Tappet Cover oil leaks

[Dave Mann]

I have a block like yours with virtually no landing at the top and found that if you just put the cover on and tightened it up the top tipped inwards and the bottom out leaving a big gap for leakage. The solution was to lift the cover before tightening the screws, then it was leak free.

[Nigel was in Brittany]

Charles the Oxfordshire sevens cover has a rubber seal http://www.oxfordshiresevens.co.uk/parts...sis-parts/



Thats the easy bit ordering it from Oxfordshire Sevens , the hard part is getting it delivered after you have paid.

[Malcolm Parker]

My Ulster rep has an early type block and like Alan, I use a cast aluminium tappet chest cover from a Reliant SV engine which is a good tight fit top and bottom.  I use a cork sheet gasket.  I filed off the 'Reliant' name on the cover as it was readily visible if you looked at the exhaust side of the car.  So far I have had no trouble with oil leaks from the cover.

[stuartu]

Malcolm, is your block like Charles' i.e. with the threaded holes for the tappet chest studs above centre? The Reliant covers I've seen have had their holes on the centre line like the later Austin covers.

If the Reliant covers have offset holes I must find one!

Regards,
Stuart

[Alan]

Stuart - the holes are in the middle, sorry. On the Chummy I use a Cambridge cover re-drilled and redundant holes filled. It doesn't leak lots.
I filed off the "reliant" too. Not because I was bothered about the make, just I felt it was an undeserved comment on my Ulster in those days.

[Tom the Blacksmith]

Hi Charles,

Im using a similar early block and have made a valve chest cover exactly as your first post suggests. An O ring grove round three sides of the back face and one running across the top. As mentioned in previous posts there'll be little leakage from the top unless there is insufficient breathing. Belts and braces you could countersink the plate exactly where the studs come through (add a few thou clamp load) and make some matched thumb nuts so when you tighten them down it pushes the plate up against the top O ring, I decided against this on grounds that life is too short. I'll take some pics and post them up if it would be of interest. 

Tom

[Charles P]

Hi Charles,

Im using a similar early block and have made a valve chest cover exactly as your first post suggests. An O ring grove round three sides of the back face and one running across the top. As mentioned in previous posts there'll be little leakage from the top unless there is insufficient breathing. Belts and braces you could countersink the plate exactly where the studs come through (add a few thou clamp load) and make some matched thumb nuts so when you tighten them down it pushes the plate up against the top O ring, I decided against this on grounds that life is too short. I'll take some pics and post them up if it would be of interest. 

Tom

Thanks Tom (et al). Very useful content. 
I suspect that the 10mm plate is rigid enough to ensure even clamping pressure. I had a moment of wild imagination and considered getting a chum with a CNC mill to cut the Austin logo into it - and then I thought better of such a frivolous idea! I am going to seal the screws with Dowty washers to help stop the small possibility of leaks from there.
And I'll replace the 5/16 pipe used for the catchtank with a 3/4" one.

Charles

[stuartu]

Alan, thanks for the elucidation on the Reliant tappet chest cover.

Regards,
Stuart

[Malcolm Parker]

Malcolm, is your block like Charles' i.e. with the threaded holes for the tappet chest studs above centre? The Reliant covers I've seen have had their holes on the centre line like the later Austin covers.

If the Reliant covers have offset holes I must find one!

Regards,
Stuart

Stuart, I made a couple of small 'fishplates' out of 3mm steel strip.  These are fixed to the threaded holes within the tappet chest by small bolts, using PTFE tape to prevent the coolant leaking out.  The other end of the fishplates are drilled and tapped to take the normal Austin tappet cover fasteners.  That way I can use the Reliant cover without having to alter the holes.

[stuartu]

Thank you, Malcolm, why didn't I think of that? Don't answer!

Regards,
Stuart