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| Joined: | 04-24-2006 |
| Location: | Chandler, Arizona USA |
| Posts: | 18 |
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The rope seal can only be replaced by removing the crank. Perhaps others can comment on their experiences with rope seal replacement and the results. I've been-there-done-that once with so so results. For my experience, leakage was much reduced, but not entirely stopped. As best I can remember, the issue was that the ropes come in two halves that fit very tight in the grove. When pushed into place, the ends 'stick out' a little above each end of the grove and are supposed to be 'trimmed' to fit. The devil is to decide is how much 'stick out' should be left after trimming. In talking to mechanics who had experience with rope seals (they are very common in older engines) opinions very, but it seems that most agreement seemed to center on leaving about 1/64th (.015 thou) above the surface of the mating parts. I did talk to one JH owner who claimed to not trim the rope halves at all. Hmmm. Anyway, as close as I could get it, I trimmed to about .015 and there was still a very much slower drip. I'm sure others will have different stories with different results. Good luck! Please note, the .015 is measured on a fully seated rope seal. Just getting the things in there for a measurement was quite a pain.
As to the sump, Lotus had to fit the 907 over the Vauxhall front suspension, thus the front of the sump is very shallow. At the rear, where you would expect a deeper sump, Lotus again had to meet minimum ground clearance restrictions, and also, not have the sump be the lowest part of the car where every rock could, in principle, jump up and ruin your day. Therefore, the wide, relatively shallow sump. As to the 'box' for the pick up, the concern is what happens on hard, lengthy cornering, as would happen with 'sport' driving or competitive racing? The oil flows left or right, except in the smaller 'box' where the oil can't go left or right (as much) under cornering. Does it work? Not all that well. Oil sumps were changed several times within the first few years of production 907's. 907's essentially the same as the JH5 were the original engine in the Esprit, with obviously superior ability to corner and create even more problems with oil pick up. What should you do? For 'street' use, just keep the oil topped up. For track use, seriously consider that Acc-u-sump, or similar systems are very effective, legal in almost all forms of competition, and really, a lot cheaper than repairing damage caused by a spun rod bearing!