Main bearing felt seal replacement

[Hugh Conway]

I am not happy with the amount of oil that migrates through the felt seals on my Dursley as compared to the listeroid.
In previously replacing the bearings and felt seals, I noted the sealing areas on the crankshaft are nicely smooth, not scored or pitted. Carriers were also in good, clean condition.  In replacing the felts, the new ones were put  dry into the bearing carriers, then slid on to the crank. It was a bit of a PITA, as I recall, to slide the carriers past the crank ends once the felt seal was reached.
Is there an "approved" way to do this replacement? Any one have positive repeatable experience here? I am about to move the engine into its working location, so would like to make it as oil tight (a relative term. I know!) as practical before putting it into regular service.
Personal experience, tips,  and advice gratefully sought.
Thanks everyone
Cheers,
Hugh

[BruceM]

I don't know if they will fit an original but the lip seals on the DES 8/1 I did the propane conversion on were modern design, spring behind rubber lip and seal very well.  Maybe Gary can tell you if they are suitable. 

The most common cause of leaking is check valve problems...check your breather exhaust.  I used a 3/4" brass water check valve with spring removed, gravity close.  We vented it outside the engine room.

[Hugh Conway]

Thanks Bruce
The rubber seals do work quite well on my Listeroid, though as I recall, they will not work with the plain bearing carriers on the Dursley. Maybe we can get some definite information on this from another member.
I do have a very few hours on this engine since the installation of a dry sleeve, new rings, etc. Excessive blow-by could very well be a factor here, as things are not well run in yet. Still, I sure would like to know the correct way to install those felts, as I may be doing it again in future. Sure would prefer to do it right, and know it.
Maybe Gary or Butch can comment when they have an opportunity, they sure have the experience.
Cheers,
Hugh

[dieselgman]

The original Dursley felt seals work well for the long-haul because they are gentle on shaft wear. They do not seal too well on their own unless the engine is also in good shape and has no excess crankcase pressure to deal with. As mentioned, the breather valve has quite a bit to do with keeping crankcase pressure under control and a stuck valve will generally cause oil leakage. Engine ring seal is also a factor... if they leak too much, then crankcase pressures will be abnormally high and oil leakage can result.

The rubber lip seals work well but also tend to cause a wear groove on the cranks after extended running hours... (but that would be at least in the thousands or 10s of thousands of hours). We have had best overall luck with the softer rubber formulations and seals formed with double lips on other Lister models... but the Indian Listeroids use a very basic single lip type.

The seal carriers for each type are unique and do not interchange as far as I have seen thus far.

dieselgman

[38ac]

Those felts do virtually nothing to keep the oil inside the engine. I dont even put them in. Vacuum created by the breather valve is what keeps the oil inside. If blow by or bad breather operation  causes  pressures inside the crankcase to over come the vacuum created  then you have leaks.  First step is to check and repair the breather.  If you still have leaks after being assured it is working correctly then you have two choices, reduce blow by or live with it.  You cannot install Indian type seals in the factory main bearing housing. There MAY be a lip seal that works on a 2.000" shaft that will press in the housing? I have never checked that out.  There are Indian housings for bushing mains and Indian type lip seals. All of Gary's DES engines have them.

[dieselspanner]

As Butch said, there may well be a lip seal out there that will fit in place of the original felt one, if not Martins, Southampton, UK (http://www.martins-rubber.co.uk) would almost certainly be able to make them.

10 years or so back working in the old US Navy base at Hythe, Hampshire,I was stuck for one seal on the steering ram for a large hovercraft, around 35mm bore with a 20mm shaft - the cylinder, not the hovercraft!, so I drove into Southampton with the old one and they knocked up half a dozen spares for something like £50, in a couple of days.

If someone wanted to invest the time, money and sort out the sizes I'm sure they'd be happy to do a small run.

Cheers Stef