Thanks to all who offered advice. Reduced main and rod clearance to .001", reduced oil pump base plate clearance to .001, and drilled oil intake passage to 17/32 (.531). Results; 30 psi hot at 800 rpm and 60 psi at 1500 rpm using 10W-30. Great. Installed 2-piece rubber rear main seal from D&D. last year. Not a drop of oil for the first 15 minutes, then a steady drip. Then tried a rope seal carefully following the factory installation procedure, but it leaked, just not as badly as the rubber seal. Since the motor was down to remedy the low oil pressure problem I decided to try the rubber seal again this time offsetting the seal. Just as before, not a drop for the first 15 minutes, then a steady drip. Oh for an NOS asbestos seal.
Atleast the oil issue is done. Can you tel if it's the oil seal at crank or possibly the side seals of main cap.
I don't know for sure. I'm running the motor in the car without the transmission, but the flywheel is in the way of a direct view. I do hate to get my face near that spinning flywheel. Look again tomorrow.On the previous rubber seal try, on the tear down I found a black line of rubber stuck to the seal running surface. Thought I had failed to lube the surface, but not so this time. I was wishing for a vintage asbestos rope seal and got a call saying they found some real old ropes from the 60's and 70's.
Took the block and rods to the machinist with the bearings installed and had the shop grind it to fit.
I'm foggy on the various threads but IIRC, that means you purchased new bearings and had the shaft reground again just days before the late night thrash? Did they have a chance to get an indicator on your seal groove? I do realize the potential difficulty involved and timeline demands...
Yes, new bearings and a re-grind. The shop was unable to check the seal groove and could not correct the condition in any case. I choose to assemble the motor and the result was another seal failure. I have another thread here and on the British V8 forum requesting info on a shop that could machine for a 1-piece seal.
Valiant effort! The seal you inquired about is also suggested for B455 use. Is your Rover crank the same dimension as a 455? If you don't have your dimension inquiry answered yet, there's a starting point.
Thanks to member on British V8 forum, I have the 215 dimension and it it the same as the Rover. So, it may be that the seal just is not compatible with the existing rope seal groove. As you noted, the rope groove can be very sloppy. No need for precision with a rope.
Who on this board has completely solved the oil leakage problem? Exactly how did you do it? We all want to know. This is a problem area for many of us and there does not seem to be any easy solution. For some engines it is worse than others but it is a recurring problem and it should not be. There is no good reason why an effective seal around a rotating shaft cannot be achieved, industry does it millions, perhaps billions of times a day. So why do we still have this problem? Well, to start with there is the vertical seal between the main cap and the block, one on either side. That can leak. There is also the horizontal seam between the bearing and the vertical seams. And of course the pan. Each one of those corners can leak too. So even if the seal itself is perfect there are still plenty of places for the oil to get out. Then if your pcv system allow positive pressure in the crankcase under ANY condition (WOT for instance) that is still going to push oil past the seal. It is essential to be absolutely meticulous about cleaning all these surfaces of any and all oil residue before assembling the rear main cap. Lubricating the bearing is at odds with this of course and will sabotage your best efforts if allowed to do so. Then getting sealant into the required places without it being wiped off during assembly is another challenge. And in the end you never even know if you have done a good enough job of it until after the engine has been put back into service and it's too late to remedy it. I'd like to see the tips and tricks of the ones who have found the path to enlightenment. Because I'm not there yet. Jim
I don't think he has it solved with the lip seal yet, he's using a NOS rope seal AFAIK. I've only suggested a commonly seen in other makes problem, the seal groove not being machined concentric to the main line. Many rope seal engines have the problem of the tolerance being wide open or no call out on the print knowing the rope will conform anyways. I don't really know what the issue is here, I haven't looked at it his block, measured anything, done the assembly...just offering that it's an issue with other brands too. Off the shelf products aren't really available for any other make having this solved. Machinists here and there have cut blocks true to the main line and made adapters for common and similar sized seals, I've touched on the numerous ways to do this with various machines...it's not tremendously challenging to do. Finding places willing to is.
Another potential issue I rarely see is with shafts being ground having a problem locating the crank on the bevel or OD and IT being dinged or untrue, and other problems with the buck chucks, maybe more common on stroked cranks. What can happen relevant to this post is the rear main can be ground offset to the rest of the mains, as in...it has some stroke. I've seen a few that are eccentric by appx. .0017-.0022, doubling that for TIR. A light wipe of the flash coating 'might' be all you see, if you are lucky. You probably won't see that on an indicator either. It escapes even the thorough home builder when the crank is supported by the #1 and 5 bearing shells with an indicator at the center. Then the deviation is half the TIR, so .0017-.0022" with the cases I've seen as example. That is further questioned when people use the inexpensive mag base with 1" drop indicator that moves the needle about .001" when the plunger loads back and forth from the direction of rotation. A tenths test indicator is useful here. You can tell it's not just bent because the indicator wouldn't do predictable things when it's location is moved. The other tell is that (in this situation) is that if you were to remove the rear shell and support by #1 and 4 mains, the shaft would run dead true, with #5 showing the TIR as stroke evenly along it's length, not getting worse the further away from the once thought of 'bend' as it would. I cannot say for certain that an eccentrically ground (but perfectly round) rear main would cause a leak as I've always caught it before assembly. One would guess that a certain amount of rpm or run time would be damaging regardless. I think maybe rather than the crank effectively supported from 1 and 5 (like during mock up), when you add the other 4 mains they might be stronger than the fifth. You pretty much can't feel the crank wipe the coating off the bearing (depending) and it barely becomes detectable with the rest of the bearings torqued. It runs tight all the way around and at the eccentric portion of the bearing, finds a loose spot twice in rotation IF the deviation fits that scenario. The other obfuscation is that often the rear seal isn't installed until mock ups are done and during final assembly, so you would feel the seal drag anyways. I've not searched the physical limits from the manufacturers or SAE specs because it isn't profitable. I'd rather solve problems and move on. One might guess with tribal knowledge of running externally balanced engines past a certain rpm and subsequent oil leaks following crank flex could offer some insight (sbc 400 coming to mind). We know revving those up too high suffers leaks. Not many are putting much effort into solving leaks when they are approaching power levels and rpms that cause more significant carnage than a leak. People tend to guard their engineering work to some degree if it can't be protected or sold... so one might not see the solutions unless you ship them an engine along with a fat check and IF it needs done you might be asked not to share the information.
A few tricks i use are: Offsetting the the ends of the rubber seal from the parting line of where the cap meets the block. Using "the right stuff" sealant on the rubber chunks that go between the cap and the block on the sides... And be sure the pins that you tap in to expand the chunks are flush with the oil pan rail. I do think PVC issues often make leaks worse... Some other observations: 1. The rope seals have way more HP reducing drag then the rubber ones... 2. The rubber ones either seal up great or leak. I think normally its a crank surface issue and or runout. 3. The good thing about the rope seal is it can swell up after leaking a bunch. My 75 regal sat for 10 years and leaked like a siv from the rear main!!! I bought it, drove it hard for a week then parked it for 5 years and it no longer leaked at all ! It leaked about 5 liters of oil out while i drove it, i just topped it up lol...it fixed itself. It currently doesnt leak at all...
