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Fitting Ford Rocker Covers to a Rover by Peter Coombes

For those of us who chose to go the lightweight route and fit an aluminium Rover engine instead of a heavy cast iron Ford block, when you open the bonnet there is always that give away look of the distributor being mounted at the wrong angle together with the plain rocker covers with the cut outs for the SU carbs. Changing the first item is not, I believe, on the options list but you can fit Ford rocker covers to the Rover heads quite easily to hide that fact the engine is not what it should be in a Cobra. Note genuine Ford Motorsport ‘COBRA- Powered by Ford’ units as fitted in the ‘60s are available from Real Steel cheaper than Europa.

Later type (post ’66) ‘Cobra’ rocker covers Due to a different number of bolts and a different plan profile you will need to purchase a pair of adapter plates to fit between the Ford units and the Rover heads. These are available from Gerry at Hawk cars. It should be noted that Hawk provides all the necessary bolts to fit both adapters and the new rocker covers. The Ford units protrude at a steeper angle than the Rover’s, and have no cut out like the Rover units so the levers mounted on the spindles on the RH side of the carb will foul the new rocker covers. This means that the carb will need to be raised up from the inlet manifold and suitable spacer purchased. Firstly, before dismantling anything, I suggest you find out how much clearance you have from the top of the air filter to the underside of the bonnet – i.e. how much can the carb be raised without creating another problem? Attach a small pillar of plasticine or blue-tac to the air filter top plate and close the bonnet. It may take a few goes to ascertain where the closest gap is. I have a bonnet scoop, so the lowest point was at each side of the filter where the scoop blended back into the bonnet. Ascertaining that I had a 1¼” gap was encouraging.

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Some additional background info for reference is that my inlet filter is a 3” deep Edlebrock unit, mounted on a Carter/Weber carb on top of an Eldebrock Performer dual plane manifold, which I believe is considered a low rise unit. Naturally if you have a higher manifold or different carb the result will probably be different. So how much do we need to raise the carb? I have to date only added spacers totalling ¾” leaving ½” still clear between filter and bonnet for any movement of engine. This has got to be the absolute minimum, as I have been forced to remove a small portion of the closest web of the new rocker covers to clear the lever on the carb on full throttle opening. The resultant gap is very small so is not ideal! If you have space over the inlet filter, it is probably best to add a 1” spacer instead of only ¾” as I have. Also the 1” spacer is ironically cheaper than the ½” unit. I did say I would hope to save someone money. I had measured the need for a ½” spacer but got it wrong, so hence the need to add another ¼” which incidentally is only supplied as an insulated unit. There are of course many opinions from differing quarters of the benefit of the height of the spacer and whether the carb should be insulated from the heat of the manifold or not. One party will advise that an insulator spacer should be added as the carb will always be too hot and cause fuel evaporation/boiling and another will advise that to add any insulation will cause icing up of the carb. Perhaps these opinions are both correct and what works best in summer isn’t so good for the depths of winter (there are also issues over spacer design affecting carburettor performance at different parts of the rev. range, depending on use of four-hole or single hole spacers – ed.).

I started off on the basis of ‘if it ain’t broke don’t fix it’, and wanted to fit a metal only spacer to maintain my existing set up, but dimensions required ultimately forced me to add the insulated spacer. Spacers obtainable from Real Steel are ¼”, ½” or 1” thick.

Edelbrock intake with aluminium spacer in position The insulated spacer actually consists of a series of three gaskets and two 16 swg thick Ali spacers so I had thought that by buying yet another ¼” insulating spacer I could just add just half of the set. Perhaps we will see how well it works first rather than waste another £15. I was keen to maintain a good gap between filter and bonnet as you never know quite how much the engine moves. Yes, the Rover engine seems very well tied down with minimal movement.

Rover rocker shaft exposed

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So if you have been successful in raising the carb, you can now attend to the new rocker covers. Before fitting the adapters you must check the bolts lengths from rocker cover to adapter. As flange thicknesses vary Gerry has supplied these over length. Fit the cover with its gasket to the adapter on the bench and check how much to remove off the bolts. Remember which bolts will need to have attachments like hose clips and allow for these on their length. Don’t be tempted to cut the bolts whilst protruding from the adapter, as you need the adapter surface to be maintained in pristine condition to seal to the Rover heads. Having sorted the bolts’ lengths to be one thread short to allow for future gasket compression you can now fit the adapters to the Rover heads with Blue Hylomar or similar. Gerry recommends the gasket cement rather than a gasket as it will hopefully be a permanent fixture. Ensure any excess cement is wiped off before getting carried away and fitting the Ford covers. Make sure you reposition the hose clips etc. to suit the new bolting positions. You also need to make up a little bracket to re-attach the clip on the dip stick tube, as previously this was screwed to the Rover rocker cover, but the Ford unit is too thin at that point. A simple ‘L’ bracket turned downwards from the central cover screw with an M5 or M6 riv-nut will suffice. Next you need to attend to the breathers. A simple diagram with the new covers explains how one hose of 3/8” bore is fitted between a PCV valve and the inlet to a suction point on the carb. I already had a suitable tube attached, albeit previously blocked off. The oil filler cap has another hose of ½” bore connected to the inlet filter. If you have not previously had the positive crank case breathing system then you need to make a note to check on the sparking plug colour to check the engine is not running weak by sucking in extra air through the engine crankcase and into the manifold effectively below the venturis. Last, but not least, as with any modification you should always double check all bolts and fittings to ensure you haven’t forgotten to finally tighten one, and with the carb specifically both check fuel line and that the linkage all work correctly before turning the ignition key. You know it makes sense. Hopefully you can now convince more people that you have a Ford under the bonnet but without the extra 80 kgs. Have fun.

Ford rocker covers in place

Following this mod, I have two very important comments:

1] If you had to disconnect the carburettor fuel pipe during the above mod, assume that the washers on the banjo will not re-seal. In the 1.5 seconds it took for me to realise that this connection was leaking, the whole of the top of the engine was awash with fuel. I had fortunately taken my own advice and was specifically checking for leaks the moment I pushed the button to activate the fuel pump. Unfortunately, with no local Weber agents I had to get new washers from Real Steel, who only sell them with a new banjo !! The old washers were copper, but new ones are nylon so more likely to bed in and seal.

2] In starting the engine, it most definitely runs faster with the positive crankcase breather on the rocker cover connected to the manifold side of the carb. Ultimately a lot more air is getting into the engine but not via the carb so mixture will be wrong. So, if you didn’t have this facility connected with the Rover units you will need to have the carb jets adjusted for the extra air

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going in. For the time being I’ll run mine as per the previous set up with rocker breather connections only going to the inlet filter. Peter Coombes