Alternator Bracket Mod

[Catalina007]

I think I know the answer, but may need some motivation and courage
New to us M25 has the dreaded original alternator bracket
I know we need to change it, but the 34 year old studs on the manifold (which would need to be changed to larger studs in the kit to mount the new bracket) and nuts look badly rusted and may not survive putting a wench to them. Then I have a bigger problem 
I've been hitting them with penetrating oil each trip to the boat to improve my odds if I go through with this.  Any thoughts or tips?       

Also, what is the '2 nut method' of getting the studs out mentioned below?  My studs do have enough room to get a second nut on.   

NOTE: If you have any room at all to get a second nut on the stud they can be pulled without removing the manifold! Unfortunately, as can be seen, this engine had zero clearance beyond the nut necessitating removing the entire manifold to do this job. Not all engines came with studs this short. If your are long enough to get two nuts on USE THAT METHOD.....

[KWKloeber]

If the studs are too short to double nut (you already said they are) then that method is irrelevant! 

Besides, if the studs are tight enough you probably wouldn't get them out by double butting, regardless of that statement (you can't get penetrant and heat where they're needed, at the other end of the studs.)

The best info is what RC has, but it looks like you already found that?
https://pbase.com/mainecruising/universal_alternator_bracket

MAYBE (not likely) once the nuts are off you can free the studs with a locking plier, but you'll likely need to pull the exhaust manifold.

If you do pull the manifold, suggest you think about:

   - Relocating the oil pressure switch as it is on the XPA and XPB engines.
   - Installing the water cooled exhaust riser while you have the exhaust half-apart.

[Catalina007]

The studs are long enough to hold two nuts.  I dont know if they are long enough to attach the new bracket   

[KWKloeber]

Ahhh mea culpa!  I misread your post.

The first page of RC's link explains the method. As you might imagine it isn't easy because of nut rounding and it must be a thin wrench. You want to turn the inner nut against, not with, the outer nut so that the coupling is constantly being tightened.

[waughoo]

Here is a quick video that shows what the two nut method looks like.

https://youtu.be/Pvs_EFR-f4E

You basically jamb the two nuts together by tightening one against the other on the stud.  To remove the stud, use put the wrench on the nut closest to the engine.  To install a stud and torque it, use the nut furthest away from the engine.  This way, the nut you are using to manipulate the stud is always trying to get tighter against the one it is jambed against.

All that said, the video makes it pretty clear :-)

[Catalina007]

Here is a quick video that shows what the two nut method looks like.

https://youtu.be/Pvs_EFR-f4E

You basically jamb the two nuts together by tightening one against the other on the stud.  To remove the stud, use put the wrench on the nut closest to the engine.  To install a stud and torque it, use the nut furthest away from the engine.  This way, the nut you are using to manipulate the stud is always trying to get tighter against the one it is jambed against.

All that said, the video makes it pretty clear :-)

Ah thanks.  It actually clicked for me when I was driving home
Here is what they look like now

[waughoo]

Oy!!  I would say that heat and a lot of impact wrenching with a 5 point socket is the only likelyhood of success there.  I wouldnt hold much hope.

[Noah]

Try some phosphoric acid and a wire brush then some penetrating oil. Worked wonders on restoring my steering cable clamps. See before and after.

[scgunner]

Catalina007,

Your motor sure didn't get a lot of TLC from the PO, a cautionary tale. The M25 is just about bulletproof but it does require a certain amount of care. I've always said "If you take care of your motor, it will take care of you", which also goes for just about any system on your boat.

I didn't even know about the bracket upgrade until I saw it on this site(thanks again Stu)so I went ahead and made the change several years ago, when I pulled the old bracket off I found it was fatally cracked and on the verge of failure, luckily I got it before it did. Maybe I was just lucky but I don't remember the swap as being that big a deal, as I recall I did it start to finish in a short afternoon.

Concerning removal of those studs, in addition to penetrating oil and heat, there's another leg of that stool, vibration. Put a nut on those studs to protect the threads then with a small hammer start tapping the nut. It's not a quick process, don't be in a hurry, everyday or so tap those nuts with the penetrating oil 3 to 5 min. The idea is to create a vibration that will break loose those frozen threads and drive penetrant deeper into the hole. If you're willing to take the time, you just might be able to double nut those studs out cleanly.

[Bill Shreeves]

My boat was re powered with an XPB before I bought her so, I'm fortunate that this isn't an issue for me.  I'll suggest these refinements to thr process if possible.

Use a quality penetrant such as PB Blaster or Kroil.  I prefer Kroil but, PB Blaster is easier to find.

You'll get the best bite possible on the nut if you use a box wrench, preferably 6-point.  if enough threads are exposed a washer or lock washer between the nuts might facilitate the nuts being aligned enough to allow slipping a box wrench down to the lower nut

For locking the two nuts together ideally, you'll want full thread engagement of the top nut however, you might be able to cheat on a couple of threads.

