I pulled the valve cover on the exhaust side to hunt down a terrible high pitch metal on metal noise. The cam lobe on #5 is dry and making a bad sound. 5&6 don’t have as much oil in the cam bay and there is metal in just that bay. Doesn’t look or sound good, any advice on how to proceed is appreciated! BTW I’m new to Jaguar and just got a hotrod 420G!
To clarify, Kaspar, (and welcome to the list!) - in xk language’ #6 is the frontmost cylinder. So it is important in this case that you are positive about the identification of your '#5 and 6!
Oil is delivered to the head by an oil pipe at the rear of the engine, Kaspar - and it may be clogged. Banjo bolts are used to mount the pipe, and the first step is to inspect the bolt areas for leaks. Then unscrew the bolts in turn (note the washers and their placings!) and inspect them for possible clogging - then the pipe itself.
However; there is no specific lubrication for the cam lobes and tappets - they are lubed by oil ‘spilled’ from the cam bearings, collected in the cam bays. Lack of oil in the related cam bay may indicate that oil is not properly fed to the adjacent bearing(s). This may cause damage to the bearing - which may require some additional work.
Ie; the problem may be either insufficient oil feed to the cams, the front of the cam is the last to receive the oil, or a specific problem with a bearing…
Frank
xj6 85 Sov Europe (UK/NZ)
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I would pull the breather at the front, depress the plunger, loosen the tensioner (needle nose pliers work better than the special tool), remove the gear from the camshaft (don’t drop anything of course), get the camshaft out (mind whatever might be attached to the rear of it) and inspect the bearings.
Before all that, crank the engine and see where the oil is fed and how much is lost in the process. Maybe the feed is blocked, or the camshaft drilling, and it might not be impossible that the bearings are so shot that oil doesn’t make it all the way to the front. Maybe you can see where the oil starvation comes from before removing the camshaft.
Welcome and good luck
David
What is your oil pressure? Maybe the rear main is clogged up if you have the old system where the oil is not taken from the filter head but goes through the rear bearing first. Even though #6 inlet is the last cam to see oil.
Frank, thank you, you clarified what I guessed but couldn’t confirm. Yes its 5&6 that appear to be starved. I will check in to the supply and wasn’t aware that the oil came to the head externally, Thats a big help diagnosing this problem. -K
Hi, David, Thank you for the incite full information. I will dig in this morning, the thought did occur that the bearing are shot and it isn’t making enough pressure to get to the front of the motor (I hope thats not the case!). The oil pressure gauge is disconnected… To be sure the 3&4 and 1&2 don’t seem to be getting much oil either. Is it common for the bolts holding the cam gear to be wired? Also I dug in deeper and the motor is a series 1 with what appears to be a later serial # and has a S after it, not sure what that means. 7L24341-S. Again thank you for the info! -K
Since the oil is spilling out from the cam bearing wouldn’t both 5&6 be in the same boat so to say?
HI, ALL! Got it, Thank goodness I found this before driving the car… The oil supply line was plugged 5 ways from Friday! I do believe nothing to permanent was damaged may need a new tappet but thats about it.
Many thanks for saving the day and indeed my motor too. -Kaspar
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Nothing better than an inexpensive fix!!
Jeff H
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Well I hope you solve the problem! And I do have some cam shafts, and other parts of you need! Reasonable prices! Give me a shout if need to. I’m in ca. Usa
Hi, Thank you for reaching out! Yes I needs a few parts to get this car up to speed… I’ll get a list together and send you a PM. -K
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Check the condition of the cam and , Kaspar - if only lightly scored; you may smooth it by fine emery paper. And you may also measure the cam compared to the others for excessive wear…
You should clean up any metal residue in the cam bays, of course - likely very little has been drained back into the sump. Metal circulating int the engine is ‘not good’, but the oil filter is there to remove particles…
Prompt action, well done!
Frank
xj6 85 Sov Europe (UK/NZ)
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xj6 85 Sov Europe (UK/NZ)
You’re welcome - 7L is a not too early 4.2 XJ long stud block and the -S is for the compression. Not the best of the lot, so feel free to thrash it, but keep the coolant fresh 
While in there check the valve clearances. It is common that the bolts are safety wired. You will need the cam timing tool for $10-20 to install the cams with the right timing.
No worries hope it’s not to much damage!
Hi, yes the cam seems fine not even scored. The tappet got a little scoring and needs to be replaced, Clarence seemed fine especially after my little friction incident. Since the head wasn’t suppled any new oil the metal (very little) stayed in the 5&6 bath which I cleaned up and filled fresh before restarting. Got the triple carbs synced and mixture set, the motor sounds great and is super responsive!
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Replacing tappet means a camshaft removal/displacement, Kaspar - smoothing it in place may be worth while…?
Your quick diagnosis and response is commendable - but the clogged feed pipes raises some questions as to possible further episodes?
Frank
xj6 85 Sov Europe (UK/NZ)
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Good Morning, How would you propose polishing the tappet in place? I’m not going to be driving the car for awhile and will do a proper engine flush with some superb engine cleaner I can get from a local shop. My eyes and ears are on it, pretty quick check to crack the 5/8 banjo at the head when the car is running and see if it has pressure!
-K
Don’t crack the banjo, look for flow with the cover removed… and show us what the tappet looks like. Either it is still okay or it is better to take it out than to try to polish something in place.
David
What was the blockage?
There have been issues posted here re aftermarket bonded/Dowty washers used in place of the correct thin copper washers on the banjos.
Frankie
My best guess is the blockage was oil sludge that got picked up when the person that sold me the car tried to start it without changing the oil. My 420G has hopefully been saved from eminent doom! It’s all good now, motor is super smooth, the transmission is rebuilt, and I’m taking it slow with the cars reintroduction to the road.
I have a new valve cover gaskets on order. When they arrive I’ll take a poke around and see what the tappet looks like!
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