Small drip at new rear main seal- have it replaced, or wait?

[knuckleharley]

I think you do whatever it is to fix that leak because you are never going to be happy with the car if you don't.

 

If that means pulling the engine out and taking it back to the re-builder,that's what you need to do.

 

Although,if it were me,I  would remind the builder that newly rebuild engines are NOT supposed to leak oil,and that he should have paid to have it pulled because it was leaking due to HIS mistake,not yours.

 

I would also remind him that I was going to tell this to everybody I knew,and tell them you were the one who rebuilt it,and refused to pay to have your mistake corrected.

 

But,that's just me.

Edited October 4, 2020 by knuckleharley

['41 Fat Bottom Girl]

Will meet with the shop today or tomorrow to discuss and arrange the fix. 

The several drips from the front timing chain cover seal in itself isn't a big deal to me. From that, I would accept some drips in the drip pan. The rear main leak is another matter. It isn't likely to get better and there is too much leaking out. Almost 3 fl. ounces of oil every 500 miles is excessive IMHO. 

 I'm going fishing next week. It's time for a break.

Thanx to everybody for your experiences and opinions. You are all a great help on so many questions.

Motorheads forever!

[James_Douglas]

Like I said in my post above, my 251 has leaked and leaked. I have probably spent $500 on extra oil in 15 years due to the rear main bearing leak.

 

I will be looking at using the rope seal. I am even thinking of using a "plate" seal behind the rope seal as well. Although, I suspect that if the rope seals out all the oil, that the rear plate seal will burn the lip in short order with no oil on it. I may put a little lubricate behind the rope seal for the plate seal.

 

I have never seen nor heard of anyone using both. But, since they will both fit, I do not see how it could hurt anything and I have a couple of the NOS plate seals in any case.

 

James.

['41 Fat Bottom Girl]

The saga continues...Back from a week of fishing (heartily recommended- how peaceful getting away from the Covid circus and the TV so-called news!!!)

Met with the machine shop today and we discussed the oil leak at the rear main.

They believe that with a rope seal, the problem is likely because I am using the  Royal Purple 10w-30 Break In Oil .

With a 10w-30, they suggest that the molecular size is much less under heating and pressure than a straight 40W, more prone to leaking, and I should have stayed with the Valvoline VR1 40w Racing Oil through the break in period.

I am somewhat skeptical that this will reduce the leak substantially, but then, I am no expert.

I will drain it and refill with the VR1 40w and a new filter, and run it for a couple hundred miles (Maxi-pad wired up to rear main area as before) to measure the difference.

I will get back to the forum, if we find that is the fix, than it would be good for members to know to avoid Royal Purple Break In Oil if you have a rope seal.

If there is no substantial change, it is back to the shop- with a caveat- they say replacing the rear main seal won't guarantee it will be any better...oh, hooray. Good times. Grrrrr.

I will let all y'all know what I find.

Thanx 

[JBNeal]

I do not want to lecture about multi-viscosity oil characteristics or definitions, but ya might want to study up on the subject a little bit...the flathead was designed to run on SAE 30, so SAE 40 is a little thicker than that original design allowed.  Multi-viscosity oils do not thin out with heat as straight weight oils do, so it kinda sounds like them machinists might need to get their facts straight...10W-30 should not be too thin for a flathead, but should flow better than SAE 30 as ambient air temperatures drop below 50°F...

 

FWIW I recently crossed 5 counties to take a gander at a used diesel tractor for my neighbor, and found a few things that the green tractor sales gal neglected to mention when he called about it...dropped her jaw when I was able to kill the battery during a 15 minute operation test, which gave us some leverage when I pointed out the engine oil leak.  So the dealer agreed to put some green tractor mechanics on that red tractor to incentivize the sale, and they were able to correct the charging system problem but guessed that the oil leak was the oil pan gasket...that's a 3 day job that requires splitting the tractor (quoted as $3k repair bill) as that diesel engine oil pan is actually a casting that holds the front axle and transmission together...calling a red tractor mechanic, he pointed out that engine has a valve cover breather, that when clogged, would slightly pressurize the crankcase, causing oil to seep out of the crankshaft front seal, which was exactly what I was seeing (a 30 minute cleaning repair).  There was a drip on the oilpan, but no oil streaming underneath the tractor; there was caked on oil-soaked dust all under the crank pulley, but no oil slung onto any adjacent parts; and the engine and underhood only had dust on them...all signs that oil leak was very slow and not catastrophic. 

