Rope rear oil seal

[Synchro909]

I have a diamond B engine which came to me with a damaged oil slinger on the back of the crankshaft. When I had it rebuilt, they did what they could with it but it leaks terribly. I have been told that grinding off the slinger and using a rope seal from a 350 Chev engine (?) is an option.
Before I pull the motor out of the car, strip it etc, I'd like to know all I can learn about it.
Do I have the right engine - 350 Chev?
Is there any machining required and if so, what is it?
What can I expect afterwards?
Anything else I should know before trying to find a seal?
GM has all but left this country but I think I will be able to come up with a seal. I don't want to get this wrong so any help/advice will be very much appreciated.

[Terry Burtz, Calif]

The 350 Chevy engine has never used a rope seal.

Rope seals have been obsolete for about 60 years.

You can use a Chevy 2-piece seal, but you need to add weld to increase the diameter where the seal rides and then machine it for the seal.

Welding can cause distortion that is hard to correct.

You had a similar problem in 2018 with a different Model B engine that did not have a leak until you changed the rear main seal without following the installation instructions.

That leak was not your problem because you had no installation instructions.

The following is your post from 2018.


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Default Re: Burtz seal question
To broaden this thread, I have the same situation and same problem with a B motor. It is so bad, I made a janitor for it so it doesn't leave a puddle of oil where ever I stop. My situation is the same right down to replacing the seal and somehow creating a leak. What is the recommendation of the forum (for both of us)?
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Old 04-10-2018, 08:36 PM #10
Terry Burtz, Calif
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Default Re: Burtz seal question
To broaden this thread, I have the same situation and same problem with a B motor. It is so bad, I made a janitor for it so it doesn't leave a puddle of oil where ever I stop. My situation is the same right down to replacing the seal and somehow creating a leak. What is the recommendation of the forum (for both of us)?

Synchro909,
If you replaced the seal and somehow created a leak (your words), I would believe that your machine work is within tolerance, and the problem is with installation. Did you follow the instructions and pressure test the seal before installing the oil pan?



The Model B instructions are pasted below:

1) Two seals are supplied. The larger seal fits into the groove of the rear main cap (B-6327), and the smaller seal fits into the groove of the block insert (B-6335). The smaller seal will not fit properly in a poorly made reproduction block insert.
2) If desired, a replacement block insert with a groove identical to rear main cap groove can be made or purchased. In this case, discard the smaller seal and upon assembly, lubricate and carefully slip the seal over the flywheel mounting flange. A plastic sandwich bag placed over the flange will protect the seal from damage due to small burrs.
3) Thoroughly clean the grooves in the rear main bearing cap (B-6327) and block insert (B-6335) to remove all traces of dirt and oil, which may interfere with proper seal installation and sealant adhesion. Also, make sure rear main cap drain pipe is clear
4) Seat each seal with lip pointing towards front of engine (see figure) into its respective groove, and trim the ends slightly long to provide “crush” at the mating surface. A single edge razor blade and stationary disk sander work well for trimming and squaring the ends. Cut the pieces to be used long, and experiment with trimming and squaring operations on the cut off pieces.
5) Without the crankshaft in place, assemble the seal with its lip facing towards front of engine, shims, block insert, and rear main cap to the engine. Check to be sure the seal fits properly in its grooves, and is not distorted or offset relative to the rear main bearing.
6) Machine the rear slinger area of crankshaft as shown in the figure. Finished diameter shall be between 2.330 in. and 2.370 in., and concentric with the rear main journal within .001 in. to prevent whipping of the seal lip outward. Machine crankshaft to largest diameter between limits consistent with cleanup. Polish seal contact area of crankshaft to a bright smooth finish. Main bearing clearance must be between .0010 in. and .0015 in. to keep the crankshaft from whipping the seal lip outward. On final assembly, apply either an RTV silicone adhesive or Permatex #2 sparingly to both grooves and all mating surfaces where shims, rear main cap, block insert, and block meet. Avoid getting adhesive on seal lip. Also apply sealant to rear main bolts.
7) Before installing oil pan, and after adhesive has cured, test seal and rear main cap area for leakage by pressurizing the rear main cap drain pipe with motor oil to 10 psi and check for leaks.
8) If a Model B engine that has been modified to provide pressure to the connecting rods (drilled crankshaft) is using this seal, an additional oil pressure check should be done by pressurizing the rear main bearing groove that supplies connecting rod #4 to the anticipated pressure (50 psi?). If a leak occurs, it will usually be between the groove in the rear main bearing feeding rod #4 and either thru the shims or up or down the rear main bolts.



