2112

I would like to convert the lines from the pump to the factory distribution block from #6 to #8. The factory lines go through tiny bent tubes screwed into 1/4 inch pipe thread holes on the top of the block. You can see that in picture # 1. The pressure line is labeled P1. The return line is labeled T1.

In the second picture, there are two blocked fittings labeled CV (left) and RV1 (right in picture). Are these upsize replacements for P1 and T1? If not, any other suggestions to up size without disassembling the block and machining it?

Falcon

Why are you upsizing them? #8's aren't needed and don't improve anything unless you have twin pumps, and then you only need #8's between the tee and the helm (and between the helm and the return line tee). The block is only a convenient connection point to use the engine lines that would normally connect to a standard Bravo power assist valve/cylinder, but it also includes a one-way check valve (CV) to help with multiple pump setups.
There are 2 parts to the block. The end with the P & T ports is bolted to the R & L block and can be separated. There is not any interconnection between the hydraulic connections between the them.
Give Merc Racing Service a call and they may be able to send you a diagram of the circuits and connections that is in the installation manual.

2112

Thanks Falcon.

I was planning a upsize because all my other components are either # 8 (the priority valve) or #10 (the outlet on my Hardin High volume pumps). Seemed as though there would be a bottle neck at the tiny factory prebent tubes.

Falcon

The "priority valve" is probably a block with twin inlets (from the pumps) that have check valves in them to prevent backflow towards the pumps. It also acts as a tee for the 2 pumps to the inlet (P) of the helm. You should have #8 fittings and lines from the valve block to the helm. You should also have #8 fittings and lines on the return side of the helm (T) up until you tee them apart for the 2 engine connections at the connectors on the ITS block. Double flow, larger lines and fittings. You could also remove the ITS pump and return end of the block (not the R & L) and run the pump out lines directly to the "priority" block and also run the return lines directly to the coolers after a tee someplace.
You have probably went a little overboard with the high volume pumps when you are running two of them. It doesn't hurt, but one standard pump on the Merc engines can keep up with two ITS, but without maintaining power steering if the pump engine quits. Merc turns them a little faster to help keep up at idle. One pump isn't enough though when you get to MC6 drives.

2112

Yes, Yes and Yes. The priorty valve is exactly as you describe. Also, all the lines to the helm and back are #8. The only place we are not #8 is the original lines to the original single pump. They are #6 with the very tiny pre-bent fittings from the pump.

The reason I want two pumps is for pressure shoul one engine quit. The high volume pumps are overkill but that is what I have now.

I want to keep the factory lines as they are as they are all cut and secured. I was hoping there was a simple way to upsize the line from the pumps to the factory block.

2112

Wait!

Falcon, If I understand your posts, the two blocks do not feed one another so the two piss ant small lines going into top of the "add on" block just feed through the block to the two large blue #8 lines on the bottom of the block. All I need to do is take my priority valve output and return lines and connect them appropriately to those two #8 lines and remove the outer block altogether.

Am I all wrong here?

2112

I disconnected the block. Looks like I can just connect the blue lines to the priority valve. Interestingly, the factory ran a #6 line from the block to the filter and #8 to the helm and back and to the transom blocks.

Looks like I better upsize the line to the filter (and the fitting) to an #8.
For clarification, PH is the pressure side and TH is the return side, correct?

2112

This is the priorty valve. I took the check valves out for inspection. also a different view of the filter, #6 going in, #8 out the bottom to the helm.

Falcon

Yes, you are correct, you can remove the short block(s) and go directly to the appropriate connections on the oil coolers and pumps. The short block is mainly a convenient location to use the standard Bravo style pump and cooler lines. It also has a check valve incorporated into it for the pump line, which you already have in the "priority valve" block. The small lines you are worried about shouldn't cause any problems except a slightly higher normal running pressure without load, which can be important if you are on the edge for flow at idle speeds or if you are trying to minimize hp loss and temp. They are fine with normal pumps. Large lines and fittings are important mainly because of "length". The more line you have the more restriction, size helps reduce it. If you would look at internals of the valve at the output of the pump, you would see that it has an orifice that is smaller in id than those small tubes on the Bravo style lines.