While trying to figure out where the coolant leak might be coming from, I noticed some of the bolts on the transmission to prop shaft coupler are loose and spin easily. I think one of the nuts was actually able to be spun off.
I don't think this is normal!
What is the correct tightness or torque, and shouldn't these nuts be Loctite'd (i.e. low strength purple 222 so they can be removed if needed) to prevent this situation?
In the photo you can see the gap where the arrow points.
Thoughts?
Are those nylocks? Bolts look too short
Is that a lock washer under the head or am I seeing something else?
Quotedon't think this is normal!
No it's not. I see that you have a flex coupler. I think the torque and locking specs should come from the flex coupling manufacturer. If mine I'd take the coupling apart and inspect/replace nuts and bolts with same grade after you find the coupling manufacturer specifications.
If nothing else get all the coupling nuts/bolts as tight as you can. It's not like you can get a breaker bar on them, probably just standard wrenches. And check them often at first, then at least yearly.
Looks like you found a problem just before it became serious. :thumb:
Jim
pbyrne,
For the time being I'd tighten everything up. It doesn't look like it was assembled correctly, so the next thing I'd do is get a copy of the installation directions and see what's recommended. There are a couple of things that don't look right. At the head of the bolt I can't tell if those are lock washers or bushing washers(this makes more sense). Next the bolts aren't long enough to capture the nyloc, which defeats the purpose, if you can't use longer bolts due to clearance issues you'd be better off using a standard bolt with a lock washer.
Do you think this is a standard installed part of a 2000 34 MKII?
I'm getting the impression that it's a bit of an unknown...
Quote from: Jim Hardesty on April 01, 2021, 05:11:21 AM
Quotedon't think this is normal!
No it's not. I see that you have a flex coupler. I think the torque and locking specs should come from the flex coupling manufacturer. If mine I'd take the coupling apart and inspect/replace nuts and bolts with same grade after you find the coupling manufacturer specifications.
If nothing else get all the coupling nuts/bolts as tight as you can. It's not like you can get a breaker bar on them, probably just standard wrenches. And check them often at first, then at least yearly.
Looks like you found a problem just before it became serious. :thumb:
Jim
Jim,
What does your boat look like? We have approximately the same age and model.
Is this what you have installed; is it OEM?
Quote from: Jim Hardesty on April 01, 2021, 05:11:21 AM
Quotedon't think this is normal!
No it's not. I see that you have a flex coupler. I think the torque and locking specs should come from the flex coupling manufacturer. If mine I'd take the coupling apart and inspect/replace nuts and bolts with same grade after you find the coupling manufacturer specifications.
If nothing else get all the coupling nuts/bolts as tight as you can. It's not like you can get a breaker bar on them, probably just standard wrenches. And check them often at first, then at least yearly.
Looks like you found a problem just before it became serious. :thumb:
Jim
QuoteWhat does your boat look like? We have approximately the same age and model.
Is this what you have installed; is it OEM?
Have the OEM coupling. For me works good. My story, bought Shamrock she was 5 years old about 400 engine hours, the cutlass bearing was worn, second season I changed cutlass bearing and aligned engine, was out of line quite a bit don't think the selling dealer did his job commissioning. Since then I've put 1200+ engine hours on, is smooth and the cutlass bearing is just starting to wear, still good for a few seasons.
Jim
I guess that means this is not OEM. I'll have to take a closer look and see who makes it. I haven't found anything in the docs I have.
Any suggestions on who may have made it?
Quote from: Jim Hardesty on April 01, 2021, 08:21:25 AM
QuoteWhat does your boat look like? We have approximately the same age and model.
Is this what you have installed; is it OEM?
Have the OEM coupling. For me works good. My story, bought Shamrock she was 5 years old about 400 engine hours, the cutlass bearing was worn, second season I changed cutlass bearing and aligned engine, was out of line quite a bit don't think the selling dealer did his job commissioning. Since then I've put 1200+ engine hours on, is smooth and the cutlass bearing is just starting to wear, still good for a few seasons.
Jim
Ditto what Jim said. Coupler manufacturer should have torque specs for bolting on the coupler. I changed my coupler in December and used the torque specs from Buck Algonquin (non flexible).
