atkinsom

I Just picked up my newly rebuilt 455 that the engine builder put together using a rope seal for the rear main. The builder always prefers to use a rope seal as opposed to the neoprene one for the fords. However, the rear main seal appears to be leaking pretty good through the torque converter cover holes once the motor is started. The motor has less than 50 miles on it right now after the break in but I'm really concerned about the leak which is dirty in color. The oil dipstick is fairly clean but is a bit dirty but not unexpected I figure for a new motor breaking itself in. The engine builder says this is normal and will take a couple of weeks to seal up after driving the car around and putting on miles. Is this true or am I being stalled due to him possibly having to pull the motor and redo?

pogo69

i would give it some more miles and heat cycles to set up especially a rope type seal maybe recheck at a couple 100 miles i dont know why he would prefer a fiber seal unless the crank seal area was rough....if he use a bunch of moly it could be the cause for dirty looking oil, give it some more time

gearheads78

I have no personal experience with a new rope seal install but I have heard others say that before. Just not sure it is true or not.

atkinsom

OK thanks guys...going to try to get 3-400 hundred miles in after it stops raining this weekend. Let's see if that leak seals up as the builder says...thanks again

pogo69

thats a good plan i think it will...good luck

Smitty275

A rope seal 'seals' because there is enough of it packed in tight enough to stop oil from getting by. More time and miles is not going to stop it from leaking. All your going to end up with is a filthy transmission and under carriage. Not sure why he would refuse to use a modern seal that is proven to work in favor of a rope seal that is a major pia to put in right. If it took miles to get a rope seal to stop leaking then why did millions of GM cars roll out of dealerships not leaking a drop with next to nothing on the odometer?

dc2x4drvr

Rope seals available today don't have asbestos in them, so they're prone to leaking. Pull the motor and install a Ford 460 seal.

pogo69

are you sure about that? ... if the seal was not packed deep enough in the cap or block and the torque crush shortened it i can see that, the fact it lacks asbestos shouldnt cause it to leak

dc2x4drvr

The asbestos is why they didn't leak, I've heard of quite a few rear main seals leaking since the seal was changed, why take a chance?

pogo69

if you dont have a nice smooth surface on the crank for the ford seal to ride on than that will leak, thats really the only reason i can think of for not using the ford seal. i think the fact that this guy already has the rope seal in and is not thrilled at the moment its not going to help with what 'should of been done'' he might as well just wait it out like his builder says, drive it a while and it may stop leaking...if it doesnt then it will have to be replaced

Smitty275

I guess it'll stop leaking when the oil gets low enough.

atkinsom

Spoke to the builder again and he swears it will stop leaking. He wants me to drive it about 500 miles and go on a couple of longer 30-45 minute trips. He says he has great success with a rope seal over the long term as opposed to the ford seal. I understand what he's saying but it freaks me out when you see a palm size amount of oil leaking through the torque converter holes on startup. He's a well known old school builder with a great rep so I suppose I have to go with his requests. I will say he's been nothing but very understanding/informative about the process and on the off chance that it doesn't seal up(rare he says) he'll take care of it quickly....I guess that's all I can ask for. Thanks for all the responses and I'll keep the thread up to date as I move along.


PS Keeping a quart of oil with me as I drive

atkinsom

Well just to follow up on this thread. The rope seal DID in fact seal up very nice indeed just like the builder said so kudos to him and others that forced me to be patient Not a drop of oil coming from that location. Motor is awesome so he did a bang up job.

However, issues have become complicated as the new mondello 8qrt pan is leaking ever so slightly from the weld where the nut goes in and as well from the flange/cup location immediately below the rear main seal. The pan has a deformity which doesn't allow it to seal nicely against the block. A huge PIA as I now have to take the hood off and pull the motor up a few inches with my mechanic using a cherry picker to get that pan out. Hopefully Lynn at Mondello will understand that I couldn't see these issues unless I used it first and issue me an exchange.


EDIT: Lynn exchanged oil pan without batting an eye...very nice about the whole thing.

pogo69

Lynn seems to be a pretty reasonable guy i cant see him not replacing it ...take a few pics of it just in case