Gasket for deck fuel filler

dgadee

Well-known member
Joined
13 Oct 2010
Messages
3,678
Visit site
The gasket for the deck fuel filler was breaking up and was letting water into the diesel tank. I forgot to source this over the winter. Do I need a nitrile replacement? Where can these be got? I presume each filler is different so unlikely to get from the local chandlers?

Philip
 

Martin_J

Well-known member
Joined
19 Apr 2006
Messages
4,284
Location
Portsmouth, UK
Visit site
Hi.. It's probably a standard o-ring and others will probably reply shortly with reasons for and against Nitrile.

I just replaced mine (fuel and water fillers) with nitrile o-rings but just two minutes ago read that Viton has better resistance against new bio diesels than nitrile.

I have not tried this place but they appear to be local to the South Coast and sell this sort of size o-ring (in Viton) from about £0.14 each!!!

http://www.polymax.co.uk/acatalog/Viton_O-Rings.html

Would have to guess at 3.53mm cross section but I could measure right now if needed (as an example)..
 

vyv_cox

Well-known member
Joined
16 May 2001
Messages
25,518
Location
France, sailing Aegean Sea.
coxeng.co.uk
Viton will undoubtedly have better resistance to bio-diesel than nitrile does, but for intermittent contact in a non-critical duty I doubt very much that it is justified. Although if you can get them in the right size for 14 pence you might as well go for them!

Many chandlers stock a big range of O-rings, they come in a compartmentalised box in a variety of sizes and sections. I'm fairly sure that they will be nitrile.
 

Martin_J

Well-known member
Joined
19 Apr 2006
Messages
4,284
Location
Portsmouth, UK
Visit site
As Vyv says.. there is probably very little diesel contact with this o-ring... unless you regularly overfill or splash when filling!

Looks like that website needs a minimum £10 order.. but I might just use them to replace all my Lewmar hatch handle o-rings.. (Off subject - but is Viton or Nitrile softer and which has more springiness to return it to it's original shape?)
 

vyv_cox

Well-known member
Joined
16 May 2001
Messages
25,518
Location
France, sailing Aegean Sea.
coxeng.co.uk
As Vyv says.. there is probably very little diesel contact with this o-ring... unless you regularly overfill or splash when filling!

Looks like that website needs a minimum £10 order.. but I might just use them to replace all my Lewmar hatch handle o-rings.. (Off subject - but is Viton or Nitrile softer and which has more springiness to return it to it's original shape?)

Most elastomers can be made in a range of hardnesses. The harder it is, the less elastic. By the time Viton gets up to 95 - 98 Durometer it is close to being a plastic. For good elasticity you want about 70 or less. Should be stated in most cases. Nitrile is good for most oil and water purposes - it's not often that we need a Viton on a boat. Sometimes neoprene (chloroprene) is used, water resistance is good and oil resistance not far behind nitrile.
 

Martin_J

Well-known member
Joined
19 Apr 2006
Messages
4,284
Location
Portsmouth, UK
Visit site
Vyv.. thanks. It looks from that Polymax website that their Nitrile are 70.

FWIW - my current fuel filler o-ring appears to have an ID (Internal diameter) of 44mm. I'm still wondering whether my filler cap o-rings should be replaced with 44.04 x 3.53mm or 44 x 3mm. Needs better measuring.
 

rob2

Active member
Joined
23 Aug 2005
Messages
4,093
Location
Hampshire UK
Visit site
If it is a gasket rather than an o-ring, then you will probably have to remove it and trace for making a copy. There are rubber factors just about everywhere who will be able to cut you a new gasket from sheet material. For anyone in the Solent area, there is Portmere Rubber, Victoria Street, Northam, Southampton SO14 5QZ Tel. 01703 223628 www.portmererubber.co.uk/

Rob.
 

dgadee

Well-known member
Joined
13 Oct 2010
Messages
3,678
Visit site
Yes, it is a gasket, but I don't know whether the original was an o-ring or not. I've decided (after not being able to find a ready made gasket) to give it a go with an o-ring (and test with a hose) and see what happens.

Philip
 
Top