At the moment I don't know who makes it. I'll make another trip to the boat and see if I can find something on it that will identify the manufacturer.
Who are the top manufactures for couplers? Maybe I can get lucky searching their site.
Quote from: Patches on April 01, 2021, 08:56:51 AM
Ditto what Jim said. Coupler manufacturer should have torque specs for bolting on the coupler. I changed my coupler in December and used the torque specs from Buck Algonquin (non flexible).
Quote from: pbyrne on April 01, 2021, 08:56:33 AM
Do you think this is a standard installed part of a 2000 34 MKII?
I'm getting the impression that it's a bit of an unknown...
I guess that means this is not OEM. I'll have to take a closer look and see who makes it. I haven't found anything in the docs I have.
Any suggestions on who may have made it?
It is not OEM. All C34s came with a standard stuffing box. It's in your boat manual.
There are only a few different options. If I was looking for what it could be, I would Google terms like
--- alternate stuffing box material
--- prop savers
unless somebody here knows and pipes up.
Good advice so far about those nuts and bolts.
Good thing you caught it in time.
Good luck.
Looks like an R&D brand?
http://www.randdmarine.com/flexiblesc.asp
I'm with Ken, the bolts are too short for the locking nuts and are not contacting the locking media. Buy longer bolts and new ny-lock nuts and tighten them up.
That looks like a close match. How do you take the bolts out without completely disassembling the unit?
Quote from: Noah on April 01, 2021, 09:54:24 AM
Looks like an R&D brand?
http://www.randdmarine.com/flexiblesc.asp
Guys : I agree with Kevin, that flexible coupling was not installed properly!!!
It appears that the nuts are nylon lock nuts and NO torque is required!! With that type of nut the normal rule is to have at least 1 (best 2) thread showing!! I believe that the bolts with the nuts on the transmission side just need to be tightened so there is 1 thread outside the nut or at least part of 1 thread!!
If you can't get a thread on the outside of the nuts, then get a thinner lock nut!! Simple as that !!
A few thoughts
Good to know! I was having nightmares about pulling the shaft out to get enough room... :shock:
It does seem in the photo that some have some thread peeking out. I'll have to look in person.
Are these nuts reusable, or should I be replacing them for new ones to get the best adhesion from the nylon nuts?
Also, I'm assuming I tighten to something like tight plus a 1/3 turn?
Quote from: Ron Hill on April 01, 2021, 03:01:15 PM
Guys : I agree with Kevin, that flexible coupling was not installed properly!!!
It appears that the nuts are nylon lock nuts and NO torque is required!! With that type of nut the normal rule is to have at least 1 (best 2) thread showing!! I believe that the bolts with the nuts on the transmission side just need to be tightened so there is 1-2 threads outside the nut!!
If you can't get a thread on the outside of the nuts, then get a thinner lock nut!! Simple as that !!
A few thoughts
If you can't find a manual or instructions for torque you can always go generic. There's tables online for torque values by bolt/thread size/type. i.e., (just a made up example) grade 5, steel 3/8" UNC (coarse pitch) or UNF (fine pitch) thread, max torque = nn ft-lbs.
In that application I'd think I'd trust lock tight, or lock washer, or spring lock, or deformed locking nut - over a nylock. No data, just my gut.
Hmm. How do you determine those values?
I emailed R&D marine, but they are GMT, so closed at the moment. Hopefully they can help.
The link indicates torque numbers, but I'm not sure which is correct. http://www.randdmarine.com/flexiblescinst.asp
Can you loctite those nuts? I have Loctite 222 low strength. Maybe something higher? This is something that should never be backing off unless deliberately removed.
You know, I didn't check if they are nylon to be honest. It's just what the kind people here have been mentioning...maybe they aren't nylon?
Quote from: KWKloeber on April 01, 2021, 04:18:46 PM
If you can't find a manual or instructions for torque you can always go generic. There's tables online for torque values by bolt/thread size/type. i.e., (just a made up example) grade 5, steel 3/8" UNC (coarse pitch) or UNF (fine pitch) thread, max torque = nn ft-lbs.
