on my XK120…
since engine rebuild by a “professional” the front crankshaft seal has leaked oil.
thought maybe this would bed in over time but not happening.
original type rope seal is in place now.
can the front crankshaft seal be removed without removing the engine or the crankshaft?
can a new style seal be shoved in there?
and how to do it?
thanks!
George
Correction, was wrong.
George:
On my '53 I had a similar problem following a rebuild. I dropped the sump and, on the advice of a Jaguar restorer, replaced the sump section rope seal with a couple from an E-type. It was my understanding that replacing the section in the front timing cover would require cylinder head removal so I only did the lower half. The E-type rope seal has a wire running through it and I fitted, if memory serves, two side by side it into the recess on the XK sump using some silicone sealant. This has reduced the weepage drastically and now following a good run I only see a sweat of oil on the front of the sump, no major drips. If you check the archives I recall other owners have fitted the more modern lip seal and there has been discussion about how it is done by, among others, Tom Brady as I recall. Maybe they can chime in as I cannot recall off hand what it entailed.
Chris.
Hi George,
Lots of info on this if you search…
Heres my experience. Problem fixed.
The rope seal is two halves, in the sump and in the front timing cover.
Yes, the sump and timing cover can be removed without removing the head.
I did it once to replace the chain tensioner spring.
You will want the radiator out of there first.
Then the water pump and crank damper come off.
Take note when removing the sump that one of the bolts in the right front corner is shorter than all the others. Be sure to put it back in the right place.
There are 4 studs extending down from the head through the front cover which are removed by the double nut method.
Then you should be able to get at all the other front cover bolts and remove it.
Installing the rope seal is a tricky job, involving careful hand work.
Mine does leak a little bit, but I don’t expect it to be as leak free as a modern car.
If you remove the sump you can remove the “old” rope seal from above the crankshaft by pulling it out. When you put the new one in use a short length of small wire pushed into the center of the seal and out the side and then wrapped around the outside on the end of the seal. Pull the seal into place with the wire. You should have an excess of anywhere from a quarter to a half inch of seal on each side. Push all of it in so it is flush with the block. Many people not familiar with rope seals cut off the excess and that makes the seal too loose.
George, it is difficult but I did it ones on my XJ6, loosen the oil pan and put it in with a little force.
It can be done in the front of the engine.
Frank.
I’m about to put in a modern lip seal myself after the previous two attempts failed. My strategy this time was to source a replacement timing cover and purchase a steel cased lip seal (expensive) and have the groove in the timing cover machined out to accept the seal - a tiny bit larger than a tight fit to allow for a bed of silicone later. I also had the lower outside shoulders “relieved” so that a seal can be slipped in without taking off the timing cover in the future. When I take the one off the car it will need checking for height against the replacement timing cover, and the new one (which has never been machined) will almost certainly need to have a skim off its top edge to make a snug fit against the head gasket.
The sump also needs to be dropped and I’ve heard that its groove doesn’t require maching to take the new seal. I’m hoping not, anyway!
My car is an early one with the front engine mounts on the large plate mounted on the timing cover. Therefore the engine needs to be supported somehow, and I’ve acquired a couple of lifting brackets from a later Jag (thinner that the loop type ones that straddle the plug valley on the head). There will be enough thread on the head studs to mount these, and they will only be on temporarily so that the front of the engine can be supported on an engine hoist while the operation takes place.
I will also be replacing the spacer that fits on the crankshaft nose which the seal runs on. I’ve chosen the later type which has an O-ring in the bore, thus eliminating another possible path for an oil leak.
With a bead of silicone in both timing cover and sump grooves it will all need to be buttoned up fairly quickly before the silicone sets, so the seal can find its own centre on the crank.
The XJ6 has a lip seal in the front, the 120 seems to have a rope seal in the front.
At the back there’s no seal and later a rope seal was used.
It can probably be pushed in from below easier than the one at the back.
