Engine Mounting Bolts

[Bones]

Before I throw my teddy out the window, I thought I would post on here. My engine has worked perfectly, but I am now moored up, wanting to be not moored up, and there is a terrible banging noise when it kicks over. It rocks, and I think it might be the engine bolts.. how do I tell and what are they meant to look like. Anyone able to tell me what I am looking for - I am hoping the bent twisted bit down below is meant to be there.

 

I think I shall give up boating.

Edited March 30, 2008 by Bones

[Bones]

Hmm well, it seems to be ok now, but it does remind me I have no idea what they are meant to look like, and having looked at mine I am QUITE sure the bolts are not meant to be padded out with random bits of metal!

[Bullfrog]

Hi Bones - this happened to ours last summer. Nasty banging noise whenever revs were idling. Mounting bolts (nuts actually) were loose and allowing the engine to dance about.

 

On our boat the engine "flange" sits between a sandwich of nuts and washers on the engine mounting studs.

 

I made the mistake of tightening the nylox nuts on top of mounts downwards, thus putting the engine out of allignment. I should have instead brought up the nuts from under the mount to take up the "slack" Subsequently sorted out by mechanic at Cowroast who spent about 3 hours with feeler gauges putting it all back where it belonged.

 

Lesson learned and now passed on to you!

 

Regards

 

David

[Bones]

super duper, but how do I tell if it is aligned?

 

Hi Bones - this happened to ours last summer. Nasty banging noise whenever revs were idling. Mounting bolts (nuts actually) were loose and allowing the engine to dance about.

 

On our boat the engine "flange" sits between a sandwich of nuts and washers on the engine mounting studs.

 

I made the mistake of tightening the nylox nuts on top of mounts downwards, thus putting the engine out of allignment. I should have instead brought up the nuts from under the mount to take up the "slack" Subsequently sorted out by mechanic at Cowroast who spent about 3 hours with feeler gauges putting it all back where it belonged.

 

Lesson learned and now passed on to you!

 

Regards

 

David

[blackrose]

super duper, but how do I tell if it is aligned?

 

To do it properly I think you need a needle guage measuring the amount of lateral motion on the prop shaft as you revolve it by hand.

 

A simple but inaccurate method is to just grab the prop shaft with your hand and twist it. If it revolves without any noticeable resistance or lateral movement it might be ok. Switch off your engine start battery isolator beforehand.

Edited March 30, 2008 by blackrose

[Bones]

To do it properly I think you need a needle guage measuring the amount of lateral motion on the prop shaft as you revolve it by hand.

 

A simple but inaccurate method is to just grab the prop shaft with your hand and twist it. If it revolves without any noticeable resistance or lateral movement it might be ok. Switch off your engine start battery isolator beforehand.

 

 

okay... the thing is, I think one of mine might have dropped, it looks like one of the corners is lower than the rest, but perhaps it is meant to be like that. I felt around the bolts and they all seem tightish.

 

Is there any way of determining what/where the banging is coming from?

[Malarky]

Could be components in U.J, fexidrive or suchlike.

 

To check alignment, you have to accertain that the shaft slides smoothly and centrally into your coupling, when this is achieved the engine is aligned.

[Bones]

Could be components in U.J, fexidrive or suchlike.

 

To check alignment, you have to accertain that the shaft slides smoothly and centrally into your coupling, when this is achieved the engine is aligned.

 

I have flexidrive.....

 

I think this is a job for when I am in better humour, I just can't get my head round it right now....

 

So, when I am. I check to see whether it is aligned, by spinning the drive and see whether it catches is that right?

 

I wish my dad lived nearby!

[Bones]

Spurred on by a rare moment of enthusiasm (and I promised myself some gin) it doesn't catch when I turn the bit between the aquadrive and the engine. It just goes around nice and smoothly all the way around. I can't spin it like a spinning top but I can turn it pretty easily.

 

What next?

[Malarky]

I have flexidrive.....

