Lateral Adjustment for Shaft Alignment
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Boat Maintenance
Forum Discription: Discuss maintenance of your Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=30460
Printed Date: November-17-2024 at 6:40pm
Topic: Lateral Adjustment for Shaft Alignment
Posted By: RedandWhite73
Subject: Lateral Adjustment for Shaft Alignment
Date Posted: June-26-2013 at 10:44pm
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Someday I will stop bothering everyone with questions, today is not that day. I am in the process of aligning the transmission coupling and the drive shaft coupling. I had to install 1/2" shims under the front engine mounts in order to raise the engine enough to meet the coupling. I have watched the alignment video and it provides a great tutorial. It isn't clear to me how the engine/trans side of the coupling is adjusted laterally. I attached a few pictures of the rear mount and the coupling mating approach. I need to get the engine side to slide about 3/8". Any advice is appreciated.    
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Replies:
Posted By: SNobsessed
Date Posted: June-26-2013 at 11:47pm
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R&W - You are right in asking questions if you are unsure of the procedure. In you 1st picture, there is a bolt head right above the exhaust hose (called a pinch bot). Loosen that up, it may have a nut on the other side. If the bolt head backs out, tap it a little with a hammer, as it has to float freely for adjustment. Do this for all 4 mounts. Once the pinch bolts are free, then the mounts can slide side to side. It will take some force; see 'Bones 71' alignment thread for how he used a jack. You may have to soak the rods with penetrating oil to get them to move. Good luck, let us know how it turns out. Why are you having to move the engine so much? Did you replace the strut? ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: TRBenj
Date Posted: June-27-2013 at 8:46am
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By "exhaust hose", Chris meant "raw water pickup hose". ------------- |
Posted By: RedandWhite73
Date Posted: June-27-2013 at 11:11am
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Thanks for the reply SNobsessed. That seems pretty straight forward. My thinking was to get the engine/trans aligned laterally, then fix the up and down. You are correct as for the reason for the large adjustments. I hit a rock pile, sheared off the rudder, trashed the strut/shaft/prop, and ruined the fiberglass under the strut. I replaced the strut with the same model (6A6), but when placed next to each other they seemed slightly different. Maybe its just my eyes playing tricks on me. One last question. I can't fit my 1 1/16" socket in between the couplings to torque in the shaft side coupling. I thought I could either remove the packing from the stuffing box and screw the retaining-housing (pardon my incorrect nomenclature) side all the way down to gain the extra inch or two, or cut length from rubber hose portion. What are your thoughts? |
Posted By: TRBenj
Date Posted: June-27-2013 at 11:42am
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I did the same strut replacement on our BFN (original 6A to replacement 6A6) and noted some significant casting differences as well. We chose to alter the base of the strut in order to get it aligned with the log properly... took nearly 1/16" off the forward mating surface (down to about nothing in the rear). How does yours line up with the log when the shaft spins freely? Thats the most important thing to check before proceeding with the forward half of the alignment (so dont skip this step!). The packing gland and log hose should be removed for this. Those 2 methods of increasing clearance to get the socket onto the ARE will both work... doing both might make your life easier. I assume you were planning to replace the packing anyways while you had it all apart? ------------- |
Posted By: RedandWhite73
Date Posted: June-27-2013 at 12:06pm
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I spent quite a bit of time getting the log and strut to align perfectly before I proceeded to the forward alignment. I had to shim the back of the strut with two washers (different thicknesses) in order to get it properly aligned. I was amazed at the difference in ease of free spin when it is properly aligned compared to even slightly out of true. I also replaced the packing with a product from West Marine. Is there any reason the log hose is so long? |
Posted By: TRBenj
Date Posted: June-27-2013 at 12:10pm
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No, that log hose can be cut down a good bit... so long as the packing gland and log dont bottom out on each other, youre good to go. ------------- |
Posted By: RedandWhite73
Date Posted: June-28-2013 at 10:48am
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I got log and lateral adjustment taken care of last night. Which brings me to my next question: When I join the two couplings together as I tighten the four bolts it becomes next to impossible to spin the shaft. I assume this means my alignment is still slightly off. Is the best way to adjust this to leave the couplings tightened together and tweak the up/down motor mounts until is spins like it should, or should I detach the couplings, then make adjustments? |
Posted By: TRBenj
Date Posted: June-28-2013 at 11:04am
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Detach the couplings and align the powertrain to where the shaft spins free. Otherwise, you would have no idea which way everything needed to move. Three thousands (.003") is the maximum difference you can have between any 2 places on the coupler faces and still be within spec. You may want to watch Pete's alignment video. When youre done and are reattaching the couplers, you should be able to spin the shaft with your hand pretty easily. The prop should move with one finger. If either of the above is untrue, then youre likely still bound up and misaligned. ------------- |
Posted By: Robb
Date Posted: June-28-2013 at 2:52pm
