Alignment still an issue
 

In getting my engine and gimbal bearing properly aligned it's dead on. The problem is I needed to locate the center line of the crank roughly 1-1/2" to left of the hull center line. I can determine this just from eyeballing it, but I also took measurements. I realize my hull may not be perfect, but this seems extreme. What could be a probable cause for this? My exhaust is thru hull, and I'm going from manifolds to CMI elbow top headers. It's a cinch the tail pipes are not going to line up with the original holes. This is what has me concerned with the engine seemingly cocked to one side. The plywood on the transom was replaced along with the engine bed. I still need to determine where to drill the front mount holes. If I move the front of the engine to what looks to be centered, the coupler will not line up under any condition. I,m stumped and this problem is holding up the whole project. I would greatly appreciate any opinions!

What kind of boat.... Bayliner??? Sorry I had to ask.

The transom assembly can’t be square n relation to the stringers. If this is true the boat was not constructed properly or the transom is soft and the inner plate is cocked. You can check easily with a framing square or mark each stringer at 2’ from the transom and the measure diagonally from each transom plate mounting ear to the mark on the opposite stringer. The measurements should be equal if the transom plate is square.

The boat is an '88 Nordic Crestliner Rampage 26'. Not high end, but probably comparable to a Wellcraft of the the time. I can't say what position the original block was in. I never really took notice. I doubt it's a case of soft wood on the transom. I replaced it last summer. I also tightened the transom plate bolts as evenly as possible. I would think a diagonal measurement should tell me something. It's hard to comprehend the transom would be off square. Maybe I should mention the transom is pitched back maybe 12 degrees if that has any relevance? Common sense tells me the geometry of the transom plate dictates the location of the block. Would it not also be in relation to the transom assembly? Would it be feasible to shim one side of the transom plate? If I can't figure this out, I may just have to go with what appears to be a cockeyed engine! Or is it???

First, there is NOTHING straight, square or true on a fiberglass boat..lol

When I raised my X we located the X on the back of the transom, centered the jig to that, drilled and cut. Then mounted the transom assbly and lowered the motor in and snugged the ream mounts in the bellhousing, then used the hoist to align it so the alignment bar when in and out easily, left the bar in and drilled the front mount holes and tightend everything down.

Once the transom assembly and innerplate are on, the alignment bar is going to dictate where the front mount goes. It may not look or seem right, but the bar is the truth

I agree. It can be very hard to get a precise measurement or reference where a glass hull is concerned. I'm trying to figure out if I'm seeing an illusion or is it really that far off? Measurements tell me it is, but can I trust them? My eyes looking at the center of the keel (if that's what it's still called?) tell me I'm right!

Have you tried to loosen one or both of the rear bolts? If you really are that far from centered they should be in a real bind. Did you square the gimble bearing up before you started? I get everything lined up mathematically before I drop the engine in and the adjustments are always very minor after that. The engine has to be perpendicular to the inner plate side to side and up and down. I use straight edges and a framing square.

First I had an issue with a new bell housing because of the new style bushings. I had to swap out the double spiral for a single lock washer. That worked out well. I'm measuring from the edge of the inboard decking (floor boards) to the shaft of the circulating pump. When the block is centered, the rear mount bolts tend to bind. This tells me the block is not square to the transom plate. I also used a drywall T square from the transom along the length of the block as a reference. It can be tricky with a pitched transom. I have a chain hoist at the front and rear of the block, so making adjustments isn't too difficult. I had to nurse the gimbal bearing a bit, but the alignment bar seems to favor the engine off to one side. I'm beginning to think it is what it is, and there is nothing I can do about it. Unless of course someone has a solution. I appreciate the feedback!

Not sure what is going on with your boat but if you set your mounts up so they are exactly square to the inner plate you will be within ****hairs of the goal. Here are some really bad pictures of the important measurements.
https://cimg2.ibsrv.net/gimg/www.off...ea874e29b.jpeg
https://cimg4.ibsrv.net/gimg/www.off...2a12b47e8.jpeg
A is from the starboard mount stud to the port transom plate bolt and B is the opposite. C and D are between straight edges laid across front mounts and rear mounts.

Sorry to hear about your issues. That sucks but certainly not the first time for something like this. Like phragle mentioned nothing truly square in a wooden or glass etc boat. I might not be getting a 100% but can you shim anywhere to find a happy medium. My biggest concern would be the potential stress on the side load of seals / bearings. I might have missed it but if you drop your transom mount bolts in place from what I understand is your engine is not parallel to your stringers resulting in not mating with the front mounts. If you can get the drive on without force is it possible to do as motioned above with shimming or offsetting forward mounts. Kinda funny I've used a drywall square myself in the bilge for various reasons over the years but typically leaves me scratching my head for reasons like phragle said.

