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I'm going to pull the motor on my '66 S Type to fix leaks and check to make sure everything is in good shape. There are so many leaks that I'm sure that the rear main needs to be replaced and want to get a collective idea on wether to use an original type rope seal or go the the upgraded modern type seals which includes machining the crank. I know there is a thread in which both seals have been used but I'd like to get some first hand experience from those who have replaced theirs on how both the old and new type seals are working.
If you are going this far I would machine the scroll off the crank to a 3" IIRC diameter and fit an SKF Flexseal. There is a thread on the subject. I will see if I can find it for you.
This thread gives you all the right connections for the kit. Read from post No 11 on Rob Beere in Coventry
To answer your question directly.~ If I had the option today I would use the SKF seal as used by Rob Beere.
I still have the rope seal in my newly rebuilt engine (not fully run in yet). The SKF seal was not available when we built my motor years ago but if you read my thread in my signature you will understand my delay ~ long expat assignment. I had all the necessary Churchill tools for the job. The secret is NEVER to trim the rope seal. Continue to work the seal with a wooden hammer handle or similar into the groove & finally use the Churchill sizing & centering tool. My seal is bone dry. Zero leaks. The seal must be kept wet with oil & the car used or started regularly.
Last edited by Glyn M Ruck; Apr 7, 2023 at 06:23 PM.
The Rob Beere seal as Glyn says or the cheap and very dirty solution of fit an oil catcher and drain. I think some early, scroll only engines had the latter arrangement. I would not have my crankshaft machined for any of the so called upgrade seals other than that from Rob Beere.
Before removing the engine, there are some simple things to check. Leaks can be exacerbated if the sump is overfilled, perhaps due the wrong dipstick, or if there is pressure in the crankcase due the ventilation to the plenum being blocked.
Interesting diagnosis with the ventilation plenum. One of the worst leaks on the engine is on the left side at the junction of the head and timing chain cover. Once the engine is warm oil drips out of that spot in a steady stream. I'm going to pull the engine regardless to paint the engine bay and install a new Wiring Harness.
Presume you are not getting any coolant in your oil? Timing chain covers can corrode through behind the water pump. Sounds like the head must come off anyway. Someone might have shaved the block & forgot about doing the same to the timing cover/chaincase.
Last edited by Glyn M Ruck; Apr 8, 2023 at 12:55 AM.
Interesting diagnosis with the ventilation plenum. One of the worst leaks on the engine is on the left side at the junction of the head and timing chain cover. Once the engine is warm oil drips out of that spot in a steady stream. I'm going to pull the engine regardless to paint the engine bay and install a new Wiring Harness.
I put a baffle in that area on the inside.
The chain goes flying by that area slinging a steady stream of oil right at that joint.
Pulled the engine on Easter Sunday. What a beast to get out! First impressions are that someone had previously pulled the engine to do some work. Every single bolt that held it in place was barely tightened. Nothing was torqued to spec. A lot of oil coming out from between the head and cylinder block at the rear of the engine as well. Hoping that the head isn't warped since the previous owner installed an aluminum radiator. My fear is that at some point it overheated.
We had to cut the exhaust to get it out.
A lot more will be learned when the head is removed.
Before taking the head off and before cleaning the oil away, have a good look for where it's coming out. In the picture, it seems to be from around the head gasket, but check the pipes carrying oil to the back of the head especially where they attach at the tapped holes.
I'll take more pictures but definitely leaking oil from in between the head gasket in three places.
Since nothing else was properly torqued when it was last put back together it wouldn't surprise me that the head was not torqued down correctly either.
Last edited by Felixbobcat; Apr 12, 2023 at 11:49 AM.
There is no oil to leak from the head gasket area, oil does not flow from the block to the head or vice-versa.
As Peter said check the pipes at the back of the head, including the banjo bolts. (are they snug ?)
More common leaking problems in that area is the back end cap and its O-ring on the exhaust side, the rev counter seal and the valve cover gaskets.
When you have the head off, check the mating surface for the valve covers for trueness with your straight edge.
That gets left out and when they are snugged down, the end of the gasket gets pinched and leaks where your mess is.
It leaks from the places I mentioned, collects on the edge of the block where oil and road dirt create the cakey mess, it only appears that it's coming from the block/head gasket area.
What happens is the head is planed, but the warp is still left (if it was warped).
This fixes the deck, but not where the cam covers meet.
The whole head has to be straightened first, and that very often gets missed.
Go to 21:00 and continue on from there, but watch it all from the beginning.
Jeff you are correct about no oil coming out from between the head and block. Upon further inspection, oil has been migrating down the small valley between the two and then flowing down the side of the block. On the left side it is probably coming from the leak at the timing chain cover. I haven't been able to determine were the oil is coming from on the right side yet. No leak has been detected from the oil pipes. Banjo bolts and fibre washers are dry. No oil is weeping from the valve covers as well.
Pulled the transmission and clutch. No oil on the friction plate however there is some chattering marks on the pressure plate. Inside of the bell housing is covered in oil and dirt. Looks just like the outside!
3.8 rear main seal opinions
