Big oil loss on rear sid
 

Good evening everyone.


My Green Roadster has recently developed an oil drip problem. Within about 1,000 miles, the oil loss on the rear clutch side suddenly increased to more than 300 ml/0,6 pint on 100 miles, and the trend is increasing.



It's not dripping down the oil pan, but from the clutch bell housing bore = rear crankshaft bearing.


It's thick 60-weight oil, and I keep the oil level in the lower quarter of the dipstick.


If I've read and understood that correctly, it's due to a blockage in the oil return tube on the rear crankshaft bearing. However, that's unlikely, since I change the HD cleaning oil (API SC) every 1,000 miles and use an oil filter.


Does anyone have any other advice?
Thanks in advance!

Re: Big oil loss on rear sid
 

OK, here is my advice. Drop the pan and remove the rear bearing cap. Inspect for damage.

Re: Big oil loss on rear sid
 

To much crankshaft end play can also cause that.

Re: Big oil loss on rear sid
 

My car started leaking more oil a couple of years ago. When I inspected the rear main bearing I found the babbitt bearing had come apart and the thrust surface broke off and lying in the pan. Sounds like you have the same problem but I hope not.

https://live.staticflickr.com/972/41...eb50ebc4bf.jpg

Re: Big oil loss on rear sid
 

This is kind of what I found last year also, and that is what I expect Werner will find.

Drop the oil pan and see what you can see.

Re: Big oil loss on rear sid
 

Make sure your breather oil fill pipe is not restricted somehow which would cause crankcase pressure to build up and force oil out the rear bearing.

Re: Big oil loss on rear sid
 

The oil return tube on the rear bearing might be clogged, but it also may have broken off, which will cause a leak too (ask me how I know). You need to drop the pan and inspect the situation.

Re: Big oil loss on rear sid
 

DITTO.


1. Be sure that someone did not stuff a "pot cleaner" (green plastic or copper mesh) in breather cap on top of breather tube.

Water vapor collects in cap and mixes with combustion by products and then dries out to become a "gooey glue" which dries and plugs up breather. Then too much crankcase pressure then forces oil out rear main cap.

If plugged enough, 5 quarts of oil can be forced out rear main cap in about 70 miles of driving.

This has happened two times that I know about.

2. Anything which restricts air flow out of the breather tube will force oil out rear main cap.

3. Did someone install breather cap and slam cap down with their fist, which damages cap and blocks air flow? (that is bends tabs inside cap).

4. See Service bulletin 326 for photos

Re: Big oil loss on rear sid
 

Maybe 60 weight oil is too thick and does not drain fast enough?

try 20W-50

Re: Big oil loss on rear sid
 

Is "their" oil viscosity rating the same as ours. I don't know, just asking.

Re: Big oil loss on rear sid
 

Good question ... do not know either.

Re: Big oil loss on rear sid
 

Good evening Model A friends,
Thank you all for the initial advice. It's a pleasure to read them.


The oil used is labeled like International SAE Class 60, or SAE 20W-50.


Since I electrically preheat the engine before every start, the thick SAE 60 isn't the cause.


The crankcase breather is free-breathing; I have the attachment with a flexible pipe at the rear.


I'll remove the oil pan and try to figure out how to remove the rear main bearing. It's unlikely to be an easy task, as I've unfortunately become a bit unfit myself.

Re: Big oil loss on rear sid
 

Good luck. I use the 20W-50 oil too. It does not need to be warmed up as it behaves as 20 weight oil when cold.

I am a little unfit myself, mostly because of my advanced age. I found it easier to remove the engine and put in on an engine stand to work on the bearings while the engine is up side down.

My club will have technical days where we invite all the club members over to a member's house to analysis a problem and effect a fix. The host will supply food and drinks to the participants. This can be instructive for all involved and usually gets a problem fixed.

