Yanmar seawater pump - seal orientation

[West Coast]

Hi all. Servicing a Yanmar 4JH5E seawater pump. Question relates to an odd shaped rubber seal on the rhs of the photo below, which way round should this go? It is not a conventional lip seal with a spring

thanks!

 

[Boater Sam]

It is a standard liquid seal. The thin lip side runs on either a stainless steel or polished ceramic face so that it doesn't wear too quickly. Looking at your picture, the liquid to be retained will be on the left of the seal so that any liquid pressure presses the thin lip of the seal harder onto the running face which will be on the right of the seal in you picture.

 

[oldgit]

Hi all. Servicing a Yanmar 4JH5E seawater pump. Question relates to an odd shaped rubber seal on the rhs of the photo below, which way round should this go? It is not a conventional lip seal with a spring

thanks!View attachment 152216

From free downloadable manual on Yanmar website.
Couple of pages on the pump in the Service manual also a Parts manual online, with much better detail than this image.

 

[ean_p]

Hi all. Servicing a Yanmar 4JH5E seawater pump. Question relates to an odd shaped rubber seal on the rhs of the photo below, which way round should this go? It is not a conventional lip seal with a spring

thanks!View attachment 152216

Look into V Ring seals. It would depend upon how the fixed and rotating elements of the mechanical seal assembly are sealing on the shaft and housing( for the fixed component) as ordinarily there would be no requirement for this additional seal.
The V Ring is 'fixed' by friction to the shaft and rotates with the shaft. It seals generally on a face that is at right angles to the axis of the shaft though it can also seal on a surface that is parallel to the shaft. It can seal from either direction dependent upon the compression on the lip and the available pressure to energise the seal, both of course dependent upon its specific installation mode.

 

[West Coast]

Thanks all for your replies. I have the engine workshop manual, and there is an exploded drawing but not detailed enough to show the seal,orientation. Will do some research into V ring seals

 

[Boater Sam]

Thanks all for your replies. I have the engine workshop manual, and there is an exploded drawing but not detailed enough to show the seal,orientation. Will do some research into V ring seals

In the drawing, the lip seal is item 6. Its the first part after the impeller. The thin lip edge is on the left, bearing on the smooth face of the spring unit which I think is white ceramic material.

 

[ean_p]

In the drawing, the lip seal is item 6. Its the first part after the impeller. The thin lip edge is on the left, bearing on the smooth face of the spring unit which I think is white ceramic material.

#6 is the mechanical seal, though that drawing isn't relevant to the array in the photo provided I think.
This drawing seems more pertinent;
Yanmar Shop - FIG 16. COOLING PUMP(SEA WATER) Schematic

In which case the seals are as shown in the photo but the water is to the left and the engine is to the right. Thr v ring would then possibly bear against the oil seal outer face or a surface within the pump casing. Not being able to see the casing internally makes it difficult!
Of course it could also all be bollocks too but there you go.....!

 

[Boater Sam]

#6 is the mechanical seal, though that drawing isn't relevant to the array in the photo provided I think.
This drawing seems more pertinent;
Yanmar Shop - FIG 16. COOLING PUMP(SEA WATER) Schematic

In which case the seals are as shown in the photo but the water is to the left and the engine is to the right. Thr v ring would then possibly bear against the oil seal outer face or a surface within the pump casing. Not being able to see the casing internally makes it difficult!
Of course it could also all be bollocks too but there you go.....!

The vee seal will not bear on the casing, it has to be onto ceramic or stainless steel else it would wear away too quickly. I am pretty certain that the spring unit has a ceramic face, in the photograph everything is the wrong way round or in the wrong place.

 

[ean_p]

The vee seal will not bear on the casing, it has to be onto ceramic or stainless steel else it would wear away too quickly. I am pretty certain that the spring unit has a ceramic face, in the photograph everything is the wrong way round or in the wrong place.

I think we may be talking about two different things here Sam.
The mechanical seal is the white object ( ceramic face of the non rotating element of the mechanical seal) and the black object ( the carbon face on the rotating element of the mechanical seal). They are facing each other and separated by the 'ie' writing on the pen. Together these two components make up the one mechanical seal. The V Ring seal is the elastomeric object at the end on the right hand side. Its 'sealing ' lip is that edge that is at the end of the cone on its right hand side and so the extreme right hand edge of the array in the photo. It works like a rotating 'lip seal' and so seals against a fixed object be that a machined surface within the case or the smooth face of a wear plate or oil seal front face whereas most 'lip seals' are stationary and seal on a moving shaft.
So if the exploded diagram in post #7 is correct then the pump has essentially two chambers within the casing, one for the impeller and seal and one for the bearing housing.
The bearing housing is sealed at its outside end by the lip seal (item 14) which prevents oil from the engine timing case weeping out along the shaft.
The impeller housing is sealed at its outside end by the gasket and cover plate ( items 6 & 9). It is then sealed at its inside ( shaft) end by the mechanical seal assembly (item 11) which prevents water from the impeller chamber leaking along the shaft ( via the seal on the shaft within the rotating element, the 'spring object in the photo) and out of the casing structure by the seal in its housing of the stationary element ( the black and white object, second from right in the photo). It then depends as to how the impeller housing is separated from the bearing housing. If as I suspect the shaft emerges from the impeller housing out into the outside world before then entering the bearing housing an inch or so later then I would suggest that the V Ring seal is positioned between the stationary element of the mechanical seal and the end 'wall' of the impeller housing so as to seal on the end wall around the hole through which the shaft passes . Its function here would be to keep out dust / debris which would otherwise travel along the shaft ( as its not sealed in the area of the fixed element of the mechanical seal)and possibly get between and damage the two sliding faces of the mechanical seal ( the carbon and ceramic faces).