 

I think this is a job for when I am in better humour, I just can't get my head round it right now....

 

So, when I am. I check to see whether it is aligned, by spinning the drive and see whether it catches is that right?

 

I wish my dad lived nearby!

 

You have to loosen the shaft from the flexidrive and hope you have enough space between the prop and rudder to slide the shaft out.

 

Then slide it back in, if you are out of alignment it either won't slide home, or you will hear a slight "knock" as it hits the edge on the way in, this is where you start to fine tune your mountings untill you eliminate any sounds of complaint. Then tighten the flexidrive up again, I think its 16lb you tighten the nuts to, but prob. best check. These are tightened and loosened muh the same as wheel nuts to help keep the preasure even.

[Bones]

good lordy! That is WAY beyond me right now. Do RCR cover this do you know?

[Bullfrog]

Is there any way of determining what/where the banging is coming from?

 

Sorry Bones we had to go out, just got back.

 

On ours the banging was the whole engine jumping around on it's slack mounts. I could see the engine bouncing about 3/4" up and down on the studs, in time with the banging noise. Once the nuts had been tightened every thing went quiet again, but as I said it's important that the right ones are tightened and in such a way as to not mis-allign the engine and the prop-shaft.

 

Sorry if I'm not making it clear enough, but getting it right is a skilled job needing gauges etc.

 

On the plus side, despite the horrible din, no permanent damage was done, and that includes cruising up and down the Hatton flight to visit Stratford then all the way back to Cowroast before the job was done properly.

 

Regards

 

David.

Edited March 30, 2008 by Bullfrog

[blackrose]

You have to loosen the shaft from the flexidrive and hope you have enough space between the prop and rudder to slide the shaft out.

 

Then slide it back in, if you are out of alignment it either won't slide home, or you will hear a slight "knock" as it hits the edge on the way in, this is where you start to fine tune your mountings untill you eliminate any sounds of complaint. Then tighten the flexidrive up again, I think its 16lb you tighten the nuts to, but prob. best check. These are tightened and loosened muh the same as wheel nuts to help keep the preasure even.

 

Couldn't you improvise a needle guage?

 

Using a few toothpicks taped to various points where they just touch the shaft. Turn the shaft slowly by hand and see where gaps appear between the end of the tootpicks & shaft, or where the shaft starts to rub and move the toothpicks.

 

No?

[Bones]

Sorry Bones we had to go out, just got back.

 

On ours the banging was the whole engine jumping around on it's slack mounts. I could see the engine bouncing about 3/4" up and down on the studs, in time with the banging noise. Once the nuts had been tightened every thing went quite again, but as I said it's important that the right ones are tightened and in such a way as to not mis-allign the engine and the prop-shaft.

 

Sorry if I'm not making it clear enough, but getting it right is a skilled job needing gauges etc.

 

On the plus side, despite the horrible din, no permanent damage was done, and that includes cruising up and down the Hatton flight to visit Stratford then all the way back to Cowroast before the job was done properly.

 

Regards

 

David.

 

it only bangs when it is turning over.........

[Malarky]

Dont know anything about RCR but the allowed tolerences are just about percievable to the human eye, if you have a good eye for this type of thing ,that is.

So, if it seems one of the mountings has swiveled down then maybee it has, what are the random bits of metal? Do they calibrate how high each mounting should be, In which case have any, that previously gave you the correct height, dropped in the bilge near the lower mounting.

 

I don,t think you should be getting a banging noise from this area unless the mountings are loose though.

 

Are your oil levels OK?

[Bones]

Dont know anything about RCR but the allowed tolerences are just about percievable to the human eye, if you have a good eye for this type of thing ,that is.

So, if it seems one of the mountings has swiveled down then maybee it has, what are the random bits of metal? Do they calibrate how high each mounting should be, In which case have any, that previously gave you the correct height, dropped in the bilge near the lower mounting.

