mcraymond3

I got a set of the merc i.t.s. caps for my XR's. Do you have to pull the drives to install them?

RedDog382

I'm not familiar with the I.T.S. caps, but I have put Max Machine on my XR's and did not need to remove the drives.

Really admire your boat ... one sweet ride you're putting together!

mcraymond3

Thanks. That is what I thought. How hard was it to install the Max top caps?

shawn

Mcraymond, please take some pictures of your progress, I want to learn how to do it. How do you measure the end play to see if you need to use shims?

thanks
Shawn

hillbilly24

up until very recently Bravo uppers were non shimmable so top aftemaket top caps were just a bolt and run item. Merc came out with the new shimmable Bravo drive this year, I'm not sure what the serial break is though. If it is shimmable you will have to remove the drive, split the upper from the lower, remove the input shaft and bearing assembaly, and pull the rear cover and shift mechanism off. then install your new top cap and turn the drive upside down, unsert an old driveshaft into the upper and check rolling torque using a dial type inch pound torque wrench. if rolling torque is too low you need to ass shims if it is too high you need to remove shims. you have to wind up with the same amount under the gears set as above it though to keep it centerd so you canr just add and remove shims from the top. all and all its not that tough of a job but you need the right tools and a good factory manual.

mcraymond3

These drives are over a year old.

Sean H

that sounds like a pain... i am glad i have old drives for a change....

hillbilly24

It is a little more work but is a stringer drive becuase of it. precise backlash and tooth pattern is important to gear strengh. there can also be a small amount of power loss if gears are to tight like 2-3 HP at the prop. too loose and you give the gears momentum when you pull the prop out of the water then come crashing back in and thats when they break. by shimming it exactley it also places the load directly on the strongest portion of the gear face.

mcraymond3

All this has me wondering if I even want to switch mine out. Stupid me thought all you had to do was bolt them on.

Mr Gadgets

Aside from the fact that your older drive is not setup with this new technique, you can just measure the old cap and the new one and shim accordingly.
I use 1" parallel bars laid on the cap mounting surface. I use a bridge depth mic to measure down to the surface that the shim sits in. If the two caps measure the same, it will go together the same. If not, do the math and add or subtract the difference and use the appropiate shim.
I have measured a few of the ITS caps and they seem to be very close to stock caps. But it all depends on the run at that time. .001" doesnt seem like much, but it is. Aside from the fact that the gears were not setup for the proper, or read that tighter specs, you wont gain anything by only setting up the upper gear. The whole assembly needs to be measured and shimmed accordingly. Imco has been doing this for years. Merc is using a different proceedure to get similar results. End result the drive will last longer if properly set up..
Just my .02..... hope it helps

Dick