In that application I'd think I'd trust lock tight, or lock washer, or spring lock, or deformed locking nut - over a nylock. No data, just my gut.
Quote from: pbyrne on April 01, 2021, 04:45:18 PM
Hmm. How do you determine those values?
I emailed R&D marine, but they are GMT, so closed at the moment. Hopefully they can help.
The link indicates torque numbers, but I'm not sure which is correct. http://www.randdmarine.com/flexiblescinst.asp
Can you loctite those nuts? I have Loctite 222 low strength. Maybe something higher? This is something that should never be backing off unless deliberately removed.
You know, I didn't check if they are nylon to be honest. It's just what the kind people here have been mentioning...maybe they aren't nylon?
pb, the reason they are suggesting they are nylocks nuts is because of the shape. Looking at your photo in your OP, there is the body of the nut with a slight dimple and bump above. Compare that to the nut at the bottom of that same bolt (or machine screw). Often folks put nylocks in that kind of situation because there isn't room for a regular nut and lock washer, like yours.
I have had a coupling that for many years had a propensity for throwing nuts off the coupling bolts. Mine is a standard box and coupling, but same concept, same issue. Because of space or lack thereof in front of the coupling, I resorted to fine thread bolts and loctite blue, because I couldn't get a lock washer (neither split or star) in there. Once I did that they stayed in place. The fine threads helped.
You really don't need any torque tables for this, tighten them, use locktite. If they ever do pop off, my experience is that they end up right below where they fell off. Ask me how I know... :D
Good luck.
Not sure you "don't need torque tables" Once you determine if it is indeed the R&D coupler, or whatever brand, I would use the torque values they recommend.
Quote from: pbyrne on April 01, 2021, 04:45:18 PM
Hmm. How do you determine those values?
The link indicates torque numbers, but I'm not sure which is correct. http://www.randdmarine.com/flexiblescinst.asp
Ok you answered your own question. You have the torque values, you simply need to determine what size bolts they are - I simpluly guessed (they looked larger than 1/4," smaller than 1/2".)
Measure one, take one off and match it up, etc etc.
Ah! Thanks for the explanation.
So loctite can be used with the nylon nuts? Do you think it best to get new ones?
Also, did you just go with a regular nut with the blue loctite for the fine thread bolt?
Quote from: Stu Jackson on April 01, 2021, 05:50:41 PM
Quote from: pbyrne on April 01, 2021, 04:45:18 PM
Hmm. How do you determine those values?
I emailed R&D marine, but they are GMT, so closed at the moment. Hopefully they can help.
The link indicates torque numbers, but I'm not sure which is correct. http://www.randdmarine.com/flexiblescinst.asp
Can you loctite those nuts? I have Loctite 222 low strength. Maybe something higher? This is something that should never be backing off unless deliberately removed.
You know, I didn't check if they are nylon to be honest. It's just what the kind people here have been mentioning...maybe they aren't nylon?
pb, the reason they are suggesting they are nylocks nuts is because of the shape. Looking at your photo in your OP, there is the body of the nut with a slight dimple and bump above. Compare that to the nut at the bottom of that same bolt (or machine screw). Often folks put nylocks in that kind of situation because there isn't room for a regular nut and lock washer, like yours.
I have had a coupling that for many years had a propensity for throwing nuts off the coupling bolts. Mine is a standard box and coupling, but same concept, same issue. Because of space or lack thereof in front of the coupling, I resorted to fine thread bolts and loctite blue, because I couldn't get a lock washer (neither split or star) in there. Once I did that they stayed in place. The fine threads helped.
You really don't need any torque tables for this, tighten them, use locktite. If they ever do pop off, my experience is that they end up right below where they fell off. Ask me how I know... :D
Good luck.
Quote from: pbyrne on April 01, 2021, 07:23:21 PM
So loctite can be used with the nylon nuts? Do you think it best to get new ones?
Loctite is used on metal to metal threads, so technically yes. But there is no reason to use nylocks.
Let me say, with all due respect to those who disagree, a nylock nut is for convenience, not to really to save space. At least not to save space and do a critical fastening correctly.
