Engine allignment - help needed please

sbrockman

sbrockman

Active Member
Joined
10 Mar 2005
Messages
56
Location
NE Scotland
Visit site
Sorry if this appears a bit obvious to some of you. I want to check my engine/prop shaft alignment. I believe it involves slackening the bolts on the coupling and checking the gap with a feeler gauage but am not really sure how to proceed.
How do I go about this? do I slacken all of the bolts on the coupling at once?

Any help or advice appreciated
eng-prop-3.jpg


Many thanks

Steve b
 
If you are saying that there is only one bearing, and you have a flexible coupling, then I have the same problem, and nobody has come up with a satisfactory answer! To check it against movement in the cutlass seems a bit inaccurate. Do you have a stuffing box of a deep sea seal or similar? Presumably a stuffing box gives a fair bit of rigidity and maybe this is enough. I do not! You need to slacken all the bolts and take out the flexible coupling, assuming there is enough shaft to mate up the two surfaces, and assuming the shaft is rigid enough with whatever quality of bearing arrangement you have. may depend on how worn your cutlass is. Will be interested if you get a satifactory answer.
 
I assume the white thing is a flexible coupling in which case to do the full job you have to take it out and measure the gaps between the two metal coupling halves with feeler guages if they can be pulled close together or gauge blocks and feelers if not (for which there are plenty of explanations how to do that on the internet if you do a google, including how to support the shaft while doing so).

HOWEVER my main contribution is - if the white thing is a flexible coupling and it AND its flat surfaces are true and in good condition, then I have aligned my own engine by not loosening or releasing the coupling at all by simply laying a straight edge (eg a steel rule) across the face of the flexible coupling and adjusting the engine mounts until the flexible coupling is flat when in all angles of rotation. I have found this is sufficient to get my own engine ok in alignment, but even if that were not so, I think I would do the same thing to get it at least approximately right before doing the more frustrating measure between the faces method.

If you just want to check that the alignment is ok, which reading your post literally is what you want to do rather than go straight into doing an alignment, then the straight edge is the way to go if that is possible.

John
 
From what I remember, you measure between the coupling bolt head and the shaft plate with a feeler gauge (at the arrow), rotate 90 degrees then measure again, then again and again for all 4 bolts. You do this when the bolts are tightened.
szhahz.jpg

These measurements should all be the same. If not adjust the engine mounts up or down until they are. Somewhere, I have the R&D instructions, if I can find them, I will post them.

Even better, found their website here.
 
Remove the R & D completely and see if there is enough lenth in the shaft to mate the serface of the box and the shaft coupling. this is far more acurate it will also tell you if the engine if phyisically out hight wise or side wise and not just angulaly. by the looks of it you will also need to remove the rust from the two faces before checking as it will give inacurate readings.
 
Looking at your link Mr Escargot it looks like with that make of flexible coupling the straight edge solution will not work due to the boss on it (although looks like no boss on the engine side of it in the posters photo?).

Still, may be useful to know for others.

John
 
I've only just done this on a new engine installation and as an engineer this is what you need to do.
Firstly do an initial check by releasing the flex coupling from the gear box -then slide it back up and try to mate it with the gear box coupling - if it goes together first time the alignment is OK - but if it won't go together then do the following.

1. Remove the flexible completely.

2. Pull the shaft forward until it meets with the gearbox coupling.

3. If it doesn't meet then release the shaft coupling bolts and slide the coupling up the shaft until it does - then re-tighten the shaft bolts.

4. The two should mate but they probably won't - so adjust the engine mount bolts until they do. This can be achieved by using 2 sets of feeler gauges - place 1 set at (say) 6 o/c and check the gap at 12 o/c - then do the same checks at 3 & 9. To do this I suggest that you use the 25 tho' feeler at the bottom and then measure the gap on the opposite side with the other set.

Helpful Hint.

The engine mounts should have a plain nut on the bottom and a nylock on top - if however someone has fitted a shake-proof or spring washer under the top nut - remove it.

5. This will let you know which way the engine has to go to get the whole lot to line up.

6. After every adjustment make sure all the engine mounting bolts are tight and then "shake" the engine with your hand and let it settle before trying to marry the couplings.

7. When you are satisfied that the engine is "in-line" release the shaft coupling - refit the flexi, re-tighten the shaft coupling - and then one at a time, release the top mounting nuts and refit the spring washers (if you have any).

Peter.

PS
This is one of those jobs that will either be over in 30 mins or you'll still be pulling your hair out 4-5 hrs later /forums/images/graemlins/smile.gif
Also, because you have "disturbed" the coupling bolts I strongly suggest that you check them again after 5-10 hours running.
 
Do any ajustment or checking of alignment in the water, but I do highly reccomend that you speak to R&D first, as to the proceedure. their *manual* will save you loads of time and wont be confusing. It also looks as if the red headed bolt is in the wrong way Round and should be in the position of the one arrowed? Lescargo is correct with his proceedure and you have to rotate the coupling using the same bolt (ie the red bolt head the right way round, which is prepared so that there are no Knobs or excressences on it that may effect any measurement)but it shouldn`t make too much difference if you use one of the others initially, for the sake of a rough check! if you do find out that you need to ajust ,then you may (as previously suggested) want to take the R&D off and replace the bolts or clean them up! and correctly assemble it.
 
Check with R&D. The manual has the procedure outlined wihout removing the coupling.
There is one marked (red) bolt.You need to check its heads clearance against the coupling face with a feeler gauge. Whilst rotating 90 degree three times the clearance should stay the same with a small allowed tolerance (have forgotten how much however)
 
Many thanks for all replies, I'll certainly get in touch with R&D to see what they are saying. When I bought the boat a couple of years ago and had the new engine etc installed I remember the engineer checking the alignment. He certainly didn't remove anything, he seemed to slacken off a few nuts and have a poke around with a feeler gauage. Unfortunately I wasn't paying attention and he has subsequently retired! Such is life...
Thanks again for all the helpful advice

Steve B
 
You must log in or register to reply here.

Share this page

Top