Re: Big oil loss on rear sid
 

Werner, I would remove the rear cap and check the clearance with plastic gauge (green) if you can get it. Another option is to use aluminum foil. A strip folded to about 3/8 x 2 inches (measures .002 of an inch thick) in the rear cap. Turn with hand crank just a little to see if it moves. It should not. It should hold with 2 strips and turn with 1 strip. Remove shims as needed. If the thrust is broken in the block check out Berts Model A Store on-line for a bronze rear main seal with thrust. Part # A-6336. Good Luck! Dan in Reno Nedada

Re: Big oil loss on rear sid
 

As I said in post 8, item #2 above any restriction in air flow will force oil out rear main.

There have been several versions of these devices made over the last 90 years.

Some are more restrictive than others.

55 years ago I had one installed which increased the amount of back pressure and leaked oil out rear main bearing. After removing "draft tube attachment", the leak was about 1/3 as much (2/3rds less)

Re: Big oil loss on rear sid
 

Good evening and thanks to all!


What please are the advantages of using a bronze main bearing oil seal compared to the aluminum version?


My problem is that Mikes Shop doesn't ship (the bronze version) to the EU/Germany. I can currently still easily get the aluminum version from MACs and probably also from Don Snyder. -




I checked the crankcase breather; it's completely free and clean, without any sludge. -




Regarding my comment above about oil viscosity: The term "weight" is an American expression and has never been used in Germany. "Weight 60" essentially means "heavy oil," which generally means "thick." The correct term is the international SAE designation, which refers to the standardized viscosity grades.
"Weight 60" does not directly correspond to SAE 60.

Re: Big oil loss on rear sid
 

I think you are going to find anything Model A related hard to get from MAC's.

Help me understand. You walk into an auto parts store and ask for "Heavy Oil" for your engine?

Re: Big oil loss on rear sid
 

Yes, it has become more difficult for end consumers to obtain US spare parts here. The customs and import declarations have become so complicated and extensive that many companies no longer want to deal with the considerable paperwork involved. -


Regarding the oil specifications:
No, it's the other way around.

I specify the SAE viscosity grade. For example, SAE 20W-50 (a multi-grade oil for summer and winter use). Or SAE 60, a thick, single-grade oil (for worn-out engines).


In addition, I specify the API class. For modern gasoline engines, this is, for example, API SM. For modern gasoline engines, this is, for example, API >SM. For classic cars, API SC is the best choice. It doesn't corrode non-ferrous metals like copper, bronze, or brass, and it's compatible with old rubber seals.
And yet, it still provides some wear protection, has corrosion protection, and also contains cleaning additives to prevent sludge and deposits.


From API SC upwards, these were known as "HD" oils, meaning Heavy Duty.



Beste Sommerwettergruesse!

Re: Big oil loss on rear sid
 

Time for black market Model A parts?

Re: Big oil loss on rear sid
 

Autsch!





At all, what please are the advantages of using a bronze main bearing oil seal compared to the aluminum version?

Re: Big oil loss on rear sid
 

In general Bronze will wear better, but Aluminum is good for many miles. It really depends on the alloys used for the Bronze and Aluminum.

Re: Big oil loss on rear sid
 

Werner, The advantage of a bronze bearing seal is that it has a thrust shoulder. If the thrust on the rear main is broken or cracked the aluminum seal can be replaced with the bronze seal and help prevent crank forward movement. The bronze is stronger than the type 11 babbitt I use. When doing a complete babbitt job I use them to take the stress of the other 3 thrust shoulders. I have successfully used them as a partial fix when a club member wants to keep his car on the road. Dan

Re: Big oil loss on rear sid
 

"Bronze Rear Main Thrust Washer- USA made. Replaces the A6335 rear main seal. Gives the engine a better rear main thrust surface." dansluck, how do you even install that thing? Can he do it with the motor in the car?

Re: Big oil loss on rear sid
 

Yes, that would be very interesting to me as well. I found this video:
https://www.youtube.com/watch?v=8MH3HtTnshQ.

According to it, the installation only requires to remove the oil pan. If I understand correctly, that's related to the crescent-shaped sealing washer too.


