H4B
Well-Known Member
How do I know if the engine mountings need changing. Approaching 30 years old but no obvious problems as in vibration. Firm believer in ' if it ain't broke don't fix' , but ?
Buhk Dv20 Engine mounts
- Thread starter H4B
- Start date
30boat
N/A
Those mounts are so hard that they're almost solid.I'd leave them alone.
robmcg
Well-Known Member
Have a bit of a visual inspection to see if the rubber part is still bonded to the metal parts and that the rubber is complete and not delaminating. Check your cutlass bearing - excessive wear will indicate the engine is out of alignment which could be due to the mounts giving up. I am having the mounts on our DV36 changed at the moment. They are 16 years old but a fuel leak destroyed the rubber on one rear mount and the front two had started to delaminate. All 4 mounts are about £200 from Bukh.
VicMallows
Well-Known Member
Or about £100 direct from the UK agent ROBUSH.
robmcg
Well-Known Member
Just ensure you buy the correct combination of the mounts as they come in 3 stiffness varieties. In the DV36 case they also use different rated mounts on the front and rear. Also make sure Robush supply the shims that are needed to realign the gearbox to the shaft.
VicMallows
Well-Known Member
For the DV20 (which the OP has) Bukh now supply the same mounts for front and back - exactly the same ones as Robush supply. Robush won't supply the shims but if the old ones are not reusable or you need extra/different ones then making some is trivial. (I had miraculously actually kept the full set of spare shims from the original install 25 years ago 
)
)
NickRobinson
Well-Known Member
Mistroma
Well-Known Member
Many years since I bought DV20 mounts from Robush and I remember them being ~30% price of ones from a BUKH dealer. I assume that they finally realised that they were cheap and possibly bumped the price. I think I paid about £64 for 4 and might still have the part number somewhere, though that was about 6 years ago.
Just checked my archives and found the invoice for RAB2 mounts M12 55sh (10-00179-01) at £19 each incl. VAT. Only dealt with Robush but it sounds as if AvIndustrial are worth checking.
You can get the spec. here for the parts I bought to help find a similar part from AvIndustrial. http://www.missionsupplyonline.com/pdf/RAB.pdf Might be useful if you ever need to get new mounts. Mine only failed due to a fuel leak and it sounds as yours are still fine.
This has been discussed here several times and I remember the point about differences between front & back mounts. I also seem to remember that being a red-herring as they had been identical for some time. Certainly wouldn't consider original BUKH mounts as, just get the part nos. from the existing mounts. I seem to remember Robush saying that they mainly sold them for small site-generators and that was why they were cheap.
Just checked my archives and found the invoice for RAB2 mounts M12 55sh (10-00179-01) at £19 each incl. VAT. Only dealt with Robush but it sounds as if AvIndustrial are worth checking.
You can get the spec. here for the parts I bought to help find a similar part from AvIndustrial. http://www.missionsupplyonline.com/pdf/RAB.pdf Might be useful if you ever need to get new mounts. Mine only failed due to a fuel leak and it sounds as yours are still fine.
This has been discussed here several times and I remember the point about differences between front & back mounts. I also seem to remember that being a red-herring as they had been identical for some time. Certainly wouldn't consider original BUKH mounts as, just get the part nos. from the existing mounts. I seem to remember Robush saying that they mainly sold them for small site-generators and that was why they were cheap.
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robmcg
Well-Known Member
Have checked and DV20 mounts are identical front and back. DV36 are different front and back. Manufacturer is Trelleborg. Shims should be hardened and not cheap penny washer replacements.
H4B
Well-Known Member
Closer inspection has found some delamination so thank you for the parts info.
Do I have to remove engine completely to replace and anyone care to guess how easy it's going to be to release the bolts from the mounts and the mounts from the bearers. Look untouched since build 83, but engine may have been out before my ownership.
Any tips?
Do I have to remove engine completely to replace and anyone care to guess how easy it's going to be to release the bolts from the mounts and the mounts from the bearers. Look untouched since build 83, but engine may have been out before my ownership.
