Glen-L.com

Please bare with me on this, this is a really simple question but I can't find a picture I can understand, and I've tried looking at my own boat but its far too coverd up to make anything out...

How exstally does a stern/out drive unit mate to the inboard engine?

I recently saw a stern drive removed from a boat at our marina, and having looked at pictures on the net... there is a shaft that comes out the rear of the upper stern drive section and through the transom bracket, I asumed this shaft went on through the transom, then on the other side theres a bracket on the inside of the transom that conects to the engine bell housing then the shaft continues on to the engines flywheel whitch has drive splines in the centre of it... then all gears and the clutch is within the upper and lower stern drive?

The only picture I can find of an engine and stern drive together out of a boat... makes it look like theres a gearbox there between the inside of the transom and engine bell housing?

I'm trying to work this out so I can find out how to go about mating a Rover V8 engine up to (hopfully) a alpha 1 stern drive... I've been looking and looking for any mention of the rover v8 being used with a stern drive (all I can find is jet boats) but... I'm aware that
the rover v8 is atuchally based on the buick 215 engine... and Mercury has had their hands on the engine. You would think this would make it easy to find what I'm looking for! Surly if Mercury used the engine it should be dead easy to find a bell housing (or w/e I need) to mate a Buick 215 (rover v8) up to their alpha one stern drive...

I've tried searching such terms as "Buick 215 to Alpha One stern/out drive" and also what engine Mercury produced based on the 215, but no luck!

Thanks for taking the time to read!

The motor mates to the outdrive via a shaft that runs through a gimbal bearing to the outdrive. Pretty simple process until you have to align the motor up. It takes a special tool that is around $120 and if you can insert it and remove it with one finger and very little pressure then you dont have it in right. Took me a few hours of cussing and pulling hair out to get it right.

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Why not is why!

Ah so what I called the transom mounting bracket is infact called the gimbal, thanks for that!

What goes on behind the transom inside the boat, thats the bit I dont get?

You surly have to have a bell housing? in this case what does the other end of the bell housing mount to... just the transom, or is there another special bracket, and the transom is sandwaged inbetween the gimbal and this bracket?

Does the shaft out of the stern drive that passes through the gimbal, does this shaft locate in to the engines flywheel?

A picture from the inside of the boat taken, when theres no engine in the bay but the stern drive is still attached would really help! but I can't find one.

You should have something like one of these on the flywheel and the drive shaft just slots into it, There is a plate on the back of the transom that holds the steering system and has two rubber grommets that the bell housing bolt on to.



This is the shaft that goes in.



And this is the plate.



This is the bell housing.



You should be able to get all the parts you need here. http://www.lancingmarine.com/

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Malahini, SEAN-NÓS http://www.youtube.com/watch?v=Qd6vkPjEy4U
http://www.youtube.com/watch?v=8uDVzcVpdhc
crackerbox build http://s753.photobucket.com/albums/xx17 ... =slideshow

Browsing PPT's MerCruiser Parts Finder will hopefuly shed some light on how these parts are assembled :

Query # 1 :

1. Select Mercruiser from the Product Type drop-down box
2. Select Small Block V8 Engines from the drop-down list.
3. Click on Show Models button.
4. Select engine model and click on Mounting brackets and flywheel housing

Query # 2 :

1. Select Mercruiser from the Product Type drop-down box
2. Select Alpha Drives
3. Click on Show Models button
4. Select outdrive model and click on Bell Housing

The Buick 215 isn't listed in the Small Block V8 list in query # 1, so you'd have to talk to a knowledgeable MerCruiser Parts guy, or fabricate an adapter plate to mate the Rover V8 to the Alpha Bell Housing.

Related Links :

Mercruiser engine sterndrive models Installation Manual :


http://www.boatfix.com/merc/Install/gas/86017211.pdf

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Paul Kane Chelsea, PQ

Building the Glen-L Hot Rod : http://www.boats.chelseacoachworks.com

I am interested in the Rover V8 as a straight inboard with a Velvet Drive transmission. You mentioned the rover as a jet drive, many of those jet parts should help me out.
There is many variations on sterndrives, even within Mercruiser line. IF you saw one with a transmission between the bellhousing and transom, and it was mercruiser, then it must have been their TRS drive. TRS is a racing animal that used a Velvet Drive tranny and the lower unit was direct drive for small size of streamlining. I have only seen that mated to BBC and larger.