To use a one-piece seal, the replacement block insert with a groove identical to the groove in the rear main cap is manufactured by Dan Price. This part is recommended for high output engines.
http://www.dan4banger.com

Baypac is correct that the seal does not see much pressure. If the drain pipe is not obstructed, the seal is only subjected to slightly more than crankcase pressure.

Terry Burtz
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Old 04-10-2018, 11:18 PM #11
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Smile Re: Burtz seal question
Quote:
Originally Posted by Terry Burtz, Calif View Post
To broaden this thread, I have the same situation and same problem with a B motor. It is so bad, I made a janitor for it so it doesn't leave a puddle of oil where ever I stop. My situation is the same right down to replacing the seal and somehow creating a leak. What is the recommendation of the forum (for both of us)?

Synchro909,
If you replaced the seal and somehow created a leak (your words), I would believe that your machine work is within tolerance, and the problem is with installation. Did you follow the instructions and pressure test the seal before installing the oil pan?



The Model B instructions are pasted below:

1) Two seals are supplied. The larger seal fits into the groove of the rear main cap (B-6327), and the smaller seal fits into the groove of the block insert (B-6335). The smaller seal will not fit properly in a poorly made reproduction block insert.
2) If desired, a replacement block insert with a groove identical to rear main cap groove can be made or purchased. In this case, discard the smaller seal and upon assembly, lubricate and carefully slip the seal over the flywheel mounting flange. A plastic sandwich bag placed over the flange will protect the seal from damage due to small burrs.
3) Thoroughly clean the grooves in the rear main bearing cap (B-6327) and block insert (B-6335) to remove all traces of dirt and oil, which may interfere with proper seal installation and sealant adhesion. Also, make sure rear main cap drain pipe is clear
4) Seat each seal with lip pointing towards front of engine (see figure) into its respective groove, and trim the ends slightly long to provide “crush” at the mating surface. A single edge razor blade and stationary disk sander work well for trimming and squaring the ends. Cut the pieces to be used long, and experiment with trimming and squaring operations on the cut off pieces.
5) Without the crankshaft in place, assemble the seal with its lip facing towards front of engine, shims, block insert, and rear main cap to the engine. Check to be sure the seal fits properly in its grooves, and is not distorted or offset relative to the rear main bearing.
6) Machine the rear slinger area of crankshaft as shown in the figure. Finished diameter shall be between 2.330 in. and 2.370 in., and concentric with the rear main journal within .001 in. to prevent whipping of the seal lip outward. Machine crankshaft to largest diameter between limits consistent with cleanup. Polish seal contact area of crankshaft to a bright smooth finish. Main bearing clearance must be between .0010 in. and .0015 in. to keep the crankshaft from whipping the seal lip outward. On final assembly, apply either an RTV silicone adhesive or Permatex #2 sparingly to both grooves and all mating surfaces where shims, rear main cap, block insert, and block meet. Avoid getting adhesive on seal lip. Also apply sealant to rear main bolts.
7) Before installing oil pan, and after adhesive has cured, test seal and rear main cap area for leakage by pressurizing the rear main cap drain pipe with motor oil to 10 psi and check for leaks.
8) If a Model B engine that has been modified to provide pressure to the connecting rods (drilled crankshaft) is using this seal, an additional oil pressure check should be done by pressurizing the rear main bearing groove that supplies connecting rod #4 to the anticipated pressure (50 psi?). If a leak occurs, it will usually be between the groove in the rear main bearing feeding rod #4 and either thru the shims or up or down the rear main bolts.



