Broken Drive Shaft?!?!

[TMS1155]

First of all what you are not getting is the FACT that the only alignment that will affect the coupler is the alignment between the bearing and coupler. Second is that a double u-joint will not allow side loading, a single one will. But I guess if Im wrong and your right I better start calling all the customers from the last 35 years and tell them to bring their boats back for me to recheck them.
Every example you have used pertains to bad mounts. If mounts are bad You cant align eng Plain and simple.
Every car Ive seen has a double u-joint there just further apart.
Bell housing on alpha or bravo have nothing to do with eng alignment.

[Tinkerer]

NO car has a double U joint like a boat. NONE
A car has two U joints ( one at each end of the shaft.) NOT two ( double ) U joints back to back like a boat does.
remove one end of the drive shaft on any car - then go to the other end that is still attached and see if you can move the shaft up or down without moving the other end of the shaft. Now try this on the DOUBLE U joint assembly that a boat has.
See how you can move the whole assembly around - That is why a double U joint WILL allow side loading and a single will NOT.

Quote: First of all what you are not getting is the FACT that the only alignment that will affect the coupler is the alignment between the bearing and coupler.

Side loading caused by the two shafts not being lined up end for end WILL also cause the coupler to go out.

FACT - if the rear mounts sag you CAN get the alignment tool to go in smoothly by lowering the front of the engine.

IF YOU DON'T BELIEVE ME TRY IT --- i WILL PUT $1000 ON IT - ARE YOU WILLING TO PLAY???

[Tinkerer]

Bell housing has EVERYTHING to do with checking rear mount sag without tearing everything apart. The tool I made checks for rear mount sag in 10 seconds.

[Tinkerer]

Side loading ONLY comes into play with high HP boats - so if you don't work on them then you wouldn't ever find this out. You would just take it as abnormal early wear of the splines. Add enough HP and you wont have time to wear the splines ( if they are greased ) What happens is you flex the rubber part of the coupler untill it overheats and blows up. ( rubber melts )

[TMS1155]

OK, one more time and Im done Because this is going nowhere, I wont change your mind and you wont change mine!
Drive shaft in a car is the same as on the drive only longer. Take the same example you used and take off one u-joint and try to move the shaft going into the gimbal bearing (just picture the center of yoke the same as the drive shaft only shorter) you cant move the shaft side to side just like in the car. The reason for the double u-joint is to allow the drive to trim and turn without causing sideload. If you only had one u-joint it would destroy the gimbal housing and a bunch of other stuff as soon as you turn or trim the drive.
As far as getting the tool in with BAD mounts by lowering the front of the eng 2 inches you may be right but the tool would be at such an angle it would require lifting the bell housing up to get it in.
What you designed may check for bad mounts (if so I think thats great!) But it still doesnt help with alignment. If your mounts are correct tool works 100% If not after doing it enough times you know if the mounts are broken as soon as you put the tool in.
You can tell if mounts are bad just by looking where eng mounts to transom housing. If mounts are bad you can move the big washer on top of the mount(after breaking away any corrosion in salt water boat)
Im not looking to argue about this, Im just looking to help explain How the alignment is done.
(I've been doing this for about 35 years and never had a return failure on a coupler or engine alignment.)

[TMS1155]

Side loading ONLY comes into play with high HP boats - so if you don't work on them then you wouldn't ever find this out. You would just take it as abnormal early wear of the splines. Add enough HP and you wont have time to wear the splines ( if they are greased ) What happens is you flex the rubber part of the coupler untill it overheats and blows up. ( rubber melts )

Add enough HP to anything and it will break faster than it normally would. And yes I've owned and worked on a "few" HP boats over the years. The side loading you are talking about is from the engine twisting the mounts that are not designed for the H/P you putting on them. Thats why they make the offshore solid mounts

[TMS1155]

No I believe they are all the same. I would assume the bearing would swivel to compensate for the slightly different transom angles. Shouldn't matter since it is constantly swiveling for trim angle and steering.

Blackhawk, just so you know, the gimbal bearing does not swival once the drive shaft is installed the u-joints do that. The gimbal bearing only holds the back end of the input shaft in place so the double u-joint wont whip around like it does before you install the drive.

[MOBILEMERCMAN]

Tinkerer, Are you still talking about a 20 yer issue? Are you trying to sell your new fangled tool?

I too with TMS have never had recurring alignment issues. How can I or anyone trust your input at this point. This is not an argument.

High powered boats should have non adjustable plate mounts. If the rear mounts fail change them. This a simple procedure.

[DAREDEVIL]

Isn't there a different transom assembly for each different angle transom?

WHAT ????????????????

[DAREDEVIL]

DING DING DING - Blackhawk has it figured out. He IS correct.

TMS - You are wrong. the gimbal bearing swivels so even if the rear mounts drop 1/2 in inch you can still get the engine to align with the Merc tool by lowering the front of the motor. If you don't believe me try it for yourself.

Show me a car that uses a double U joint like a boat does...
The double U joint will allow sideways loading - a single U joint will NOT.
Sideways loading will flex the shaft in the coupler and blow the coupler.
The adapter I made is very similar to the TRS plate that goes onto the alignment tool.
It checks the alignment of the engine, gimbal bearing and the outdrive hat.
If the rear mounts are sagged the tool will not align with the hat.

