The Stovebolt Site Forums The Shop Area Engine Shop From a Drip to a Drain, on the budget!

I know what the answer is before I even ask it, but I’m hoping someone will tell me that its normal and to just keep driving her the way I have been and its gonna go away, NOT!

I’ve put 500 miles on her so far since I first bought my ’50, 3604 and finished the valve job and the other mechanicals so she’s safe to drive on the highway. Compression is 130 across the board and she runs a nice as can be, just the normal tappet noises and what you would expect to hear from the crankcase vents on an old engine. I get her all wiped down so she looked real purty and take her out for a little exercise and I gotta wipe her down again when we get back home. Like most of them are supposed to do, she’s got a little drip problem, but, maybe a little more than normal!

I’ve got no smoke at all, none on acceleration, none at throttle off, none on start up, no smoke at all. Plugs are burning real purty also. At the VC and side cover it’s a little moist, just a little, not enough to even speak about, more like a little mist from the breather.
But the pan, now that’s another story. That’s where the Depends comes in to the picture.
Oil drippin’ from the pan, oil drippin’ from the fly wheel cover, oil drippin from the bottom of the transmission. How much earl ya leakin’, bout a quart every 100miles he says. Now that’s way to much and I was wondering if any O’ you guys are getting that kind of oil mileage out of your 216’s? What I don’t want to here is CHANGE YOUR REAR MAIN SEAL DUMMY!!! But I think that’s what’s next at this point.

How many problems am I gonna encounter dropping the pan? The crank has to be dropped some to get the new upper rope in, does this mean that the trans and all has to be pulled back to do that? The reason I’m so hesitant about dropping the pan is that once I get into it, due to my character, I’m gonna start thinking why not just new bearings, and then while I’m in there, why not just rebuild the oil pump, and if I gotta pull the trans back it might be a good time to drop it and rebuild it, I’m this far so I should probably change the clutch and have the flywheel ground. Ya know, I might just be better off pulling the darn engine and have the short block rebuilt now instead of later! Boy do I hate to think about stopping that leak!!!!!
Denny Graham
Sandwich, IL

Well, my truck spits a little oil from all of the places you have mentioned but it takes me about 5 years to 'loose' a quart of engine oil and about 2 cups of tranny oil per year because of lousy torque tube seal. I think you do know the answer Denny and you know you won't rest until you pull 'er down. I think it's about time for me to replace main seals on my truck and am not looking forward to that. Shoot, maybe I'll just wait until the garage floor becomes a persistent mess then I'll just rebuild.

read my request for help on these darn seals

You said you know the answer and I'm sure you do. So just determine to do that and put all that other junk out of your mind. You said it runs great so it doesn't need that other stuff. JUST SAY NO.

That is the only way your ever going to get ahead of the game.

Yeah Denny, you could just say NO and keep wiping it down after each run. But I believe your such a perfectionist you won't be satisfied until you rebuild that engine.
Just say YES and get er done.

I usually replace the rope seals with the neoprene lip seals. I put them in a little off center so the seals seam doesn't line up with the main cap seam. You won't have to drop the crank that way, I just turn the crank while pushing the seal into place, letting the crank pull it into it's groove.

If you're dead set on using a rope, pre-form the block side using the main cap. Stuff it into the cap until it takes the shape. Also, buy a couple of extras so when you trash one you still have parts on hand,
Scott

Denny:
The pan will be an easy drop, while in you can inspect and fit the shims on the rods to the proper clearance if there is wear, the beauth of babbitt,

The rear main, I have heard that the upper can be left alone and only the lower cap portion be changed and see if this helps, I have a best gasket rear main for you to feel and will bring the same when I venture out to Sandwich. In just a few hours, you could have the job done and see if it solves the problem, the lower is the weak part of the seal and under most hydro pressure.

Paull Gossett

As mentioned the pan is not hard to drop. Pull the rear main cap and just do it!! The last time I did this was a 50 model several years ago. I think I still have the little "rope gizmo" which I called a "chinese rope".. You put the gasket in on end of it and put it around the crank, attach the little "T" handle and pull. The harder you have to pull the tighter it gets on the end of the seal. I figure most of you have seen or used these.
I might caution that if you cut the rope seal to SHORT you will definitely still have an oil leak. Once I got that fixed the other "dripping spots" went away. Seemed it was blowing back on the tranny and other places. Good luck Denny!

You might want to read the thread at Inliners and oldgmctrucks.com about the 270/302 rear main seal issues.

I'm pretty sure you are going to be unhappy with the neoprene unless you polish the crankshaft seal area before you install it- rope and neoprene wear the seal area a bit different and neoprene wants a nice polished surface to ride against or it wears out fast.

