Diesel Fuel Tank Inspection Port?

nigelmercier

nigelmercier

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I'm considering fitting an inspection port in the top of my diesel fuel tank. I figure I can then dip, sample and drain (by syphon) without taking out the fuel gauge sender. The tank is black plastic, perhaps HDPE? I think about 50mm diameter would be about right, preferably easy to open without tools.

Any suggestions?
 
I'm not sure I'd bother doing that - and I speak as someone who's suffered with the dreaded diesel bug. If your tank is clean(ish) and if you're treating the fuel you put in to it with a decent bug killer, why would you want to go delving around in it?
 
Have you got a fuel level sender in the tank?I have been using it for years for inspection, dipping, and one case as an inlet to a pump to take the fuel through a filter and back to the tank filler to clean the dreaded diesel bug. Simples?
 
We've got a couple of blank pipe outlets on our plastic tank at the top. If I unscrew the covers I can get a thin copper tube right down to the bottom corner where the crud and water will be (if any). Getting it all set up now, and will then use an oil pump to sample what's there.
 
pvb said:
Obviously too much spare time!
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Look, I have reasons OK! More than I stated, but not relevant to my question. Why give me a hard time just because you don't think it is necessary? [Later] Ahh, now I understand, over 1000 posts a year - and I have too much spare time! Memo to self: "Do not feed the trolls!"

So I ask again, has anyone anything relevant to say about fitting an inspection port?
 
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nigelmercier said:
So I ask again, has anyone anything relevant to say about fitting an inspection port?
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The owner of the sailing school I went to mentioned they had fitted them to the school boats and managed to get out a handful or two of crud every year. Although they would have used more diesel than most.

.
 
Seabuilt has a very good product. http://www.seabuilt.com/compatibility.php I have used it and it is great. They are much bigger then you want though. I am going to put one in the tank of my new boat soon. They do make custom sizes. I think in your case I would use one of these so that I can clean the tank out and then drill and tap the lid to fit a 50mm plug. Assuming you can find a 50mm plug of the correct size. I imagine a plumbing or hydraulic shop would carry one.
 
nigelmercier said:
Look, I have reasons OK! More than I stated, but not relevant to my question. Why give me a hard time just because you don't think it is necessary? [Later] Ahh, now I understand, over 1000 posts a year - and I have too much spare time! Memo to self: "Do not feed the trolls!"

So I ask again, has anyone anything relevant to say about fitting an inspection port?
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Speak to Tek Tanks. They have a range of inspection hatches that they fit to plastic tanks. Not sure whether they can be retrofitted.
 
nigelmercier said:
The tank is black plastic, perhaps HDPE? I think about 50mm diameter would be about right, preferably easy to open without tools.
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Most inspection hatches are bigger than that, but if you only want 50mm or so, you might consider a flat brass Essex flange with 2.25" internal BSP thread, as used for fitting immersion heaters. This can be fitted from outside the tank without needing internal access. You'd also need a blanking plug for it, which would need a spanner to open it, although I'm sure you could get some sort of handle brazed on to it.

The Norwegian company Wema makes a good plastic inspection hatch, again able to be fitted from outside, but it's for a 115mm diameter hole. You can buy these from industrial suppliers or people like Tek Tanks.
 
nigelmercier said:
I'm OK with a bit larger. I haven't found anything remotely like an inspection port!
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There are lots of fairly simple inspection ports available, with a hand-operated lid, but I'm not sure I'd want one on the top of a fuel tank subject to the sort of motion found in a sailboat. For your application, you need something fairly secure.
 
nigelmercier said:
Look, I have reasons OK! More than I stated, but not relevant to my question. Why give me a hard time just because you don't think it is necessary? [Later] Ahh, now I understand, over 1000 posts a year - and I have too much spare time! Memo to self: "Do not feed the trolls!"
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Love it. I thought it a very good question as I'm also considering fitting one, My problem is my tank is under and behind the chart table with no access from above other than dismantleing the Instrument panel and chart table. I would have to fit one on the side of the tank. The WEMA product looks perfect for the job and reasonably priced, The Seabuilt one looks better but a bit costly . Would this be a bad idea?

Only access I have is from the cupboard you can just see in this pic.
 
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Spyro said:
I would have to fit one on the side of the tank. The WEMA product looks perfect for the job. Would this be a bad idea?
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Reckon it would be a bad idea, the Wema doesn't look like it has sufficient sealing capability to reliably keep the diesel in the right place.

The Seabuilt system is clever, but hideously expensive, with prices starting at around £100. It would surely be easy enough to get someone to make up a stainless copy of a Seabuilt hatch for less than that?
 
pvb said:
Reckon it would be a bad idea, the Wema doesn't look like it has sufficient sealing capability to reliably keep the diesel in the right place.

The Seabuilt system is clever, but hideously expensive, with prices starting at around £100. It would surely be easy enough to get someone to make up a stainless copy of a Seabuilt hatch for less than that?
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It looks OK when you see it here.
http://www.wema.com/publish_files/FLB_-_163110.pdf

The clever bit about the seabuilt one is the hinged backing plate I imagine this would be quite tricky to build and the amount of time required would outway the cost of the seabuilt product.
I've also considered cutting a hole and fitting a cover plate fixed on with self tappers or tapping holes and fixing with bolts but I don't think the tank would be thick enough. What could I use for a gasket that would resist diesel if I went down that route.
 
Spyro said:
The clever bit about the seabuilt one is the hinged backing plate I imagine this would be quite tricky to build and the amount of time required would outway the cost of the seabuilt product.
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The backing plate isn't hinged. It's just a simple circular ring cut in two. The gasket holds it together and acts as a "hinge" - look at the pics on the demo.

Spyro said:
What could I use for a gasket that would resist diesel if I went down that route.
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Nitrile sheet ideally. Neoprene at a push.
 
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pvb said:
The backing plate isn't hinged. It's just a simple circular ring cut in two. The gasket holds it together and acts as a "hinge" - look at the pics on the demo.



Nitrile sheet ideally. Neoprene at a push.
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I saw the demo vid, I just assumed it was hinged

Thanks
 
Spyro said:
I saw the demo vid, I just assumed it was hinged
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It's not very clear; here's a pic showing the inside split ring.

accessplate_large-250x250.jpg
 
I have Tektanks with nice big inspection ports. Having said that, they are not the sort of thing you just flip open easily, so not used for a quick look.

For getting crud out and sampling the fuel, we have a tube fitting that goes into a housing on top of the tank. It has a small valve on the top with a little pipe leading from it. By slipping the flexible end of a Pela suction pump over the pipe I can suck out a samlpe of fuel from the bottom of the tank without using any inspection ports.

Not sure if that helps, but I guess it's better than telling you not to bother!
 
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