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Purchasing engine for 20' barrelback

Posted: Wed Aug 07, 2019 11:32 am
by DavO
I've been asking related questions on this site for the past several months, and now is the time when I need to purchase an engine I will be using so that I can properly drill the propeller shaft in the bottom of my 20 foot barrelback. As for me, I am a carpenter hobbiest who knows very little about engines, so I need a turn-key solution. I was hoping to find a V6 solution to have a little extra leg room in the back seat, but not having any luck. I have talked to a few vendors who want to sell me a brand new engine to meet 2019 EPA standards. Their packages for a V8 MPI, including remanf. transmission, is coming in around $15k. Ouch.

Can anyone help with solutions that would work today, including vendors to work with? Hopefully not overly-complicated solutions, but true turn-key.

Re: Purchasing engine for 20' barrelback

Posted: Wed Aug 07, 2019 12:08 pm
by TomB
We're in similar knowledge positions, needing turn-key. If you have your heart set on a V6...https://www.michiganmotorz.com/complete ... p-244.html They can recommend and marry a transmission and send it out ready to install. I talked to Michigan Motorz several times, always got what sounded like good advice. They are the re-power experts up this way.

But I ultimately went with a small block V8 (following several others on the forum) using https://www.skidim.com/prodinfo.asp?number=1630. I am happy with their advice and product. Looking for turn-key, I got the engine, transmission, drive shaft, and wire harness from engine to gauges from them. Talk to Vince, extension 3.

Tom

Re: Purchasing engine for 20' barrelback

Posted: Wed Aug 07, 2019 1:04 pm
by DavO
Thanks Tom. I think we talked about this some on one of your posts - appreciate you chiming in. I called your guy, and they have stopped selling the PCM EX343 in 5.7. Only 6.0 now. I will look elsewhere for the 5.7. I might have some luck with a place called Chamberlains (I think).

And hopefully not to get into a long discussion, as per another post, what was your transmission ratio, shaft size, and propeller size - if you don't mind sharing?

Re: Purchasing engine for 20' barrelback

Posted: Wed Aug 07, 2019 1:12 pm
by Jimbob
I got a new mercruiser v6 mpi from Michigan Motorz. It was an i/o version. Michigan Motorz swapped out the i/o drive with a velvet drive transmission. They did a nice job. It was around 13k. You could probably save a lot of money by purchasing a re-built v6 from them, and having them mate it to the velvet drive transmission.
Jim

Re: Purchasing engine for 20' barrelback

Posted: Wed Aug 07, 2019 1:14 pm
by DavO
Thanks Jim. How long ago did you do this?

Re: Purchasing engine for 20' barrelback

Posted: Wed Aug 07, 2019 1:17 pm
by Bill Edmundson
I'm not sure how fast you want to go. But, 115 hp will get you to nearly 40 mph. Fifty MPH will take about 230 hp. I know that doesn't answer your question. It may give you an idea.

Bill

Re: Purchasing engine for 20' barrelback

Posted: Wed Aug 07, 2019 1:41 pm
by TomB
Too bad about the EX 343 no longer available, they still have it on the website.

I have a 1" shaft. 1.23:1 transmission with 8* down angle. No prop yet.

Catalytic converter, closed cooling, each added a fair bit.. $$$$$$$$$$$$$$$$$$$ I went without.

Tom

Re: Purchasing engine for 20' barrelback

Posted: Wed Aug 07, 2019 2:16 pm
by Roberta
With the locations for the rudder port and prop shaft strut already drawn on the plans, your engine choice isn't all that relevant. Placing the strut in the recommended location and using the recommended angle and drop, your prop shaft hole location is already determined. I would not alter the location of those items because you could adversely change handling characteristics and make removing the prop and prop shaft difficult.

Roberta

Re: Purchasing engine for 20' barrelback

Posted: Wed Aug 07, 2019 3:08 pm
by DavO
Thanks Roberta. I must be confused. I read that different people have different down-angles, and many people warn about having room for the prop and the ability to remove the prop.

Re: Purchasing engine for 20' barrelback

Posted: Wed Aug 07, 2019 3:28 pm
by Roberta
Down angle transmissions are a little shorter than the Velvet drive 71s and 72s. I went with a Liberty A velvet drive which is 8 degree down angle and can run full speed in either direction. They do hang lower than the 71/72s causing the engine to be mounted a few inches higher.

I offset the rudder port to allow the prop shaft to pass by the rudder easier. This required modifying the keel area to accommodate the rudder port mounting flange. Go back into the Roberta's Torpedo thread and look at the engine, rudder and prop installations. You'll get some ideas as to what is involved.

Roberta :D

Re: Purchasing engine for 20' barrelback

Posted: Wed Aug 07, 2019 3:33 pm
by Bill Edmundson
Most down angles are 8*. I think most of the plans the shaft as 12* from the stringer (14* from the keel). This means with the down angle the engine is tilted just 4* to the stringers. The keel often slopes up at 2*. If you have a straight gear the engine will need to be tilted 12*.

I know this all seems a little bazaar. Just layout the angles and will start it make sense.

Bill

Re: Purchasing engine for 20' barrelback

Posted: Wed Aug 07, 2019 5:43 pm
by TomB
The 8* down angle helped when I layed out the engine on the barrelback plan. I used the rudder location and hole location as Roberta recommends. The 8* allows the engine to set almost level, on plan at the transmission and lower in the front providing another 1-2" between the top front of the engine and the hatch. This is the drawing I used for the barrelback.
4.3L_SPEC_SHEET.jpg


It turns out I lied, I have a 9* down angle. This is the drawing for that. I think the 6L would be essentially the same.
PCM Ex383 down angle.jpg
Tom

Re: Purchasing engine for 20' barrelback

Posted: Thu Aug 08, 2019 4:48 am
by Hercdrvr
I’m a proponent of a donor hull. $4500 got me an Engine with 365hrs , transmission, shaft, rudder and the trailer. Strut was slightly bent so I bought a new one.
I had a lot of fun finding a good donor boat and dismantling it. The disassembly went surprisingly fast. It’s a one day job pulling all the parts.
Good luck, my Barrel-back journey won’t look exactly like yours,
Matt B

Re: Purchasing engine for 20' barrelback

Posted: Thu Aug 08, 2019 5:20 am
by kens
I'll second the motion for a donor boat, and you might get a trailer too.
The 4.3L V6 is common in the sterndrive boats, and conversion to velvet drive is pretty much straight forward.
May I suggest calling michigan motorz and request info on a 'kit' to do the sterndrive-velvetdrive conversion, I'll betcha they can sell you a kit.