Rear Main Leak – Bear with me

Re: Rear Main Leak – Bear with me

The main bearing leak from excessive clearance or crankshaft end play will leak at the back of the bearing cap and follow the contour of the cap to the front.rear main bearing bolts should be sealed with rtv as part of assembly.Wash the area with brake clean and idle the engine,lay under and watch the area,if the oil doesn't track from the flywheel side of the bearing forward to the pan cork it is migrating through the main bearing bolt hole.
 
Re: Rear Main Leak – Bear with me

Spinelli - what do you think is causing the oil to leak down the rear main bolt ?
Railcarmover - dumb question - how do you seal the rear main bolts with rev ?

I installed a rebuilt engine last month - and have a leak at the rear of the engine - symptoms look identical to Spinelli’s pics.

Many thanks
 
Re: Rear Main Leak – Bear with me

On all the main bolts that extend through to the OUTSIDE of the engine (5 of the 6) I seal with ultra black silicon. Only the passenger side center main bolt has both ends inside the sealed sections of the block & doesn't need to be sealed.
 
Re: Rear Main Leak – Bear with me

As Ray says I use RTV and hard washers on all main bearing bolt nuts except the center inner...I use regular grade 8 nuts with loctite blue too. Engine oil will track up the main bolts.I found Vw aircooled engine case stud hard washers fit the A main bolt perfectly,hard washers give a positive surface for the nut seat,unlike ford grey iron..
 
Re: Rear Main Leak – Bear with me

I'm experiencing the same thing - I feel your frustration. I can see oil coming from the inspection plate next to the oil pan after about 10 min idle -- pulsing like a slow bleeding artery. I have a mechanic friend who will be helping but thoughts towards either a plugged or missing oil return tube, problems with the shims, or possibly a bad Babbit. He said if Babbit is ok he will drill an extra hole in the Babbit to assist with oil return to the pan.

Looking forward to seeing your progress.
 
Re: Rear Main Leak – Bear with me

You say it is a pressurized oil system, what seal was used in the rear cap and block?
 
Re: Rear Main Leak – Bear with me

Railcarmover said:
The main bearing leak from excessive clearance or crankshaft end play will leak at the back of the bearing cap and follow the contour of the cap to the front.rear main bearing bolts should be sealed with rtv as part of assembly.Wash the area with brake clean and idle the engine,lay under and watch the area,if the oil doesn't track from the flywheel side of the bearing forward to the pan cork it is migrating through the main bearing bolt hole.
Click to expand...


I'll try that.
Thanks
 
Re: Rear Main Leak – Bear with me

Have you measured the crank thrust by stepping on the clutch and watching if the front pulley(engine) moves foreword? Worn thrust was mentioned, but I didn’t see where it was checked?
 
Re: Rear Main Leak – Bear with me

saxman657 said:
I'm experiencing the same thing - I feel your frustration. I can see oil coming from the inspection plate next to the oil pan after about 10 min idle -- pulsing like a slow bleeding artery. I have a mechanic friend who will be helping but thoughts towards either a plugged or missing oil return tube, problems with the shims, or possibly a bad Babbit. He said if Babbit is ok he will drill an extra hole in the Babbit to assist with oil return to the pan.

Looking forward to seeing your progress.
Click to expand...

First thing to do is to see if all the oil passage is open.

If the drain hole in the rear of the cap won't take the oil now, how will drilling another hole in the cap to feed it more oil, really overwhelming the system, help? Also any oil taken away from the rear of the cap, the thrust will suffer.

Thrust clearance should be set at .003, to .003-50, any thing over .006 is pumping oil. If the rear main bolts, and the shims are not sealed, oil is going through. The shaft set for clearance, as every body knows.

Herm.
 
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