 

I don,t think you should be getting a banging noise from this area unless the mountings are loose though.

 

Are your oil levels OK?

 

Oil is fine it really sounds like the engine banging on something. The engine is standing on a tube of metal, and mounted in four corners - 3 of those corners are on the metal, the third of those corners seems not to be and is mounted below it (about an inch in this case), it doesn't look like it has fallen through it, it looks as though the end of the tube of metal has been pulled apart. Oh dear, I am not very good at explaining this.

 

At least the nearby pub does honey roast peanuts.

[Malarky]

Sounds like one mounting has become undescribable! I heard of a car driven for a short distance when the wheel fell off; working on the theories of alignment that occured there, can you hammer a piece of wood/branch or something near or in the area to bring it up and stop the banging while you go to get it sorted. Where are you?

[Chris J W]

Oh dear, I am not very good at explaining this.

 

At least the nearby pub does honey roast peanuts.

 

Post a pic?

[Bones]

Post a pic?

of peanuts? Or me eating them?

Sounds like one mounting has become undescribable! I heard of a car driven for a short distance when the wheel fell off; working on the theories of alignment that occured there, can you hammer a piece of wood/branch or something near or in the area to bring it up and stop the banging while you go to get it sorted. Where are you?

hammering, banging.... ooooh! Sounds like my kinda DIY. I am in Wolvercote... sulking. I think I will call RCR tomorrow afternoon and see whether they want to come and glare at it. Edited March 30, 2008 by Bones

[Malarky]

I take it RCR is like AA where you've allready paid them to come out. If your realy stuck though that's my old patch(totaly understand why you'd want to move), I'd be happy to help.

Alchemy boats is up the way, and they may have learnt to weld by now if you'r lucky, I would,nt advise them for anything too technical though.

[Chris J W]

of peanuts? Or me eating them?

 

Erm. The latter. And perhaps one of the engine ole?

[Bones]

I take it RCR is like AA where you've allready paid them to come out. If your realy stuck though that's my old patch(totaly understand why you'd want to move), I'd be happy to help.

Alchemy boats is up the way, and they may have learnt to weld by now if you'r lucky, I would,nt advise them for anything too technical though.

 

RCR are like the AA, I will see what htey have to say tomorrow, and see whether they can come out in the afternoon. So, watch this space. I may be in better humour tomorrow too.

 

The pub is good, but I would like to be elsewhere!

[hnb2907]

good lordy! That is WAY beyond me right now. Do RCR cover this do you know?

Exactly the same happened to me on my old boat, luckily the day before I went through the Harecastle - where it could have been worse. I'd noticed that it was running a bit lumpy and noisier than normal for a few hours, and when I enaged reverse all hell broke loose and decided it was time to investigate.

 

Rang RCR at daft-o'clock in the evening and was advised as a short term measure, that if the top bolts were not loose and hadnot been moved, just to wind the bottom nuts back up. What appears to have happened was that the bottom nuts had never been tightened enough and had worked their way loose, subsequently the engine dropped at an angle. Having tightened up, everything lined "ok" - there was no noticable misalignment or friction of the shaft in the stern tube. Kept an eye on it for the next couple of days until it was properly checked out by someone better at mechanics than me.

 

It was a learning experience and is now on my regular maintainance checklist...

 

 

Cheers,

Chris.

[Bullfrog]

.... was advised as a short term measure, that if the top bolts were not loose and had not been moved, just to wind the bottom nuts back up. What appears to have happened was that the bottom nuts had never been tightened enough and had worked their way loose, subsequently the engine dropped at an angle. Having tightened up, everything lined "ok" - there was no noticable misalignment or friction of the shaft in the stern tube. Kept an eye on it for the next couple of days until it was properly checked out by someone better at mechanics than me.

 

 

There you go Bones - exactly the same as our experience. Take heart, it won't be that bad!

 

David

[chris w]

................ you have to accertain that the shaft slides smoothly and centrally into your coupling,