Restorers can use a piece of sheet glass and a feeler gauge to check the “truth” of the cover or offer the Rocker Cover up to a spare Cylinder Head. It is easier for checks to occur at bench level.
The Cover should also be checked for wind or twist. A visual check first, followed again by use of a glass sheet, will soon obviate any problems in this regard.
The Rocker Cover is fairly easily “wound” back to a flat profile by the use of one’s hands. Work at it and keep re-checking against the glass sheet or Cylinder Head surface.
On TF’s at least, the Rocker Cover Oil Cap has a safety chain attached to the Rocker Cover by a solid aluminium rivet. Sometimes the rivet works loose (allowing leaks to occur) or is missing altogether. This rivet is easily turned up on a lathe. I like to have a small base or “land” on the rivet as well as the original flat type rivet head. The rivet can be readily peened over on the inside of the cover to effect a perfect seal.
The Rocker Cover Cap on TF’s was generally supplied in cadmium plated steel with the top centre finger hold release knob being nickel plated. The original cork junk gasket material used on the cap invariably results in a poor seal. Nitrile sheet is a far superior product and seals very well. To renew the seal and re-cadmium plate the cap, the riveted end of the finger hold’s shank located under the cap will need to be carefully ground down to just enable the retaining washer to be released. The finger hold can now be re-nickel plated at this stage. For re-assembly to occur, use a lathe to turn down (2mm approx.) the “shoulder” of the previously ground down finger hold shank. This procedure will enable the washer to be again held in place by re-peening the end of the finger hold shank over it. Don’t forget to fit the nitrile seal and then the circular Enots copper patented (Pat. No. 280261) locking tabs first. Incidentally, the reproduction safety chain holding the cap to the Rocker Cover rivet is often the incorrect size. This rather tedious work on the Rocker Cover Cap will be worth the effort, with no leaks resulting.
There appears to be some controversy regarding the paint colour of TF Rocker Covers. Some say the Cover was a rather drab looking greenish-grey colour yet others feel the colour was a light aluminium-grey tone. I have restored nine (9) TF Rocker Covers. In each case the brass Rocker Clearance plate had not been removed ex factory. Upon removing the plate, the paint underneath in each and every one, was the light aluminium-grey colour. I have found Acrylic Lacquer paint type works sufficiently well on Rocker Covers. A spray putty coat, followed by undercoat, then top colour coat, is effective. A clear lacquer over the final top coat helps seal the colour from oil, etc. Rubbing back between coats gives the desired finished result. Mask off all orifices on the Rocker Cover before any painting commences.
When finally fitting up the Rocker Cover to the Cylinder Head, a smear of the good old ‘tried and true’ sticky Permatex Aviation Gasket Cement applied on the underside of the surface of the gasket is very useful. This helps keep the gasket in the same position when the Rocker Cover has to be removed, for example, to check and adjust the valve clearances.
The Engine Side Plate Cover can also be prone to leaking oil. Again carefully check for, and rectify, localised imperfections, warp or wind. The original grey ‘muck’ metal (Mazak) three (3) setscrews which hold the Side Plate to the engine block, often stretch over time thereby losing Side Engine Plate pressure onto its sealing gasket. I have seen the hex heads of these dreadful original setscrews crack off their shank altogether!
Instead, brass setscrews (with a fibre washer placed under the head) are now available and work splendidly. For the Concours buffs, a flat grey colour painted over the brass hex heads will keep even the most fastidious Judge guessing.
Whilst discussing Rocker Covers and Cylinder Heads, confusion exists on the correct number that came originally with TF1250 Cylinder Heads. It is often erroneously written up by various authors that the cast number ex factory for TF1250 heads was 168422. This is not correct. TF1250’s had the number 168425 cast/stamped in with the first five (5) digits cast in and the number 5 stamped in.
MGTF Engine Bay and Rocker Cover.
In summary, attention to detail on Rocker Covers and Side Engine Plates will bring the reward of leak free seals. Correct, efficient gasket sealing is reflected in the accurate surfacing on which gaskets are to be applied.
TF3719, TF5164, TF9177
Perth, Western Australia