Help with drystacking a 2 piece

[CompKing]

I’m running a 2 piece exhaust plate that I have done some mods to and want to dry stack.It’s a 2.4 with no stats and 1/8” washers,poppet removed with a hose off each head and one off the poppet cover.I’ve opened the top of the plate up and built up with weld the bottom rear of the plate to block the 4 water holes for the tuner and allow me to open up the middle part of the exhaust port.

[CompKing]

The way it is now warm cooling water ends up in camber A flows through the hole where the poppet used to be dumping some water out the hose on the poppet cover.The rest goes down the triangle passage B and either into the downhousing through hole D or through passage E around the back of the ports to fitting C and since I have the 4 tuner cooling holes welded all that water exits out side the housing.

To dry it up I plan on tapping hole D and putting a brass 45 elbow with a plug in the end them dill a 1/16” hole in the end aimed at the water pump for cooling.Now to dump the rest outside the housing I’m looking for opinions.

One way is to leave fitting C and let water flow around the back of the plate through passage E . Then drill and tap at F1 and install a ¼” pipe 45 elbow with a 3/8 hose.

Or I could remove the fitting at C and plug leaving chamber E dry and installing a ¼” pipe 45 elbow with a 3/8 hose at both F1 &F2.

Anyone got a opinion or other ideas?

[dan agnew]

completed the mods on our two piece we welded up like you and ran warwe around the back but instead we drilled and tapped holes straight out back of lower plate and ran hoses off brass fittings and down the exhaust housing about six inches. now the other thing is supposidly you should have one hose off the heads and leave the cross over hose as is. one dump hose out of cowling

Danny

[CompKing]

I like the idea of tapping off the back at G as the hole that feeds the elbow I have marked with C is quite small but since the passage feeding that chamber is only 5/16" I would think 1 fitting is enough.I think I'll still tap one in at F1,I can always adjust with restricters.

I was also wondering about pluging the small hole in the water feed port.Is it some sort of pressure relief for running with stats & poppet?Don't see that on the one piece, think it would be OK to plug it?

[pirogue]

compking,

I just did a 2.5 mid plate and all the cooling mods and it goes like this.

your A&E chambers are now dry on mine

your D is now a dump along with the dump hose off poppet cover.

then i dump off each head with 3/16 holes.

I have good water press. like 25 at 7k+ and i think 18 at 5k. temps never get passed 125 @ 80deg ambient but around 110 @ 55deg ambient. don't know readings on water.

I didn't notice my guide tube on water pump hsg is melted. i will have to direct water down there some how.

Also keep in mind this is a 2.5 with minimal time on mods. would hate to be resposnsible for burning your motor.

good luck

[CompKing]

pirogue,
I can see the E chamber being dry if you plug the 5/16 hole but your A has to have water as thats where the block drains to.
If you don't restrict the D hole down to 1/16 like us1 did in his one peice mods I wouldn't call it dry staked.
I think I know what I'm going to do just tring to chose the best place to add the external dumps.

[pirogue]

i plugged D and press .went sky high. you dry stack when you welded holes. I guess your going to have to play with it like i did. let us know the end result:)

[CompKing]

If you pluged D without adding some kind of extra external dump I'm sure you did have high pres:eek:
I'll see what I get for replys tomorrow but I think I'm going to dump at G off the rear of the plate and F1 off the side.

[QUICKSILVER]

If you are melting the water pump housing, you can make a baffle that seperates it from the exhaust. Use 1/16 aluminum sheet metal and make it to conform to the shape of the mid section. Just above the water pump there is a cross section in the mid housing. Make a lip that goes in front of that so it can't slide back and restrict the exhaust. At the top the mid narrows for two stud holes. Make the baffle fit in front of these. The tuner will also keep it from sliding back at the top. You can direct a little water in there too.

[pirogue]

a 1/16 hole leaves a bit more press. relief to be desired. i also stated i had a dump of poppet cover:eek:

[CompKing]

Well I haven't got any more input but between us1's how to and talking to Jay I came up with this.I'm going to run a line down to the water pump and restrict it down to 3- 1/16" holes to shower the pump.I tapped in a 1/4" pipe 90° 3/8 hose fitting off the port side and will keep the original piss tube fitting.Then I'm going to drill 2 1/16" holes somplace in the area in fig 5 angled away from the tuner towards the down housing to cool it and help keep it looking good.My down housing is out being powder coated so I can't see where I want those holes or finish mounting the cooling tube for the waterpump.

[CompKing]

Been working on the drystack some more and added a 2nd 3/8 hose dump off the other side and pluged the small 1/8 hole on the port side.the 2 dumps plus the poppet line might be more flow than I need but I can allways restrict or plug one.

[CompKing]

On the inside to keep the housing from discoloring I installed the 2 rear fittings with 1/16 holes aimed away from the tuner and at the housing wall.

[CompKing]

Not sure on the one off the original dump:confused: should I run a line down to the pump with a 1/16 hole right on the pump?Or cap it and drill a 1/16 hole just aimed at the pump like us1 did?Or do I have enough water with just the 2 in the back?

[CompKing]

Hard to get this pic of inside the housing so its not very good:(

[O/B Dude]

I am dry stacking my 260 and took interest in this thread. Those 1/16" spray holes to cool the driveshaft housing seem like a neat idea, but did you consider the problems you are likely to have with those things cloggin up with debris? I have found sand, pebbles, sticks the thickness of toothpicks and other vegetation in my cooling system. They will pass right through everywhere except those 1/16" holes. Just a thought.

[CompKing]

O/B Dude
I thought about the cloging myself and have a couple ideas there.US1 said he never had one pug on his setup so I don't know if it would even be a problem?:confused: I was hoping for some input from a Greg Moss,Jay Smith, us1 or anyone with some drystacking experience.:)

[O/B Dude]

CompKing, I IM'd Greg Moss a while back when I read something about him putting an article on S&F about dry stacking. He e-mailed me with all the info I needed. He really knows outboards, and I'm really impressed with the guy's knowledge. I talked to him about this thread and he told me a 1/16" inch hole could clog with debris and that I aughta drill two 1/8" holes for cooling the pump instead of four 1/16" holes. I thought about having some kind of nozzle to atomize the water into a spray and maybe put a screen in front of it. Then I figured the screen would definitely clog up with small crap. On the other hand, US1 has a lot of experience and I trust him too. Since I found a bunch of crud in my exhaust divider that was probably big enough to cause a problem with smaller holes, I decided to go with the 1/8" holes. Guess it depends on how much crud floats around at your favorite boating place.

Good luck and thanks for posting the pictures.

OBD

[Superdave]

We need your 2 piece article in Racers Hangout
Dave