Denny ,
heres a simple answer too all your ?'s ..
if ya thought abought it ya prob. should just do it ..
ya thought abought the probs...so they are things that eventually will need adressed so they are future probs that you are
goin to have to deal with
Just do it once an be done .
just my 2 pennies

Yaaaa, I'm kinda funnin with ya guys here. I do have this tendency of going to far with somethings. Kind of like a domino effect ya know, one thing leads to another and so on.
Mostly I was wonderin if the pan would clear the tie rod and axle, it looks like it but I’m looking at it with the weight on the wheels, if jack up the frame I’m sure it will clear.

I’ve never change the rope with the engine in the frame, I have, put a lot of them in with the crank out of the engines on the bench. I can recall when I was a Chevy parts man hearing a lot of cussing from the line mechanics when they had to change rear main seals. Pulling the new one in doesn’t worry me all that much, getting the old upper out was always a problem, that’s the one I’m concerned about and that was why I was questioning whether I needed to drop the crank. Driving the upper seal round I can envision it getting tighter and tighter, the rivet effect. (lots O’ effects happening here)

If I changed the lower I surely would change the upper. It would seem logical that there would be more potential for leakage at the lower half of the seal but I’m sure the upper half is contributing to the drip also. I’m not real sure that there is a neoprene seal for the 216. I thought that I had read somewhere that they were not available. It’s a mute point anyway, cuz I’m putting in the rope seal for just those reasons that were mentioned. Covers More area and defects!!!
I probably would tighten up the rods while in there, wouldn’t hurt no matter what shape they are in and just might help quiet her down for the rest of the summer. I’m planning a complete rebuild of the short block this winter when I’ll fit the rods up with inserts, and planning to replace those cast Iron **** ons with alum then also.
That’s why Munk, the tranny also need a diaper, there is so much earl blowing back that every thing aft of the rear main is dripping wet. I’m very surprised that I’m not getting clutch chatter, I’m sure as bad as this is leaking that the clutch is saturated.
Denny Graham
Sandwich, IL

Denny,
you are right about troubles getting the old one out. I tried that with mine and I couldn't budge it. After dropping the crank it came out without a problem. My new seal is the new non-asbestos type and it works perfectly. Apparently you can remove the tranny, the front cover and then lower the crank while it hangs by the rods. This gives room to do the job, so I am told.

Fred

Just reading an article that Bob Adler did from 1998 that ran on the Chevytrucks.org site entitled "Bob Adler on rear main seals".
According to him and fel-pro if ya drop the crank even the slightest amount your gonna have a leak at the front seal. I taint about to take the whole front of the engine apart at this time to replace the front seal, so that's out. He doesn't specifically address the upper half of the seal, only installing the bottom half rope.
I'm now thinking about just pulling the pan and rear main cap and that should take care of 90% of the leak. Maybe that will improve the oil mileage enough for me to get 500 miles to a quart.
www.chevytrucks.org/tech/bobadler-1.htm
Denny Graham
Sandwich, IL

Denny, if you're going to do the short block this winter, then I'd just change the lower half of the seal. That should stop quite a bit of the leaking, and buy you time until the rebuild.

Denny,
according to one of the oldtimers, the usual treatment would be to replace the bottom half and also adjust the clearance in the rear main. I guess the theory was that excess clearance would enhance the leak.

Fred

Denny?
I have an extra best rear main for the 248 bmc, I am not sure if it exchanges with the 216 but It is a much better quality than what Victor supplied. As long as the channel profile in the cap is the same, the seal will work. I would cut it a little long and glue the ends. This Best seal fells more like the dogturd rope that was oem. I understand that they took the asbestos out and it has been hard to do as well without it. Langdon has the dogturd type, he may well just supply Bests himself.

Set me know, I'll send it.

Pgossett
See if it is the same part if so, I will send it to you to evaluate and use. I would also cut it a little long

Denny?
I have an extra best rear main for the 248 bmc, I am not sure if it exchanges with the 216 but It is a much better quality than what Victor supplied. As long as the channel profile in the cap is the same, the seal will work. I would cut it a little long and glue the ends. This Best seal fells more like the dogturd rope that was oem. I understand that they took the asbestos out and it has been hard to do as well without it. Langdon has the dogturd type, he may well just supply Bests himself.

Set me know, I'll send it.

Pgossett
See if it is the same part if so, I will send it to you to evaluate and use. I would also cut it a little long

Thanks Paull, sent ya an email.

Denny G
Sandwich, IL

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