Any tips?
robmcg
Well-Known Member
It will certainly be easier to move the engine out of the way but it could be tackled one corner at a time if you have the room. Tackle the bolts with penetrating fluid about a week or so before you start to give them the best chance of moving. I have decided to leave the job to the professionals as I don't really have the kit to move 285kg around. Our engine is being moved forward into the galley to get the job done - but we are tight on space either side of the engine. Realignment is apparently more difficult because of the shims. Our shaft is connected directly to the gearbox with no damper or flexible coupling so realignment has to be absolutely spot on (mind you, it's waaaaaay out at the moment).
VicMallows
Well-Known Member
I had no difficulty replacing the BUKH mounts on my Sadler29 last year with the engine in situ. I used a combination of a pulley-hoist to a wooden beam over the companionway, and a scissor-type car jack. The BUKH mounts are in fact much easier to replace than many because you only need to raise the engine a tiny amount to slide the mounts out/in. As robmcg says, apply a GOOD penetrating fluid liberally in advance. You will of course need to detach the shaft coupling.
You will certainly need good socket spanners and probably several extension bars. All my bolts came undone quite easily - although the mounts had already been changed previously about 15 years ago. On a Sadler, the mounting bolts screw into tapped metal plates embedded in the GRP engine bearers, but I don't know how Westerly did things. If you think you may ever need to do the job again (or want to be kind to a future owner) make sure you smear all bolts with silicone sealant or similar on reassembly.
I don't find alignment using the shims difficult, but you do have to be able to 'visualise' how you need to move the engine to achieve things.
(Incidentally, If you ever need to remove the gearbox from the engine with it in situ THAT is REAL pain - at least on a Sadler29
)
You will certainly need good socket spanners and probably several extension bars. All my bolts came undone quite easily - although the mounts had already been changed previously about 15 years ago. On a Sadler, the mounting bolts screw into tapped metal plates embedded in the GRP engine bearers, but I don't know how Westerly did things. If you think you may ever need to do the job again (or want to be kind to a future owner) make sure you smear all bolts with silicone sealant or similar on reassembly.
I don't find alignment using the shims difficult, but you do have to be able to 'visualise' how you need to move the engine to achieve things.
(Incidentally, If you ever need to remove the gearbox from the engine with it in situ THAT is REAL pain - at least on a Sadler29
)
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Mistroma
Well-Known Member
Ditto for BUKH DV20 in a Southerly 95, mounts easy to swap one by one without moving the engine. I don't remember the loads being very high as the engine is just being twisted very slightly on remaining 3 mounts. I seem to remember just levering the engine up and using wood to hold in place during swap. I think that I cut it sl. long with a notch to catch the bracket and tapped a wedge into the side of the sump well.
I can't see any point in removing the engine unless access is so limited that you can't reach the mounts. In that case, you'd have problems aligning after replacement. So removal would just be extra work for little gain.
I can't see any point in removing the engine unless access is so limited that you can't reach the mounts. In that case, you'd have problems aligning after replacement. So removal would just be extra work for little gain.
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robmcg
Well-Known Member
Freshwater DV36 is considerably bigger and heavier Tradewind 35 has poor access My alignment was already shocking Extra work is more costly
Tradewind 35 has poor access My alignment was already shocking Extra work is more costly H4B
Well-Known Member
For the DV20 (which the OP has) Bukh now supply the same mounts for front and back - exactly the same ones as Robush supply. Robush won't supply the shims but if the old ones are not reusable or you need extra/different ones then making some is trivial. (I had miraculously actually kept the full set of spare shims from the original install 25 years ago
What should the shims be made of , (accepting the obvious, steel) grade?
VicMallows
Well-Known Member
I've no idea what they SHOULD be made of. The original BUKH shims I have appear to be made of ordinary sheet steel (the sort that rusts!). IIRC they supplied 0.25mm/0.5mm/0.5mm/1.0mm thicknesses. Mine have been perfectly re-usable when I've replaced the mounts ..... but then my bilge does tend to be quite oily
ghostlymoron
Well-Known Member
If they are thirty years old, they need changing.
colind3782
Well-Known Member
37 years old now!
ghostlymoron
Well-Known Member
Oh dear, didn't notice it was an old thread.
vic008
Well-Known Member
Have never understood how to share the engine weight equally over 4 mounts. Three mounts yes, but 4?