Most sterndrives have the transmission in the lower unit just like a outboard motor.

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God Bless our Troops; especially our Snipers

Here is a link you might like http://thejetboatproject.me.uk/homepage ... image.html the rebuild is very detailed.

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Malahini, SEAN-NÓS http://www.youtube.com/watch?v=Qd6vkPjEy4U
http://www.youtube.com/watch?v=8uDVzcVpdhc
crackerbox build http://s753.photobucket.com/albums/xx17 ... =slideshow

Thanks for all the replys chaps thats fantastic! dead helpful!

I'm clear on how it works now for sure, the part that bolts to the flywheel and acepts the shaft has cleared lots up too, spot on!

Now to kuckle down a see if I can afford to do this idea I've got

I'm looking for a inboard hull (21ft it seems like) with enough space up front for a small bed to sleep two, then the plan is to install a rover 4.6 (225hp) not sure what performance I'll get with 225hp in a 21ft boat but it has to go fairly well!? I'm undesided yet though wether to build it or buy one, finding one thats a project is proving very hard though.

Ounce again, many thanks for the excellent replys Really precise!

Where will you be using the boat,if it's salt water you will have to go with a closed cooling system as the rover v8 is aluminum I think.
Might be worth looking for a mercruiser or chevy engine as it's a lot easier to get parts that match up.

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Malahini, SEAN-NÓS http://www.youtube.com/watch?v=Qd6vkPjEy4U
http://www.youtube.com/watch?v=8uDVzcVpdhc
crackerbox build http://s753.photobucket.com/albums/xx17 ... =slideshow

I'm deffinatly going closed cooling for sure, I've yet to look in to the design of heat exchangers though and wether or not I'll be making one myself (I work in the car trade and fabrication is no problem, I have both tig/mig welders myself) As far as I know theres a water pump within the Alpha 1, and the idea is to use that for cooling, so thats the feed for the heat exchanger I asume.

The reason I fancied a rover V8 over a U.S. cast lump, was purly because I'm most familiar with them. I've had a Ford Capri now for some years witch has had varios different Rover V8's in states of tune, also the weight! the U.S. lumps even with the ally heads on weigh tons!

I was planning on using the intake manifod from the rover then using a Megasquirt mapable ECU, this would run the ignition as well, cutting out the isues with dizzy's on a boat, also hopefully with injectors it will solve the problems with carbs on boats as well.

Just the alternator and starter that I will have to get marine ones (there the only two I'm aware of) I THINK the alternator shouldnt be a problem as its belt driven, so If I make up a bracket and fashion the right pully on it (CNC time) I guess I can use anything as long as the output is suitable.

As for the cooling of the exhaust manifolds, I dont THINK... I will be bothering, I'm going to have the exhaust headers facing up and have the exhaust pipes comming straight horizontal out the back so the wind gets to them (no cover on engine bay)

I've live mapped the odd megasquirt in afew friends cars from my laptop in the passenger seat while its being driven, but a boat will be very interesting to setup! I don't think I'll bother trying to tune the engine up at all with porting/cams/upping the CR, but after the Megasquirt has been delt with it should produce abit more HP anyway.

If you use closed cooling system, you need two pumps....one for raw water, and one for coolant.

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Boat building can best be defined as an endless series of
tragedies obscured by the occasional miracle, followed by a good bottle of beer.

Don't Dream Your Life, Live Your Dream

Would the engines orginal water pump not suffice? Instead of pumping through a rad it pumps through a heat exchanger?

Then the Alpha pumps through the other core of the heat exchanger?

Thats the way my 454 works. It did not come set up for fresh water cooling so I had to add it and the engine pump runs the fresh water and the jasco pump in my case takes care of the sea water.

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John Amundsen
Monte Carlo
Winter Haven, FL

Maybe it will be done by G6 and maybe not.