When replacing the rear main seal is it better to go with the original rope style or the newer neoprene (rubber) style on a 235 engine? Can anyone recommend a specific product?
"Best Gasket" makes a rope seal that's the only one worth considering, and I believe they have recently introduced a lip seal that fits the 235/261 engines also. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
If the main bearings are of the shimmed variety, you need to use a rope seal. Its a little muddy as to when shims were no longer used in 235s. Somewhere beginning around '54-'55.
1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission
The neoprene seal was introduced in 56. So 55 and earlier used a rope seal. You can use a rope seal in a 56 and up motor, but you cannot retrofit a neoprene seal to a 55 and earlier motor. The rear main cap is machined differently, deeper really, and the neoprene sinks into the cap on the earlier motors.
For as really permanent fix, have the block and rear main cap bored to fit a Chicago Rawhide #38647 full circle lip seal. That requires stripping the engine down to a bare block and setting it up in a Bridgeport mill, or using a fixture like I designed a couple of years ago that adapts a cylinder boring machine to the back of the engine block. Setup on the Bridgeport takes several hours, and is very expensive. With my fixture in place, I can be making cast iron chips in 30-45 minutes, and the whole process takes a bit over one hour to complete.
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
