Tahoe 23 engine/transmission

Designs for inboard or outboard power

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TomB
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Re: Tahoe 23 engine/transmission

Post by TomB » Sun Sep 09, 2018 6:26 pm

So the shopping/homework continues...

A starboard helm and a hole for the rudder dictate counterclockwise/right hand prop rotation. Since most engines are clockwise/left hand, I looked for in line transmission with full power forward and reverse. I came up with two, ZF-45C and ZF-63C. I didn't find anything at Velvet Drive, Twin Disk, or PCM. It looks like ZF/Hurth has a corner on the market for starboard helm. Am I missing something?

Tom

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kens
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Re: Tahoe 23 engine/transmission

Post by kens » Sun Sep 09, 2018 7:02 pm

Yeah, your missing something.
The VelvetDrive can be run in starboard rotation.........provided.........you have a starboard rotation engine.
For example, the 1:1 velvet-drive is "output rotation same as input rotation".
What that means is if you want r/h rotation shaft you have to have a r/h rotation engine to do it. It can be done.
Since 'standard rotation' engine is accepted a CCW looking at the flywheel, standard rotation is L/H.
The VelvetDrive 71c an 72c tranny can turn either way, but, you flip over the pump input cover at the bellhousing input, to get R/H rotation.
you can do it, but you must pay attention to it. It is exactly spelled out in the books and manuals.

The down angle trannys all take L/H rotation "input" exclusively, and their "output" is customer choice.
Oak is over rated, everything about it takes extra time; then it warps, splits or checks !!! :roll:

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kens
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Re: Tahoe 23 engine/transmission

Post by kens » Sun Sep 09, 2018 7:13 pm

TomB wrote:So the shopping/homework continues...

A starboard helm and a hole for the rudder dictate counterclockwise/right hand prop rotation. Since most engines are clockwise/left hand, I looked for in line transmission with full power forward and reverse. I came up with two, ZF-45C and ZF-63C. I didn't find anything at Velvet Drive, Twin Disk, or PCM. It looks like ZF/Hurth has a corner on the market for starboard helm. Am I missing something?

Tom

When they say 'full power in reverse' they are speaking bologna.
Nobody can do 'full power reverse'. After about 1/3 throttle in reverse, the prop cavitates, the stern pulls to 'prop walk' , the engine revs go wild, and all hell breaks loose, vibrations, cavitation, prop walk, calamity ensues all further throttle inputs.

When they say "full power" reverse, what they really mean is either prop rotation can be selected as "forward"

G12 is coming up and I would like to hoist a beer to anyone putting "full power reverse in front of the dock"
I gotta see that !!!!
Oak is over rated, everything about it takes extra time; then it warps, splits or checks !!! :roll:

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sscobra
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Re: Tahoe 23 engine/transmission

Post by sscobra » Sun Sep 09, 2018 9:56 pm

I am late to this discussion, so I might have missed something. I used the PCM 343 engine with their 9 degree down angle transmission. I went with a starboard helm which meant a right hand prop. The engine still turns clockwise viewed from the front so the transmission is running in "reverse" in order for the boat to go forward. Running full power in forward or reverse just means the transmission can handle full engine power in either its forward or reverse position, which the PCM transmission can do. It doesn't mean running the boat full power in reverse. The transmission is in "reverse" but the boat is going forward. The PCM transmission doesn't care what is called forward or reverse. Just set up the controls so pushing the shift/throttle control forward makes the boat go forward. This is much cheaper than paying extra for engine that runs counterclockwise instead of clockwise viewed from the front of the engine. Skip
Built the Glen-L Monaco, 2016.

TomB
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Re: Tahoe 23 engine/transmission

Post by TomB » Mon Sep 10, 2018 5:20 am

When they say "full power" reverse, what they really mean is either prop rotation can be selected as "forward"
Yes, as I look at transmissions with full power in both rotations, I am looking for a way to get correct prop rotation without the extra spending on a "non-standard" engine. Although, I have used full throttle in reverse under the category of "NO BREAKS!!!" :D :D

Skip, Thanks for your comment. I pick up a lot from your build and don't doubt your experience. Where did you buy your PCM? I am looking at skidim.com (Discount Inboard Marine). They sell a PCM ex343, standard left hand rotation. They say the PCM-40 is out of production and replaced by the PCM-80. I am, at the moment, trying to go with an inline transmission, that would be PCM-80i. They sell it and say "This kit only works with LEFT HAND rotation engines" pointing toward a port helm. I will give them a call and report back.

Tom

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Re: Tahoe 23 engine/transmission

Post by TomB » Mon Sep 10, 2018 11:52 am

I talked to Vince at Discount Marine (skidim.com). They sell PCM.

