Paul Jameson's KH Article

[Ian.McCandlish]

Good morning,

I'm about to fit new valve guides to the head of my '49 Mk 1 Sq.4. What are valve guide seals, where do I get them and how easy are they to fit? The engineering shop which is going to reface the head and fit the valves asked me if it had valve guide seals. That resulted in a blank look from me in response! If they help to stop a problem with over-oiling fitting them sounds like a good idea to me.

Thanks

Ian

[Knud.Degnbol]

I once put some valve stem seals meant for an Austin/Morris Mini into my cast iron Square. I went for a short ride and removed the cover on return.
Lucky for me. They were already damaged by heat, so they were crumbling and fell apart. I could remove all of them without getting anything into the lower regions of the engine.
So they are not good enough.

[roger.fellows]

Hi Ian, are you aware of the mods to later squares including chamfering the rocker arms and fitting 'shrouds' inside the valve springs? David Anderson has posted various bits about Viton rings and other related measures. Sorry, not too helpful, tea being served, but there's quite a lot on the forum if you dig. Roger

[nevhunter]

Its likely that valve guide seals that work OK on car engines will not put up with the temperatures in many aircooled applications. Most of the oil will go down the inlet valve guides and they can be made quite a good fit to the stem, without problems in enclosed and lubricated situations.. Chamfer the top of the guide so oil doesn't collect there. Nev

[markus.nikot]

My MkI is successful fitted with valve guide seals at the inlets.
Don't use them at the outlets, these valves needs lubrication - from my experience with sticking valves if trying to keep the oil mist out.

The guides has to be modified to hold the seals and the rocker box bottom needs machining for lowering the overall hight, avoiding touching the valve spring collar. The seals came from Volvo (sorry don't have the order number) and available in different materials. The Teflon (bright white) version is doing the hot job.

Markus

[Ian.McCandlish]

All,

thanks for the valuable advice on valve guides etc. I've just received them from Draganfly and will set about removing the old ones and fitting the new asap. I had thought about doing it today but I'd need to put my cylinder head in the oven; I dont think thats going to happen this side of Xmas....oil and carbon infused turkey! not a good taste sensation!

Re chamfering the rocker arms. I have the detail on whats required. Dare I set about them with a file or grinding stone or is it best left to the engineering shop?

Thanks and seasons greetings to all

Ian

[simon.holyfield]

I've just done 6 miles around town, ambient temperature 10 degrees Celsius, oil pressure starting at 60 psi cold and dropping to about 5 at idle. I'm running in on supermarket 20W/50 (API SE). It runs at about 25 psi at 30 mph.

What do you all think of that? Should I be concerned? Change my oil?

[paul.jameson]

Simon,
You could try SAE 50. That would stop you using the bike at this time of year as you wouldn't be able to kick it over fast enough to start it ! Seriously though, the oil you are using should be fine, but I would recommend using Morris's Running-in oil for the first 750 miles or so. This isn't so much for the bearings as for the bores. You may find the honing marks remain at ridiculous mileages (like 5000, Bob Brassington) otherwise and the danger of a partial seizure is that much greater. The advice from Morris's as related in my KH article has been tried on several engines now and it seems to work

[david.anderson]

Ian
While we are a bit off topic Roger has mentioned some of my experience with over oiling of the valve guides on my mk2 square4. I initially considered fitting viton seals both umbrella type or positive seals but I eventually fitted the steel umbrella seals that were fitted to the later mk2s. the forum link below discusses using the later set up on a mk1 and subject to checking the clearance to the top of the guide is ok at full lift, it appears an easy conversion.

http://forum.arielownersmcc.com/viewt ... f=21&t=888


the following link may also be of help and contains a diagram of the setup. The later springs and retainers are available from drags but the umbrella shrouds were not. You may be able to try club spares or have them made.

http://forum.arielownersmcc.com/viewt ... f=4&t=2877

there is also another post where a member was considering having guides made to accommodate modern positive seals and the member was looking for any interest. I have been unable to find that post but you may be able to with a search.

With regard to my 4, the steel umbrella shrouds have proved effective but I found it necessary to assemble the split retainers with some silicone to the ends. The top of the valve retainer for the later springs is a dish which holds oil which then runs down the gap between the split retainers and over oils the guide.

It is also possible to fit the fat O rings to the valve stem as fitted to some mini minors, but the O rings fail in a short time due to the heat of the 4. A fat viton O ring would probably be satisfactory but the guide should be shortened a little to prevent binding. O ring type valve stem seals only seal at full valve lift.
David

[simon.holyfield]

Anyone out there using Penrite multigrades? There is a 20w/60 that looks interesting, API SC spec.