Another Catalina 30 Exhaust Rebuild.

[yeahjohn]

I had been having some minor carbon monoxide issues, low readings on the meters after extended motoring, as well as leaking water from the Catalina 30 Aqualift muffler. I finally bit the bullet and decided to order parts and get the party started. After a suggestion by Neil I purchased a Centek #1500003 and was just planning on swapping it out. After taking off the hot section we realized that it was all original from Catalina. We assumed it was new thanks to clean wrapping on the hot section but it was simply re-wrapped old pipe. The hot section had a giant crack in the top as well as the fact that it was completely clogged. I have been having dismal engine performance and low rpm ranges since I purchased that boat this could be why... fingers crossed that the engine give me a few more knots now. Check the pictures. One issue was are having is the flange gasket seems to not be leaking or burning the gasket, we used a gasket and sealant... is there no gasket used there? Thanks.

[hcrisp]

Pipe

Is that galvanized pipe?
Howard

[hanleyclifford]

Notice the mixing of iron and bronze/brass in the section thus creating the perfect galvanic cell (with the help of salt water) - the residue is plain to see.

[JOHN COOKSON]

Any Ideas?

Notice the mixing of iron and bronze/brass in the section thus creating the perfect galvanic cell (with the help of salt water) - the residue is plain to see.

So what's the work around? How does one get rid of the brass injection port? Would an iron T fitting work? The angle wouldn't be the same.
If I had access to a welding rig I'd try to weld one up.

TRUE GRIT

[Rod Worrell]

Blocked Exhaust

First, thanks, all of you, for replying to my question about the limitation of using galvanized pipe for the hot section of our exhaust pipes in the previous "Stainless" thread. Good explanatons!

Also in that thread, Mo included a set of pictures of his "before and after" exhaust rebuild. It appears that the threaded in-line fitting with the tee for the manifold water hose to connect onto is also steel (and not bronze as on the C30 above or even my C30). So, Mo, is it steel and did you make this fitting or where can we also get it?

The other item I noticed in Mo's "after" picture was how he has the exhaust flange attached to the manifold. Mo's looks like studs with nuts. Our's happens to be bolted on, in which case, wouldn't you know that one bolt came out fine, but the other would not, eventually twisting off and causing me to successfully drill out and re-tap. I think the stud and nut version offers a better method to remove flange whenever needed down the road. Is anyone else's bolted on as standard practice?

For the "blockage" part - two thoughts: At least on the C30 example, how about using a real "tee" fitting at the first turn instead of the 90 degree elbow and putting a plug on the now available port which could be removed from time to time in order to ream out any build-up of blockage down stream toward the aqua lift? I also think what you all may be thinking and that would be that any of the crud would then fall into the muffler, causing it to next clog up. What says that the muffler isn't also clogging up anyway? Have not ever heard of flushing out the muffler. Your thoughts?

Rod Worrell - Dixie
1979 Catalina 30
#1337 TRBS

[ndutton]

The standard Universal exhaust flange attachment is bolted but you are correct, studs are (in my opinion) better and that's not limited to the exhaust attachment. Pictured are the studs, stainless set screws actually, for the exhaust flange on my engine. I also switched from bolts to studs on the water jacket side plate (MMI offers a kit), water pump and carburetor. The latter two are for convenience rather than corroded, frozen bolts.

I think the concerns over the dissimilarity of a bronze water injection fitting (such as MMI sells) in a black iron exhaust hot section are overblown for a couple of reasons:

1. The MMI fitting is not in contact with the black iron section because it's attached by an insulating hose.
2. Under normal operating conditions there is no salt water in the iron section, only starting at the bronze injection fitting and downstream.

That said, my water injection is an angled and welded arrangement in the hot pipe like the MMI Catalina style exhaust product pictured here.

[Rod Worrell]

Neil's Bac-up A4

Neil that is one fine looking restoration of an Atomic 4 (the one you got for free?)! Besides the thought of using stainless set screws (with the allen wrench head), the wiring also is inspirational. Something more to apply to Dixie's A4.

