Out of curiosity more than anything else, I was just wondering if there would be any benefits to be gained by fitting modern valve guide seals to an Austin Seven engine?
These greatly improve the BMC overhead valve A, B and C series engines which had rudimentary valve guide seals in the form of little fat O-rings which didn't seam to do much of anything.
Given that the valves and guides hang down on the Seven as opposed to being the other way up in the head, perhaps they don't require seals because gravity helps keep oil from being drawn into the guide and valve stem?
Joined: Aug 2017 Posts: 682 Threads: 17
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6 Location: The far North East of England
Car type: 1934 Austin 7 AVH Van (in bits & incomplete!), 1936 Morris 8 Series I Tourer
Side tracking slightly from your opening question - are these modern valve guide seals available 'off the shelf' for the BMC A, B & C OHV series engines ? I've a slightly earlier and somewhat similar 1946 to 48 Wolseley 8 OHV engine with these little fat O-rings and would be interested if I could replace them with something more modern and effective .
Seals are primarily to reduce oil consumption as many ohv engines pour oil over the guides. Not a factor on a Seven. Wear is not insignificant even without. Might improve idle slightly. But one of th virtues of the Seven is relative simplicity.
17-12-2019, 05:57 AM (This post was last modified: 17-12-2019, 03:00 PM by Chris KC.)
I suggest unless you can think of an actual benefit, the current set-up which works quite well is better left alone. A7's don't as far as I'm aware suck much oil from the valve chest into the cylinders unless horribly worn, which if so is easily remedied. And there are a whole load of places I'd look before this to reduce oil consumption.
Hi Jeff,
these seal are generally off the shelf by sizes or ones specifically made for OEM application. The ones we've been using require the valve guides to have the tops machined to allow the seal to lock on to the guide when pushed on. Discussion with your favored machine shop should be able to ascertain if they can find and install a suitable guide seal.
Stephen