 

So back to my original opinion, if ya run the recommended oil viscosity, and keep the crankcase vented (or upgrade to PCV over the draft tube), then that oil leak may not be worth repairing when compared to just cleaning up after the leak and keeping the oil level topped off on a regular basis...

[RobertKB]

I kinda agree with the above post. I believe you are over thinking the problem.  I have a rebuilt engine in my 51 Dodge. Ever since I got it back it has leaked a bit of oil. I put a bit of cardboard under it. Cars back then tended to leak. If you want a leak proof engine then run a new vehicle. Just enjoy the old girl and live with a couple of flaws. There are lots of things in life more worthy of your concern.

['41 Fat Bottom Girl]

Thanx guys, but losing 3 ounces of oil every 500 miles on a just rebuilt engine? You know it isn't going to get better.

I have rebuilt a couple of flatties myself in the 70's and had seeping and drips, but this is a lot of oil. Right now the leak is a heck of a lot more than when I took it down for a rebuild at 90K miles. 

Sorry, something isn't right. I will see if the straight 40w makes a difference. To your points- if I can cut it down to half of that, I will live with it. 

I hear what you are saying, and please don't get me wrong- I do really appreciate all your experiences and suggestions.

I will let you know.

['41 Fat Bottom Girl]

Just FYI,

Per my shop manual for D-19, D-22 and D-24 it states SAE 20w for engine oil for summer driving above 32F.

And SAE 10w for first 1,000 miles on a new engine. So I have been well above those weights. 

I have had to wait 20 years to be able to justify the cost do this rebuild and for other engine parts, and I plan on driving it a lot.  All I want is what is usual and customary for the acceptable amount of leakage on a new seal. I don't think I am being unreasonable, I could certainly accept some oil in the drip pan and on the undercarriage. I've had a lot of old cars. This ain't my first barbecue.

Here is a good visual for what would be leaking from the new rear main seal every 500 miles. I suppose for some this would be OK, but I think it is excessive.

My regards, and my thanx to all.

[Sniper]

I don't buy into the "oil cars leak oil" with a freshly rebuilt engine regardless.

 

Betcha The Freewheeling Tony Smith's engines don't leak a drop.

[DJK]

14 hours ago, '41 Fat Bottom Girl said:

Just FYI,

Per my shop manual for D-19, D-22 and D-24 it states SAE 20w for engine oil for summer driving above 32F.

And SAE 10w for first 1,000 miles on a new engine. So I have been well above those weights. 

I have had to wait 20 years to be able to justify the cost do this rebuild and for other engine parts, and I plan on driving it a lot.  All I want is what is usual and customary for the acceptable amount of leakage on a new seal. I don't think I am being unreasonable, I could certainly accept some oil in the drip pan and on the undercarriage. I've had a lot of old cars. This ain't my first barbecue.

Here is a good visual for what would be leaking from the new rear main seal every 500 miles. I suppose for some this would be OK, but I think it is excessive.

My regards, and my thanx to all.

I am using 15-40 non-synthetic diesel oil and still have a leak with new rope seal. 

[knuckleharley]

12 hours ago, DJK said:

I am using 15-40 non-synthetic diesel oil and still have a leak with new rope seal. 

Similar to,but not identical.

 

I switched to15w-40 conventional diesel oil in my stock 51 Ford V-8 engine,ad went from 35 psi at ideal to 5 psi,and from 60 psi at 60 mph,to 40 psi at 60 MPH.

 

Only reason I tried this is it is getting harder to find and buy 30 and 40 wt non-detergent oil.

['41 Fat Bottom Girl]

The rebuilt engine saga continues...

