Just be sure the new acorn nuts from one of the usuals are threaded square to the sealing surface. I had some leakers, and upon inspection the bottom of the nut was not square to the thread. !@#$%^&*
Same here with the RTV, always works.
After reading all the input on sealing the cam cover acorn nuts, this is what I did.
From Mcmaster-Carr, O-rings #9262K578 and washers #97725A540
The washers are 1/16 oversize, so I turned them down to match the original diameter. For added insurance a small dab of silicon sealer. I wiped the studs clean with acetone first.
I haven’t driven it much yet, but so far so good.
Alan Brown. 1963 E-type coupe
On our car leaks from these acorn seals were considerable - not just minor seepage. The system suffered all the listed defects - aftermarket nuts seal surface not parallel with the thread, thread not deep enough, some studs ever so slightly bent, some studs ever so slightly high, washers not flat, available washers wrong diameter, washers needed annealing, gasket (cometic) maybe a different thickness. Answer to above issues? Anneal all washers, use sealant and the sealant fixes the issues. After an engine is assembled chasing down the stud issue is pretty hard, as any problem you didn’t catch by due care is pretty subtle. Our car sure put a lot of oil out from these stupid nuts.
If you don’t drive it, it’ll never leak 
I wish that were true, even sitting in the garage for a few weeks it will find it’s way out, the only way I know to keep them from leaking is to leave the fluids in their OEM containers. 
Cheers,
LLynn
2 Likes
Why didn’t you just order the 97725A200?
A friend back in Calgary who had apprenticed with RR in England in the early 50’s showed me a RR manual from the 30"s where the torque specs for the nuts and bolts used was described as: “An experienced fitter will know…”
The Workshop Manuals I still have, for a PIII Rolls, state that.
Back then, there were no torque figures, just experienced fitters…
1 Like
I use my built-in torque wrench. Grasping a 1/4" drive ratchet with my thumb at head and two-fingers on the handle. Hard to overtighten that way. Cometic gaskets and aluminum crush washers keep the leaks away for good.
Glenn
I went one better…or less good, as the case may be! A 7/16ths wrench, cut down to about 1.5 inches long.
Kirbert,
The O.D. should be .5625
Part# 97725A200, the O.D. is .547 it is also too thin.
Part# 97725A540, the I.D. and thickness is just right. The O-ring has a snug fit and is twice the thickness of the washer for good compression.
I know it is a pain to do the turning work, but for me it was the best solution.
Alan.