transom plate cutout questions....my mech is giving me stories

[oops!]

the boat is at the mechanics getting the drive hole cut out.

i just talked to the mechanic who has been all day measuring for the hole.

he says because i dont know what motor is going in....a v8 (350 base ) poss a 383) or a v6 (4.3).....an alpha or a volvo....that he doesn't know where to cut the hole.......

1. he says that there is a difference in hole hight between the 4.3 v6 and the 350......he says the hole is different due to the different motors.....

i thought the 4.3 was a 350 with a giant saw taken to 2 cyls?....so....same block !

he says that the same alpha drive has to be at different heights, due to the motor size......that means if i cut the hole for the 4.3.....and mount the alpha 1 on the back.....that i would never be able to go to the 350....because the anti cav plate would be in the wrong spot. ????

2. he also says....that the volvo hole is different than the merc hole...(different sizes)........


3.....it sounds to me like horse feathers.......espec about the difference between the 4.3 and 350 hole size.....its the same durn drive....!


what is the truth guys ?

thanks
oops

 

[Don S]

Re: transom plate cutout questions....my mech is giving me stories

You might want to take the boat away from him before he puts a saw blade to it.

1. he says that there is a difference in hole hight between the 4.3 v6 and the 350......he says the hole is different due to the different motors.....

Nope, same basic height for both. The 7.4 Bravo has a couple extra bolt holes at the top with a Bravo drive, but the cutout is still the same and same basic X dimension.

2. he also says....that the volvo hole is different than the merc hole...(different sizes)........

Same hole as the SX and DPS and the newer SX-A and DPS-A. But not the same as the older 290 style drive.

 

[Bondo]

Re: transom plate cutout questions....my mech is giving me stories

3.....it sounds to me like horse feathers.......espec about the difference between the 4.3 and 350 hole size.....its the same durn drive....!

Ayuh,.... Something left behind a Bull was what came to My mind,...
I can't Believe that you're allowing Anybody but yourself to even touch that barge of your's....

You need to find a Different Rigger....

I understand the newer Volvos use the Same cut-out as the Mercruisers,....??...
And,...
#3 is Right,...
An Alpha needs to be fitted the same for Either motor....

Maybe Don might have a link to a Rigging Manual...
I've got paper copies around here somewhere...

You've just got to find the crankshaft centerline, know the distance between the crankshaft centerline,+ the propshaft centerlines,+ how far below the hull's centerline you want the Prop....

I have a couple of "Merc. Holes" that I use for templates,...
1 was cut out of an old glass boat I junked,+ another out of an old tinboat I junked...

When I refit old OMC Stringer fitted hulls,...
I use 1 of the old glass cut-outs,+ epoxy it into the rebuild...
Then all you have to do is drill the wood out of the way,.....


edit; I must have been typing Real slow with My 1 finger on this 1, although it is a rather Long post for Me,...5 Minutes after Don,..??..:redface:

The 7.4 Bravo has a couple extra bolt holes at the top with a Bravo drive, but the cutout is still the same and same basic X dimension.

Just a comment on this,... I do agree,...
But,...
The different Bravos have slightly different crankshaft to propshaft centerlines......
And,..
The Alpha, Gen.IIs also use the "Extra" 2 holes at the top....

1 more thing,...
Some of the old Mod.1s are slightly Narrower, but the holes can be redrilled to the Alpha configuration,...

Without Leaks....

 

[oops!]

Re: transom plate cutout questions....my mech is giving me stories

my friends.....again....thank you......


im going there right now

 

[bomar76]

Re: transom plate cutout questions....my mech is giving me stories

That guy is an idiot.
Go get your boat away from that hack.

 

[Don S]

Re: transom plate cutout questions....my mech is giving me stories

What you need to do is leave the transom alone untill you figure out what you are going to put there. Including year. I have templates, manuals and all sorts of good stuff. But you have to at least have a plan on what year stuff you are putting in. Then you can get EXACT info and I can give you the right X dimentions. The templace for the cutout is Volvo, but might as well put it at Mercs Dimensions. The X dimension is off by about 1/8" on some dimensions but I have pulled old Mercruisers out and installed brand New Volvo in the same hole and all worked perfect.

 

[oops!]

Re: transom plate cutout questions....my mech is giving me stories

What you need to do is leave the transom alone untill you figure out what you are going to put there. Including year.

this would be optimal.......however.

i need to water test the hull before i can make the 12 k decision between the drive and motor package. if the hull doesnt work.....or fails.....its better to have it fail with the package i have ...not a shiney new one.

the test will be with the 4.3 alpha one package.....which is what i asked him to cut.

it is my experiance....that when the work slows down..(all things being equal) ..it is only because you dont know how to do it.......(a lesson ive learned from boat building )

i took the advice of the members here and picked up my boat......he had it at a fiberglass shop.......i think he was trying to farm the work out.

i obviously have some reading to do on this forum........and my only course of action now is to cut it myself.

the good news is.......its back where i can work on it when im learning more here

again........i owe you all !

thank you
ward

 

[Don S]

Re: transom plate cutout questions....my mech is giving me stories

Well, here is as link to the 2000 or 2001 Instalation manual
http://www.boatfix.com/merc/Install/gas/86017211.pdf

Page 13 gives you the X dimension. you can read the rest of it on how to locate it on the transom.
I will have to upload the Volvo template (It uses the same spot for the X dimension = crankshaft Centerline) that gives all the dimensions for hole locations. Will post it later if you want it.


