How do you add a spacer to a number4,
Do you need a shaft coupling ?
Oil tubes ?
O rings ?

You need a set longer studs ,O rings for the studs,O ring spacer/drive pattern ,and a little loctite 574 to stick the O rings in place, and for proper sealing.

And a little more gearlube.

The triangular driveshaft is long enough to add a 2 inch and a 5 inch spacer together for a total of 3 inch (or 76 mm)

there is no oil tube in the drive.


stirling

Thanks Stirling you have been a big help.I should get my new drives tomorrow.

I believe he means 2" + 1" for a total of three inches if we are talking about the old SSM IV drives. If you are buying spacers they came in two varieties, SSM IV used 7/8" diameter trim pins and SSM V used 1" diameter trim pins. They were very tough in their day and I would prefer them to "Bravos" of any flavor on a heavy boat with lots of engine torque. A shame they never made a steering gimbal for the SSM IV or the SSM V drives similar to the VIs'. Last time I looked for parts for IVs' & Vs' they were getting hard to find. Common ratios were 1.25, 1.33, 1.4, and 1.5 uppers times whatever lower ratio you had to arrive at overall ratio. The most popular ratio for race was the 1.68:1. A 1.5 upper on a 1.125 lower, the old lettering system was "W" for 1.125:1 and "S" for 1:1 on the lower. An "X" indicated 1.5 ratio upper but who knows if they were changed and someone did not keep up with the lettering system if they changed ratio. Always best to rotate them to check. Avoid the "newer" small tooth upper gears if you have a choice as they were inferior to the earlier "Capitol" gear sets. Did not have much trouble with the 1:1 lower gears but the 1.125s were far and away more popular in racing. We used to use 3M weather strip adhesive for the "O" rings. It just takes a little on the bottom of the "O" ring, if you glob it on like many did it will just stick to the opposite side of the groove and pull itself out when you split them again. Proper procedure is to locate where big "O" ring is glued together and put seam at the back. I sometimes would grasp either side of the seam and strech (yeah, I know never do that!) jus a little bit so "O" ring would not try to creep out before glue dried.Seven studs per unit, the front one was a very little shorter than the rest important to note if you put the shorter one in the upper instead of the lower you may not get much stud in the nyloc of the nut. Loc-tite 271 "red" is fine for the stud to housing threads. Don't over do it, just a thin coat is enough to hold stud and help prevent corrosion.

Oh my gosh did I type all that? Sorry to rattle on but I am an old fart that took pride in building many, many of these drives.

Nice to hear the codes that indicates the ratio,s ,I didn,t know that,I will check mine to see if its original.
How many tooth have the capitol gears ?
I am curieus what sort gears I have.

Shame merc does not supply all the parts anymore ,but there is a lot old stock for sale ,even here in Europe (Netherlands) there is a lot parts /drives for sale for resonable prices.


stirling

Ok I have just my new drives , #4s big shafts , no spacer,shafts are perfect, BUT in the front of the drive, my old drives have a bolted plate under the U joint, the new ones have an open cavity 4inch X 8 inch or so. Is something missing? No bolt holes exist ?

Boatman747;
Are your old drives #3s'? They had the front cover bolted on.

Also if they are, the #4 drive with zero spacer is five inches shorter.

Stirling;
I'll have to scare up my old parts catalogs and notes for the tooth count. It is the smallest straight cut pinion though. All the "newer" gearsets had spiral bevel gears. The only spiral gear I remember from the old sets is the 1.33 upper. I had to upgrade my membership, I'll contact you as soon as I can. I have not been on in forever and never did post much at all for many reasons. Please don't take offense if I am somewhat slow to respond.

No they are 4 s

Drives are the same lungth minus the spacer

The III and IIIa are five inches deeper than the IV or V.
The front plate was eliminated as they moved to the five drive. The plate was still on early IVs'. Maybe there were transition drives? Are you sure your new drives are not Vs'? There was a "V" stamped at the factory between the spacer pads on Vs'. And the rear cover of all Vs' has four 1/2" studs/nuts and no socket head bolts.
Been a long time, strain on my brain.