Rod Worrell
1979 Catalina 30 - Dixie
TRBS #1337

[ndutton]

Free is never free but in my case . . . .

True, I picked it up for free but then the spending began. By the time I was through I had about $1K into it, still not bad for the result. Within a month of picking up the A-4 I also picked up a seized 3 cylinder Universal diesel M25XP. I made the decision early on against resto so I parted it out over the following year, the same year as the A-4 rebuild. Just this week I sold the final part off the diesel (alternator) bringing the total sales to $950.00.

So the part-out of the diesel paid for the A-4 restoration. All told I'm calling it a wash or in other words, a true free A-4 spare engine ready to drop in.

Significant beer expense not included.

[yeahjohn]

Good info guys. I am simply glad that the new exhaust system is operational and much better than what I had in place. I had an interesting conversation about vented loops and anti-siphons with a popular mechanic down at the harbor and he suggested that a loop does not function between the manifold and mixing elbow and needs to be in line between the raw water line and water pump... I know in 100% of all catalina 30 applications I have ever seen the break is between the manifold and mixing elbow. Would placing it before the water pump serve the same purpose? I didnt really get it and smiled the entire time.

[Rbyham]

Id like to hear the answer to this question as well. Mine is looped between manifold and mixing elbow.

Good info guys. I am simply glad that the new exhaust system is operational and much better than what I had in place. I had an interesting conversation about vented loops and anti-siphons with a popular mechanic down at the harbor and he suggested that a loop does not function between the manifold and mixing elbow and needs to be in line between the raw water line and water pump... I know in 100% of all catalina 30 applications I have ever seen the break is between the manifold and mixing elbow. Would placing it before the water pump serve the same purpose? I didnt really get it and smiled the entire time.

[Rbyham]

Another question... what caused that clog? Is that salt deposit and is it dependent on running temperature. I seem to recall that salt begins to settle out about 140 degrees or something like that....

[ndutton]

SHEESH! where do these guys come from?

I had an interesting conversation about vented loops and anti-siphons with a popular mechanic down at the harbor and he suggested that a loop does not function between the manifold and mixing elbow and needs to be in line between the raw water line and water pump... Would placing it before the water pump serve the same purpose?

The popular mechanic is an idiot, not that he doesn't know but that he pretends he does.

The way either an anti-siphon valve or vented loop functions is to let air into a waterline when it's at negative pressure (suction) such as would be the case in a siphon. Allowing air into the line breaks the siphon. Consider the pressure gradient in the raw water line as the raw water pump SUCKS water from the thru-hull. A valve positioned therein would open (a loop is always open) and now you're sucking air.

No, the anti-siphon belongs in a positive pressure position AFTER the raw water pump. The water injection line to the exhaust mixer is normally positive pressure in operation but negative pressure in a siphon. That's where an anti-siphon belongs.

[joe_db]

Yes - a siphon break BEFORE the pump would prevent the pump from working. Why would anyone try this

[yeahjohn]

Ugh! So I have been chasing down problem after problem with this exhaust rebuild. After replacing all exhaust and muffler the exhaust hose ended up having a hole in it as well. Replaced the exhaust house. Now I appear to have a manifold issue. On the hot side of the manifold I can feel exhaust coming out. There is no smoke but I had a low carbon monoxide reading... Again. So chased it down and noticed air pushing out from between the engine and manifold. Is there a posibility that while messing around with the exhaust flange the manifold was loosened up?

Should I simply attempt to retorque the bolts and see what happens? Or can the gasket get damaged? Thanks!

[BadaBing]

It is an inexpensive gasket. But if you over torque the manifold studs you will have a new and exciting experience.
Could be that this is partly the result of that clogged hot pipe. The hot exhaust gas had to go somewhere. Might have blown out the manifold gasket. You "might" try giving it a little turn. Moyer recommends ,if I remember correctly 25-30 lbs on these nuts.Check that number please before you put a wrench on them.
If you are close to the recommended torque I would suspect a blown manifold gasket. Easy to fix.
Studs are not