Replacing rear seal w/engine in car?

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ValiantOne

ValiantOne

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Hey all.
I am currently doing a 4 speed swap in my car. Old trans is out. There is ALL manner of oil leaking out the back end of my 273. The engine will ultimately be swapped for a 5.9 Mag motor so I don't want to go nuts, but I am thinking all this oil could be bad news for a clutch plate.

So should go ahead and do a rear seal and oil pan gasket? Is doing this with the engine in the car a bear? The FSM gives instructions for dropping the pan in the car so II assume it is possible. But thought I'd ask those who had done it first.

Thanks

CE
 
Pressure test the crankcase first, to positively locate the source of the leak. I'd hate to see you spend 4 agonizing hours changing that seal, for it to change nothing.
I pressurize through the dipstick tube at 3 to 4 psi, after having blocked all escape routes; such as the pcv port and valve cover breathers. Then a soapy water test will find all leaks. Pay particular attention to the oil-pressure sender(or can if equipped), the dizzy base, and the back china-wall. Of course if the tranny is off, that makes checking the rear mainseal all the easier. Also check the intake manifold to head seal, the front china-wall and the fuelpump mount. Along with everything else that shows signs of seepage.
good luck
 
AJ/FormS said:
Pressure test the crankcase first, to positively locate the source of the leak. I'd hate to see you spend 4 agonizing hours changing that seal, for it to change nothing.
I pressurize through the dipstick tube at 3 to 4 psi, after having blocked all escape routes; such as the pcv port and valve cover breathers. Then a soapy water test will find all leaks. Pay particular attention to the oil-pressure sender(or can if equipped), the dizzy base, and the back china-wall. Of course if the tranny is off, that makes checking the rear mainseal all the easier. Also check the intake manifold to head seal, the front china-wall and the fuelpump mount. Along with everything else that shows signs of seepage.
good luck
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Interesting. How do you regulate 3\4 psi?
 
The trickiest part is to drive the upper half of the seal out. You might succeed by using a piece of soft brass rod to drive it out; it will curve around the crank as it goes in, and not damage the crank surface. If that does not work, then you'll probably have to loosen all the crank main caps a bit at a time to lower the crank a bit.
 
I've done it before and consider myself lucky to have had a seal that came out easy and in one piece. It is a pain to do but easier than doin it with the engine on a stand since the whole engine comes out.
 
Trying to get the oil pan up without knocking the gaskets out of place can be tricky...
 
It may just be me, but I would think that since the trans is already out, that means there really isn't much work left to remove the engine. If you are sure it is the rear main, then it would likely take less time and be easier to pull the engine and change it than struggle underneath the car and hope you can get it done correctly. Again, it could just be me!
 
To get 3 psi just use a spray gun reg. Harbor freight has them cheep!:burnout:MT
 
Well, to change the gasket or seal for the sake of changing it , if it was not the source of the leak, is to risk the introduction of a leak. So if you do end up finding a leak there then be sure to retest after replacing parts.
The neoprene seal is easy to replace, I've done it in situ, several times. The rope seals are only a bit more difficult. I would gladly rather change it, in situ, than to pull the engine. Even without a hoist. And I have a milodon roadrace pan. And I'm 62 yrs young. And 210lbs. Piece of cake. 3M weatherstrip glue and RTV,shazzam. And if the tranny is out, double shazzam.
 
krazykuda said:
Trying to get the oil pan up without knocking the gaskets out of place can be tricky...
Click to expand...
I literally rarely curse , getting that *&#$!@$$ oilpan back on without bumping the goop!!:banghead:
it makes me :violent1: oh forget it , never again - I'll pull the motor first...
 
I changed the rear main seal in the vehicle on a 318 once.... but it was in a 78 d200. The pan was a pain to get off and on and I had to loosen and then retorque all the main bolts. I doubt you could take the pan off while its still in the car without undoing the mounts anyway, might as well pull it out. For sure check the intake gasket and oil sender first, look at the plug behind the cam too
 
Well I think you all have convinced me to just pull the engine. The rear end / manual trans project has officially entered "project creep" stage.

So I can see some oil coming down from the rear of the intake too. It is also coming down the sides if the block. I also have a exhaust leak I know of. I think I'll just pull the engine, put it on a stand, get a complete engine gasket set and have at it.

If I am going through all this would you all change the head gaskets too? They're serviceable, but likely 47 years old.
 