Dankeschön!

Re: Big oil loss on rear sid
 

Did you remember the gasket between the block and the flywheel housing?

Charlie Stephens

Re: Big oil loss on rear sid
 

The oil isn't dripping along the oil pan, but only from the clutch housing. -






Has anyone ever done this repair from underneath with the engine still installed?

Re: Big oil loss on rear sid
 

I agree that if missing or gasket is damaged that this gasket will leak from bottom of flywheel housing AKA "clutch housing".

Re: Big oil loss on rear sid
 

Benson,


thanks, but I can not open the attachment.

Re: Big oil loss on rear sid
 

I had the leak between the flywheel housing and block that has been talked about. The only cure was to take the engine out, use a different flywheel housing that was flat, and put the gasket in with plenty of gasket cement. The oil was dripping from the bottom of the flywheel housing. In my case I had to take the exhaust manifold off to see the leak.

Re: Big oil loss on rear sid
 

Sometimes it helps to put fluorescent dye in the oil (or coolant) to trace a leak. You can see the leak with an ultraviolet light and trace it to it's source.

Re: Big oil loss on rear sid
 

So what did you do to fix the Babbitted main cap? I am faced with a rear main cap almost the same. I’m hoping I can get a shop that can repour my lower cap half and mill it, fingers crossed!

Re: Big oil loss on rear sid
 

Since I planned on keeping this car and touring, I decided to pull the engine and have it completely rebuilt with inserts installed at the advice of my machinist because I don't want any (hopefully) issues down the road.

Re: Big oil loss on rear sid
 

I haven't done this work yet. I've been a bit ill and can't lie under the car for long periods of time.
But I took an oil sample, and spectral analysis didn't reveal any noticeably increased metal abrasion.

Re: Big oil loss on rear sid
 

When the bearing comes apart in chunks, like mine did, it may not show any metal abrasion!

Re: Big oil loss on rear sid
 

Hallo und guten Abend.


I've only made a little progress. The two nuts on the rear bearing cap are so tight that I can't loosen them.





https://www.fordbarn.com/forum/attac...1&d=1761943314



I'll have to try it again with an impact wrench tomorrow. In the oil pan, I only found a little steel shaving, 3 x 2 mm and 0.05 mm thick.




However, the aluminum camshaft gear was rubbing against the cork gasket that protrudes on the inside. Since the oil pan and filter screen were clean, the sludge is in the oil filter.



https://www.fordbarn.com/forum/attac...1&d=1761943555

A note for those who insist on using unalloyed motor oil: The picture shows how clean the oil pan and the intermediate plate are. They were only degreased with brake cleaner. I use exclusively 20W-50 HD Oil classified API SC.


https://www.fordbarn.com/forum/attac...1&d=1761943664


Bis morgen, beste Oelfinger Gruesse!

Re: Big oil loss on rear sid
 

Please don't use that blue silicone gasket sealer. I have seen way too many expensive engines ruined because of it. Although the Model A engine does not have a lot of oil passages, it does tend to plug things up.

Re: Big oil loss on rear sid
 

I agree.

Same problem with the orange silicone gasket sealer!

More that a few times I have seen it plug up oil drain passages and oil drain pipe in rear main bearing caps especially when too much was used.

Pieces of the silicone break loose and flow down passages and plug them up.

Re: Big oil loss on rear sid
 

Yes well, thanks for the important/helpful information. That's thick "Hylomar H" what I use. It was also called "Rolls Royce Paste" 50 years ago. It stays soft.


What recommendations do you have, please?


Dankeschoen!

Re: Big oil loss on rear sid
 

Werner , put a piece of pipe on your tool to break it loose https://youtu.be/8MH3HtTnshQ?si=5Cu0E0l7BJ8JgZsJ

Re: Big oil loss on rear sid
 

I‘ve seen people applying it with a roller, so you only have a very thin layer and any additional amount can be cut-off prior to putting everything together again…

Bitte sehr…