Fuel pump what internal type thread?

[Duffer]

Hi, I just bought a replacement fuel pump, number FFP508. It has in/outlets which are internal threaded type, and I wish to convert these to push on fuel lines with jubilee clips if possible.

The pump is made by First Line and neither the seller or the main supplier can answer my question.
I tried a BSP thread adaptor and that isn't right, and my thread gauges seem to indicate it isn't metric or Whitworth either.
To help, here is a piccy of the sort of thing- this must be a standard thread for fuel pumps, but, sadly I have no idea what thread type it is?
http://www.ebay.co.uk/itm/VAUXHALL-VIVA ... SwojxZnJiP
TIA
Cheers, Andy

[1972nail]

It's probably the American 'NPT' thread. Much of the UK GM fuel and cooling stuff from in the 60's and 70's is NPT.

[droopsnoot]

If it's the same thread as the pump I've got on the hatch, I believe they're 1/2" UNF thread. For me the issue is trying to get a decent seal - I've never had success with getting an olive to compress on the pipe, and flaring never worked.

I recently bought some "hose tail" kits: https://www.ssldieselparts.co.uk/hose-t ... p-378.html

I must stress though that I haven't fitted them yet. I have an idea that there was a problem with them, but I think it might be that I should have gone for 6mm pipe instead of 8mm pipe.

[Duffer]

Cheers, Droopsnoot, I ordered those adaptors with UNF fine after I found my UNF tap and it seems damn close. Anyway nowt a bit of ptfe tape or red sealant can't sort come the day. Thanks

[droopsnoot]

Anyway nowt a bit of ptfe tape or red sealant can't sort come the day. Thanks

I hope they're OK. I've never had good luck with PTFE tape on fuel line fittings, but a lot of the trouble I've had is with the olive rather than the thread, and is mainly down to me not being sure how much weight I can put on it to compress it on to the pipe. I'm always a bit worried about stripping the thread out of the alloy pump body.

[Duffer]

Hi Droopsnoot and all,
I got those adaptors, and all is fine my old Viva HC is back working now thanks!
A Few notes, firstly I packed behind the olives on the adaptors with 7 turns of PTFE, I also put 7 turns of PTFE tape on the thread part.
You will know when it is right, tighten them up by hand and if there is a sense of friction, and a slight backward springiness as you do that, you will know that is about right.
Put the adaptors on first, hand tightened, then position them especially the elbow so as to not touch the hot engine- then you can do them up quite tight, the PTFE tape helps you get the right feel. I did them up to just before the end of the thread stopped showing to the outside world with a 1/2 inch AF spanner I think.
I also put a few turns of insulating tape under the jubilee clip fixings push on fuel hose, as sometimes old jubilee clips can be sharp- and that stops them causing damage.

Re: Pumps, do NOT buy the FFP509 pump, as that can't be fitted without the fuel line running in to the oil dipstick.
The FFP508 is tested and fine and the Simpatico branded one should be the same!
Make sure you place the pump arm ABOVE the moving wheel inside the moving arm hole on the engine when fitting, and take care not to overtighten the two fixing bolts!

I hope that helps someone out there!
Cheers, Andy

[droopsnoot]

Great to know that they fit, especially as I haven't put mine on yet.

Mine's an OHC engine, and the reason I don't like the OHC version of that pump is that the front outlet (or inlet, I forget which) is very close to the distributor wheel, so the 90-degree version is needed.