Forums > Sailing General

Raw Water Pump Gasket

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Created by Yara Two weeks ago, 9 May 2020
Yara
NSW, 1019 posts
9 May 2020 10:41PM
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Slowly going through maintenance on the Space Sailer. Want to check the raw water impeller on the VolvoPenta 2001 engine. I would like to replace the water pump gasket, and can make one easily, but I have no idea what thickness gasket material is required.
Whenever I have checked out boats, the raw water pump always seems to have a salt encrusted rim. Looks like this gasket, or lack thereof, is a common problem.
Any idea what thickness to buy?

cisco
QLD, 11724 posts
10 May 2020 8:10AM
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Chart paper should be about right.

Jolene
1197 posts
10 May 2020 6:45AM
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Have you had a look at it to confirm there is a gasket or is it an o ring ? If it does have a gasket the thickness may be important to the cover plate impeller clearance. To thick and you will lose pump efficiency. I usually measure the housing and impeller heights before making a gasket, that is if I have to make one.

Ramona
NSW, 5571 posts
10 May 2020 8:45AM
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Very thin.

Datawiz
VIC, 556 posts
10 May 2020 8:53AM
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Select to expand quote
Jolene said..
Have you had a look at it to confirm there is a gasket or is it an o ring ? If it does have a gasket the thickness may be important to the cover plate impeller clearance. To thick and you will lose pump efficiency. I usually measure the housing and impeller heights before making a gasket, that is if I have to make one.


Good to see someone has an analytical approach to a problem rather than jumping in head first.....

cisco
QLD, 11724 posts
10 May 2020 3:47PM
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If one thickness of chart paper is not enough, add another.

Yara
NSW, 1019 posts
10 May 2020 5:58PM
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Select to expand quote
cisco said..
If one thickness of chart paper is not enough, add another.



How do you find out it is too thin? If the plate is jammed against the rotor you might destroy it. However I cannot imagine a designer would make clearances that critical.
I think I will go with 0.4mm which seems to be the minimum on the market.

Craig66
NSW, 1927 posts
10 May 2020 6:41PM
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Select to expand quote
Yara said..


cisco said..
If one thickness of chart paper is not enough, add another.





How do you find out it is too thin? If the plate is jammed against the rotor you might destroy it. However I cannot imagine a designer would make clearances that critical.
I think I will go with 0.4mm which seems to be the minimum on the market.



Put the faces together dry, metal to metal, spin rotor by hand, you will know if binds.

wongaga
336 posts
10 May 2020 5:55PM
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For a little low-pressure gasket like that, it's almost certainly to be pretty thin, about .5 mm. But as said, use two thicknesses if you need to.

I got sick of the ridiculous Yanmar prices and measured the remains of the previous OEM gasket with the vernier then bought a minimum-quantity roll of paper from a bearing shop. For less than the cost of one OEM gasket I got enough paper to cover the next 1,000 engine services. Tapped them out with a little ball-pein hammer and now I have the next 5 years sorted.

Guitz
VIC, 474 posts
11 May 2020 3:14PM
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Last gasket i made for a jabsco raw water pump i used a manila folder to cut out the gasket, coated it with oil and it's still ok 5 years on.

Yara
NSW, 1019 posts
Friday , 22 May 2020 9:39AM
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So the genuine Volvo-Penta part 833994 is only $6, and easily available, no need to make one unless in emergency. And the thickness? 0.15mm. Pretty darn thin, so not easy to make, and gasket paper this thin also not that easy to buy, and will cost more than the genuine article.

Jolene
1197 posts
Friday , 22 May 2020 6:13PM
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I have a great little laser cutter/ engraver that I mostly use for cutting small gaskets. I would probably do more with it but I need more practice with the CAD software. I sometimes use it for cutting fiberglass cloth for intricate parts as it seems to melt the cut edge and stop the piece coming apart

cisco
QLD, 11724 posts
Friday , 22 May 2020 9:58PM
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Chart paper, hole punch, scissors and grease.

Can this thread move on??

garymalmgren
466 posts
Friday , 22 May 2020 8:07PM
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Can this thread move on??

To where?

Oh, to here,

gary

Yara
NSW, 1019 posts
Tuesday , 26 May 2020 12:36PM
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Select to expand quote
cisco said..
Chart paper, hole punch, scissors and grease.

Can this thread move on??


Just for you Cisco, I measured the thickness of one of my paper charts, and yes, it was 0.15mm, just like the genuine gasket. However I am not going to attack my charts with a scissors unless desperate! :-)

cisco
QLD, 11724 posts
Tuesday , 27 May 2020 12:21AM
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Good one Yara.

In the Navy out of date charts are passed on to the engineering department for recycling as gasket material for precision fit machinery.

In our application one could probably make 50 raw water pump gaskets from a chart so a if the chart is still in use on the chart table I really do not think a three inch square taken out of one corner of your chart in a time of need for gasket material is going to compromise navigation capabilities of the vessel to any great extent.

What would we all be doing if we did not have such important matters as this to discuss??????????????

Charriot
QLD, 816 posts
Wednesday , 27 May 2020 6:38AM
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I have spare 50 charts, iam in qld. Manila folder plus touch of non hardening liquid gasket.



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"Raw Water Pump Gasket" started by Yara