V8 mechanical fuel pump fittings
- Thread starter John
- Start date
Hi John,
The thread on the AC pump is actually of U.S origin, which is probably as would be expected given that AC is a U.S company. In actual fact, AC stands for Albert Champion, who was a French road cyclist born in 1878. He won the 1899 Paris-Roubaix, a race that still runs to this day. Upon retiring from cycling, he moved to the United States where he founded the Champion Ignition Company in 1908. A year later, the company name changed to AC, after his initials. Over one century later, Champion spark plugs and anything AC is directly related to this former French cyclist.
Apologies, I digress, so back to your question. I am sure I have the thread size written down somewhere, just can't lay my hands upon it at present. The thread though is a NPSM (National Pipe Straight Mechancial Thread), which are quite different to NPT, although both exhibit 60 degree thread tapers. The seal is made between the two tapers, one upon the pipe, the other within the pump. No seal is made with the actual thread.
I'll see if I can locate the actual thread size for you John.
Ron.
The thread on the AC pump is actually of U.S origin, which is probably as would be expected given that AC is a U.S company. In actual fact, AC stands for Albert Champion, who was a French road cyclist born in 1878. He won the 1899 Paris-Roubaix, a race that still runs to this day. Upon retiring from cycling, he moved to the United States where he founded the Champion Ignition Company in 1908. A year later, the company name changed to AC, after his initials. Over one century later, Champion spark plugs and anything AC is directly related to this former French cyclist.
Apologies, I digress, so back to your question. I am sure I have the thread size written down somewhere, just can't lay my hands upon it at present. The thread though is a NPSM (National Pipe Straight Mechancial Thread), which are quite different to NPT, although both exhibit 60 degree thread tapers. The seal is made between the two tapers, one upon the pipe, the other within the pump. No seal is made with the actual thread.
I'll see if I can locate the actual thread size for you John.
Ron.
Cheers Ron, that info is awesome, useless to me but extremely interesting non the less 
I am now away to Google NPSM, see a small nugget of info will go a long way. (I hope the SM bit doesn't throw up all sorts of scary nightmare inducing things :shock: )
John.
Edit, Don't dig too deep Ron, Wikipedia wins again, I just wanted to know what tap I might need to clean up the threads, but I've found it was the bolt on the diaphragm casing bottoming out causing a slight weep, not the inlet union.
I am now away to Google NPSM, see a small nugget of info will go a long way. (I hope the SM bit doesn't throw up all sorts of scary nightmare inducing things :shock: )
John.
Edit, Don't dig too deep Ron, Wikipedia wins again, I just wanted to know what tap I might need to clean up the threads, but I've found it was the bolt on the diaphragm casing bottoming out causing a slight weep, not the inlet union.
Let us share a red faced moment there Stina, well sort of, mine had more washers than the book said, so I removed two........ Someone had previously fitted a longer bolt, I have now added a spring washer as per the parts book and a flat and it is hopefully holding the bottom plate on, but the thread is a bit bald in places . As insurance I picked up a spare pump from Tom at Lake view garage this afternoon to recon.
John.
. As insurance I picked up a spare pump from Tom at Lake view garage this afternoon to recon.John.
Now that is interesting Junkman, for what you say is completely different to the information that I have.
Given that I have purchased fittings that are NPSM and they work perfectly, leaves me a little perplexed.
Oh and in future, don't be rude in your posts!
Ron.
Given that I have purchased fittings that are NPSM and they work perfectly, leaves me a little perplexed.
Oh and in future, don't be rude in your posts!
Ron.
Junkman
Member
Oh yeah?
After findig what I thought is a bit of useful info among this heap of irrelevant drivel,
I tried to obtain NPSM fittings, not an easy task in today's UK.
Hence I ordered me some from America, at considerable cost, I have you know.
Of course they turned out to be the wrong ones!
I tried them in the completely unmolested 26,000 mile original pump in my car - they don't fit.
I tried them in a pump I have lying around - they don't fit.
I took pump and fittings to a local hydraulic engineering company and it took them 30 seconds
to figure out that the threads are BSP and not NPSM.
So, now I have 30 quid worth of NPSM fittings ready for the bin, thanks to this forum.
I might be less pissed off if it didn't happen regularly that so called information provided here
is mere bollox.
I am livid!
After findig what I thought is a bit of useful info among this heap of irrelevant drivel,
I tried to obtain NPSM fittings, not an easy task in today's UK.
Hence I ordered me some from America, at considerable cost, I have you know.
Of course they turned out to be the wrong ones!
I tried them in the completely unmolested 26,000 mile original pump in my car - they don't fit.
I tried them in a pump I have lying around - they don't fit.
I took pump and fittings to a local hydraulic engineering company and it took them 30 seconds
to figure out that the threads are BSP and not NPSM.
So, now I have 30 quid worth of NPSM fittings ready for the bin, thanks to this forum.
I might be less pissed off if it didn't happen regularly that so called information provided here
is mere bollox.
I am livid!
I always use advice given on forums as part of my research, and rarely take anything as gospel. All advice given on here, and other forums that I frequent are subject to people's opinion, sometimes their interpretation of the question, sometimes their firm belief that the advice given is true, and many other factors. Please don't get me wrong, there are certain people who you just trust implicitly and we know who they are, but the rest of us are just relaying our own experiences and opinions based on driving, owning and maintaining our own vehicles.
My first car was a P6, back in 1977 and I have (except for few years of poverty) always owned one since, and I have rebuilt just about every bit of them, but I don't know everything, and never will.
I will always do my best to help anyone on here, and so does everyone else on here.
However, you cannot make everyone, or indeed anyone, on here responsible for your actions. If you wish to take information from a short discussion on threads from two years ago and buy things on the back of it, then that really is your responsibilty.
This is a discussion group who are all here because of our interest in Rovers, especially the P6, and the mass of knowledge on here is quite frankly incredible, but we are not the technical branch of The Rover Company Limited.
Richard
My first car was a P6, back in 1977 and I have (except for few years of poverty) always owned one since, and I have rebuilt just about every bit of them, but I don't know everything, and never will.
I will always do my best to help anyone on here, and so does everyone else on here.
However, you cannot make everyone, or indeed anyone, on here responsible for your actions. If you wish to take information from a short discussion on threads from two years ago and buy things on the back of it, then that really is your responsibilty.
This is a discussion group who are all here because of our interest in Rovers, especially the P6, and the mass of knowledge on here is quite frankly incredible, but we are not the technical branch of The Rover Company Limited.
Richard
I based the information that I provided, on fittings that I purchased for my AC mechanical pump from Pirtek. I took along the pump and one of the exisiting fittings. I was surplied with two brass fittings which screwed in perfectly. The gent from Pirtek said that they were NPSM fittings, so I wasn't going to argue with him.
As Richard so eloquently said, we all provide information as best we can so as to help others. I for one don't do it to so as to wilfully mislead!!
Ron.
As Richard so eloquently said, we all provide information as best we can so as to help others. I for one don't do it to so as to wilfully mislead!!
Ron.
unstable load
Well-Known Member
It's not outside the realms of possibility that the pumps could differ after nearly 50 years and a big aftermarket manufacturing base, either.