That’s what I thought. Some kind of design copyright maybe? But how to Enforce?
I have fitted a split plastic Chrysler 360(?) seal to my 4.7 stroker and am
about to fit the SNGB split seal to the 3.8-bored 3.4 for the D. I wanted to try but will likely stay stock for my ‘pipeline’
Engines
Peter
Yup enforcing is toe stubber, so collaboration and trade secret is the easiest route. Start loading them up. Should be downhill from there to western NC 
Gonna run some more before I have to eat crow! I don’t want to do any more engine pulls!
I’ve heard that one of the rope issues is the car sitting for some time tending to have the rope “grab” on the crank. I’m guessing this is due to moisture and acid formation in the oil. All the more reason to make sure the crankcase emissions paths are up to snuff.
It’s not really supposed to touch the crank. However, that issue may explain why the Ford 460 rope seal is graphite impregnated.
So that’s what makes the viton so good. It is in contact (as I sized it) and the Teflon character keeps it slippery so that it should take the crankcase air pulsation with, hopefully, no weeping. Really hoping the additional temperature resistance gives it further endurance.
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back in 1950s , chevy used rope seals, after the V8s were made with rope till 1957, for 58 they came out with a split Neoprene seal , that is what has been used since then , altho the best way is a full circle two lip seal mounted with a removable plate!
why Jaguar stayed with rope 1989 we will never know , but it is the cause of much grief , untill just before Ford came online(may have been one of the reason that Ford said OK sale)!
also talking just yesterday ,guy 1995 6L said his car leaves a few drops overnight on cardboard on floor! 45K miles, something weird about Jag V12s!
ron
And there’s the bugger, “ removable plate “!
That means engine yank and I just didn’t want that headache thus the inplace experiment. Imagine doing the experiment with the engine pull and then it fails! At least this way the labor is a lot less and likely to be reattempted if it failed, though I would not be happy!
I had also done a plate deflector but even so some hit the hot pipes and looked like a fire under the car.
The rear main seal is just one of the common leak paths in this car. Another is the bolts holding the crankcase baffles to the bottom of the block that have head inside the sump but the threaded holes lead upward outside the sump. Oil seeps upward through the threads.
Oops, excuse me. The SIII E-type doesn’t have that problem; all the bolt heads are outside the sump. That particular leak path came with the XJ-S/12 with introduction of the sandwich plate / oil pan scheme.
One problem the SIII does reportedly have is a filter head that gets distorted over time and starts leaking at its joint with the block. That filter head got changed several times, including when the full flow oil cooling was introduced. But reportedly the later filter heads were heftier and less prone to distortion.
You’ve got to wonder if some of the leakage isn’t due to fault in drafting of crankcase vapors. I would speculate that it might be evident by placing a piece of cereal box over the valve cover oil fill. If it pulsates off it would certainly provide the drive to push pull oil across gasket interface or the seal that has set and is then a noncontact as Ron had said.
I guess if one thinks about this rope seal it is evident that it will crap out. This is a fibrous structure that will take a set. Reflect on clothes that are dried and sit undisturbed, wrinkles everywhere. They don’t “bounce” back!
Gee, having had one in hand, my impression was that it would last virtually forever. It’s not just a hemp rope, it’s some sort of synthetic fiber, and it’s embedded in wax. It’s deliberately designed so you can shape it using the installation tool so that it rides close to but not quite touching the crank.
I’m out of my depth here but I was under the impression that a small leakage after shut down was inherent in the design of a scroll seal, i.e. the slinging effect of the scroll ceases when the crank stops and what is in there may ooze out.
Generally speaking, your assumption is correct.
All true. However, the rear main is supposed to be above the oil level in the sump. Perhaps a problem results if you park it nose-high on an incline?
anyway so much for the FAMOUS Jag oil leaks!
my FORD V10 motorhome has almost 100K on it, and amazingly that engine has absolutly no oil leaks, the bottom of the engine is dry and dusty, i use a rag and wipe it off on bottom and its slightly dusty!
ron
Oddly enough, my 35-year old Ford moho, with a 460 in it (back when Ferds were known to have weepy mains’ls) is also nearly dusty dry.
Update on performance. Just did an 86 mile run between a couple of cites and got 15.6 mpg. That was mixed driving from traffic lights to 60mph cruises. Any perspective with others?
Max
On the last Oil Leak I averaged 13 but I think I was running pretty rich, have averaged 15-16 on previous Oil Leaks (WTol 5200 miles) with the '73. Yours sounds great at 15.6
Cheers,
LLynn
Lynn
I found it useful to use a laser temperature sensor in multiple carbs. The key is to match casting temperature by picking identical location on each carb after reaching operating temperature. The 6 webers have 12 brass plugs ideally symmetrical for the readings on my setup.
I thought the idea was to attain similar temperatures on the exhaust manifold runners, not on the carbs themselves.
The air/fuel dispersion in the Venturi creates a cooling effect and seems to be notable by a few degrees. For example, at ambient 59F all the carbs read around 42F with one of the 12 readings giving 37F. A tweak of the suspect idle jet brought it up as well as the air fuel gages confirmed the improvement.
I tried the exhaust checks but are more difficult to get a repeatable point and greater delta of readings. I was surprised to get so consistent readings on the carbs even after the drive which still gave the 40-43F amongst all the 12 readings.
Just occurred to me that I could plant 12 thermocouple wires in the brass recesses to see how the main jets are doing when highway driving. Talk about instrument panel gages!!!
I do believe a worthwhile experiment! Will decide if 12 gages or a single with a 12 position switch.
Could be done on the exhausts but now you’d look for the delta from idle to highway.
Now you see how it took so much time to get this system developed: one thing just leads to another.
Cool! That’s a new one to me!