Author Topic: A7/A10 Oil Leak Spots? Pointers please!  (Read 466 times)

Offline Peter Gee

  • Valued Contributor
  • ****
  • Join Date: Apr 2015
  • Posts: 268
  • Karma: 1
A7/A10 Oil Leak Spots? Pointers please!
« on: 04.09. 2018 18:59 »
My first build of a  BSA twin (59A7SS) in 25 years and I can't remember if you have to keep a look out for certain oil leak notorious spots, and the remedies.

My Triumph remedy is dry-building with "cure":  mostly using  a sparse application of Three Bond 1184 with progressive tightening over 36 hours from 5ft lbs to  spec torque, allowing a perfectly contoured thin plastic gasket to form besides whatever gasket is standard. Have overcome notorious Unit leak spots like Pushrod tubes and Rocker Boxes this way. I can normally manage a leak proof Triumph.

Help appreciated as I am about to bolt together my engine and gearbox.

Peter in Kenya

Offline Dipstick

  • Moving Up
  • **
  • Join Date: Aug 2018
  • Posts: 12
  • Karma: 1
Re: A7/A10 Oil Leak Spots? Pointers please!
« Reply #1 on: 04.09. 2018 20:25 »
I will follow this topic with a lot of interest Peter. Because I am also about to build my A7 1959 block.  I bought a tube of loctite 518 for the crankcase.

'78 XT500, '59 A7, '79 XS650, WR450F

Offline Peter Gee

  • Valued Contributor
  • ****
  • Join Date: Apr 2015
  • Posts: 268
  • Karma: 1
Re: A7/A10 Oil Leak Spots? Pointers please!
« Reply #2 on: 04.09. 2018 21:11 »
Sadly Dipstick I cannot get Loctite 518 here in Africa. But Three Bond is very good, not exactly the same ( its not anaerobic for example.)

The problem of British bikes is

(a) The vertical sealing of the crankcases vs horizontal of Japanese and most Italian

(b) Very narrow joining surfaces for some places, especially rocker boxes. Nobody complains that their magneto to crankcase joint leaks, because it is very  wide!

(c) Abuse by previous owners. I have sometimes used Epoxy Steel to fill deep marks in joining surfaces, then filed down with fine hand files.

(d) Inadequate breathing of the engine- so much so that some recommend fitting a whole new breather from the rocker boxes, but this only takes  care  of upper pressurization, not lower.

(e) Impatience -- not allowing for time to cure of the various joints before oiling the engine and firing. As I said I apply enough Three Bond to "squeeze out" a half millimetre, maby 2-3  ft lbs torque( convert to metric, I can't)..then wait 12 hours, torque more.,. after 24 hours torque full and trim off the excess. I use anti-seize compound or moly grease to prevent seizure on first firing. Only after the engine has rested for a full cure of more than 48 hours do I add oil.

(f) No Flattening: every old bike needs to be surfaced, all components because after many years of life, the metal has cooled and heated at very different rates. for example 25 years ago someone went very fast in below zero weather, then his engine got splashed by cold water(!).....it is held together by the bolts and screws, but then "opens up" when you rebuild the engine. I use a glass plate 10mm minimum "float" glass, which is 100% flat by laws of physics + good German emery paper for all small surfaces, using the correct rub technique. For large surfaces, such as cylinder heads, rand crancases, the engineer is told to use proper shaving machines to totally flatten the surfaces, if any out of flat is detected. For this a "float" glass thick plate in very necessary

However do not flatten Triumph Cylinder heads this way. They need a straightening machine instead.