If the two nuts are very closely aligned you might get away with a deep socket over both nuts.

IMO, the fastest way to ruin a nut is with an adjustable wrench.

[Catalina007]

Catalina007,

Your motor sure didn't get a lot of TLC from the PO, a cautionary tale. The M25 is just about bulletproof but it does require a certain amount of care. I've always said "If you take care of your motor, it will take care of you", which also goes for just about any system on your boat.

I didn't even know about the bracket upgrade until I saw it on this site(thanks again Stu)so I went ahead and made the change several years ago, when I pulled the old bracket off I found it was fatally cracked and on the verge of failure, luckily I got it before it did. Maybe I was just lucky but I don't remember the swap as being that big a deal, as I recall I did it start to finish in a short afternoon.

Concerning removal of those studs, in addition to penetrating oil and heat, there's another leg of that stool, vibration. Put a nut on those studs to protect the threads then with a small hammer start tapping the nut. It's not a quick process, don't be in a hurry, everyday or so tap those nuts with the penetrating oil 3 to 5 min. The idea is to create a vibration that will break loose those frozen threads and drive penetrant deeper into the hole. If you're willing to take the time, you just might be able to double nut those studs out cleanly.

I think first i need to derust and clean those threads  with ospho or something, but yes been hitting it with PB Blaster 

i dont think the actual bracket swap is big deal IF the studs come out  but I think a broken stud would  mean pulling the engine out
to repair

[Stu Jackson]

I think first i need to derust and clean those threads  with ospho or something, but yes been hitting it with PB Blaster 

i dont think the actual bracket swap is big deal IF the studs come out  but I think a broken stud would  mean pulling the engine out
to repair

IIRC, Maine Sail's article simply has the exhaust manifold removed without removing the engine.

[Catalina007]

I think first i need to derust and clean those threads  with ospho or something, but yes been hitting it with PB Blaster 

i dont think the actual bracket swap is big deal IF the studs come out  but I think a broken stud would  mean pulling the engine out
to repair

IIRC, Maine Sail's article simply has the exhaust manifold removed without removing the engine.

This is what keeps me up at night.   If one of the inner studs on the attached diagram breaks where it attaches to the head


 

[KWKloeber]

007

what you mean by inner stud. There's just full length studs, all are the same length and are identical.

If you snap one, the best you can hope is that it's at the nut, then you have full length remaining.
But if it snaps at the head, it wouldn't be necessary to pull the engine.  Unlike the 34, the 30 has side access to the exhaust manifold.  It would be a lot easier drilling a stud to remove it if the galley cabinet is pulled.

I really don't see how Blaster is going to help much. All you're blasting is the nut which you don't want to move anyway.  You're  not getting to the threads that you need to release. If the nut was off then you MIGHT get some blaster inching toward the threads in the head.

The best thing you could hope for is that the threads in the head aren't all corroded (they likely are not) and the nuts are welded (corroded) onto the stud so tightly that they won't turn no matter the force applied.  If you had the longer studs that didn't need to be removed then you'd be hoping for the opposite scenario.

Basically you need to make a decision whether to:
- remove (or snap off or split or grind off) the nuts and remove the manifold so you can assuredly remove the studs, or
- take a chance double-nutting and trying to remove the studs, leaving the manifold in place.

The 1st is 100% guaranteed success, but more work needing to deal with the exhaust riser. While the latter has a who-knows success rate.

-Ken

[Catalina007]

007

what you mean by inner stud. There's just full length studs, all are the same length and are identical.

If you snap one, the best you can hope is that it's at the nut, then you have full length remaining.
But if it snaps at the head, it wouldn't be necessary to pull the engine.  Unlike the 34, the 30 has side access to the exhaust manifold.  It would be a lot easier drilling a stud to remove it if the galley cabinet is pulled.

I really don't see how Blaster is going to help much. All you're blasting is the nut which you don't want to move anyway.  You're  not getting to the threads that you need to release. If the nut was off then you MIGHT get some blaster inching toward the threads in the head.

The best thing you could hope for is that the threads in the head aren't all corroded (they likely are not) and the nuts are welded (corroded) onto the stud so tightly that they won't turn no matter the force applied.  If you had the longer studs that didn't need to be removed then you'd be hoping for the opposite scenario.

Basically you need to make a decision whether to:
- remove (or snap off or split or grind off) the nuts and remove the manifold so you can assuredly remove the studs, or
- take a chance double-nutting and trying to remove the studs, leaving the manifold in place.

The 1st is 100% guaranteed success, but more work needing to deal with the exhaust riser. While the latter has a who-knows success rate.

-Ken

Thank you. Agree and it makes sense.
(I meant the interior end of the stud).