What is the part number of your original timing cover? I have a box of them and may have the right spare.
Free, not buying/selling.
Mike
I already have one, Mike, and the machining has been done. Just waiting on helicoiling for the sump bolts. But many thanks for the offer of help!
Chris
Hi George and Chris,
Yes we have discussed this front rope seal quite a bit. Coventry Auto Components supplies a retrofit seal that Dave C covered in his thread in an answer to your question above. That seal requires some grinding away of the front cover in situ and he showed excellent pictures of that process and described its installation in detail in the thread he highlighted above. I am happy to hear Dave’s efforts worked out well.
The other option is to remove the sump and timing cover and install a retrofit lip seal as described in detail in the below link, including a nice video by Nick Saltarelli. The string is long but I think worth wading through since many good questions are asked and answered. Or skip to post number 96 to get right to the seal discussion.
Regarding the rope seal versus the modern lip seal, the rope seal may work for a while but will eventually leak oil all over the front of your engine and make a mess. The modern lip seal will eliminate that leak path completely. The amount of leakage is dependent upon how much you drive your car, since the leak only occurs when the crankshaft is rotating. The same goes for the rear scroll crankshaft seal that you have. An upgrade is also available for that leak path and eliminates it. That requires a major effort, engine, transmission, and crankshaft removal and machining away of the scroll. Realistically that would be done during a complete engine rebuild, but I highly recommend it.
I have been lucky this winter, being located in New England near Boston, MA. We have had an exceptionally warm winter with virtually no snow and very little ice, resulting in clean roads devoid of sand and salt. I have been driving my 52 120 FHC quite often, approaching 2800 miles this season, since April of last year. The engine now has 6000 miles on it and remains clean. In the 2800 miles so far this season there is no measurable oil consumption. This is because it has modern three piece oil control rings on the Mahle pistons, front and rear crankshaft lip seals, and valve stem seals. I also paid close attention to sealing all of the threaded leak paths on the front timing cover and the head.
Best regards,
Tom Brady
Fascinating news…
My rear rope seal is dry but the lip seal isn’t. I blame the government. I assembled it and could have done a better job with the sealant but the timing covers are usually caked in oil (even 8 years from being made), so don’t expect salvation. You’re very lucky if it’s and stays perfectly dry!
David, yes, it was a lip seal in the front, didn’t know that the XK120 had rope in the front. I restore a XK150 with a 3.4Liter engine and metal oil pan.
The rear seal rope’s are difficult I think under the car, because of the two Allen keys on top behind the flywheel. Need a very long Allen key and then pushed in.
I tried to fix my own rear seal, but there wasn’t enough room for a extra seal, pity.
Frank.
After reading all the reports of leaky Front Seals, I was reluctant to drop the Sump. My Front Seal was not leaking…so I hated to disturb it. Well…some things just don’t line up with the way I think. This is my Leak Free Front Seal.
It was spinning in there a while…well polished! Perhaps that is how it worked…as a ’ Centrifugal Slinger ’ !
I found some of the old material on the backside if the Crank Damper…
And some on the Oil Pickup.
I’ll work at installing another Rope Seal. The worst it can do is…Leak?
Brand, can’t you put in a lip seal in the front? From the later cars?
The space is the same, I think.
Frank.
XK120 rope seal groove OD = 2.550"
width = .500"
C.2173 Distance Piece OD = 1.994"
XK140 lip seal groove OD = 2.730"
width = .510"
Both engines use the same C.2173 distance piece (i.e. sleeve)
Working on my other engine a 4.2Liter, did weigh the pistons and bore them out to the same weight, also install the later con rods of the XJ6 series 3, took them apart and did the same to these con rods, now they are the same in grams.
The oil spanner was a little difficult to hold the piston in the house when bolted on.
Frank.
You could’ve locked the spanner. It then releases when compressed. A 120 should have a different spanner consisting of a long flat spring steel and a spring, so not important here?
