Home
Page
welcome to our website
About Us
information about our Club
Contacts
our Officers and Committee
Events Diary
our events for the
months ahead
Event Reports
from the last four months
Member's Cars
a selection of
our active "Sevens"
Joys of being a 7'er
and a few stories
Do you fancy an Austin Seven?
advice on buying a "Seven"
Photo Gallery
of our past activities and
"Sevens" in close up
From the Past
Items from 1920/30s
magazines
Registration Marks
in the UK from 1903
Help at the roadside
fuel and electrical problems
Austin Seven Journal
advice for Austin Agents
& Service Depots
Austin Seven
Handbooks
information for the
new owner
Technical Articles
our Members help you
with various tasks
Austin Big Seven
Sixlite & Forlite
Magazine Articles
relevant to Sevens
Road Tests
for the most popular "Sevens"
Parts and Services
sources of spares etc
Quick Tips
a few handy ideas
Other Articles
of interest, not technical
Austin Seven Books
some of the books available
A7CA and FBHVC
CA7C is an active supporter
Links to other Austin
Seven Sites
Website Policy
on advertisements and links
The camshaft bronze bush is prevented from moving due to a small square head bolt, which is located in front of the engine block. However, when this was new it was not a problem, but after time the hole in the bronze bush and the pin start to wear due to the continual lateral movement of the camshaft timing gear. The bolt starts to leak..... and there is a slight increase in noise from the timing gears.
So how
to over come this?
A good suggestion from Tony Leslie [Holmsdale Sevens] is to replace this bolt and pin arrangement with a stud and lock nut. This is similar to what Austin did on the magneto engine [so why did they change?].
You will need:-
1 x 5/16" BSF tap and suitable tapping drill; 1 x 5/16" dia drill; 1 x 5/16" BSF engine block stud; washer and nut and preferable nylock nut [as it will seal the thread from any possible leakage]. Fibre washer.
Carefully drill and tap the camshaft bush 5/16" BSF. [Ensure you drill it square to the bush]
Drill out the engine case thread with the 5/16"Dia. This is where the locating bolt was originally fitted. [Again ensure that it is drilled square to the case]
Using a new stud ensure that the tread is cut off, so that when it is screwed
into the bronze bush it is unable to touch the cam shaft itself.
Fit the camshaft bush as you would normally do, then screw in the stud. This is a little more of a fiddle BUT worth it.
Fit the fibre washer, metal washer and then tighten the stud down with the nylock nut. JOB Done !
You may notice from the photograph below of the bronze bush that it has two grooves around the body. Because I am using an up-rated pump I wanted to make sure that no oil escaped between the bush and the aluminium housing. To seal the bush to the housing I have used two ‘O’ rings.
The size of the two ‘O’ rings is 1.25"ID X 0.125" Sec, the shore hardness value is 70~75 [quite soft].
No more
leaks or movement from the bronze bush.
This article, written by Mike Davies, originally appeared in CA7C Seven Focus
in Mar 2006 pp16-17.
See also:
Camshaft Bearings - Ruby 3-bearing engine