Ariel Owners Motorcycle Club

I took the 2 oil pipe unions off the timing gear cover today and was surprised to find a fibre washer between the case and the union (nothing in the parts book). These are a 1/4" bsp parallel thread. I also found some PTFE in the thread.

I thought (but could well be wrong) that parallel threads do require either PTFE or a washer, or perhaps both, but is PTFE ok to use with oil?

I think all those unions that I've seen have had a fibre washer under them.
By PTFE I assume you mean tape around the threads? Shouldn't be a problem with oil but in my experience the fibre washer does the trick.

SG

hi i have used a dowty washer or a collapsible copper washer and i have had no leaks or if i use ptfe tape i use the the one for gas its is a lot thicker

PTFE tape is fine with oil, can be a problem if some gets inside the engine! Also works on petrol taps. A fibre washer is listed. Dowty washers are great but be aware that they are generally thicker than std fibre ones.

Care with ptfe tape please, as small bits of it can dislodge and block small oil ways.

As Mark has said be carefull with PTFE tape, I dont know when it was first available in the world but we first had it in 1969 and it was very expensive 10 shillings a roll but the same thickness as the tape for Gas is now,it was only in the late seventies that we had a written warning in our wage-packets of the dangers of removing it from threads with an oxy-acetylene torch which was a lot easier to do than by hand,and smokers who roll their own, ptfe fibres on their fingers were getting into the roll-up cigarette and causing flu-like like symptoms. It is handy to have a roll in a tool-kit for an emergency repair but I wouldnt use it on an engine or oil lines,and definitely not used on a parallel thread which should have a shoulder or back-nut and a sealing washer ,and a tapered thread that is a bit loose can be packed out with hemp and something like Wellseal or dare I say Stag compound put on it, there are more suitable thread sealants available than ptfe tape which is good for plumbing,Loctite 55 pipe sealing cord is great stuff and has more or less replaced ptfe tape, it cured the leaks on my front fork seal holders ,but I would be carefull where else on the bike I would use it, it is a bit like hemp and is gap filling but I am sure there is ptfe in it, one dispenser will last a long time