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View Full Version : Conversion to Rack and Pinion Helm on '93 Mastercraft ProStar 190 - Cable Length?


glgisler
01-28-2012, 01:13 PM
Because of the available clearance, the rack cable must exit the helm on the starboard side of the boat, whereas the rotary cable exits on the portside, so it is obvious the rack cable will need to be somewhat longer. I have come up with this length by disconnecting the rotary cable at the helm and routing it to the starboard side, then measuring the distance from the end of the cable jacket to the helm.
Seems reasonable, but if anyone done this conversion on a 91 to 94 ProStar190 and knows this cable length, I would certainly appreciate that information.
Gary

glgisler
03-31-2012, 02:09 PM
None of the responses to this post remain, perhaps because this was my first post and I was listed as “guest”. So, sorry I don’t remember who responded and provided that cable length recommendation, but I wanted to thank you, because it was perfect. The 19’ cable makes a very nice, gradual loop from the rack to the starboard gunwale, and down to the pass-through under the floor board. In this configuration, it is much less restricted than was the rotary helm cable, which exited the helm to port, almost immediately encountering the center bulkheand forcing a right angle turn towards the bow, then having to make a 180° bend back towards the transom.
Before the conversion, I had > 1.5” play at the OD of the steering wheel (Teleflex technical service bulletin says up to 2” is OK??), and steering while underway required some effort. Now the steering is very smooth and feels almost frictionless, with no discernible backlash (play in the steering), making it easy to hold a good line through the slalom course.
Before I started this project, I talked to both Teleflex and Skidim. Teleflex told me that as long as my helm was the Big T rotary with tilt, the rack and pinion helm is effectively a bolt on. I found this to be accurate – the rack helm bolts to existing holes in the dashboard adaptor plate (2 bolts instead of 3), and interfaces to the existing tilt mechanism. I have attached photos of this adaptor plate, and the part numbers of the helm and cable which were on the Skidim packing list.
This conversion to rack and pinion was really pretty easy and the results were certainly worth the effort. Mounting instructions come with the rack, but here’s some info not addressed:
1. I removed both the engine box and the floor board cover over the drive shaft. I also removed the driver’s seat so I could get under the dash more easily.
2. Bolts or screws which don’t have locking hardware are usually loctited, or have a plastic or epoxy patch on the threads to lock them. The tilt mechanism to adaptor plate screws, which are ¼-20, stainless steel Phillips heads, were extremely difficult to remove, to the point that I thought the threads were stripping. I wound up rounding out one of the heads, so I was compelled to remove the dash adaptor so I could work on my workbench. After getting this screw out, I ran a tap through the threads in the adapter plate, and they were fine. When I reassembled the tilt onto the adaptor, I used SS hex head bolts and lockwashers.
3. When I removed the cable support tube near the tiller, I unbolted it from the boat and slid it off the cable, so as not to change the fore and aft adjustment on the tube clamp which sets the “throw” at the tiller. I checked this when I reassembled, and the rudder travel was equal on each side of zero.
4. The only “modification” I had to make was to remove the combination radio/CD deck, which protruded behind the dash ~ 6 inches and interfered with the rack housing. I’ve never had a radio in my skiboat, so I would’ve just left it out, but since there were speakers in the boat, I went online and found a radio with an MP3 input jack that was only 4.72” deep (Dual Audio XR4110) for $45.

Cloaked
03-31-2012, 04:39 PM
Interesting. Have you had an opportunity to test it or still waiting for the inaugural CY12 launch?

Any pics of the route going in through the floor? I can't seem to picture how you routed it out starboard to pass through the foot rest and through the floor without the same contorted bends that the port exit creates.

Also you spoke of slalom course precision... does the R&P setup allow for a right-hand pull on the rudder? Or is it dead on and not have any room (or need) for the pull to negate the neutral position of steering (that can allow for the boat to drift a bit in the course guide buoys)?

I am still absorbing your comments about the install, but I too am looking for a smooth steer. What is the reference to the part at the top of the picture (SH91610P)? Is that something you added, removed?

My 93 has a 17' cable coming port side as you described. How or where does the extra 2' go and still route through the foot rest, through the floor port and back to the steering mount in the rear? Seems like a lot of extra cable.

Thanks for the write-up.
.

Tessimm
03-31-2012, 04:51 PM
Oh, that's Great SIR !!

glgisler
04-01-2012, 08:17 PM
I have had the boat out a number of times, and it steers great. The R&P is pretty much dead on, but since my rudder has been chamfered, the boat does pull slightly to the right, but you wouldn't know it unless you let go of the wheel.

Since the rack cable exits from the starboard side, it has all the space towards the gunwale in which to turn towards the front of the boat, and as it’s making this turn it can simultaneously be headed down towards the floor, so instead of two distinct bends, a sharp 90 and a more gradual 180, it’s now just effectively one bend, a continuous, gradual 180. The extra 2’ of cable length is needed to get from the boat centerline to the starboard gunwale. I have to say, that when I got that 19’ cable, I was skeptical – it looked way long.

I got some picts of the cable and helm by crawling under the bow and shooting aft. I have put them all on one page with labels. The picts start by looking at the port side of the helm where the radio can be seen, then panning to starboard. You can see that the cable lays in there nicely, with no extreme bends. I’m sure that a 17’ cable would be too short, maybe an 18’ would work (if that is available), but I really don’t see any problem with having a little extra cable – keeps the bends shallow and facilitates installation.

The SH91610P is the pinion helm. You will see that it matches the part number I listed below on the same sheet. The dimension indicated is the one that should be identical to the helm you have. If you don’t have a tilt helm, the end will be completely different, and you’d either have to order the tilt mechanism or get the non-tilt version of the pinion helm, but in that case I would advise checking with Teleflex for compatibility. I have also included pictures of the OEM tilt helm for reference.

Cloaked
04-01-2012, 08:22 PM
Thank you. I got under my dash yesterday and looked. I see what you are talking about with the exit of the cable, etc.... I am torn about the radio though. I cannot find a unit that is ~4.5 - 5" max in depth that has pre-amp outputs as basic needs for my stereo / amp. That is my only show-stopper right now. I really want the nice steering though.

I do have the tilt helm on the steering unit.

Thank you again for the write up and information. I like a slight pull on the rudder. Never had anything except that feel since my first inboard in 1979. Thanks again.

MBrandt-TT
05-19-2013, 01:33 PM
Very informative. Does anyone have experience with a rack & pinion upgrade on a '95 PS 190 or similar dash? Wondering if there would be any clearance problems with the rack.

88 PS190
05-20-2013, 01:38 PM
I've been interested in a hydraulic steering. I've always liked the feel of a hydraulic rudder.

Cloaked
05-20-2013, 04:43 PM
I've been interested in a hydraulic steering. I've always liked the feel of a hydraulic rudder.
Thread jacker....

88 PS190
05-20-2013, 04:56 PM
I can accept that. My point being that hydraulic eliminates certain factors - such as having the travel of the rack to contend with, or the routing of the cable, flexible hydraulic lines can often be turned and routed.

You have a thread from 2012 - being pulled up by a new post. Go wherever we want with this one, but IMO the main thing a ski boat helm needs is lack of play.

Cloaked
05-20-2013, 08:56 PM
Just messing with you.... I am no one to say what goes on here...

.

MBrandt-TT
06-10-2013, 01:38 AM
We did the upgrade on the '95 PS190 today and the new pinion and rack with a 19 ft cable fit great.