Not to jump in here ,,,,,,but you are saying if my rear mounts sag down ( 1/8 inch ) all i have to do is lower the front and i will still have the coupler in one line with the gimbal bearing ??????? mmhhhhh makes no sense at all !!!!!!!!

[DAREDEVIL]

The only reason i know of when the driveshaft breaks ,,,,, is overtrimm ( knockeling the u joint ) or stuck drive @ wot !!!!!!!!!
And wear ( rust age ) !!!!!!!!!!!!

Later

[DAREDEVIL]

FACT - if the rear mounts sag you CAN get the alignment tool to go in smoothly by lowering the front of the engine.

IF YOU DON'T BELIEVE ME TRY IT --- i WILL PUT $1000 ON IT - ARE YOU WILLING TO PLAY???[/QUOTE]

When are u going to send me the check ????????????

IT WILL NOT WORK !!!!!!!!

[DAREDEVIL]

[QUOTE=Tinkerer;272252]NO car has a double U joint like a boat. NONE
A car has two U joints ( one at each end of the shaft.) NOT two ( double ) U joints back to back like a boat does.


MHHHHHHHHHH,,,???????? isn't it the same .......just longer ?????????

THINK ABOUT IT !!!!!!!!

Only diffrents is the car has a flange and the drive has a yoke !!

[DAREDEVIL]

QUOTE

See how you can move the whole assembly around - That is why a double U joint WILL allow side loading and a single will NOT.




how can that be if the double u joint is behind the bearing that is fixed ?????

[DAREDEVIL]

[QUOTE=Tinkerer;272252]


Side loading caused by the two shafts not being lined up end for end WILL also cause the coupler to go out.



I think u mean nockeling !!!!!!!!!! because if u trim or turn it does that and so everytime i have my 650 ft # 800 HP engine @ 7000 RPM in a turn i would blow it up ??? mmmmmhhhhh

wonder why it never happend

[DAREDEVIL]

Bell housing has EVERYTHING to do with checking rear mount sag without tearing everything apart. The tool I made checks for rear mount sag in 10 seconds.

Its the angle of the bearing that is fixed so it does not matter where the bellhousing is !!!!

ALSO ,,,if u had a flexing rear mount ( due to HP ,,which i think its due to thin or week steel ) the damn thing would vibrate that u would feel it in any kind of boat.


If the engine would sag down in the rear ,,,,,the inner gimbal assmbl would explode at the bearing ,,,u can't angle something thru it unless its to thin ,,,i think u are using an aluminum broom handle as an aligment tool ,,,then it could work what your talking about ?! mmmmhhh

This is to much for me and i am not even a mechanic ,,,,,but not even in theory that would work what your trying to explain.

I just hope your costumers read this before they hire u !!!!!!!!!!!!!!

[insanity]

NO car has a double U joint like a boat. NONE
A car has two U joints ( one at each end of the shaft.) NOT two ( double ) U joints back to back like a boat does.
remove one end of the drive shaft on any car - then go to the other end that is still attached and see if you can move the shaft up or down without moving the other end of the shaft. Now try this on the DOUBLE U joint assembly that a boat has.
See how you can move the whole assembly around - That is why a double U joint WILL allow side loading and a single will NOT.

Quote: First of all what you are not getting is the FACT that the only alignment that will affect the coupler is the alignment between the bearing and coupler.

Side loading caused by the two shafts not being lined up end for end WILL also cause the coupler to go out.

FACT - if the rear mounts sag you CAN get the alignment tool to go in smoothly by lowering the front of the engine.

IF YOU DON'T BELIEVE ME TRY IT --- i WILL PUT $1000 ON IT - ARE YOU WILLING TO PLAY???

Maybe not cars per se, but there are a lot of trucks that have double-cardan u-joints exactly like a drive double u-joint. Especially the front driveshaft in most solid front axle 4x4's.

[Tinkerer]

You guys just don't get it. Put your $ were your mouth is.

I work with couplers for a living - if the shafts dont align the coupler will go bad fast.
If you don't believe me go try it you will find that I am right.
OH and PM me for my address to send the check.

And a boat double U joint is NOT the same as a car but farther apart. The car drive shaft is supported at each end ( one by the transmission the other by the axle.) ( The boat is supported at each end also - but one end is the rubber coupler - Isn't that the whole isue )
The drive shaft can't move sideways. ( sideways force is side loading ) With the boat U joint the two U joints are back to back - if the shafts ends don't line up then it puts sideways force on the gimbal bearing and thus on the coupler.
Oh and I have been working on HP boats for 31 years. ( that is all that I work on.)
20 years or today the same still holds true.
If you think the boat is the same as in a car. Tell me what happens if you put too much angle on a car U joint. THEY BIND

FACTS ARE FACTS

If you guys cant understand what I am saying - don't argue - JUST GO TRY IT FOR YOURSELF.....

YOU WILL FIND THAT I AM RIGHT......

[Tinkerer]

daredevil - the angle of the gimbal bearing is not fixed. they swivel in their mount.

[Tinkerer]

You guys like to call names.
If you guys are not willing to go try if for yourselves - then I am done here.
PROVE ME WRONG.

Boy are you guys going to feel dumb.