Oil leak rebuilt 348

Jerry B

Well Known Member
In 2000 I rebuilt a 409-409. Oil dripping from dust pan from the beginning. Probably under the car a dozen times in the first year trying to figure it out. Found the 4 speed leaking out the front and oil pressure switch leaking. Fixed them but still dripped but not a significant amount. The engine now has 39000 miles on it and the drip is still the same. Just put cardboard on the garage floor and go the the car wash about 3 times a year to wash out under the car. Just doesn't seem worth it to pull the engine to replace the rear main seal and still possibly get the same result.
 

427John

Well Known Member
I have built 2 engines with rope seals, no W's though, one was a Flathead Ford the other was a GM Holden 6 (1958), when I did the Holden a wise old Mechanic told me "son soak those rope seals in oil for a few days before you put them in and roll them into place with a piece of broom handle", I was about 17 at the time, neither of these 2 engines leaked from the rear main seal. Whether this is right or wrong, but it worked for me at the time.
I always used the rounded end of the broomhandle rolling it in a little at a time being careful not squish any out over the edge of the seal groove,also if your block still has the little pointed anchor in it (they sometimes get removed to allow the use of a rubber seal)make sure to start there and work your way out from there on either side,that area can be the hardest to get the rope to fully seat in the groove since the point actually has to push up into the rope.
 

Jim123

Member
Thanks again guys, the speed shop has a line of cars in front of me so it will take a bit of time to get my beast up on the lift and take a hard look. Upholstery took for ever so I lost my place in the cue for service on the engine. Does anyone know of a 1958 Impala owner in need of a front bench seat? A Tremec 6 speed Magnum installation has necessitated going with a couple of bucket seats. The bench is in perfect condition but I obviously don’t need it.
many thanks!
Jim
 

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Jim123

Member
Checking back in gents,
The Impala finally made its way to the lift and its the pan gasket/pan. The engine is coming out Wednesday and my thought is to replace not only the gasket but also the pan. It should have been done with the rebuilt and was not. Anyone have a good source for acquiring a 348 pan for my build in a hurry? The current pan looks like it’s been beat up and it’s silly to pay for the labor to lift the motor and not insure a good fit.
Many thanks!
Jim
 

Don Jacks

Well Seasoned Member
Supporting Member 3
Show Cars can likely have you one there in a couple of days and it'll even be a 6 qt,pan.You'll likely need a new pick up as well.If your block is a 5011 block it should have a neopreme seal,not a rope.
 

Jim123

Member
Thanks Don!
They open at 0730 Central and I will reach out tomorrow. Concerning your 5011 comment please explain. The car/engine is 3 hours away. Is my mechanic looking for a number on the block to ascertain that info?
Thanks again
 

Don Jacks

Well Seasoned Member
Supporting Member 3
Yes,the engines casting number which is on the drivers side rear of the block.Only the early 58 stuff had rope seals.Old sky dog can say for certain but I think they made the change around mid 58 production.That 5011 is the last 4 digits of the casting numbers.Later 348 truck castings were 962 and 655 and they too were like the 5011 blocks,.
 

Don Jacks

Well Seasoned Member
Supporting Member 3
When you're putting it back together a little silicon sealer on the "rubber" pieces and an anorobic sealer between the metal portions of the block and rear main cap works really well toward sealing that engine right up. Hope this helps.
 
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