Replacing Engine mounts Barrus Shire 45

[TeeELL]

Thanks Tony once again.  Looking at the originals it would appear that the set up is such that the ‘supporting nut’ is actually hard against the top of the rubber mount.  I will take a photo shortly to show that they really are ‘shot’.

Here are the removed parts:

 

[Eeyore]

8 hours ago, TeeELL said:

Thanks Tony once again.  Looking at the originals it would appear that the set up is such that the ‘supporting nut’ is actually hard against the top of the rubber mount.  I will take a photo shortly to show that they really are ‘shot’.

Here are the removed parts:

 

The position, as found, of the lower nuts is fine providing that the engine beds are perfectly aligned; which is unlikely.

Only one lower nut needs to be adjusted on your particular installation to achieve the best weight distribution; as it will most likely rock slightly on one diagonal. The choice should be based on your ability to reach it with a spanner when making routine checks.

The failure of the one, top left in your photo, seems to be due to over heating. The failure may also be counter intuitive; as the mount on the rocking diagonal will move far more than those carrying most of the weight, similar to the excess movement suffered by the sidewall of an under inflated tyre.

Edited May 31, 2023 by Eeyore

[TeeELL]

All done, new parts fitted and we are underway with a much quieter, vibration free boat AND the oil pressure gauge is reading properly again.  Eeyor, thanks for the advice.

 

This topic is now finished.  Thanks to all the folk who offered advice, I am now a little more knowledgeable of the world of narrowboat mechanicals.

[Tony Brooks]

You might care to see if there is a reason why the top left mount has been contaminated by fuel or oil and if you can do anything to avoid it happening again.

[MtB]

I'm still unclear how the initial symptom of oil gauge reading zero pressure was caused by failing engine mounts. 

 

Can only have been a loose wire/poor connection I'd have thought, which was hopefully traced and fixed at the same time as the mounts replaced.

 

 

[Tony Brooks]

3 minutes ago, MtB said:

I'm still unclear how the initial symptom of oil gauge reading zero pressure was caused by failing engine mounts. 

 

Can only have been a loose wire/poor connection I'd have thought, which was hopefully traced and fixed at the same time as the mounts replaced.

 

 

 That is my conclusion, and I think I said so at the start.

[TeeELL]

Well, like you I don’t see the connection (no pun intended) between the engine mounts and the oil pressure gauge reading, but all is good now and, no, I’ve not tried to trace the problem because it doesn’t exist any more :).

 

Eeyor’s comment is something I need to address as the engine is presently sitting on the same, bottom, level of the mounts.  In an idle moment I wondered if there was a clever way of determining on which diagonal I need to tweak the engine mount (rubber). Ie a container of water on the top of the engine and watch the waves?  Other than that, I plan to loosen the top nuts, raise the bottom nuts, equally, by enough to release them from the mount then see if there one nut that still has some space to rise a bit more.  Then return the settings and adjust that particular nut to even things up.

[Eeyore]

1 hour ago, TeeELL said:

Well, like you I don’t see the connection (no pun intended) between the engine mounts and the oil pressure gauge reading, but all is good now and, no, I’ve not tried to trace the problem because it doesn’t exist any more :).

 

Eeyor’s comment is something I need to address as the engine is presently sitting on the same, bottom, level of the mounts.  In an idle moment I wondered if there was a clever way of determining on which diagonal I need to tweak the engine mount (rubber). Ie a container of water on the top of the engine and watch the waves?  Other than that, I plan to loosen the top nuts, raise the bottom nuts, equally, by enough to release them from the mount then see if there one nut that still has some space to rise a bit more.  Then return the settings and adjust that particular nut to even things up.

Depends on your luck. It may be immediately obvious if there is a gap above one of the lower nuts when you release all the upper ones just by rocking the engine. Other wise just try winding up one of the lower nuts to feel if it has weight on it, reset to bottom position and try the other one on the same side of the engine. There should be a significant difference in the initial effort required to move the two nuts. The easy one is the one to adjust, as follows:

Its all a bit approximate, and I'll refer to "hard" and "easy" as found above.

Measure the rotation of the nut against a mark or piece of tape on top of the mount.

Wind the "easy" nut up until the effort to move the "hard" nut is the same as found on the "easy" nut. 

Wind the "easy" nut back down to its mid point ie if you raised it 1.5 turns you would lower it by 0.75 turns. 

Refit top nuts, job done.

Check the one lower nut is tightened up onto the mounting bracket during routine maintenance.

Edited June 1, 2023 by Eeyore

[TeeELL]

Eeyore,

  that sums up what I plan to do.