The shop's direction to reduce the leak by using 40 w Valvoline VR1 instead of the Royal purple 10-30w that I previously had in the car didn't help ( I was skeptical, as some of you were). In my second test using the heavier weight oil, in 500 miles of driving I would lose 3 1/2 fl. oz. of 40w oil from the rear main seal. Below is a pic that gives a good visual. That's too much oil from a leak.

I also adjusted the tappets before I started this latest leak test because the engine was at 300 miles in the break-in period since their rebuild. I found that the locking nut on the tappet on #3 exhaust could be turned easily with no friction. My concern is it will not hold adjustment. How the assembler didn't notice that is beyond me. Also found that the tappets on cylinders #5 and #6 had been adjusted too tight from the shop- had to turn them 1 to 1-1/2 turns to get zero clearance before I adjusted them to .008" on the intakes and .011 on the exhausts (hot). I hope in the only 300 miles of driving I didn't burn a valve, but I will have them do a pressure test again to make sure the valves are seating OK.

I am going to pull the engine myself to get it back to them. I figure 1) out of the car, they will have a better chance of fixing the rear main. It is almost impossible to do it properly in the car- and 2) with the engine out, with their pulling the camshaft to fix the lifter they won't damage my radiator taking it out or drop anything on my fenders.

Why am I pulling it myself? With them taking 9 months to do the rebuild (last November to August this year), lying to me over the first 5 months about when the parts were actually ordered, moving the shop without letting me know (I showed up there one day in April to find out they were gone) I have kind of lost any trust in them doing repairs with the engine in the car.

But they do have a new manager now in their new location, and he does seem like a good guy- so I will give them an opportunity to get it right and if all OK, let bygones be bygones. I just want this engine to be right. I have another motor I want to do, but as you can probably guess it won't go to them!  

 

 

 

[James_Douglas]

Good luck with the oil leak. What kind of gets my goat up is that Best Gasket when asked what is the ID/OD shaft tolerance for their rear main seal told me they did not have one.

 

WTF?

 

ALL seal engineers design a seal either for an exact shaft size or a size range. The fact that when asked I got such a bull **** answer does not bode well for confidence in their sealing products.

 

Like I said above, in my case I has an NOS crankshaft. Checked by the crankshaft shop. It has leaked a lot since day one. I tried changing the seal two more times. It did not help.

 

Going forward, I will try a rope. However, it takes skill and time to do a rope seal correctly. If the folks that did your engine did not catch that the lifter adjusting nuts were not tight...then one would suspect that their Q&A on the real seal may not be up to the task.

 

James.

 

 

[rallyace]

I built my own 218 last year and discovered the following: regarding the tappets, I had one loosen up a bit and once broken in I needed to adjust all of them. I did them warm and have had no issues since. The valve train will seat in once the engine is run a bit causing them to go out of spec.  Regarding the oil leaks, I also found my rear seal was leaking a bit. I run 15-40 conventional diesel oil and found that over time the leak did diminish but not disappear. I am not sure what I was losing in the beginning but I now lose about a half a quart every 1,000 miles. I don't consider that to be excessive. One quick question, did you assure that your dipstick was reading correctly?  When I did my engine I found that the dipstick that came with the engine was reading such that I had to put in almost 6 quarts to get to the full mark. I drained the oil and added 5 quarts and found that one of my other dipsticks would read full at 5 quarts so I used that dipstick.  Too much oil will find leaks and the rear main is generally the weakest link and will leak the most. As long as your oil level is above the add mark you are good to go.

['41 Fat Bottom Girl]

Thanx for your thoughts guys, and for the dipstick question. I actually have checked that when filling the filter and engine. The stick seems OK- after draining a warm engine (to no dripping at the drain) and removing the filter and cleaning out the filter canister of all residual oil and residue, I add 5 quarts of oil to the crankcase and about 1/2 quart to the filter canister with the fresh filter installed. I always prime a new, dry filter. This brings me exactly to the running mark on the stick and after driving it and check it warm and giving it time for all the oil to settle back into the pan.

