Jupiter rocker covers

[Brian Cole]

The Jupiter has been loosing a tad too much oil lately and so on my last excursion to the garage I noticed that quite a bit of oil lying on the newspaper in the sump tray, which seemed to be coming from the underside of the rear end of the offside rocker cover. So I lifted the bonnet to get a good look and found that indeed quite a bit of oil was leaking and satrurating the rear of the exhast manifold and adjacent chassis wishbones and so on.

I thought perhaps the rocker box rubber seal had failed and also noticed that the one of the seals that prevent oil from leaking around the two fixing nuts had split. I remembered reading that 4mm o'ring cord did a good job for the rocker cover and ordered some over the internet. When the it arrived I found that it fitted the groove in the underside of the cover beautifully and cut it to length with the join on the upper side of thr cover. On refitting the cover I was not happy as one end seemed not to be going down properly. I remembered reading, I think in Mike Alfrey's technical notes, that the washers under the end head stud nuts can foul the cover and on inspection I saw that the washers were protruding beyond the corners of the respective nuts. I reduced the diameter of the washers at this point and I think that the cover is now seating satisfactorily. There are small radiuses ground out of the insides off the covers which I assume are intended to clear the stud nuts and washers, but I am not sure that they will do this if the nuts are presenting a corner to the radius, and I'm wondering if a little more needs to be ground out to be on the safe side. Does anyone have thoughts on this? Having no spare seals for the fixing nuts I looked around for something to effect a temporary repair. I found a length of rubber tube that fitted over the stud that was a tight fit on the stud and in the hole in the cover, and cut a piece about 10 to 12 mm long. I pushed and twisted the piece as far in and over the stud as could and then placed a stout washer over this folowed by a nut tightened slowly. This had the effect of swelling the top of the rubber tube and appears to have formed a seal. Hardly rocket science but hopefully it will last until new seals arrive from Bill Lock.

[TedAllen]

Interesting, Brian. I'm just making up a spare engine and I've just tonight ordered some rocker cover gaskets from JCS.
It's funny, you can see things in the workshop for months or even years but when you want them....they're not there any more.
I had a pair of covers with seals in that I was going to use but I can't find them...hardly small, are they ?
So, I've dug out another pair and, of course, no seals !

The engine in the car is currently running well and not leaking oil. Instead of the rubber ' top hats ' to hold the covers on, I experimented and ended up using a 14mm Dowty seal, then a strong washer held in place by a reversed Javelin wheel nut......more surface area for the same thread.
I bought 30 seals from a firm of engineers supplies in Glasgow on the net...cost about £4, I think. been oil tight since, and they're cheap enough to fit new when you have the ' lid ' off.

Ted