318 LA rear main leak?

-
V

vghoon

Well-Known Member
Joined
Oct 4, 2013
Messages
72
Reaction score
29
Location
nsw australia
Hi from Down Under
I have a vf Valiant I have been rebuilding for the past 7 years
I had a drive of the car last week & found top gear missing on the 904
after removing & dismantling the tranny I have since ordered parts for a overhaul.
During the test drive it started leaking engine oil from the bellhousing area & after closer examination I think maybe the rear main seal. I fitted a lip seal with the wings & noticed
the rear cap not sitting flush with the block face looks to me like about a .050 gap
is this normal or should the rear cap be sitting flush on the block.?
I have cleaned the area up & run the drill on the pump to get oil pressure up to hopefully
see a oil leak but no such luck. Is the rear main oil seal problematic?
cheers Pete

20190701_150326.jpg


20190701_150322.jpg


val.jpg
 
Welcome from Perth
Nice Val is that B5 blue
Is that pan sitting on the engine rail looks like a gap
 
Hi
The pan gap is a illusion & the gasket is taking up any slack
I am just wandering weather the cap is not hard up to the block?
See this pic showing the cap is hard up to the block
Maybe I have done something wrong as its my first mopar engine.

004.jpg
 
Last edited:
I believe the rear main cap should be sitting flush like in your photo of bare block. I can look at a 66 273 i have in the morning If you want.
 
BTW would you start a new post with photos of the steering and suspension, dash, peddle assys etc. Basically all the parts that make it a right hand drive.

I know quite a few FABO members would love to see the workings of a RHD Dart/Valient
 
That rear main cap should be all the way flush against the block. Hopefully it has not run long enough to hurt that rear main bearing. I have always used a standard rear main seal and put a dab of RTV on the ends and a very light coat into the area where those "wings" are and then assemble. Never had an issue.
 
I am just reading that the 360 has a larger rear main 2.500 vs 2.700
I am wondering if the wrong seal went in ?
were there any different seals for a 318la? I put a 2 piece in it with the wings
 
I suppose anything's possible. Either way, I'd stay away from the "wings". Reminds me of a bad maxi pad commercial.
 
Doesn't the rear cap have two different surfaces? There is the large surface around the bearing that is precision machined during line bore and hone, then a little chanel or gap, and then the sealing surface around the rear main seal itself. A small dab of red anerobic sealer goes on before cap installation, but forget the number of the sealer.
Blocks that had additional line bore or hone performed will close up that little gap.
Edit: Underlined text is wrong here as it applies to 360 rear main caps, not 318 this thread is about.
 
Last edited:
No, the outer portion of the cap is not critical other than for oil seal. The inner step is what set’s the journal shape. They don’t want the outer step to hit the rail before the inner seats. So its close but a gap is not tragic. That is sealed by rtv in the corners on the pan.
 
Then explain the difference in the gap in his block and the block in post #3.
 
Even the rope seal had separate little wings that weren't attached to the actual rope, iirc they need to be removed from the cap itself to make room for the wings of the new Fel-Pro style if that's what you picked up.
 
Sublime Swinger said:
Even the rope seal had separate little wings that weren't attached to the actual rope, iirc they need to be removed from the cap itself to make room for the wings of the new Fel-Pro style if that's what you picked up.
Click to expand...

I've built a good many Pontiac engines over the years and all they ever came with was rope seals. Never have I ever seen one with wings on it.
 
Sublime Swinger said:
View attachment 1715357543
Click to expand...

I understand that, but what we are seeing with his main cap is clearly being held from tightening all the way. The gap should be almost closed and it's not. There's something wrong.....whether it's the wings, or maybe he has a 360 seal in the 318. At any rate, it's leaking and he has to tear it back apart.
 
RustyRatRod said:
Then explain the difference in the gap in his block and the block in post #3.
Click to expand...

The one in the picture could have been aligned honed. You cut the mating surface of the caps, brings the outer surfaces closer than his are.
 
RustyRatRod said:
I understand that, but what we are seeing with his main cap is clearly being held from tightening all the way. The gap should be almost closed and it's not. There's something wrong.....whether it's the wings, or maybe he has a 360 seal in the 318. At any rate, it's leaking and he has to tear it back apart.
Click to expand...
What I had explained earlier was maybe the little wings from the previous install didn't get removed from the cap which would make the cap not seal correctly if he used this new style of seal. The pic I provided was a from a rear main on a 70 318LA I did about a month ago.
 
furrystump said:
The one in the picture could have been aligned honed. You cut the mating surface of the caps, brings the outer surfaces closer than his are.
Click to expand...

Entirely possible.
 
Sublime Swinger said:
What I had explained earlier was maybe the little wings from the previous install didn't get removed from the cap which would make the cap not seal correctly if he used this new style of seal. The pic I provided was a from a rear main on a 70 318LA I did about a month ago.
Click to expand...

Absolutely another possibility. No question he has "an issue" there of "some sort".
 
You must log in or register to reply here.
-

Back
Top