To use a one-piece seal, the replacement block insert with a groove identical to the groove in the rear main cap is manufactured by Dan Price. This part is recommended for high output engines.
http://www.dan4banger.com

Baypac is correct that the seal does not see much pressure. If the drain pipe is not obstructed, the seal is only subjected to slightly more than crankcase pressure.

Terry Burtz


Hey Terry,
Good to hear from you and learn that you are still among us !!
I've had your rear seal creation on a new B crank that Dan made many years ago. Never a drop has leaked yet ! And, I run a 45 lb custom Stipe pump, and run it hard.
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Old 04-11-2018, 04:32 AM #12
Synchro909
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Default Re: Burtz seal question
Terry, I won't quote the whole thing again but respond direct.
There were no instructions came with the seal and I accept the problem is probably with the installation. I did what seemed to be the right thing and no, I didn't test it for the same reason. Are those one piece seals still available? That's what I have. If not, I think I have worked out a way of replacing the slinger (or I could just leave the janitor on it)
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Old 04-11-2018, 07:12 PM #13
Terry Burtz, Calif
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Default Re: Burtz seal question
Synchro909, the Model B seal has been in production since 1976.
They are available from nearly all of the Model A parts dealers, and all come with instructions. The package contains 2 seals (different x-sections) instructions and figure.
If you want a one piece seal, make sure that you have the part from Dan Price.
If possible, contact the person that installed the previous seal that didn't leak.
Regarding the slinger, avoid welding in this area as it will cause warpage that cannot be fixed by machining.
Terry Burtz
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Old 04-11-2018, 08:58 PM #14
Synchro909
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Default Re: Burtz seal question
Terry, My seal came loose with no instructions, as I said and I'm starting to wish the supplier (I can't remember which one it was) hadn't done that. Who knows, I may have been sent one that someone else returned so who knows what condition it was in before I started. It may have been damaged beyond being able to work even before I got it.
I might be well advised to buy another seal for when (if) the motor is out again. It will do no harm on the shelf.
Thanks for your input.
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[Synchro909]

Originally Posted by Terry Burtz, Calif

The 350 Chevy engine has never used a rope seal.

Rope seals have been obsolete for about 60 years.

Thanks for that, Terry. I was a little surprised when I heard they used a rope seal - it didn't sound right. Assuming the journal size is the same as the B engine, what did they use and can it be grafted in? What are my options?
I have heard of somebody over there who can replace slingers that have been damaged or removed from A engines but he won't give any details that might allow me to fix this B engine.
With bores only 0.040 oversize and main bearings 0.010 undersized, this is a very good motor but for this one thing. I'd like to save it if I can. Ideas please?

[Zoom]

Synchro,
I know at one time some rebuilders were machining the slinger down (but not completely off) and using the rope seal that fit a 1950 era Chevy 216 inline six on Model A engines. I don't know if that info helps but from your description I think that might be the method you have been told about.

[Synchro909]

Originally Posted by Zoom

Synchro,
I know at one time some rebuilders were machining the slinger down (but not completely off) and using the rope seal that fit a 1950 era Chevy 216 inline six on Model A engines. I don't know if that info helps but from your description I think that might be the method you have been told about.

Thanks, Zoom. That does sound like it was what was meant. How readily available are those seals over there? Once I have one in my hand, I and my machinist should be able to work out how to fit it into the Ford engine. No Chevs have been sold here since 1948 at least.
I'll make some enquiries about finding one here but I'm not holding my breath.

[Zoom]

Sponsored Links (Register now to hide all advertisements)

Most of the parts houses can get them in a day or two so they are available here.

[CT Jack]

I would like to share a personal experience that you might want to investigate relative to your rear main oil leak problem. When I had my 31 engine rebuilt by J&M Rebuilders Southborough, MA, the rear main end cap area began to indicate severe leaking during the initial break in sequence. Under normal conditions we all know our engines leak oil primarily in the area around the rear main end cap. J&M and myself mutually agreed the engine should be returned to them for a complete check of all clearances, fits, and possible seal related issues. Their in-depth teardown investigation revealed that the bell housing surface that mates to the rear surface of the engine block was .020" out-of-flatness. The paper gasket used to seal between the mating surfaces was too thin to seal and caused oil to leak down the back surface of the block and flood the area around the rear end cap. This condition gave the false appearance that the end cap had a serious leak.
The cam in a Model A engine is supported by holes bored into the block. The rear support is a through hole without a seal. If the seal between the bell housing and the engine block is malfunctions then oil from the cam can leak down between the mating surfaces. J&M removed the bell housing and had the mounting surface machine ground to remove the .020" surface variation eliminated. Problem solved, no more leaking.