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This isn't as straightforward of a task as some might think, but Tim is absolutely correct..............you must align the motor with trans to the shaft's "sweet spot" within the log. When I did this a couple of years ago, I made a v-block out of wood for the shaft to rest on so that I could figure out the shaft's sweet spot (centered and spins freely) within the log. Once you have it, then you can easily adjust the powertrain to the shaft coupler without it moving on you. It was then easier to figure out which way the powertrain had to move in order to achieve <= .003" gap between the faces of the couplers. The rest was history. |
Posted By: RedandWhite73
Date Posted: June-28-2013 at 3:13pm
| I think I underestimated the tediousness of the process. I will have to spend more time lining it up first. Thanks for the tips. |
Posted By: Gary S
Date Posted: June-28-2013 at 3:59pm
If you have a dirty neutral would you be able to do that? I am on the verge of a dirty neutral. Sometimes it turns most times not,but if I disconnect the shaft from the trans,the trans does not turn all that easy. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
TRBenj wrote:Posted By: RedandWhite73
Date Posted: June-28-2013 at 7:52pm
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Thanks for the alignment tips. I have one more question. I was able to shim the front motor mounts to them where I needed. Unfortunately, the rear motor mounts are about 1/8" too short. I made some steel shims to put between the mount and the stringer and removed the three lag screws on the top. I was unable to find any other bolts holding the mounts in place after thorough examination. When I placed the jack under and tried to raise it, the mount wouldn't budge. I am worried about putting too much stress on the fiberglass as the boat is no spring chicken. I also decided against putting jack under the rear coupling as I imagine it is pretty sensitive. Does anyone have any helpful tips to raising the rear of the engine? |
Posted By: TRBenj
Date Posted: June-28-2013 at 9:17pm
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Can you get a bottle jack under the exhaust manifold? If not, you can always lift from above. A chain bolted to the rear of each head and a come along will lift the rear up pretty easy. ------------- |
Posted By: RedandWhite73
Date Posted: June-28-2013 at 9:37pm
| Good idea. I'll give the come along a shot in the morning. |
Posted By: gR@HaM
Date Posted: March-11-2014 at 9:50pm
An old thread I know but would be interested to get the answer on this, I too have the beginnings of a dirty neutral and the trans is difficult to turn ------------- '82 Ski Tique |
Posted By: 8122pbrainard
Date Posted: March-11-2014 at 10:46pm
Graham, Unfortunately the only cure for a dirty neutral is a trans rebuild. What is happening is the clutch plates are warped and dragging. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: SNobsessed
Date Posted: March-12-2014 at 1:27am
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My boat has had dirty neutral since I bought it 7 years ago, has not gotten any worse. ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: gR@HaM
Date Posted: March-12-2014 at 6:13am
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Thanks, understood. Although what I'm really wondering is whether the occasional dirty neutral explains the stiffness in turning the trans output coupler or there could be more to it. Is your prop more difficult to turn once attached to the trans? ------------- '82 Ski Tique |
Posted By: TRBenj
Date Posted: March-12-2014 at 11:08am
| You should still be able to rotate the prop with one finger. If you cant, its not aligned properly. |
Posted By: BuffaloBFN
Date Posted: March-12-2014 at 11:23am
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IMHO- the strut should be mounted right to the hull. Vibration will be significantly reduced. ------------- http://correctcraftfan.com/diaries/details.asp?ID=2331&sort=&pagenum=12&yrstart=1986&yrend=1990" rel="nofollow - 1988 BFN-sold "It's a Livin' Thing...What a Terrible Thing to Lose" ELO |
Posted By: gR@HaM
Date Posted: March-12-2014 at 2:15pm
The trans is hard to turn on its own, it wouldn't get that much easier after attaching the prop.. ------------- '82 Ski Tique |
Posted By: TRBenj
Date Posted: March-12-2014 at 2:20pm
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How are you basing "hard to turn on its own"? By hand, on the output coupler? That only has a 4-5" diameter, so a 2-2.5" moment arm. At the prop, you have a 6.5" moment arm. I have several trannies with dirty neutral and when properly aligned, I can spin the prop with one finger. |
Posted By: gR@HaM
Date Posted: March-12-2014 at 6:00pm
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Ok Tim, I shall recheck once properly dialed in. Thanks ------------- '82 Ski Tique |
Posted By: MrMcD
Date Posted: March-13-2014 at 4:17am
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The dirty neutral should not affect your prop alignment check. Leave all 4 bolts out of the coupler, clean both mating surfaces very well. Coat the mating surface with a very thin film of grease. The coupler will mate up and center with the trans when properly aligned and spin freely in the coupler. The Trans does not need to turn while you align it. Just spin the shaft but be careful to not let it slip to the rear as you spin the shaft. I do not understand the reason for adding shims. All 4 engine mounts can slide in and out and up and down unless they are stuck in current position. If stuck, start spraying them with penetrating oil. You might even add heat to help pull the oil into the adjustment slides. Tapping on the slides may help get the moving. If it does not spin freely your alignment is still off. Does this tranny have good oil in it? I was able to easily get my new shaft within .0015 at the coupler last month. I never added the bolts in the tranny connection till the coupler was in perfect alignment. Thanks to many tips on here. I used the idea for a wood block with a v notch, it was necessary to eliminate shaft sag while working on alignment. I set the wood so the shaft was in the log center and spun free in the sweet spot. Then aligned the engine to it. Easy 1 finger spin of the prop now. |