and wash out the manifolds so we can see what we have. Still not sure if we can see any cracks even if there are any.

Can you guys tell me why, the I/O engines (I also own a 26' Excel with a GM 454 Mercruiser) have a lower riser? It the chance of water intrusion from a wave or sudden stop, less with an I/O than with a straight inboard?
Also, What are the advantages or disadvantages of using aluminum exhaust on a raw water cooled boat on freshwater?

Thanks
Bob"
 
"The engine shop could magnafl

"The engine shop could magnaflux the manifolds. Excellent tests for cracks but won't help over most of the inner jacket surface UNLESS he has a borescope or similar device to "see" the hidden surfaces.

The riser height required is driven by the hull layout. The engine OEM will specify a minimum "fall distance" from the exhaust hose connection to the transom discharge. Depending upon the hull design, the stringer layout, and other hull designer features, this distance may be satisfied without any riser. See any OEM's installation manual for details.

I/O's usually integrate the exhaust system into the package. in addition, many use a "shutter" in the exhaust. The exception is a thru-transom install where that "fall distance" comes back into play.

Unless specially treated (not cheap) stay away from aluminum on a wet exhaust. The corrosive nature of the exhuast mix will destroy it in short order. The only advantage would be weight savings. Due to the short life span (read that high maintenance) that advantage would become trivial real quick."
 
"Thanks Mark.
I met with my e

"Thanks Mark.
I met with my engine guy today, and we agree the cleaning and inspection on these 20 year old manifolds is somewhat a waste of money. He also agrees with you on the use of aluminum.
Here's what I have so far:
The old "log" manifolds rise a total of 12" above the exhaust ports and then drop 10". The drop you spoke about is about 10" between the final exhaust outlet and the transom.
Using the "Merc" style, center riser, I will see a total rise of about 8" with only a couple inches in drop, so I will see more incline to the transom with the newer style.
The only thing I will lose is the large upside down "U".
The Carver has an exhaust bypass a little above the water line, but has a flapper to keep the back wash out.

I'm guessing here, but I think I need to make sure the final "high" point in the exhaust system is about the water line in the boat.????



Hope this all makes sense.

Bob"
 
"I was following you up to the

"I was following you up to the question....maybe I've just been up too long this week.

You can get the current Crusader Install manual off their www site. Look in the owners section, then under manuals...couple MB sized pdf file if i remember. though it covers the new stuff, the exhaust requirements for the critcal distances have not changed."
 
hi all; new member and in the

hi all; new member and in the process of buying a 81 mariner with 270s. i have had it surveyed and came back in good shape all around. i need to replace one motor soon and manifolds. thinking of going with a new long block and need to replace manifolds. what are good after market manifolds for these motors
 
i need to specify exhaust mani

i need to specify exhaust manifolds and risers i suppose. i have also found that there is a loyal crowd with the mariner and with carver. any feedback with issues on this model and make would helpful. love the look and lay out of this 33'
 
"Mark,
Thanks, I downloaded t

"Mark,
Thanks, I downloaded the Crusader Installation Manual, and see they want a minimum of 12" above the water line.
I think I'm going to scrap all the old "log" style manifolds and update with "merc" style center risers. I did the math, and on the Carver I would be right at 12" with the standard set up, so I will add a 4" or 6" spacer under the elbow.

Do you guys know which is a better brand, Osco, HGE, or GLM?

I don't think I will go with aluminum, going to stay with cast iron.

Bob"
 
I'd go OSCO. No experience

I'd go OSCO. No experience with the other two but there are several postings on the other engine boards that aren't high on GLM....I don't remember seeing HGE - that search button up at the top will find them if there.

greg's point about fitting within the hull is valid. I trust you checked and have enough space outside and above the engines ("above" being really different)?
 
"Mark makes a great point. I l

"Mark makes a great point. I love those style manifolds but after going down today to look a some other fun boating projects, I found that the height of the center riser is my limitation depending on exactly where the rise occurs. I would not be able to close my hatch covers as the aluminum center beam hatch support may hit"
 
When I was looking at replacin

When I was looking at replacing the entire set up the place I spoke with "claimed" that the riser would not be any taller then the carb. Rather then find he was wrong I went with the old style again.
 
"Thanks guys,
I have both eng

"Thanks guys,
I have both engines out and sitting in the garage, so I will need to do some measuring.
I think I will have the opposite problem, however, as the old "log" style had an 8" riser, and the elbow was well above the carbs.
I will re-look at some pre removal photos and make some measurements today.

Thanks Guys
Bob"
 
"I saw the elbows going aft &#

"I saw the elbows going aft (in the earlier, "installed" photo) but saw the shaft going forward on the starboard engine and was confused a bit. figured safer to ask. I've never seen a real one.

I'd guess they have all those 90 degree bends in there to minimizeany water flowing backwards in the exhaust plumbing...I bet those 90-degree fittings make for a substantial mass."
 
"Mark,
very substantial....<[

"Mark,
very substantial....
crazy.gif

Do you see any reason why the GM Small Block 305
"Merc" style manifolds would not work?
I may need the 6" extension riser, more pipe (one 45 Deg. elbow for the outboard side). Are there any advantages to having all that iron on the old style?




Thanks
Bob"
 
Looking at those pics it doesn

Looking at those pics it doesn't look like you have room for the merc parts. I am pretty sure it will make the whole set-up wider overall. It doesn't look like you have that much room on the fuel tank side. IMHO I would stick with the proven OEM exhaust parts. They will last you another 15-20 years with no manifold/riser gasket problems you will likely have with the merc set-up.
 
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