Have you tried turning the engine over at all? Could be your coupler is just stuck in one position. Put your alignment bar in and hit the bar with a rubber malet from side to side a couple times. Loosen you rear mounts and rock the engine around a bit. Retighten the rear mounts and then check your alignment with the bar. Something just may not be seated all thr way.
Steve

ph1971. Thank's for the diagrams! I get what your saying. I can't take the engine out but I can raise it a few feet off the stringers. I will give it a shot. Thank's again!

I tried everything you said and then some. The bar refuses to go in unless the block is off center. At one point it was dead on. This sure is a mystery!?

My boat may very well have come from the builder that way. I did the entire engine compartment over so I will never know. My new stringers are of the same dimensions and very close to the original locations and everything looks kosher. I intend to try what ph1971 suggested. If I come to the conclusion my transom is off somehow, then shimming one side of the transom plate is my only option. Just for the record, everything is new except for the transom assembly. it was rebuilt. Thank's for the feed back!

Wow, what an issue.. Regardless, seems the motor must be square to the TA so..front mounts must go where they want once motor square.

what did you torque the transom nuts to?does it look like the transom may be crushing to 1 side?

I also have been scratching my head over your situation. Only other thing can come up with is check the fitment between the back of your block and the flywheel cover assembly (bellhousing in a car) . Make sure it is not somehow cocked or binding somewhere, perhaps something wedged between them (like the ground cable or a washer). The flywheel cover not mating properly to the rear engine block would produce this. Keep us posted.

If I remember I may have torqued to 35. The inner transom is solid, no crushing evident. The coupler and flywheel housing were assembled out of the boat. I replaced the 2 pieces 3/4 plywood on the transom and glassed over it. I can't swear there is no deviation in my work. I'm trying to figure out how much of an offset in the transom plate would affect engine alignment. For example, what would 1/8" translate to at the front mount?

What kind of power you running. My only advice would be to get measurements as ph1971 illustrated and would determine where the problem is. If it’s in your work **** happens but as long as your confident you have the bond and strength needed just adjust forward mounts accordingly and run it. Someone here might be able to determine whether you can shim the inner assembly and caulk. I have no clue on that but I’d say you might have some deviation in your work. Take your time and get it the best you can for safety and performance and go have fun.

Are all the transom bolts showing the same amount thread?

Hi. Power is 600 hp 502 built up from a GM crate short block. I usually go overboard when it comes to building anything. I would say my transom job should be reasonably uniform. Nothing about the transom plate looks weird or out of place. Shimming said plate would be very unorthodox, but possible. Side loading on the grease seal may be the only down side. I'm sure the gimbal bearing can compensate. I mite just say fork it, and move forward. I don't usually give up on something until every possible option has been exhausted. Happy boating!

Ok so not your low hp 454/330 hp deal. You'll get it right. It's always something... Trust me.

This is my last thought on this, Be very careful you did not crack the inner transom plate while torqueing. They are very easy to crack and would exhibit your symptoms. Check very closely for cracks, modifying Ph's diagrams you can check this and also the transom squareness to the stringers. 3-4-5 formula will be very helpful..

Stupid question, you are moving the gimbals bearing to align it with the center line of the engine where it should be on the centerline or are you moving the engine to align with the bar in the gimbal as it happens to be sitting in the transom assembly (TA) and that is giving you your 1 1/2" cant from center line ?

As simple as it sounds, some people that do their own work haven't realized the gimbal bearing functions as a gimbal... (some techs haven't!)

How much movement can you get in the Gimbal with the Alignment bar? ( not putting it into the coupler just moving the bearing?)

On a single I/O the center of the transom / input shaft in directly in line with the prop shaft which is inline with the crank and mounted in line with the keel for straight tracking. To have your rear engine mounts bolted on the inner TA and the engine dictating the true center-line is 1 1/2 inches port or starboard would indicate that the drive/TA is not centered on the transom or the process is off/

the drawings in earlier posts and Glenamy's 3-4-5 are on the money...

A 330 was the original power plant. Spun a bearing a few years back and decided I wanted bigger balls under the hood. I went for a better exhaust system, FW cooling and a new Bravo X. Talk about being over budget. My wife is a very understanding girl!

I agree with the above. Center the engine in the boat and tighten the rear mounts. Install alignment tool into coupler and using a mallet tap up/down left right on end of mallet until alignment tool slides in and out easily. This aligns the gimbal bearing to the engine. Install front mounts and align again.

