bubba22349":2ikrylj8 said:Simonsalz":2ikrylj8 said:bubba22349":2ikrylj8 said: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 Edited
Would this be it?
Yes that's looks like a Genuine ("NOS") Ford made seal. It would be interesting to measure and compare the Ford seal against the Newer FelPro seal to see how or if they are making them different.
wsa111":nbizh0t0 said:At this point i believe you could try a rope seal.
Otherwise i am taking a guess that whoever line bored the block removed too much from the rear main cap & it is smashing the seal into the crankshaft.
Last shot is replace the block & install another crankshaft.
chad":1exr84n4 said:or to see relation to a 200. I assume the same but not labeled for that motor or yr.
Simonsalz":jy73ckj8 said:bubba22349":jy73ckj8 said:Simonsalz":jy73ckj8 said:Would this be it?
Yes that's looks like a Genuine ("NOS") Ford made seal. It would be interesting to measure and compare the Ford seal against the Newer FelPro seal to see how or if they are making them different.
I’m tempted to order it to check
But also would I be able to measure the felpro seal and compare it to another gasket (full circle neoprene for instance) to see if the crush is different? I may sound like an idiot but it’s evident something is making the seal push too tight on the crank and I just realized the front crank seal has never leaked.
bubba22349":2uxdvjxf said:Simonsalz":2uxdvjxf said:bubba22349":2uxdvjxf said:Yes that's looks like a Genuine ("NOS") Ford made seal. It would be interesting to measure and compare the Ford seal against the Newer FelPro seal to see how or if they are making them different.
I’m tempted to order it to check
But also would I be able to measure the felpro seal and compare it to another gasket (full circle neoprene for instance) to see if the crush is different? I may sound like an idiot but it’s evident something is making the seal push too tight on the crank and I just realized the front crank seal has never leaked.
Yes for sure they can be measured. If I had the two seals I would start by setting them on top of each other to examine the difference or making a line around them on paper and use that to see differences. Then you can use a Dial Caliper or a Micrometer to measure the seal thickness and height, all of these would be fairly easy to do except for the seal lips height, this is because if you put too much presure on it its going to start moving. Yes you are right the front seals have been made correctly over the years, and usally outlast the engine. Good luck
bubba22349":347izrjw said: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 Edited
chad":3sr3qppm said:as U no, doin the same thing gets the same results - X 2 do something different, anything
(take notes, only change 1 thing).
will C what we can do frm here, good luck!
drag-200stang":1wr63jqo said:What do you mean trim the seal to fit ?
I do not remember that needing to be done, that maybe your problem...No crush to make tight.
Let us see what other members say.
wsa111":3u3ocodq said:At this point i believe you could try a rope seal.
Otherwise i am taking a guess that whoever line bored the block removed too much from the rear main cap & it is smashing the seal into the crankshaft.
Last shot is replace the block & install another crankshaft.
Simonsalz":m94shj42 said:bubba22349":m94shj42 said: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 Edited
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.
drag-200stang":1kue1grb said:Ok that makes sense.
I thought that you were going to try a nos neoprene seal that may be made to the right spec. versus today's offshore stuff.
chad":2gchazt1 said:U put the lill pin back in for the rope seal?
"... I made sure to follow all proper steps ..."
like 2 hear more. Similar with the neoprene U may B following best practices (use no other) but I
can't tell.
Also
some here R saying machined/unmachined prts may B interfering...