Incorrect Engine Mounts Installed?

[Buffalo Barge]

So we have a Perkins 4.154 engine which weighs 195kg (430lbs) and PRM 260 gearbox 48-65kg. We recently had the mounts replaced by the RCR canal contracting. The used these at the back and we continued to feel heavy vibration.

 

https://www.midlandchandlers.co.uk/products/r-d-flexible-engine-mount-230-207010

 

RCR speculated at the time that the prop shaft may be bent. We've come out of water, prop and prop shaft are both fine. The engineer at the yard however has stated that the mounts fitted by the RCR are incorrect for the weight of our engine. In the description for these it says says it says from 79-230lbs. Does that mean the mounts are only suitable for engines between that weight or that each mount can sustain that weight?  

 

These mounts are fitted at the front which say capacity 160kg

 

https://www.midlandchandlers.co.uk/search?query=Ea-053

 

Much appreciated for any advice provided

[Eeyore]

We definitely need photos in order to make any sense of the situation as described; as the two mounts you mention are different in just about every way possible.

[Stilllearning]

I haven't worked on one of those engines in over 20 years, but I do remember the engine mounts all being the same.

Edited October 16 by Stilllearning

[Peugeot 106]

12 hours ago, Buffalo Barge said:

So we have a Perkins 4.154 engine which weighs 195kg (430lbs) and PRM 260 gearbox 48-65kg. We recently had the mounts replaced by the RCR canal contracting. The used these at the back and we continued to feel heavy vibration.

 

https://www.midlandchandlers.co.uk/products/r-d-flexible-engine-mount-230-207010

 

RCR speculated at the time that the prop shaft may be bent. We've come out of water, prop and prop shaft are both fine. The engineer at the yard however has stated that the mounts fitted by the RCR are incorrect for the weight of our engine. In the description for these it says says it says from 79-230lbs. Does that mean the mounts are only suitable for engines between that weight or that each mount can sustain that weight?  

 

These mounts are fitted at the front which say capacity 160kg

 

https://www.midlandchandlers.co.uk/search?query=Ea-053

 

Much appreciated for any advice provided

R&D Marine supply engine mounts and will size them if you give them engine and gearbox details. It may be worth giving them a ring. As I understand it there are different types “ hard” and “soft” mounts but give them a ring

[IanD]

12 hours ago, Buffalo Barge said:

So we have a Perkins 4.154 engine which weighs 195kg (430lbs) and PRM 260 gearbox 48-65kg. We recently had the mounts replaced by the RCR canal contracting. The used these at the back and we continued to feel heavy vibration.

 

https://www.midlandchandlers.co.uk/products/r-d-flexible-engine-mount-230-207010

 

RCR speculated at the time that the prop shaft may be bent. We've come out of water, prop and prop shaft are both fine. The engineer at the yard however has stated that the mounts fitted by the RCR are incorrect for the weight of our engine. In the description for these it says says it says from 79-230lbs. Does that mean the mounts are only suitable for engines between that weight or that each mount can sustain that weight?  

 

These mounts are fitted at the front which say capacity 160kg

 

https://www.midlandchandlers.co.uk/search?query=Ea-053

 

Much appreciated for any advice provided

The quoted capacity is the maximum weight on each mount.

 

With the normal four mounts, the weight on each is unlikely to be the same unless the centre of gravity of the engine+gearbox happens to be midway between them -- so this depends on where the weight is distributed and where the mounts are positioned on the engine.

 

If there are vibration problems it's often because the mounts are too stiff, and this depends on how much they deflect under load -- the ones fitted at the front say "hard mounts" (160kg rating) so these are probably too stiff. Even the R&D ones (230lbs=105kg) say "low height with minimum deflection" so these could also be too stiff. Mounts which are underloaded (load much smaller than rating) will also be too stiff -- the four mounts you have added together are rated at 530kg but the engine and gearbox weigh 260kg, which is only 65kg/mount if evenly distributed.

 

It looks to me that you need softer mounts with lower load rating and possibly higher deflection (especially at the front), but it's impossible to make any recommendation without knowing what restrictions you have on mount height, foot size/bolt spacing and so on.

[MtB]

15 hours ago, Buffalo Barge said:

So we have a Perkins 4.154 engine which weighs 195kg (430lbs) and PRM 260 gearbox 48-65kg. We recently had the mounts replaced by the RCR canal contracting. The used these at the back and we continued to feel heavy vibration.

 

 

The question leaping off the page at me is what instructions did you give when you engaged RCR? 

 

Did you ask them to diagnose and fix "heavy vibration"? Or did you ask them to replace the engine mounts? 

 

Or something else?

 

[matty40s]

3 hours ago, MtB said:

 

The question leaping off the page at me is what instructions did you give when you engaged RCR? 

Did you ask them to diagnose and fix "heavy vibration"? Or did you ask them to replace the engine mounts? 

Or something else?

 

Knowing RCR, he reported a faulty tunnel lamp....

[Peugeot 106]

2 hours ago, matty40s said:

Knowing RCR, he reported a faulty tunnel lamp....

I only used RCR once for a broken fuel pipe. He was very helpful and knew his stuff. I’m sure he would have been fine with a rocker cover gasket.  Let’s face it RCR aren’t unique in having some contractors of dubious intelligence. The same could be said of plenty of so called marine engineers and come to think of it some forum members too! I suspect that people mostly post about bad experiences.

7 minutes ago, Peugeot 106 said:

I only used RCR once for a broken fuel pipe. He was very helpful and knew his stuff. I’m sure he would have been fine with a rocker cover gasket.  Let’s face it RCR aren’t unique in having some contractors of dubious intelligence. The same could be said of plenty of so called marine engineers and come to think of it some forum members too! I suspect that people mostly post about bad experiences.

Apologies posts mixed up but the same sentiment applies