[Jim Brierley]

Most 40's and 50's cars used rope seals. I'd ask your local engine rebuilder if they have some, maybe just laying around? You can also use graphite impregnated rope available at many hardware stores, usually on a roll. I've used such a seal on B engines, with no alteration to the crank or slinger. I bent 3/16" copper tubing to lay inside the slinger and or cap (?) to support the rope. The rope must fit tight against the crank and slinger & cap, tight enough to make the engine a little difficult to turn by hand. I soak the rope in oil before final installation. Good luck!

[Synchro909]

Zoom, Those seals being available over there doesn't surprise me but it is not possible to have one posted here. USPS don't deliver.

CT Jack, This being a B engine, the camshaft bearings are pressure fed so a leak from the rear cam bearing is a real possibility. IMO, it would be easy for the flywheel housing to distort enough that it didn't retain the ability to seal at that location. I wondered about putting in an "O" ring and drilling a small hole from behind the camshaft back into the crankcase to relieve the pressure

Jim, Your comment is very interesting but my engine has no slinger. Do you think your method would work in it? Is the graphite impregnated rope you refer to the same as what is used in the water pump? I wondered about giving it a good coat of Teflon before assembly rather than oil. I imagine I would want no more than 0.001 clearance in the rear main bearing for the rope seal.

The ideal solution would be to find another crankshaft that still has the slinger, have it ground to suit (mains are only 0.010" under), and drill for pressure feed to the rod journals like the current one but the chances of finding one here are zero to none.

[updraught]

Auto Surplus here have all sorts of stuff since they took over Vanguards years ago.
https://www.autosurplus.com.au/chevr...5-261-6-cylind

[katy]

Synchro909, can buy the chev seal here for ~$30 cdn, and mail to you if you're interested.

[Synchro909]

Thank you to both Updraught and Katy. I'll try the local supplier first because of the time factor. I had a parcel posted from Canada back in March and I'm still waiting for it.
I think (hope) I am in with a chance with a rope seal.

[Bruce of MN]

Did Holdens have that same Chevy (or close enough) engine?

[Y-Blockhead]

Not sure which engines were available to you but the rear main seal for Ford Y-Blocks (239"-312") from 1953 to 1964 had a rope seal that may work for you. There were V-Blocks in Australia. I think I may have some I could send you but you say you don't get postage from US?

[katy]

Will any of those "rope seals" fit and work in a stock Model A engine w/the original slinger?

[Synchro909]

Originally Posted by katy

Will any of those "rope seals" fit and work in a stock Model A engine w/the original slinger?

I am talking about a B engine but have been wondering the same thing. Is there any machining required to the block and or cap to take the rope seal when the the slinger is no longer there?

[Synchro909]

Originally Posted by Bruce of MN

Did Holdens have that same Chevy (or close enough) engine?

I don't know but I will be asking around. What capacity was the Y block.

[Oldcarbearings]

Arnold we (OLDCARBEARINGS) more than likely have both a listing on Chevrolet 216 crankshaft rear/rear main oilseal in our automotive application catalogs&on the shelf,
We do have both a listing&part number for chevrolet 350 crankshaft rear/rear main oil seal,
Regards&thanks,
Adrian.

[katy]

Originally Posted by Synchro909

What capacity was the Y block.

https://en.wikipedia.org/wiki/Ford_Y-block_engine

[Synchro909]

Originally Posted by katy

https://en.wikipedia.org/wiki/Ford_Y-block_engine

Thanks, Katy.
It was Ford's replacement for the old side valve engine. I remember them coming on the market.