Ariel Owners Motorcycle Club

Guys,

Two thousand miles ago I completed the rebuild of my W/NG engine, and it's all worked out fine apart from a persistent oil leak which appears above the magneto chain cover.

I've finally mastered sealing the oil banjos, but I've still got a weep which comes from the bottom pushrod tube seals (I think, unless it's coming down the barrel behind the tubes).

These seals are new. Do you guys fit them dry or with a smear of sealant?

Fitted dry, Simon make sure the cups which hold the seals the bottom one can move up if it's been fatigued at any time . This will reduce the effectiveness of the bottom seal.

Dave

Wot Dave says - I've always found that new (as in NOS) seals crush down a lot, so I'd expect to see the head being held up by maybe even 1/8" on the timing side.

However, thinking back a long, long time to when I was buying original seals, there seemed to be 2 different types of compound used (if you lined up the four seals from a gasket set and looked at he appearance carefully you could just make out there were two pairs) and one compound was more heat-resistant. If the less heat resistant seals were fitted at the top (ie under the head) they could collapse relatively quickly, especially on the front (exhaust) seal.

SG

You may get some oil down the two head bolts that are in the rocker boxes, especially IF the inner lip surface of the cylinder is the only one in contact.
careful facing the underside of those bolts can aid sealing.. Nev

I had to have a couple of goes at these annoyingly.
The standard drags seals are too tall imo for the tubes on my postwar VH. I had to resolder the tube cups that were pushed up, fit trimmed seals that only have a small amount of compression and smear a small amount of RTV urethane to fix it all.
M - downunder.

nevhunter wrote: ↑Tue Feb 28, 2023 2:20 am You may get some oil down the two head bolts that are in the rocker boxes, especially IF the inner lip surface of the cylinder is the only one in contact.
careful facing the underside of those bolts can aid sealing.. Nev

That's interesting. Anyone else seen this? I take it those bolt holes open into the gap between the fins.

My leak could well be coming from the head joint.

It was the late Bob Brassington's favourite mystery oil leak.

Nev could be right… I once had a leak which in the end arose at the two head studs inside the rocker boxes... I fitted a tight copper washer underneath the studs and it did’t leak anymore you also can take a bonded steel ring.

I had persistent leaks with my VH.
In the end i had to resolder the bottom cups on the tubes and trim the rubbers (from Drags) a little to only have about 1-2mm of compression when the head was pulled down.
I also used a black RTV sealant that cures like rubber so its invisible when wiped away at installation.
Regards
Michael.