Has anyone tried the Best Kevlar rope seal? I can't seem to get a regular seal to stay in my engine.  I have been in the process of having this engine built for about the last three years, and to be quite honest, I am getting tired of it. It is a 292 bored 80 over with a 312 crank machined to fit.  The first time it was put together the head bolts were improperly installed and it filled with water.  Got that problem resolved and now I can't keep the rear main seal form leaking. Recently put in the second one and shortly thereafter it started leaking.  Any suggestions would be appreciated.

Jan  Urbanczyk  Major USMC Ret.

                                                                 Bowie Maryland

I had three best gaskets seals in my 312 and all of them leaked.I bought a rear main seal from Don Hyde two years ago and so far no leak,probably 5000 miles. Don machines a Chrysler seal to fit a 312,Do a search on Ford Craft for more info.

Carl

I've had the most success with the Best Gasket "Graph Tite" rope rear main seal part # 5249A.



It's a graphite impregnated rope seal so it will never dry out. It comes with the side seals and detailed installation instructions.



This fits all Y blocks from 239 to 312



I've also tried the silicone rear main for the 312 and it still weeps a bit when it sits.

Larry D

Winnipeg, MB Canada Eh!


'57 Fairlane 500 Club Victoria

'58 Custom 300 Tudor

'56 Crown Victoria

'61 Starliner Z Code

'51 Ford Victoria

I will try that best number, I don't know what is happening with my motor, but it seals up and then after a few miles it starts to leave large puddles. How hard is this graphite seal to install with motor in car?

Jan  Urbanczyk  Major USMC Ret.

                                                                 Bowie Maryland

Jan: Not saying your main seal isn't leaking.. but according to Ted Eaton, sometimes those leaks can be traced to the rear Camshaft Plug not being installed & sealed properly. That allows oil to leak down in the same area. Also, Ted notes that it's important that the plug not be jambed up tight against the back of the cam, removing clearance at the front. It's worth a look.

Paul

Thanks Paul, I will check that this time.

Jan  Urbanczyk  Major USMC Ret.

                                                                 Bowie Maryland

Jan; re your question on installing the Graph Tite rope seal. I undertook doing that and decided without loosening the main bearings & possibly having special tools, it looked like a potential mini disaster. So, I installed the lower piece only. It still leaks some, but it's hard to evaluate, because the front seal in the Fordomatic is leaking also. Sorry, I can't be of more help.

By the way both types of seals are available promply by mail from "Gasket City" in Hamilton Ontario Canada.

Paul

Gasket City in Canada has been my supplier as well. My machine shop tells me if you are using a rope seal you want a roughened area on the crankshaft where the seal rides as the factory had, if it's a rubber or silicone seal you need to have this area polished smooth or it will just wear the seal prematurely. Maybe Ted Eaton or some of the other engine builders on this site, can offer some advise on crank surface finish in the seal area.

Larry D

Winnipeg, MB Canada Eh!


'57 Fairlane 500 Club Victoria

'58 Custom 300 Tudor

'56 Crown Victoria

'61 Starliner Z Code

'51 Ford Victoria

 spotted this whilst searching for pump repair kit

stuey

Then and Now Automotive Specials/Clearance Items

                                                                                               

For the 292 blocks, I use either the ‘black’ Fel-Pro or ‘black’ Best Gasket neoprene rear main seals and have had no leakage issues with either of these in the 292 blocks.  For the 312 engines, I use the ‘black’ seal from FordCraft and that particular seal is a re-machined Chrysler seal.  The Best Gasket ‘orange’ seal for the 312 engines has had a history of early failure rates so those are to be avoided until the design is changed up.

 

On the 292’s, the hash marks on the rear main seal journal have not been a problem but any pitting or roughness otherwise on the crankshaft will force the seal to fail much earlier.  When re-machining the 312 cranks to a 292 rear main seal, the seal journals end up being mirror smooth with no hash marks and I’ve had no troubles with those either when using the appropriate Fel-Pro or Best Gasket neoprene neoprene rear seal.  The seal retainer itself can be the source of oil leaks so particular care must be taken to insure it’s sealed to the block well also.  And don’t forget that oil pump as any leaks from it are easily blamed on the rear main seal along with rear block galley plugs and the camshaft rear plug.

 

Here’s the link to the rear main seal installation article that was originally published in Y-Block Magazine.

Rear Main Seal Installation Tips

Lorena, Texas (South of Waco)