Great question though, I have experienced a dipstick lying before...

( BTW, no intentional slur on my idiot brother-in-law...)

[greg g]

Growing up I remember my father having three cars, 49 wayfarer, 54 Meadowbrook, and a 60 Dart.  Back then he did his own oil changes.  I do remember observing and assisting when a bit older.  He never put enough oil in to reach the full mark. He always ran the cars at Add, and said no when the gas station guy said it's down to add, do you want a quart. I asked why, he said that a bunch of engineers got paid a lot of money and decided that the engine would be fine at the add mark so the other half quart wasn't technically necessary.   I also remember having the garage cleaned out and set up as a bar for a family reunion and one of my uncle's wondering why there was no oily spot on the floor where the car was parked. He and my father then got into a discussion regarding the wisdom of dad's oil strategy.

 

When I notice my P15 oil gauge wavering around corners or under brisk acceleration, checking the dip stick will reveal it's just below add.  A pint will steady the needle for the next 800 to 900 miles.  On our Berkshire tour in Sept, we put on just over 500 miles, and oil was not a concern.  And yes the car does sit above absorbant pads in the garage that get changed 2x a summer.  I guess I have decided to live with it marking it's territory and not being shocked that a 74 year old vehicle sheds a bit of lubricant from a couple places.

['41 Fat Bottom Girl]

Cool! And, that helps explain on my '41 dipstick a 1/2 Full mark, a Running Level mark, and a Full mark. Did not understand any reasoning for it before. 

I have stayed around Running Level. A pretty sharp guy told me to do that many moons ago... Thanx for sending on the experiences you and your Dad have had.

 

 

['41 Fat Bottom Girl]

This is how it all ended up-

Problems solved! The shop that rebuilt the engine fixed them within a few weeks after I pulled the engine again. It ended up that the lip on the new rear main seal used in the rebuild was bad (it had the style pictured below) and the adjustment lock nut on the one of the new lifters was because of a bad part too. As not to have possible wear issues on the broken in newly-ground cam by putting in a new lifter, they just fixed the lock nut instead of replacing the whole lifter. Makes sense.

Next I will adjust the lifters again and it will run even better.

I felt bad for the machine shop- with the Covid crap last year their second assembler and a couple machinists wouldn't come back to work when the shop opened up again in April because they said with unemployment and the Covid bonus payments from the Government they didn't have to work. Such integrity...That put a hurt on the shop taking care of their customers while they looked for good people. Those guys have been replaced and the shop is doing great and able to take care of their customers in a timely fashion again. They sure did a great job on taking care of the issues I had.

FYI- I put 100 miles on the car and not a drop of oil from the rear main seal, so it can be done!

If I do get some seepage in the future I won't care. This was a HUGE improvement. I knew something was wrong.

Thanx to all of you for your help and advice.

Back on the road again and I am loving it!

Bruce

 

[Plymouthy Adams]

WAVE THAT BANNER ....LET THE GOOD TIMES ROLL

 

Edited February 16, 2021 by Plymouthy Adams

[DJK]

Great to hear of positive results. I am curious if your engine had a rope seal initially and a rubber seal is working fine. My engine is still at the machine shop!!!

['41 Fat Bottom Girl]

Hi DJK,

This is the style of rear seal in this 1941 218 engine (original to the car) rather than a rope type seal. 

I don't know what year these blocks changed over from the rope.

The back of the block and the bearing cap have the six threaded mounting holes, which I believe are not provided in engines  that came with the rope type seals, which had rope seal channels in the block and cap.

Pic below shows the back of the engine when it was pulled to have it rebuilt.

Good luck with your rebuild!

 

[DJK]

23 minutes ago, '41 Fat Bottom Girl said:

Hi DJK,

This is the style of rear seal in this 1941 218 engine (original to the car) rather than a rope type seal. 

I don't know what year these blocks changed over from the rope.

The back of the block and the bearing cap have the six threaded mounting holes, which I believe are not provided in engines  that came with the rope type seals, which had rope seal channels in the block and cap.

