Anyone good with Thread sizes and pitches?

[jumping350]

So basically need to change the nozzle on my fuel pressure regulator to a AN fitting.

Bought about 5 now the closest one being a 1/8 NPT (whatever that is).

Anyway it goes in one thread and goes tight and wont budge so obviously wrong thread pitch, the width is spot on though.

What thread pitch is 1/8 NPT? would a 1/16 NPT solve my problem? im thinking that will be too small, ive contacted about 3 places who seem to take forever to get back to me so thought would see if anyone on here knew?

here are pics of both, the blue one is 1/8 NPT have no idea what the other one is (the one i need to match )

 

 

Any help much appreciated

[Tricky-Ricky]

NPT threads are tapered, you will probably need an adapter/converter.

 

NPT data here, http://www.engineeringtoolbox.com/npt-national-pipe-taper-threads-d_750.html

AN to NPT, http://www.aircoolednut.com/erkson/ttt/AN-NPT_thread_sizes.jpg

[Fodder]

Im not able to give you the answer but if you have an old fashioned hardware store close by id go there.

 

If they haven't got what you need they will certainly be able to tell you what you need.

 

Edit: Google "fasteners" and your town, you may find there's a specialist. There's one a few miles away from me and no matter what you take in they will have the correct nut, bolt or adapter

Edited December 22, 2014 by Fodder

[jumping350]

So I have an ISO thread? the shop sells the fitting in all threads so may not need a converter just need to figure out what thread I have would it be like m6x100 or something along those lines/format? or am i way off the mark?

Edited December 22, 2014 by jumping350

[Fodder]

So I have an ISO thread? the shop sells the fitting in all threads so may not need a converter just need to figure out what thread I have would it be like m6x100 or something along those lines/format? or am i way off the mark?

 

Have you took it into the shop? If they are good they should be able to tell you and supply.

[jumping350]

the place that has it all is online store, ive emailed them the pics but twice now they said they havent recieved email there is a AN fitting place up the road but they wont tell you anything unless you buy something that costs over £100 (and they don't have what I want), and all the little shops unfortunately have closed down now

Edited December 22, 2014 by jumping350

[GMballistic]

Just fyi as you asked: According to Wiki 1/8th NPT (national pipe thread) has a thread pitch of 0.03703704" or 0.9407mm.

 

Not sure that'll help but there you go.

[jumping350]

thats whats killing me GM all the numbers!! point this and point that

[Tricky-Ricky]

Your problem is that if its 1/4NPT thread is 18TPI closest AN size is -4 and the thread is 20TPI, the difference between them is 2 TPI (teeth per inch) that's why its locking up, you will need an NPT to AN converter, there are company's that sell AN fittings and adapters on ebay.

[jumping350]

Thanks Tricky,makes sense, when i type that into ebay it comes up with the stuff ive bought already, would you know which one I would need?

http://stores.ebay.co.uk/Motorsport-Tools-UK__W0QQ_sidZ87353699?_nkw=an6&submit=

[Tricky-Ricky]

I did say IF the existing thread is 1/4NPT, you first need to get a thread gauge, that way you will know for sure what TPI it is, and if it measures at 1/4 and not a metric size which I suspect it is, once you know this, you just have to match the converter size with whatever AN size you need for your fuel lines.

[jumping350]

I still maybe lost but IF hypothetically speaking if existing thread was 1/4 NPT then could I just get this? as it has right AN fitting..im geting confused with a converter?

http://www.ebay.co.uk/itm/Motamec-6-AN6-JIC-1-4-NPT-Straight-Aluminium-Alloy-Fitting-Adapter-/231073694846?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item35cd10c47e

Will nip to my mates garage he must be able to find out what thread it is

Thanks

[Iwantone]

Take a look in the box where you throw all the old nuts, bolts, washers and screws that you have remaining when you have finished a job. See if one of the bolts will screw into the hole WITHOUT being forced. That way you should be able to find the thread size. You may well have a standard metric hole of, say, M6 x 1mm pitch. There is also a little app for Android phones that puts the various pitches on screen so that you can lay the thread you are trying to identify on top of it and compare the pitches. Don't force mismatching threads together.

 

Steve

[jumping350]

thanks il take a look at app, I thought supercharger install was going to be a pain ive not got passed this yet no didnt force as soon as it started to go tight I backed off and screwed the old one back in just to make sure

[Tricky-Ricky]

I would say that if its an aftermarket FPR then its unlikely to be as small as 1/4NPT, it needs to be bigger than that, fuel flow would be impaired if it was, the bolt idea is good if you have a decent selection, I would suspect that its more like 8 or 10mm at minimum, what make is the FPR? and have you a pic?

[jumping350]

yeah its the same width as the 1/8 so thought any other variation from that would mean it would be too big or too small?

no idea what make

heres a pic

 

Il get a pic of the holes at bottom and side of FPR when i get back in from shops

I measured the widths with a micrometer the other day and wrote them down and lost them, now my mate has borrowed them

Edited December 22, 2014 by jumping350

[Tricky-Ricky]

I was just looking at your build thread, and found the pic, that looks suspiciously like a cheap ebay FPR, please don't use this! they are mostly rubbish and don't keep constant pressures, so could lead to killing your motor, invest in a decent known make like Aeromotive or similar, and these will have proper AN fittings anyway.

[GMballistic]

I was looking at this AEM FPR for mine before I realized the FRS I had bought came with one anyway so I didn't need to buy it.

Link: http://www.tarmacsportz.co.uk/GB/350z_AEM_Black_Fuel_Pressure_Regulator/350z-350z-25-302BK_.aspx

 

Sure Chris could do you a good price on it and then you could sell on the other FPR on eBay or similar to recoup some cash.

[jumping350]

Thanks both, It was in my box of tricks I had so not sure where it came from, I had already looked into replacing it anyway the other day with one with AN Fittings as this seems to be a long winded affair!!