The PCM Ex 343 is still available and can be paired with a PCM transmission. UNLESS, you want to pay an extra $2000 so you can have a catalytic converter and Y exhaust shown on the PCM website. (He promised to send the EPA questionnaire to help with the converter decision. It is a one page questionnaire, I should be able to work through it easily enough.)

As Skip wrote, the PCM transmission with 1.23:1 and 9* down angle reverses the power for a starboard helm is available. They do not offer a transmission inline starboard helm installations. (He also promised to send a drawing of the EX 343/1.23:1 angled so I can check against what will fit in my boat.) The cost of engine/transmission including shipping was less than I expected. He said it is about $800 less to buy the combination than to buy the engine and transmission separately.

Tom

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Re: Tahoe 23 engine/transmission

Post by TomB » Mon Sep 10, 2018 4:10 pm

I came up with two, ZF-45C and ZF-63C. I didn't find anything at Velvet Drive, Twin Disk, or PCM. It looks like ZF/Hurth has a corner on the market for starboard helm. Am I missing something?
. Well, not exactly...

I talked with Loren at Michigan Motorz and learned that the ZF-45C and ZF-63C are inline but transmit power the same as the engine. :( He recommended the ZF-45A or ZF-63A. Both can reverse the rotation of power coming off the engine.

Vince at Discount Marine sent me a schematic of the PCM Ex343 with a PCM 1.23:1 9* down angle transmission. As Skip wrote earlier it works with a starboard helm. The transmission output is about 3" off the crank centerline. I sketched it over the drawing I had done earlier...AND IT WORKS!!!! :D :D :D :D

I have a couple of more questions for Vince, but it looks good so far.

Tom

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Bill Edmundson
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Re: Tahoe 23 engine/transmission

Post by Bill Edmundson » Mon Sep 10, 2018 4:25 pm

I have the 63a. I run it left hand. Running left they have characteristic click at idle.

Bill
Mini -Tug, KH Tahoe 19 & Bartender 24 - There can be no miracle recoveries without first screwing up.
Tahoe 19 Build

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billy c
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Re: Tahoe 23 engine/transmission

Post by billy c » Mon Sep 10, 2018 4:38 pm

Tom
Now that you figured out what will work for the Tahoe, check your local dealers. I looked at their site and it appears to have quite a few dealers in your area. They can get the package for you and also do the inspection required by most manufacturers (I am not sure about PCM but this was true for my Mercruiser.) before the warranty goes into effect. This can be especially important too if you need installation help, warranty service and may have a year before you will actually launch the boat and start the warranty.
Billy
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Billy's Belle Isle website

TomB
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Re: Tahoe 23 engine/transmission

Post by TomB » Mon Sep 10, 2018 4:45 pm

Good comments. Thanks. Do I need a closed cooling/fresh water cooling system? No plans to put the boat in salt water.

Tom

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Roberta
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Re: Tahoe 23 engine/transmission

Post by Roberta » Mon Sep 10, 2018 4:54 pm

Closed cooling systems are better at regulating correct operating temperature and are easier to winterize.

Roberta
Roberta "Queen of the Boat Builders"
Built Zip "Oliver IV", Super Spartan "Jimmy 70", and Torpedo "The Glen L".

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billy c
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Re: Tahoe 23 engine/transmission

Post by billy c » Mon Sep 10, 2018 5:02 pm

I never needed a closed system in fresh water use. You can go either way on that one.
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kens
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Re: Tahoe 23 engine/transmission

Post by kens » Mon Sep 10, 2018 8:01 pm

I been running raw water system in salt water for 10 years now, and it was a used engine when I got it.
Oak is over rated, everything about it takes extra time; then it warps, splits or checks !!! :roll:

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sscobra
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Re: Tahoe 23 engine/transmission

Post by sscobra » Mon Sep 10, 2018 10:02 pm

I bought my engine from Discount Marine. They are good people. I didn't want the catalytic system with the single exhaust. I had to go through some hoops to purchase a non smog engine from them. They just needed a note stating that I was putting the engine in a old design boat so they could protect themselves. PCM required that. I bought the engine with the fresh water cooling system and antifreeze in the engine. I didn't want to worry about winter preparation and the antifreeze keeps corrosion out of the engine. I had to reposition the antifreeze overflow tank to the back of the engine to get the engine to fit under my hatch, and the down angle transmission allowed me to lower the front of the engine which also made it easy to get under the hatch. You should have plenty of room in the Tahoe. If you buy that engine, you will love it. Skip
Built the Glen-L Monaco, 2016.

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jamundsen
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Re: Tahoe 23 engine/transmission

Post by jamundsen » Thu Oct 11, 2018 6:57 pm

What’s this winterization thing y’all are talking about? I don’t think we have that in Florida.
John Amundsen
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Work tends to get in the way of boat building

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