Pic below shows the back of the engine when it was pulled to have it rebuilt.

Good luck with your rebuild!

 

 Mine has a rope seal that sits in a groove of a retainer that attaches just like yours. According to Best Gaskets, there are three different seals for these engines: rope(fits in groove of retainer which is bolted to block and main cap, rubber seal like yours with retainer and a rubber seal that fits into a groove in block and rear main cap. So confusing!!!

[James_Douglas]

On 2/16/2021 at 3:03 PM, '41 Fat Bottom Girl said:

This is how it all ended up-

Problems solved! The shop that rebuilt the engine fixed them within a few weeks after I pulled the engine again. It ended up that the lip on the new rear main seal used in the rebuild was bad (it had the style pictured below) and the adjustment lock nut on the one of the new lifters was because of a bad part too. As not to have possible wear issues on the broken in newly-ground cam by putting in a new lifter, they just fixed the lock nut instead of replacing the whole lifter. Makes sense.

Next I will adjust the lifters again and it will run even better.

I felt bad for the machine shop- with the Covid crap last year their second assembler and a couple machinists wouldn't come back to work when the shop opened up again in April because they said with unemployment and the Covid bonus payments from the Government they didn't have to work. Such integrity...That put a hurt on the shop taking care of their customers while they looked for good people. Those guys have been replaced and the shop is doing great and able to take care of their customers in a timely fashion again. They sure did a great job on taking care of the issues I had.

FYI- I put 100 miles on the car and not a drop of oil from the rear main seal, so it can be done!

If I do get some seepage in the future I won't care. This was a HUGE improvement. I knew something was wrong.

Thanx to all of you for your help and advice.

Back on the road again and I am loving it!

Bruce

 

Can you go into more detail on the statement that the, " lip on the new rear main seal used in the rebuild was bad" ?

 

Bad How? Bad out of the box? Bad because they installed it incorrectly? ...

 

James

['41 Fat Bottom Girl]

Hi JD,

The seal lip on the bottom half-plate had a slight distortion that caused it not to be a perfect radius, kinda like it was bent over a bit, but not scuffed..  

Tiny bit of distortion. I do not know if this was a result of the way it was handled/ packaged by the manufacturer, or caused before or during assembly.

In addition to that, because I wasn't the one to disassemble it, I can't tell you if the "h" side pieces were installed correctly or not, or if the corners and butting surfaces were clean and sealed properly. The shop was pretty certain it was the bad part and this was an anomaly.

If you are going this route, if you inspect your seal wiping lip to make certain it is not damaged and installed and sealed properly, using a bit of grease on the seal lip and being careful not to get grease or oil where you need to seal it, you should be fine.

I now have 160+ miles on mine with city and freeway driving and I can't see a drop of oil. If it seeps a bit in future I won't care. Now I am very happy with that seal.

Good Luck! 

Motorheads forever!

[James_Douglas]

23 hours ago, '41 Fat Bottom Girl said:

Hi JD,

The seal lip on the bottom half-plate had a slight distortion that caused it not to be a perfect radius, kinda like it was bent over a bit, but not scuffed..  

Tiny bit of distortion. I do not know if this was a result of the way it was handled/ packaged by the manufacturer, or caused before or during assembly.

In addition to that, because I wasn't the one to disassemble it, I can't tell you if the "h" side pieces were installed correctly or not, or if the corners and butting surfaces were clean and sealed properly. The shop was pretty certain it was the bad part and this was an anomaly.

If you are going this route, if you inspect your seal wiping lip to make certain it is not damaged and installed and sealed properly, using a bit of grease on the seal lip and being careful not to get grease or oil where you need to seal it, you should be fine.

I now have 160+ miles on mine with city and freeway driving and I can't see a drop of oil. If it seeps a bit in future I won't care. Now I am very happy with that seal.

Good Luck! 

Motorheads forever!

Thanks for the update. I think I will do the rope WITH the plate seal on the back. I will assume that enough oil will get past the rope to keep the plate seal wet so it does not burn on a dry shaft...