Offline muskrat

  • Global Moderator
  • Wise & Enlightened
  • **
  • Join Date: Jul 2009
  • Posts: 8064
  • Karma: 106
  • Lake Conjola NSW Oz
    • Shoalhaven Classic Motorcycle Club Inc
Re: A7/A10 Oil Leak Spots? Pointers please!
« Reply #3 on: 04.09. 2018 21:16 »
G'day Peter & Dipstick.
Obviously the rockerbox gives the most amount of leaks and many different personal remedies. I've had moderate success with copper gaskets and copper paint on them but at least 25% of the time I'll get a leak. I make my own gaskets out of 0.8mm oil jointing and use Permatex #3 non hardening sparingly on both sides of the gasket (a retorque is advised after first rum). Most of the time the gasket can be reused.
Other places of concern are the sliding plate behind the clutch and the end of the countershaft (where the mainshaft exits the countershaft).
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7

Offline Peter Gee

  • Valued Contributor
  • ****
  • Join Date: Apr 2015
  • Posts: 268
  • Karma: 1
Re: A7/A10 Oil Leak Spots? Pointers please!
« Reply #4 on: 04.09. 2018 21:24 »
Many thanks Musky, these are exact places I also thought  problems would occur. What is it with Britbike manufacturers that they thought 6mm and if that on some Triumphs was an adequate jointing surface for rocker boxes?

Offline Dipstick

  • Moving Up
  • **
  • Join Date: Aug 2018
  • Posts: 12
  • Karma: 1
Re: A7/A10 Oil Leak Spots? Pointers please!
« Reply #5 on: 05.09. 2018 06:59 »
Good and practical info, thank you for that.  It's the first British bike I restore and though common sense will help, the experience from whom who went through everything before is valuable  *smile*.

Referring to the torque sequence.  Doesn't it affect the crank end float if you torque with a pause between few stages?  I mean could the liquid gasket form a thicker layer between the case halves?

What do you suggest as a full torque for the crank case nuts?  I can't find the torque values in the shopmanual.

'78 XT500, '59 A7, '79 XS650, WR450F

Offline Peter Gee

  • Valued Contributor
  • ****
  • Join Date: Apr 2015
  • Posts: 268
  • Karma: 1
Re: A7/A10 Oil Leak Spots? Pointers please!
« Reply #6 on: 05.09. 2018 07:29 »
Dear Dipstick..use google to get a  table of foot pounds as per the size of the bolts

and choose the "FINE" setting. Most bolts will be Grade 5 mild steel, some are grade 8

https://barringtondieselclub.co.za/technical/standard-torques.html

Offline coater87

  • Wise & Enlightened
  • *
  • Join Date: Jul 2008
  • Posts: 1181
  • Karma: 6
Re: A7/A10 Oil Leak Spots? Pointers please!
« Reply #7 on: 05.09. 2018 16:37 »
 Peter,

 I dont understand the need for torque and pause with the three bond.

 Torque the bolts down in a decent pattern, torque them in steps for sure, but you should be able to go from "0" torque to "tight" in under 10 minutes.

 Then be sure to have a little brake clean on hand to get rid of the three bond bead.

 The longer you leave it laying around the harder to clean up it gets.

 Lee
Central Wisconsin in the U.S.

Online Greybeard

  • Jack of all trades; master of none.
  • Wise & Enlightened
  • *
  • Join Date: Feb 2011
  • Posts: 5784
  • Karma: 31
Re: A7/A10 Oil Leak Spots? Pointers please!
« Reply #8 on: 05.09. 2018 18:04 »
My experience: I make sure mating surfaces are flattened off. I gently use a smooth file resting across opposite faces to do this. Screw holes may need slight chamfering due to them getting pulled down around the hole.

I use paper gaskets with a smear of Blue Hylomar each side and on the case mating surfaces. Leave to dry for a couple of minutes before assembling. I do not use Allen screws as it is too easy to overtighten them causing the case to distort. Use slotted screws tightened by hand with a screwdriver, (yes, I know you could do that with Allen screws, but later you may be tempted to nip them up a bit more). Work round the case a few times to ensure settlement. Wipe off excess Hylomar with petrol or Cellulose thinners, (be careful of your paint!)

H&S look away now! A hand wetted with petrol allows a really good grip of the screwdriver.

New oil seals of course.

I generally find this process makes a pretty oil tight engine; for my style of riding.

