Full Power Hydraulic Steering Conversion Help

[mphatc]

I'm about to proceed on a full power steering conversion on my Magnum 27 . . it has twin Volvo drives . . although this is not on my Donzi, I'm posting this here because I believe others might also want to know about doing this.

There is very little information online short of buying a full system from one of the major suppliers . . and I haven't been able to find a flow schematic.
I have been able to find from many folks, that creating one's own system is much less costlier than buying a new one. Looking at parts prices confirms that.

My boat has cable steering w/o any power assist, so I need to build everything . . I have the brackets for the drives, and a tie bar and two Latham rams along with the transom brackets.

who can help . . . ?
How do I size the helm?
What do I select for a helm once I know the size?
The pump, one one engine, is it a standard PS pump as used on a car?
(my application has 2 SBC engines)

Any and all help / information appreciated.

thank you,
Mario L.

[Conquistador_del_mar]

Mario,
Here you go. You will need a PS pump which is at any automotive store and the hydraulic lines (I have the one here). I am not an expert at rigging these, but this would be a good start with your Volvo drive setup. Bill

http://www.donzi.net/forums/showpost...83&postcount=1

[mrfixxall]

Mario,,for your external steering set up i would talk to George carter,i guess you can save a bunch of money by using a helm from a forklift..as for your p/s pump i would wait until you decide which power your going with..LS or the old fashion SBC take 2 types of power steering pumps.

[gcarter]

Mario;
First, pick your cylinders. The cylinder displacement determines everything else.
Determine the displacement of one cylinder, which is the inside diameter calculated
for area times the stroke will give the displacement of one side of the piston, then
find the area of the piston rod times the stroke and subtract that volume frome
the total volume of the cylinder. Then add the two volumes together.
That volume then needs to be divided by the number of turns of the helm you want
from lock to lock. The new displacement will be the the displacement per revolution of the helm.
A Char-Lynn helm has a geroter built into the back side of it to act as a volume "regulator".
The length of the geroter gives a specific volume per revolution.
The longer geroter gives more volume per revolution and fewer turns, etc, etc.
Take a look at;
http://www.donzi.net/forums/showthread.php?t=59708 post #12.
Lots of good info there.
A standard GM power steering pump is used. A reservoir may be needed.
The pump output is plumbed to the input port of the helm. There're right and left ports and a
return port that goes back to the reservoir.
Back at the cylinders, the left port will be plumbed to the inner end of the right cylinder and
the outer end of the left cylinder, and vice versa.
There needs to be a relief valve plumbed into the the left and right lines.
Also, there needs to be a low pressure filter in the return line.
There's more, just ask some more questions.

[MOP]

Question about the hydraulic lines? What ID is needed? I have fair a bit of 3000 & 5000lbs. aircraft S/S braided stuff coiled up in my stash that could use a home, I will have to check the ID to see what it is don't remember off hand.

Phil

[HallJ]

Question about the hydraulic lines? What ID is needed? I have fair a bit of 3000 & 5000lbs. aircraft S/S braided stuff coiled up in my stash that could use a home, I will have to check the ID to see what it is don't remember off hand.

Phil

3/8 with -6 ends will do the job. 1000 PSI or higher.

Mario, you will want an "open center" Steering unit.

Jeff

[gcarter]

I want to say that while I have had a good bit of hydraulic design experience many many years ago,
Jeff was really a great, tremendous help when I started playing w/my steering system.
In fact he supplied the Word Document I posted above.

[mphatc]

WOW!!! Looks like I asked the right group for help here. A bit of reading and some measurements on my cylinders and I'll certaily have some more questions.

Thank you!
Mario

[mphatc]

I called Latham Marine yesterday and spoke with Tom. What a wealth of knowledge . .in three minutes I learned more from him and he did all the calculations while conversing on the phone. I had the model numbers of the Latham rams as reference.

As I'll set this up as full power steering and run Redline synthetic PS fluid which allows for a higher temperature operation than conventional PS fluid, how should I route my cooler?

As planned my engine oil coolers will run on the water pump inlets, and my engine oil thermostatically controlled. I really desire to have both engines run the same identical cooling circuits, so adding the heat load of the PS cooler to one engine seems wrong? Or is this how it is done on dual engine set ups? this is all new to me . . .

Mario L.

[gcarter]

Virtually every Merc built has the steering cooler in the circuit. There's no concern.
The engine w/o the cooler will have slightly less heat load.
The engine and oil thermostats will make up for any differences.

[In the red]

I just did an upgrade to full hydraulic on my 06 28zx. It had the twin latham rams between the drives connected to a merc brazil valve and then a teleflex cable to the helm. Everything from the transom forward is now new. Latham recommended a 114cc helm control for these rams (they don't sell charlyn). I ended up going with a 120cc charlyn, IMCO stainless column. IMCO filter in the pressure line from the pump to the helm, and the IMCO stainless reservoir kit that taps into the cap of the power steering pump. There are lots of drawings in the IMCO catalog available on their site. Ron at IMCO NEvada was very helpful and I'm really impressed with the quality of their stainless parts. They have custom length columns available so you can get the exact reach you need. I went with the 15 degree fixed column turned upside down and it matched the angle on my dash perfect. Mine is about 3 1/4 turns and very easy to turn while running.

[In the red]

I just did an upgrade to full hydraulic on my 06 28zx. It had the twin latham rams between the drives connected to a merc brazil valve and then a teleflex cable to the helm. Everything from the transom forward is now new. Latham recommended a 114cc helm control for these rams (they don't sell charlyn). I ended up going with a 120cc charlyn, IMCO stainless column. IMCO filter in the pressure line from the pump to the helm, and the IMCO stainless reservoir kit that taps into the cap of the power steering pump. There are lots of drawings in the IMCO catalog available on their site. Ron at IMCO NEvada was very helpful and I'm really impressed with the quality of their stainless parts. They have custom length columns available so you can get the exact reach you need. I went with the 15 degree fixed column turned upside down and it matched the angle on my dash perfect. Mine is about 3 1/4 turns and very easy to turn while running.

[gcarter]

Hi In The Red, your new system looks really nice. I hope it works well for you.
Just so you know, in the picture you posted is a Char-Lynn helm.
There's almost nothing else used. They are almost usniversally used in industry,
like fork lifts and industrial tractors.
This is nothing against the systems that the major players in this niche business
offer, but for anyone putting a system together themselves, high pressure
filters aren't generally used in similar industrial steering applications, only low
pressure return line filters which are a lot more user friendly.

[HallJ]

Just an idea.........

[maddad]

This thread has really helped me to understand what a solid hydraulic setup needs. HallJ, in that series of pics with the old teleflex bezel, how did the splined shaft on the helm become a 3/4 tapered shaft in pics 4-5? Or does the wheel attach to the splined shaft? I'm putting full external hydraulic steering on my old Volvo and want to use the original chrome bezel.