Their is an additive that you can put in you oil, (cant recall the name of it) and then using a Black Light the additive will turn a blue color where the leak is. I did that one time and it worked for me. Just be sure to change your oil afterwards..
 
Gator said:
Their is an additive that you can put in you oil, (cant recall the name of it) and then using a Black Light the additive will turn a blue color where the leak is. I did that one time and it worked for me. Just be sure to change your oil afterwards..
Click to expand...
I did this on my 70 340 swinger and it worked great. You could see the oil coming out of the seal area. The upper seal slid out of the block fairly easily. It turned out that the crank surface was pitted up a bit, so I had to use some emery cloth to clean it up a bit. The beast part was the black light showed the oil pan had a hairline crack/leak where the rear oil pump bolt had just rubbed a slight hole in the pan.
 
ValiantOne said:
If I am going through all this would you all change the head gaskets too? They're serviceable, but likely 47 years old.
Click to expand...
If they are sealing well, and I was not planning on any other internal work, I would not be prone to replace them. The surfaces may no longer be as flat as they once were. But if they are the originals, I assume they would be the thin shim types. One possible issue with those is at any of the block-off points where the head gaskets purposely block water flow from block to head at some of the core casting holes. The original shim gaskets can rust through at those points. If so, then the water flow may be incorrect and that may cause abnormal cooling in some cylinders.
 
Re post #13
Well if you buy a complete kit, then for sure I would do the headgaskets too. And then take the heads apart for a regrind, and replace the Tchain a/r, and clean the oil pump strainer, and replace all freezeplugs, and, and,and... see where this is headed............and a re-ring,probly cam and lifters.....and measure the total combustion chamber size,to calculate the exact Scr.....the list goes on, and on.
No! if the engine runs nice now, don't take it out,don't touch it, just fix the exact source of the leak, and drive it. You're bank account will thank you.
Then go find a nice 360 core, and stick your money into that,if you are intent on spending. You will have an instant 17% more CIDS, so that's nearly 50 more ftlbs, nearly all through the powerband. That's worth over 2 diff sizes!If you currently are running a 2.76, the stock 360 will perform better than the teener with 3.23s, right out of the gate. And will rev at least 500 to 800 rpm higher while pulling long after the teener gives up. If driven conservatively it will return a similar averageMPG , and on the hi-way, with a Metering-rod type carb, can be tuned to get excellent mpgs with conservative gearing. The bore is only 2% larger than the teener, but the stroke is over 8% longer. That translates to torque you can really feel, and make work for you.
I will not ever spend money on a teener again. A well built 360 can better anything a teener can do, including fuel mileage.Especially so when modern chambers are fitted.
Having BSed you nearly to sleep, you are, of course,free to do whatever you choose, and I wish you every success.
 
Yeah I'm definitely not letting the creep go that far.

I have an 01 Magnum which is destined for this car. It may be a year, maybe two, until I can amass/afford the parts for a full efi swap so the 273 is temporary.

That being said I don't want this thing puking oil all over the new trans, clutch and work I've already done.

Think I'll just do gaskets minus the heads and leave it at that.




AJ/FormS said:
Re post #13
Well if you buy a complete kit, then for sure I would do the headgaskets too. And then take the heads apart for a regrind, and replace the Tchain a/r, and clean the oil pump strainer, and replace all freezeplugs, and, and,and... see where this is headed............and a re-ring,probly cam and lifters.....and measure the total combustion chamber size,to calculate the exact Scr.....the list goes on, and on.
No! if the engine runs nice now, don't take it out,don't touch it, just fix the exact source of the leak, and drive it. You're bank account will thank you.
Then go find a nice 360 core, and stick your money into that,if you are intent on spending. You will have an instant 17% more CIDS, so that's nearly 50 more ftlbs, nearly all through the powerband. That's worth over 2 diff sizes!If you currently are running a 2.76, the stock 360 will perform better than the teener with 3.23s, right out of the gate. And will rev at least 500 to 800 rpm higher while pulling long after the teener gives up. If driven conservatively it will return a similar averageMPG , and on the hi-way, with a Metering-rod type carb, can be tuned to get excellent mpgs with conservative gearing. The bore is only 2% larger than the teener, but the stroke is over 8% longer. That translates to torque you can really feel, and make work for you.
I will not ever spend money on a teener again. A well built 360 can better anything a teener can do, including fuel mileage.Especially so when modern chambers are fitted.
Having BSed you nearly to sleep, you are, of course,free to do whatever you choose, and I wish you every success.
Click to expand...
 
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