View Full Version : Lined up Drive Train

01-24-2005, 02:50 PM
How do you make sure that you engine tranny and shaft are lined up and how do you realign them if they are not? on a 86 MC

01-24-2005, 04:18 PM

There is a very good link in the old archive 2>it worked for me>shaft/strut alignment.It has step by step instructions.It's a simple process just alittle time consuming.

Or---- propshaft alignment.doc

01-24-2005, 05:15 PM
how do i get back to the old archives?

01-24-2005, 06:37 PM
how do i get back to the old archives?


click on "owners"

click on "team mc classifieds"

The rest should be easy to find.

01-26-2005, 06:38 PM
Read this thead here, starting w/my post about half way down this, the second page. I pretty much cover how I think you need to go about a proper and thorough alignment.



01-27-2005, 11:30 AM
I have more time today so I thoguht I'd copy and past the pertainate infor here. As you will see, I think a proper drive train alignment starts w/the strut mounting. Read on to see why...


The Prop shaft postion (centering) in the log IS important. The shaft not being centered won't cause a vibration, but it absolutely WILL cause abnormal and excessive wear of the packing, as the shaft will essentially be "pushing against one side" of the ID of the packing.

I had this very issue when I first bought my '92 (same hull as yours). When I first bought the boat the prop shaft was pushing to the side of the packing so hard, it was litereally "sawing" through the bronze packing housing -the "adjusting nut"! I determined that my strut was bent slightly, and my prop shaft had excessive runout -by putting it in a lathe and using a dial indicator. I ended up buying:
*new prop shaft from SKIDIM,
*having the prop balanced
*new strut from Mastercraft.
*new cutlass bushings.

I installed the strut first, then slid the shaft through. The strut was such that the brand new propshaft actually HIT the ID of the log! Assuming the new strut was defective, I returned the strut and got another new strut from MC. Took it home and installed it...same thing.

There was no where near enough latitudinal "slop" in the bolts/holes to allow me to rotate the strut enough to get the shaft away from hitting the log...never mind getting it centered in the hole. I removed the strut, and used a die grinder to laterally oblong the strut mounting holes in the hull. I then installed the strut loosely and sent the prop shaft through. With a partner holding the prop shaft centered perfectly in the log, I tightened the strut bolts, and verified that the shaft was still perfectly centered. THEN, I proceeded to align the engine/trans to the newly, geometrically correct drive line. This results in less friction and wear of the goofy packing and you now KNOW that everything is stright, in-line, and properly centered. FYI, I also ditched that dumb, low-tech packing for a PSS seal. The drive system is so perfect now, you can turn the prop easily w/your pinky...something that was not even remotely possible when I first got it (took two hands!).

Soooo, IMO, I would START by doing what ever you have to do to get the propshaft centered in the log, THEN move your motor to accomidate that geometry. HTH.


With regard to centering the propshaft in the log....

I just we just "eyeballed it". The centering of the shaft in the log is not SO critical that it needs to be measured, IMO, ie.. thousands of an inch, but you do want to get it as centered as possible and you can eyball that pretty good, using the log-hole as a guide. PLUS, there is enough slop in the cutlass bushings (even new) that up by the prop log, the prop shaft can be moved slightly up, down, left and right from where it wants to lie naturally in the cutlass bushings. My goal in mounting the strut, was to get the shaft as close to centered in the log as absolutly possible (+or- slop in the bushings), so that what ever type seal I chose to use, the seal would not have any side loading on it at all.

Then, like I said above, I spent a good hour or so, moving the engine/trans around to accomodate that new propshaft geometry, getting the engine/trans aligned to the propshaft...perfectly.


With regard to doing a quick check of drive line alignment...

An edit to an earlier post of mine. I was in my garage earlier this evening, and since this was fresh on my mind due to this thread, I went over and gave my prop a spin. I CAN in fact turn it w/my pinky, even dry. It's been in the garage since late September, and being in UT, that's about as DRY as you can get!