Engine pressures may overcome normal sealing methods if the jockey is riding like he stole it! Musky, I'm looking at you.  ;)

Because I recently had a leak from one or more Primary case screws I additionally fitted small fibre washers to all of the case screws, (because I'd just bought a box of assorted fibre washers at Aldi's!).

Offline Peter Gee

  • Valued Contributor
  • ****
  • Join Date: Apr 2015
  • Posts: 268
  • Karma: 1
Re: A7/A10 Oil Leak Spots? Pointers please!
« Reply #9 on: 05.09. 2018 18:31 »
dear Coater

"Peter,

 I dont understand the need for torque and pause with the three bond.

 Torque the bolts down in a decent pattern, torque them in steps for sure, but you should be able to go from "0" torque to "tight" in under 10 minutes.

 Then be sure to have a little brake clean on hand to get rid of the three bond bead."

As stated I prefer to leave a longer time..the ThreeBond stays flexi for many hours..perhaps a day is indeed too long until final tightening, I would agree....I don't do it all in 10 minutes because IMO that squeezes out nearly all the Three Bond..but since Three Bond never "dries" and always remains in a plastic state ( though slowly harder up to it's maximum), by a progressive torquing in say 3 steps with longish waits of many hours leaves a very (cigarette paper thin) thin extra "gasket that retains plasticity and hence conformity to all the tiny imperfections. Of course I don't always use Three Bond.... Hylomar for certain surfaces, Permatex High Temp Copper Silicone for others and even Wellseal! It all depends on the joint.

Rocker Boxes are a total pain on Britbikes. There are great composite gaskets with steel mesh in between that John Healey makes and sells in USA under a brand name for Triumph..sadly not for BSA I think!

This Loctite mentioned above anaerobic sounds a complete answer, however..I wish I could get some.

Oh I also use Permatex Hydraulic Thread sealant generously on things like primary chaincase screws...it's easy to take off.

Standard thinner works wonders on any Three Bond that needs getting off.

Offline muskrat

  • Global Moderator
  • Wise & Enlightened
  • **
  • Join Date: Jul 2009
  • Posts: 8064
  • Karma: 106
  • Lake Conjola NSW Oz
    • Shoalhaven Classic Motorcycle Club Inc
Re: A7/A10 Oil Leak Spots? Pointers please!
« Reply #10 on: 05.09. 2018 21:03 »
G'day Peter.
Crank case joint rarely leaks even assembled dry. Your method would be a nightmare setting the end float. I do as coater87, all in under 10 minutes. On initial assembly to check end float I use the same joint compound as will be used in final assembly to eliminate any errr's.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7

Online Black Sheep

  • Resident Legend
  • *****
  • Join Date: Apr 2017
  • Posts: 619
  • Karma: 6
    • Where black sheep live
Re: A7/A10 Oil Leak Spots? Pointers please!
« Reply #11 on: 05.09. 2018 21:11 »
"(d) Inadequate breathing of the engine- so much so that some recommend fitting a whole new breather from the rocker boxes, but this only takes  care  of upper pressurization, not lower."

Got to disagree here. The standard breather setup works for me or at least has done since 1972. Adding breather pipes to the rocker box interferes with the timed breather and is pretty ineffective.
2 twins, 2 singles, lots of sheep

Online edboy

  • Valued Contributor
  • ****
  • Join Date: Oct 2012
  • Posts: 424
  • Karma: 3
Re: A7/A10 Oil Leak Spots? Pointers please!
« Reply #12 on: 06.09. 2018 19:29 »
a large hole in the rockerbox will draw lots of unwanted air into the crankcases/engine. any oil leaking joint will do the same. its not impossible to make the old girl oil tight and its all been discussed before but some opinions will never change. including mine.

Offline Peter Gee

  • Valued Contributor
  • ****
  • Join Date: Apr 2015
  • Posts: 268
  • Karma: 1
Re: A7/A10 Oil Leak Spots? Pointers please!
« Reply #13 on: 12.09. 2018 20:09 »
Dear Muskrat,

Yes I thought about that end float of the crank is using my "dry cure" method of Three Bond on a A10/A7...and will modify it accordingly!

Cheers

Peter