EDIT: Found that easy. Here is the template
http://www.4shared.com/account/file/69084395/1ef1e328/SX_Transom_shield_cutout_template.html

 

[oops!]

Re: transom plate cutout questions....my mech is giving me stories

You've just got to find the crankshaft centerline, know the distance between the crankshaft centerline,+ the propshaft centerlines,+ how far below the hull's centerline you want the Prop....

cannot the center line of the crank shaft be adjusted up and down by shims and left or right by moving the lag holes?.........i guess i just dont catch the true meaning of what you are saying due to my inexperiance.

(and you have no idea how much i appreciate your long posts......)

 

[Don S]

Re: transom plate cutout questions....my mech is giving me stories

cannot the center line of the crank shaft be adjusted up and down by shims and left or right by moving the lag holes?.........

Nope. What you are doing with the motor mounts is alignment. What you are determining with the cutout location is the level of the cavitation plate in relation to the keel of the boat. It should be approximatly equal with the bottom. Plus or minus a half inch, or more depending on how fast the hull is.

 

[oops!]

Re: transom plate cutout questions....my mech is giving me stories

The X dimension is off by about 1/8" on some dimensions

i was under the understanding that one eigth was the tollerances allowed?


thank you for the link.......ill read it now.....(iffen i cans understandz it )


the reason i need the cut out done soon , is.....the thickenss of the transom is not a constant,,,,,

this is due to the depth of the glass.....(i rebuilt the back end of the hull) and the fairing compound.

my plan is/was.......after the plate is cut....to take a router to to outside face of the transom..(that will be the constant)..set the router to the depth of tollerance......and just follow the edge of the cutout....(with the bit cutting the correct depth on the inside)...that should give me a starting point to level the inside edge....(where the inside plate is bolted).....

kinda confusing....i hope im giving you a clear picture

 

[oops!]

Re: transom plate cutout questions....my mech is giving me stories

Nope. What you are doing with the motor mounts is alignment. What you are determining with the cutout location is the level of the cavitation plate in relation to the keel of the boat. It should be approximatly equal with the bottom. Plus or minus a half inch, or more depending on how fast the hull is.

yes....i under stand this is the most important part of the cut out hole.....the motor can be shimed or moved to match the hole

 

[oops!]

Re: transom plate cutout questions....my mech is giving me stories

holy smokes don.....that sucker is a gold mine......gonna take me awhile to absorbe that stuff !....thanks

 

[Don S]

Re: transom plate cutout questions....my mech is giving me stories

The cutout determins where the cavitation plate sets. The motor mounts do nothing more than align the engine coupler to the gimbal bearing. Moving the engine up and down will not change the cavitation plate location one bit.

 

[Bondo]

Re: transom plate cutout questions....my mech is giving me stories

i hope im giving you a clear picture

Ayuh,...

As long as you end up with Parallel surfaces that are smooth,+ even..
Between 2",+ 2, 1/4" is the allowance,... I like to keep as close to 2" as possible...

This only has to be where the inner,+ outer transom pieces are,...
I built a gauge out of aluminum plate,...
Basically a "U" shaped gauge, with it's Legs long enough to include the required area, when passed around the cut-out hole...
I flatten the inside of the transom with a 4" grinder,+ the gauge...
While it's not as flat as the outside skin, it's flat enough so the inner plate doesn't bind,+ sits square...

 

[Don S]

Re: transom plate cutout questions....my mech is giving me stories

the reason i need the cut out done soon , is.....the thickenss of the transom is not a constant,,,,,

this is due to the depth of the glass.....(i rebuilt the back end of the hull) and the fairing compound.

my plan is/was...... Yada, Yada, Yada, yada........

Look seriously at that install manual link. That transom needs to be at a specified thickness, flatness, and parallel between the inner an outer surfaces to a certain spec. If not. It ain't gonna work my friend.

 

[JustJason]

Re: transom plate cutout questions....my mech is giving me stories

oops.....
The transom needs to be 2 to 2 1/4 inch thick. No more, no less. I know you have some holes back there already from the hook for the flip job. have a buddy on the outside of the boat hold a board firmly against the holes. You jump in and use a piece of straight wire as a depth gauge. That will let you know if your close or not on your transom.
After that all I can offer is that maybe you spraypaint the inside of the transom with some primer.... that will help you see the high and low spots better. If you need to smooth things out, instead of using bondo scrapers use a plasters/drywallers hawk to apply fiberglass. Using the handle plus an edge of the hawk should help in getting the inside of that real smooth and level.
As always....
Best!!!

We need to rename you Oceanas Coronis once you get that tug going!!!!

 

[oops!]

Re: transom plate cutout questions....my mech is giving me stories

what exactally do they mean by raising or lowering the x dimention only after product testing?

or is this just somthing that i should not pay any attention to?

im going to be constructing a 90 deg tool.....

 

[Bondo]

Re: transom plate cutout questions....my mech is giving me stories

what exactally do they mean by raising or lowering the x dimention only after product testing?

Ayuh,...

Basically,...
A Manufacturer would pop a hull out of a mold,+ build a boat...
After Testing, if the X dimention is deemed to Low, or to High,...
They would move the transom cut-out either higher, or lower on future hulls.......

In other words,....
It means absolutely Nothing to you....

 

[Don S]

Re: transom plate cutout questions....my mech is giving me stories

That is what manufacturers do to find the best location. Usually changes made on twins or single high speed hulls. Those performance boats. Most manufactures keep it to the standard X dimension.
That X diminsion is acually the centerline of the crankshaft, therefor the centerline of the ujoint shaft that goes through the gimbal bearing and into the engine coupler.