Rear main seal keeps tearing on bottom half

bubba22349":3aclmuxs said:
Simonsalz":3aclmuxs said:
bubba22349":3aclmuxs said:
:unsure: I have been a fan and proponent of using the neoprene type rear main seals (because they had less friction "for a little extra free power") since back in the late 1960's, plus I have also mostly used and recommended the FelPro brand. Recently this same issue has come up with severial other people when using the FelPro rear main seals in the early 144, 170, & 200 blocks (i.e. those that originally used a rope seal). Because of this continuing problem I believe that these latest seals are not being made to the orginal Ford Factory specs of the rear main seals like we're used or offered in the past, and or they may even be substituting a seal from another seal application. Anyway this is my theory and because this has now happened with quite a few instances there is definitely a recurring problem over the last approximately 2 or 3 years, of these rear main seal failures. But only by acquiring then doing a side by side comparison and accurate measuring of a new original Ford seal which I think is (C9AZ-6701-B) compared to one of these current FelPro seals will prove this theory.

At this time I don't know if there is another manufacture that makes the correct spec neoprene seal to fit these 200 blocks, so it is my opinion and recommendation not to waste your time installing one or the money to buy one of these seals that FelPro is currently offering. So It also my opion It's just best to use the old tried and true rope type rear main seal. Or unless you would be lucky enough to even find a "NOS" Genuine Ford neoprene rear main seal. To reinstall the rope seal you can make a replacement rear main seal locking pin for the main cap from the end of a small finish nail of the correct diameter and cut it off to fit into the main cap. Good luck (y) :nod: Edited
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Hey! sorry its been a while since i have replied, but i found a NOS rear main seal and installed it, but the leak still persists. but on the bright side, i was told it needs to "swell (because i didnt soak it over night, but i did lubricate the seal)" and that should help with the leak also. i remember when i was cutting the seal to fit it would clear the oil where the crank was mated and id assume when the engine heats the clearance gets even tighter. honestly ill be fine with it, as long as i can make it 3k miles before having to add or buy new oil. but it seems to be dripping rather fast I in still, but that could be my paranoia. I made sure to follow all proper steps and ive asked many with success in installing rope seals and did as instructed.
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Hi Simon welcome back! :banghead: Sorry but the rope seal isn't going to swell up with oil over some amount of time and seal itself, nor will the engine heating up help it to seal any better. As the engine warms up its going to expand so this going to depend on the rate of expansion of the parts I the cast iron block, the cast steel crankshaft, vs the rope seal material ect. I am not an engineer but there's a good possibility that it will even leak more when at operating temps.

:unsure: I guess to be able to determine the cause I would need to see some pictures of the install or know what your install procedure was, but I will take a stab at it. There was a tool made to install the rope seals to hammer it into the seal groove to fully seat it. I never had this tool so would use the biggest inpact socket that would fit pushing the seal into place in the groove first and then giving it a couple of light raps with a hammer to fully seat (bottoming the seal into the seal groove) after that I trim the seal ends with a fresh (Sharp) single edge razar blade the ends should be just slightly (proud) above the blocks main caps parting line so that it gives a little bit of a crush fit, you could use a .002 feeler gauge layed beside the seal as a guide for cutting nthe seal. Next Lube the seal surface with pleanty of oil, also clean & lube the cranks seal surface good too, the angle groves on the crank are there to chanel some oil onto the seals surface so the seal will last longer. A new rope seal shouldn't be leaking if installed correctly. Another way to know if the seal is installed correctly is the engine when turned off stops turning quickly due to the amount of friction of the rope seal, until over time and heat its position takes a set. You also need the retaining pin installed in the main cap to keep the seal from spinning in the groove. I have made many of these from about a 4 P finish nail with the pointed end going into seal and then cut off to fit. Sorry for your troubles, Good luck. :nod: Edited
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Thanks for the reply, I feel I’m doing something wrong but I still can’t figure out what it is and why, and honeslty it’s really driving me mad.
But for the install I was walked through by someone who installed many rope seals and specifically build these engines with no issues. I began with a NOS seal and put it in the housing (both sides) and pressed it in with a socket. After that I put the crank in and torqued all the cap bolts down so the seal could be compressed in the block. (I also cut the ends flush as the package said to do so) I made sure to put gasket sealer on the cap and block mating surface and on the end of the rope seals where they meet to insure a seal will be made
I reinstalled the pin also (I was going to use a nail, but I found the old rope pin and reinstalled it)