I'll use 3/8" as an example:
A standard nut plus a split lock washer is 0.45" high, a nylock is 0.42" high. Things have to be VERY tight for 0.03" to make a difference AND have enough bolt thread catching the nylock anyway. Way too iffy. PLUS a nylock has less (metal) thread height than a standard nut. That can be ok for a non-critical situation, but not on a critical location.
If space is limited on a critical fastening there are better options -- locktite or a standard height distorted thread locknut (grips tighter than a nylock.) If there's room there's also tall thread nuts (i.e., having more metal thread so better holding) but not in s/s. A deformed locknut has a divot in the side or top that deforms the female thread and presses against/holds tight on the bolt half of the thread) AND it doesn't compromise the height of the nut (amount of thread.)
Using a lock washer and thin nut (called a jam nut) is ok on a non-critical location but not here because it compromises the amount of metal thread. The more thread there is = the greater the holding power of the connection.
IIWMB, I would use new standard nuts (and bolts if those are not long enough) and lock washers (you could add locktite for belt/suspenders.) What appears to be a heavy washer under the bolt head looks suspect to me. I'd like to see the disassembled fasteners or a picture from the mfgr as to what goes together how.
Check with PYI, they're in Lynnwood, Washington on PDT. They sell these couplings.
https://www.pyiinc.com/flexible-shaft-couplings.html
Craig
pby : Don't try to make this complicated!! The main pressure/stress is on the bolts the locknuts just keep the bolts in place!!
I'd just tighten all the nuts and on the short bolts clean all the grease off the nuts and white coupler. Take some of you 1st Mates red fingernail polish and make a strip on the nut that goes on to the white coupler. That's called a slippage mark. Then run the engine as you normally would and periodically look at those stripes. If the nut starts to back off the painted strip line mark will break and you'll be able to see it !!! :thumb:
I have slippage marks on all of my engine mount top nuts - to let me know that the bottom nut is turning and the engine will be out of alignment if I don't get the bottom nut tightened (mount raised) so the top nut slippage mark is back in line!! Clear as mud???
I would NOT use Locktight (red) you might consider using Locktight (blue) as a last resort if the nuts are infact backing off!! :cry4`
A few thoughts
Thanks Craig.
I spoke with PYI and they recommended replacing the nuts.
Quote from: Craig Illman on April 02, 2021, 06:04:01 AM
Check with PYI, they're in Lynnwood, Washington on PDT. They sell these couplings.
https://www.pyiinc.com/flexible-shaft-couplings.html
Craig
Thanks Ron, that's is a good tip. Will do.
I inspected the nuts and out of 8, 5 are loose. I removed one to take to Fastenal for replacements. It was not very hard to remove the nut. I was able to use my fingers once a spun it with the wrench a 1/2 turn. That was a bit alarming. Probably past the nylon at that point.
My conversation with PYI provided the information that the nuts are not recommended to be reused (i.e. if they were removed) as the nylon will be worn down a bit and not hold as well as the first time.
They also suggested blue loctite for a belt and suspenders approach, but mentioned even loctite purple (low strength) is okay too.
On a standard installation it is just the nylock no threadlock.
So there you go!
Quote from: Ron Hill on April 03, 2021, 01:42:19 PM
pby : Don't try to make this complicated!! The main pressure/stress is on the bolts the locknuts just keep the bolts in place!!
I'd just tighten all the nuts and on the short bolts clean all the grease off the nuts and white coupler. Take some of you 1st Mates red fingernail polish and make a strip on the nut that goes on to the white coupler. That's called a slippage mark. Then run the engine as you normally would and periodically look at those stripes. If the nut starts to back off the painted strip line mark will break and you'll be able to see it !!! :thumb:
I have slippage marks on all of my engine mount top nuts - to let me know that the bottom nut is turning and the engine will be out of alignment if I don't get the bottom nut tightened (mount raised) so the top nut slippage mark is back in line!! Clear as mud???
I would NOT use Locktight (red) you might consider using Locktight (blue) as a last resort if the nuts are infact backing off!! :cry4`
A few thoughts
Guys : Nylon locknuts are really made for a one time use. If you decide to use them a second time you need to inspect them periodically and I'd use a painted slippage mark for ease of inspection!!
A thought