New 440 water distribution tube too long

"Hi,
Putting together new Osc

"Hi,
Putting together new Osco manifold/riser assembly's for my 440's. Put in the new water distribution tube and something didn't look right, out come the calipers and some scrap paper, sure enough the tube ends .500 from the end of the manifold, and the pipe plug goes in .470, that means the pipe plug at the opposite end is gonna almost touch the end of the tube?
I pulled the pipe plug off one of my old manifolds and it's an inch and a half from the end, not a half inch. Common sense tells me take the tube out and cut an inch off the end?
Before I cut I'd like some agreement, the old one always overheated and I don't want to copy someone elses mistake.
Thanks,
Mike"

"I'd throw the whole damn

"I'd throw the whole damn tube away (long as the water comes in the high end and goes out lower). I accidentally left one of those out of my 360s. When it ran cooler, I eventually tossed the tother three away as well.

Jeff"

"If I remeber correctly, on my

"If I remeber correctly, on my 440' the water enters the manifold from underneath the lower end and flows out of the top of the higher end going to the risers and out the exhaust? I don't have tubes either. Does this ound right?"

"Capt Ed you are correct. I d

"Capt Ed you are correct. I don't quite understand how Jeff's engines are set up but the purpose of the tube is to assure that air is not trapped in the upper/fwd end of the mainfold cooling chamber. The idea is that the coolant enters a the aft/lower end and exits at the upper end through the tube back down through the top of the manifold to the riser at the aft end. Any air present is forced back down the tube by the exiting water.

As Jeff notes, it's not so important how the water flows through the manifold, what configuration you have, it just has too without trapping air. The tube is installed from the aft end and sticks out the aft end into the top hole of the riser. For this set up you use a blocker plate at the fwd end with a pipe plug and a "no hole at top" gasket, the aft end has a gasket with a hole at the top that the pipe projects through.

Note that I did not know this until recently when I had to go through the same issue as you are. I have a different set up as it is fresh water with the water entering the top of the riser and flowing forward and up to the fwd end exiting there so both ends of my manifold have "hole at the top" gaskets. So I have no pipes, none needed. I have a solid gasket between the riser and the tail stock. The tail stock is where the salt/raw water exits to exhaust from the heart exchanger. Please see the attached Service Bulletin from OSCO. "

You have to have the tube on t

You have to have the tube on the 440 for the manifold to cool evenly. I say just cut it off and you are good.

Dan

Agreed. Only when the water c

Agreed. Only when the water comes in high in front then low out the back can you toss the copper tubes out.

Jeff

"Jeez guys, the part has been

"Jeez guys, the part has been engineered. Cutting it off or not using it may work but it's a crap shoot as they have designed it to be used a certain way. You modify it, it might work, it might work even better but unless you are a whizz at this I would highly reccommend that you not wing it. The tube is designed to project outside the manifold into the next piece, the riser! It is not too long!"

"I does not go to the riser, t

"I does not go to the riser, there are 2 holes in the aft end of the manifold above and below the elbow, water enters the lower hole and after it fills the manifold it exits via the end of the tube that is screwed into the upper aft hole. It then is connected to the elbow via a short hose and proceeds thru the elbow and riser.

Dan

Dan"

"Hi guys,
I didn't post a

"Hi guys,
I didn't post and run, I just left my laptop on the boat saturday when I bailed during some heavy rain.
Back out here this morning, placed my call to "Osco"....
I guess they're owned by "Marine Parts" or something like that now. Guy returned my call and said he called Osco and they've had no reported problems with this. I was thinking I made a "good catch" with this. Picture a gravity fead 3/4" hose, put a plate a 1/2" under it, water's still flowing, move that plate .030 under it, I ain't no "wizz" but I sure thinks that would slow down the flow of water.
I've been calling this thing a "water restriction/blockage tube" the past couple days.
Guy on the phone wasn't much help, but he did agree something wasn't right. Sure the part may be "engineered" properly, but as a guy who's spent plenty of time in an engineering department, I can tell you just because the drawing/design is right, that doesn't mean the parts being outsourced are being made properly. I was hoping to get some drawing dimensions from the guy but he did say he was gonna follow my suggestion to have Osco mate the 2 parts and see if there's a problem.
I ended cutting about 5/8" off each tube. My setup's just like the Osco service bulletin posted above. Looking inside the manifold you can see 1/2" of threads, then a 1/2" cavity (for water flow), then there's a hole for the tube to be guided through, I don't believe the tube needs to be any longer than to sit in that hole/guide. Duplicating the old setups by doing this.
A while back a mechanic was telling me Chryslers were notorious for that air pocket, usually a "service bulletin" is an correction right? I'm guessing the original 440's didn't have that tube?
Fastjeff, I know you're a senior member and I've read a lot of your posts, but my plumbing and engine angle may be different than yours, but that doesn't mean I'll forget at least one member here isn't using those tubes.
Now for my next gripe, the new style clamps thet secure the riser to the elbow, they're too tall and I can't rotate the riser past that little boss on the side of the casting. Guess I'll be salvaging a couple of those old style clamps off my old assembly's tomorrow........

Cheers,
Mike"

"Good luck, Mike. Note that I

"Good luck, Mike. Note that I mentioned (above) how yours was different from mine, and I would NOT leave the tubes out in your case.

Jeff"