Hi Peter,
Roger Forsyth used to offer CNC machined inspection caps that were taller by the amount of the fibre washer, so that an o-ring seal was used.
Neil
Copper Inspection Cap washers (ET160)
- Thread starter Dynamiteboss
- Start date
Roger Forsyth used to offer CNC machined inspection caps that were taller by the amount of the fibre washer, so that an o-ring seal was used.
Neil
Sometimes, it seems maybe by a gorilla's hand!
I am just preparing to tuck into some humble pie, I hope it tastes good! I was never convinced, or brave enough to risk losing any of my original H.R.D. valve caps, so when I first started using the Neil Videan ET160 replacements, I always made sure that they are fairly tight, I seem to remember when they were first available one of the USPs was that you could have the lettering on the cap always the right way up, as long as the cap was nipped up on the rubber seal, well I was never that worried about all the caps lettering being like a readable page of printed material, and having never got over the loss of the original shallow cap off the kickstart cover (I must have inadvertently left it loose after checking the cable abutment distance) I just can't bring myself to take the risk.
I am the same with car and van oil filter canisters, I like to tighten them with gorilla hands, but no tools, and sometimes I do need a tool to remove them, but for me that peace of mind is worth the effort of a tool assisted removal.
I am the same with car and van oil filter canisters, I like to tighten them with gorilla hands, but no tools, and sometimes I do need a tool to remove them, but for me that peace of mind is worth the effort of a tool assisted removal.
So what is an alternative to o-rings in these applications ? The copper rings are poor, same with fibre seals, even on drain screws. Best design is something with o-rings under the head and a hard shoulder or outer ring for seating the part and having a definite squash on the o-rings. So then no excessive torque is required for a good seal which keeps oil inside. And no seal will spread from lasting preload so the screw will rattle loose and fall off. Some time ago I had a drain screw from a Ford Capri sump to look at, no fibre seal or copper, no - an o-ring in a recess and a shoulder to sit on when tightened. So no creeping seals to squash and get loose.
Instead of machining the caps for keeping o-rings in place - and not reducing space inside for the rockers better have some simple small alu rings - or copper - to contain the o-rings at exact squash and some light torque, no need for much of it, almost just finger-tight. Even when the cap has come somewhat loose - unlikely - the elastic o-ring will keep it from falling off with half a millimeter preload. As reported, you will not find Japanese inspection caps with copper or fibre seals, too risky to fall off - and poor sealing properties too.
Dowty got into this business , hydraulics maybe, by producing sealing washers with sort of o-ring moulded into special washers, so these will take high oil pressures in a safe component. You will not find fibre seals in hydraulics, totally unsafe at high pressures.
Vic
Instead of machining the caps for keeping o-rings in place - and not reducing space inside for the rockers better have some simple small alu rings - or copper - to contain the o-rings at exact squash and some light torque, no need for much of it, almost just finger-tight. Even when the cap has come somewhat loose - unlikely - the elastic o-ring will keep it from falling off with half a millimeter preload. As reported, you will not find Japanese inspection caps with copper or fibre seals, too risky to fall off - and poor sealing properties too.
Dowty got into this business , hydraulics maybe, by producing sealing washers with sort of o-ring moulded into special washers, so these will take high oil pressures in a safe component. You will not find fibre seals in hydraulics, totally unsafe at high pressures.
Vic