Along with that the engine stops pretty quickly when I cut it off and noticeably cranks slower due to the seal friction. When I had just the crank installed and pulled the cap there was a definiant seperation where the seal was and how it was repelling oil and what not on the mating surface if that means anything. Also to mention I took a torque wrench to the crank and it took about 20-22 (or so lbs of torque) to rotate, is that correct?

I honestly don’t know what to do at this point and I’m about to just v8 swap the car. I love the six but I fear I’ll run into the same issue with another block.
 
not sure if it was 1 thread but there has been some very detailed posts on here abt a proper seal install.
I was hopin U found that & went by it rather than any from the company.
Some suggested a wrong application and/or engine parts out of wack. If the failure wuz at the point U put in the "rope" and it wuz 'eyeballed'' and installed by an ol 'expert' I think that's the best ur gunna get. Disassembly's measurement would B the only thing I could C as remedy. U R lucky to have a 200. Here's hopin it leaks less at the nxt stage.
 
chad":663iij3f said:
not sure if it was 1 thread but there has been some very detailed posts on here abt a proper seal install.
I was hopin U found that & went by it rather than any from the company.
Some suggested a wrong application and/or engine parts out of wack. If the failure wuz at the point U put in the "rope" and it wuz 'eyeballed'' and installed by an ol 'expert' I think that's the best ur gunna get. Disassembly's measurement would B the only thing I could C as remedy. U R lucky to have a 200. Here's hopin it leaks less at the nxt stage.
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Honeslty I think I did a mixture of both
I’ve been told to cut it flush (as the package said) more than to offset honestly and I pressed it in the best to my ability, then used the crank to compress it. You know, thinking about it even though my crank is within spec and all my bores are, would it be possible that my crank is the issue? I ended up getting another one but all the machine work was done correctly. Just food for thought. But all is within spec and I spent 2-3 hours making sure that seal was tight and all was clear and cut proper. I would believe the leak is from somewhere else, but using the previous seals I (though they are neoprene and not rope) I’m sure it’s still the rear main. The seal was the proper number and said on the box, engine was line bored and spec tested and so was the crank (but again to mention the crank was replaced with the same casting number crank If that could be a part of the issue?)

Honestly this is driving me really mad and stressing me out because everything is right on it, yet it still leaks and what not
Maybe my mind is making it worse than it really is? I’ve talked to a few people with the orginal engines and they say it doesn’t leak but I’ve always heard it it ain’t leaking somethings wrong (for rope seals of course)

I mean off your experience hav should had one with a “slow leak” mine seems to leave a 1 inch puddle every time I park it but that’s not mentioning how much is spraying out when I drive it (which it might not be bad at all)
 
I believe line boring is the culprit. It makes the seal diameter smaller.
When you install a rope seal, before you cut it, you want to take a hammer handle or a round piece of pipe & roll the seal to seat it into the block & cap groove.
 
f r u s t r a t i n g !
i often do the best I can, leave the results to its self. But that's just me ("its an ol rig, chad.").
Not sure amount of leak or if it more when running than when it just sits...
 
I am not sure if this is your problem but i will throw it out anyway.
The bolt threads are close to the out side edge of the flange and can crack to the seal surface, causing a leak.
Maybe the crack can close up and not be seen when the bolt is not tight and spreading it,and it is missed. :unsure:
 
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