 

[vyv_cox]

I think the oil seal is exactly what it says, it bears on the bearing in the drawing, although confusingly it seems to run on the cage rather than the outer raceway. It keeps the oil in the bearing. Oil is certain death to a mechanical seal in a water system.
Unfortunately it is not obvious which way round it fits in the drawing. Presumably the outer lip in the photo is big enough to cover the bearing outer raceway. Although it doesn't look it.

 

[ean_p]

I think the oil seal is exactly what it says, it bears on the bearing in the drawing, although confusingly it seems to run on the cage rather than the outer raceway. It keeps the oil in the bearing. Oil is certain death to a mechanical seal in a water system.
Unfortunately it is not obvious which way round it fits in the drawing. Presumably the outer lip in the photo is big enough to cover the bearing outer raceway. Although it doesn't look it.

Sorry Vyv are you referencing the drawing in post #3 ?
The OP's question isn't about an 'oil seal' I think and I'm not to sure the drawing in post #3 is relevent giving what is shown in the photo.

 

[vyv_cox]

Sorry Vyv are you referencing the drawing in post #3 ?
The OP's question isn't about an 'oil seal' I think and I'm not to sure the drawing in post #3 is relevent giving what is shown in the photo.

Yes, looking at the #3 drawing but I cannot understand why there would be an elastomeric seal on the water side of a mechanical seal. I wondered if the components had been mixed up on withdrawal and the elastomer is the oil seal shown in the drawing

 

[ean_p]

Yes, looking at the #3 drawing but I cannot understand why there would be an elastomeric seal on the water side of a mechanical seal. I wondered if the components had been mixed up on withdrawal and the elastomer is the oil seal shown in the drawing

Have a look at the drawing in post # 7.
I think the seal ( the V ring seal) is to stop ingress of dust / dirt along the shaft and into the internals of the mechanical seal wherein it could migrate into the seal faces and cause damage / leakage.

 

[vyv_cox]

Have a look at the drawing in post # 7.
I think the seal ( the V ring seal) is to stop ingress of dust / dirt along the shaft and into the internals of the mechanical seal wherein it could migrate into the seal faces and cause damage / leakage.

12 and 14 in the post #7 drawing seemingly are both seals doing much the same job. 14 is a lip seal keeping oil out and 12 is this odd additional one. Looks like it maybe butts up to the mechanical seal. An odd arrangement. But as shown in the OP photo.

 

[ean_p]

12 and 14 in the post #7 drawing seemingly are both seals doing much the same job. 14 is a lip seal keeping oil out and 12 is this odd additional one. Looks like it maybe butts up to the mechanical seal. An odd arrangement. But as shown in the OP photo.

yes its a V ring seal and it functions similar to an oil(lip) seal except that they are commonly fitted to shafts and so are rotating. They seal on the shaft ( or other position simply by being tight fitting usually but in larger sizes can also be clamped too. The 'working' seal is the outer end of the conical skirt which as mentioned above can act on either a surface parallel to the shaft axis or at right angles to it. They can be used to seal from either side depending on the application and operation.

 

[vyv_cox]

yes its a V ring seal and it functions similar to an oil(lip) seal except that they are commonly fitted to shafts and so are rotating. They seal on the shaft ( or other position simply by being tight fitting usually but in larger sizes can also be clamped too. The 'working' seal is the outer end of the conical skirt which as mentioned above can act on either a surface parallel to the shaft axis or at right angles to it. They can be used to seal from either side depending on the application and operation.

Not something I have come across. Hard to understand why they are used as it seems to be a pretty poorly designed thing.

 

[West Coast]

Hi all, first off, many thanks for the really helpful replies.

The pump is gear driven, with conventional lip seal (to prevent oil leaks)and shaft bearings etc on the “engine” side of the pump. This is already reassembled, straightforward. As you would expect, there is a gap in the housing, with drain slots, between the engine side and the water pump side.

The photo I provided shows the seals on the water pump side, in the orientation and sequence that I removed them. Re photo, the LHS of the photo is the impeller side. If this is the sequence I removed them, fair question to ask is why I am raising this question at all! But it did not make sense to me, and I wondered if the pump had been assembled correctly in the past.

ean-p, you’re explanation in post #9 makes complete sense now, thank you. I had been googling V ring seals, and one of the uses mentioned was indeed a debris preventer. there is no SS or ceramic face for it to run against. The part of the housing it would be positioned in is approx the same size as the outer dia of this v seal, so likely it bears lightly against this as it turns, keeping debris out.

since posting this, finally found the drawing I needed online - trying to attach it below