Let us know what you come up with when you get back at it. You've got some pretty good advice here to move forward. I still can't help but think one side or the other of your inner trans is sucked in tighter. Those measurements will get to the bottom of it quickly. Btw be careful measuring when engine is lifted above you. If you can get it above your deck slip some 2x4's nailed together or whatever you can come up with and lower engine so weight is supported from both above and below. Had a 92 z28 fall on me years ago. Damm near bit it. Something that always stays with me.

Also never share your hobby expenses with YOL. That's almost as bad as using a credit card at the strip club. Lol.

I only found out recently on this forum that a gimbal bearing actually does gimbal. I thought it was in reference to the gimbal housing. I did try using the bearing to get the alignment with the block centered with no luck. The bar doesn't even go in. I installed the drive assembly with an empty engine bed. I used a new TP and took great care tightening up the bolts. No cracks and everything looked good. I have 2 chain hoist front and rear of the engine. the support rigging is overkill so I think I'm ok. I doubt I can get the block above the deck. What is the "3-4-5 method. left right center? I will take diagonal measurements of the mounts. That should show me where I'm at!

It's not easy to hide that kind of money. The truth will set you free! :)

If you are using the newer style rear mounts , you should be using fiber washer only, no split/ lock washer( double or single) between bell housing and inner t/a. Once rear bolts are installed and tightened (with alignment tool out) , support engine and transfer chain to lifting ring at thermostat housing area (engine centerline) only ( no chain support anywhere else on engine). This lets engine center itself. Lift/lower engine until alignment tool enters coupler ( never use hammer , no matter how tempting) . When alignment feels decent, mark mounts and drill.

I’m certain that it’s only the metal washer and you omit the fiber washer on the new rubber coated transom assembly.

Not to offend or disrespect you and your capabilities but your doing something wrong or missing something. There is no voodoo to engine alignment. Bolt the flywheel housing to the inner plate, install the the alignment tool with the front of the engine hanging. Then set up your front mounts. If you can’t get the tool in the coupler with just the rear mounts in, the inner plate is not square to the outer, the flywheel housing is cocked or the coupler is twisted. Time to start over at step 1

I tried every possible combination at the rear mounts. Lock washer, flat washer, no washer. A single lock gave me the best results. I had help, and after pinning the rear mounts only snug, we gradually raised the front. Dead center of the block and hull level. Bottomed out was the sweet spot. Only until gradually moving the block left (port) did the the bar begin to show little resistance and uniform grease marks. I tried to adjust the bearing to get closer to center, but the bar became tighter with each attempt. Everything is good with the coupler, flywheel housing, TP, and TA! It was put back in exactly the same location it came from. What is the 3-4-5?
I take no offence or have an arrogant attitude toward any advice. I exercise patience when I work, and strive to be the best mechanic and craftsman I can be. You haven't offended me in any way!

"The only true knowledge consist in knowing that you know nothing!"
So-crates

3-4-5 is a method of checking for square. Essentially you measure out a triangle 3’ on one side, 4’ on the second side and if those two sides intersect at 90* the third side will be 5’. It sounds like you have found alignment to me. I would button it up and go boating.

I feel compelled to get to the bottom of what's causing this problem. Is it my hull or did I screw up somewhere? With all of the hours I have into this project, it's kind of frustrating to run into something like this. After this weekend I should know for sure. Thank's to everyone for your input!
Bob.

Is there an OSO member near your area who could potentially look at what's going on. I think it comes down to recent transom repair.

Yes, a fresh pair of eyes might spot it in no time.

I do have a friend who owns a machine shop. (A good friend to have!) He may not be familiar with boats, but I can get his opinion. When the first sheet of ply went against the transom, it was quickly clamped in every available place with bolts and pieces of wood for backup plates. Exhaust cutouts, cleat locations, swim platform holes and the opening for the drive assmbly. I think you get the idea. I preformed some surgery to find out if something may have gone wrong at the transom. I used a 7/8" hole saw to extract 2 plugs just above the TP. Nothing wrong with the plywood and a good laminate of the 2 layers. Peeking into the holes I could see the outer layer of the plywood that ripped off the plugs was still attached to the resin. I thickened the resin used as the adhesive with glass beads. I would have preferred to use foam if it wasn't so damn expensive. I come to the conclusion it has nothing to do with the transom repair. At least as far as I can tell!?

A squared + B squared = C squared! Basic geometry. I used it to square up my shed foundation. Duh!

Please let us know the final answer. Very curious