All pistons passed except number 4. All other were tip top. My friend and helper said there’s a slight chance it’s an injector stuck open because all other pistons were tip top. My 1983 (I was given these cars, a 1983 and a 1987) from my best friend’s widow. The 1983 has zero on number 6 and 5–turned out to be burned exhaust valves. However, this 1987 only failed on one piston set, no coolant in the oil, I don’t know. Also got a free 1974XJ-12 from anther widow of a friend (25 years ago these guys were Jaguar buddies, all of us got only, and some of us are gone from this world. The XJ-12L’s engine is seized and my wife is besides herself to have 3 dead Jags in the back yard. Anyway, could the 1987 failed compression check on #4 be related to a stuck injector?
Chris
An injector has no influence on compressions, when you say failed do you mean completely zero or just lower in comparison to the other 5. Valves, rings (low PSI) or a hole in the piston (zero PSI)
A head gasket may show a lower PSI but you should see other symptoms from that scenario.
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Robin is perfectly right, Chris - a failed injector will not affect compression. Even if you removed an injector compression would be unaffected…
Did you run a ‘wet’ compression test - putting some oil into the cylinder If this raises compression; bore wear is implied - adding oil will not affect anything else. The proper course of action is then head removal and inspection/valve job…
Frank
xj6 85 Sov Europe (UK/NZ)
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You’ve got to expect that any engine from 1887 will run a bit looser than when new, and most of the electrical components will also be well past their service interval too.
(I’ve amended the title)
Getting any 1887 engine to run might be a miracle let alone it being loose
Not really… there are a few. The main thing to keep in mind is that most were designed to be hit and miss.
Ha, ha! A few years ago someone brought a replica of Daimler’s 1885 Reitwagen motorcycle to a Chicago area collector car show. Nice wood work, but I did not see it running.
Anyway, I would do a cylinder leakage air test. You need an adapter, spark plug thread to air hose coupling. I simply broke out the ceramic of an old plug and welded on a male hose end, but if you are not a welder maybe auto parts stores sell such a thing. Insert it in #4 plug hole. Connect it to an air tank, turn the engine slowly and if you hear air always coming out the intake, or exhaust, or crankcase breather, you know it is a bent valve or rings or broken piston.
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No matter what, Rob - the head must come off to assess what is what, and effect a repair…
A burnt/bent valve may also be diagnosed with a valve clearance check - but still require head removal for final diagnosis…l…
Frank
xj6 85 Sov Europe (UK/NZ)
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As one might suspect, there are folks that enjoy them much like we enjoy our cars.
I saw a bit on You Rube. From rather small to huge. I noted that one of the owners of a really big one used Propane for fuel and a Ford T vibrator coil for ignition.
And, way back when a black and white movie. “Wings”, I think. WWI fighters and their pilots. If one listens to the sound track, one can detect the on/off noise. Hit and miss for rpm control?
Carl
The one lung hit and miss engines were used in fasrming and industry. I just missed getting a small one at a yard sale a couple of decades ago.
Carl
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With fixed pitch propeller and not much throttle control, Carl - they just had to cut ignition in and out for some speed control. Mainly during landing, of course - airborn they needed all the power available just to keep aloft…:
Frank
xj6 85 Sov Europe (UK/NZ)
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Interesting, indeed. My recollection as to the film was a group flying in formation. With the unmistakable on/off exhaust sounds.
In unison, that just occurred to me. Odd, so, more thn likely, sounds added. Not in real time.
Deades, later, a week ago or so, some WWII war birds were aloft
around here. A pair of P51 Mustangs, locally based. A B24, B17, a B25 and an AT advanced trainer all visiting. Far different sounds than the usual jets, small airplanes, chopers,
Carl
Interesting, early radials did control the engine RPM but on/off ignition when taxiing. But this is getting a bit off topic, could it be moved to the pub? Just a thought.
OK, by me???
Still curious as to developments on the original topic suggesting a badly busted valve.
Carl
So Chris, do you have any update?
Yes, I have given up on these two XJ-6’s, and I am sick at heart over my
inability to get them n motion.
Chris
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The first time you remove a xk head is the worst, Chris - it gets easier with practice…:
Frank
xj6 85 Sov Europe (UK/NZ)
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Frank, I’m afraid I’m just too old to start such a venture. I’m 70, and at this point, my eye sight is just good enough to drive–at least for the time being. I’m going to try to sell these cars to someone who is passionate about them, and young, the way I used to be.
Chris
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That’s fair enough, Chris - hope they get a good home…
It’s easier to sell cars that are runners - even if they have a known flaw. a failed valve is not really a deterrent…
Frank
xj6 85 Sov Europe (UK/NZ)
**
Chris, might be worth some “can mechanic - decoke in a can” if you’re at that point. Our XJ6 came of the road in '94 and back on last year. I was able to redeem one pot of two with low readings with a additive in the air induction - straight into the carbs. Maybe some varnish or debris under a valve. I’ve found that when they’ve been parked up they really need some running to see if they can improve. Later, once registered I pulled the head to fix a bent valve in the other failed pot. Nothing to lose for you? Paul