Rear Crank Seal Conversion

[mbailey]

Hi All,

Rebuilding a 67 4.2 XK engine for my E Type. Can anyone give me positive or negative feed back on dispensing
with the original Rope seal and using the modern rubber type one. I'm told that if the rope one is fitted correctly & the car is
in regular use there may be no oil leak issues, however if stored for 8 months & only used occasionally, there probably will be.
Which will be my position.
Is it worth converting ?
Best
Marc Bailey

[christopher storey]

Unequivocally, I am against it. I know of a number of XK engines which have had a conversion, and the majority of them have been failures, with continuing and in some cases prolific leakage . Although this would not matter so much if the process was reversible, in each case it has required a new crank , and the overall expense has been catastrophic . The rope seals work perfectly well if done properly - that is, pre-soaked for several days in engine oil, and properly sized and not cut off where there is a small excess protruding when the seal is placed in the recesses

[64etype]

The new style seals work fine if properly installed. Lippincot Garage, a well know Jaguar shop in the U.S. has installed many of them as has Bill Terry (Terry's Jaguar Parts). There are three designs that I am aware of. A UK design requires removal of the flywheel flange at the end of the crank...major surgery. The second uses a typical lip seal with a radial spring, which rides in a new machined carrier. The seal is sliced across the radius at one point (effectively a "clamshell"). It must be pried apart at the cut, and slipped over the (machined) journal during installation of the crank. Then the spring for the lip must be properly positioned around the lip and the two ends fastened together. Looked like potential for installation error when I evaluated the kit. Before I returned it to the vender, I ordered the Terry's kit for comparison. Bill's kit uses a stiff, molded Viton seal (no spring), which was standard for many GM engines in the 80's and 90's. It's a Federal Mogul part. Two semicircular halves ride on a new machined aluminum carrier. It's the seal of choice for many hot rodders using older big block engines in their creations. Easy to install and no apparent possibilities for error. I chose the Terry's option. The seal surface on the crank does have to be machined to a slightly smaller diameter. By the way, both Terry Lippincot and Bill Terry said they've had good success with both seals. Before I had the crank machined I asked the crank shop if they could return the crank to it's original specification and they said they could...including making a small groove for the scroll....and for not much money. This, of course, was not a typical automotive machine shop, but a professional crankshaft repair facility with automated welding machinery, etc. They were restoring a large Caterpillar diesel crank and a huge electric motor shaft when I visited.

There are numerous threads/debates on this subject, both here and on Jag Lovers site. I'm with the contingent that says rope seals leak....typically sooner than later. The GM guys with older engines are of similar persuasion.

[Moeregaard]

The Jaguar turd seals work well if installed properly. I've converted a Healey 3000 to a modern seal, but since there is a ton of room for improvement "back there" on that engine, anything is an improvement and the car in question is doing great 14 years after the modification.

What bothers me about the Jaguar retrofit is that the crank has to be machined to install the modern seal. Many people swear by the conversion, but I've heard an equal number swear at it. I've installed several of the turd seals over the years and have never had a problem.

[38E]

I think that the XK rear rope crank seal gets blamed for all kinds of leaks which are nothing to do with it.

A good way to tell if a leak is actually caused by a faulty rope seal is to take a look at the front side of the flywheel. If the seal is leaking, you'll see radial oil marks emanating from the centre and this is often not the case even though there are other leaks running down and back to the rear of the engine.

My own car is stored for at least 6 months a year and receives very light use these days and yet there are no oil leaks at all. Not even one spot. And the front of the flywheel is quite clean. I replaced the standard rope seal myself years ago when I re-assembled the engine during the restoration.

[abowie]

As Eric says, if the original seal is properly installed it will seal well.

[64etype]

Think it was Clive who said that. My experience upon disassembling my 65,000 mile engine was that the original rear seal installed by the factory had been leaking like a sieve. Classic radial oil streaks on the forward face of the flywheel and all. Now maybe that's considered to be a lot of miles for an original rope seal...I don't really know.

[mbailey]

Thanks for your feedback Guys, much appreciated but as ever somewhat differing opinions, I've decided to stick
with a new rope seal, fit it correctly & turn the engine over once a month & run up to temperature.
Best
Marc

[Heuer]

Also make sure your crankcase breather is clear of any blockage; the wire mesh and trap can become contaminated with sludge. A blocked breather means crankcase pressure will increase pushing oil out of the rear seal. Happened on my car with its very high performance engine and CMC fitted a double ended breather to cope. Not necessary for a standard engine as long as it can breathe freely.