A bank manifold came off nicely, but there is a hardwire interfering. I see no way to disconnect it. Do i need to cut and splice together?!
Couldn’t figure it out, so cut it. I will wire in connectors for future
Also, inspecting so far, old gaskets look ok, although hard to tell if they’re airtight looking at them.
But looking around 4A where i have misfire, there was a bit of oil at end of intake manifold ports at 3A and 4A. Looking down head ports, i see a tiny bit of oil resting on both intake valves. The valve stems look clean, and the valves look spotless (except for maybe the edges where oil is) I am not burning nor losing any oil since I’ve owned the car. Is this just blow by getting in? And it favors 3 and 4 because they’re right there at the throttle?
I used to get a lot of blow by on B bank, but thats almost gone since cleaning pcv valve.
I have switched to synthetic oil about 600 miles ago. Still reading full on dipstick.
Also, is this a good time to pour a bit of seafoam over intake valves?
I would never use synthetic oil in my V12 because the seals don’t have the same tolerances as newer cars and you will surely leak more oil. Conventional 20w50 is safest and it was designed for such.
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I am not familiar with the 88, out of curiosity - what is this wire on the B-bank for?
As discussed in other threads, the intakes should come off as “one piece” on all V12 - from the pre-HE to the 6.0L and I am wondering if a PO has done something or this was Jaguar assembly-line work at its best…
Hmmm, as soon as i switched to synthetic back in March, the idle rpm went up by 200 rpm, had to dial down the AAV screw. So not just oil leaks, but something else? I will switch back to 20/50 dino, thanks.
The more i inspect intake valves, the more i think its blow by. I’ve found oil in A bank throttle body before. And every port on intake manifold A, had traces of oil. Nothing on B. 4A and 5A just seem to get the most. I still am thinking of some seafoam in there overnight to clean the valves.
And just realized, that little crossover vacuum pipe that connects a and b bank and pcv, the inlet to A bank is right next to 4A!
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The wire is on A bank, and is two wires going from joint near left fender to joint behind throttle pedestal that also connects with other wires going to other things in the vicinity.
I decided to pull fuel rail, it only took an extra 15 minutes. Then i pulled intake manifolds separately.
So, B-bank intake manifold came off nicely? It would be nice to identify the “other things”.
I thought the 6.0L has the most wires in the “vee”, but apparently that’s not the case.
Don’t do that. Oil leakage has nothing to do with tolerances, that’s just nonsense. The only reason dino oil leaks less is because it’s plugging up leak paths with varnish.
At this point I’m more concerned about the oil you found. I suppose there is some chance that this residue is merely symptomatic of that cylinder not firing properly. Do you get the impression that the oil came in via the intake tract or down the valve stem?
Intake tract. Stem is spotless.
Just realized, the crossover vacuum pipe that connects A and B and PCV, the inlet to A bank intake manifold is right next to 4a. Perhaps I’m getting excessive blowby, and its coking up the intake valve.
That might explain the deposits, but I’m not as sure it would explain the misfire.
Intake valve not sealing well?
I will pour some seafoam overnight into intake valves, put new intake manifold gaskets on tomorrow and fire her up. If still misfire, I’ll send off injector for a look.
BTW, looked under distributor cap, all good. Even looked at star tooth for 4A.
Also, i always wondered, when we plug up the air pump holes in the intake manifold only 3/4", with that little hole in the gasket, doesn’t that allow exhaust pressure to come up and try to get past gasket into intake? The original air pipes go into the head. Shouldn’t we try to plug head holes?
That requires more disassembly, and there doesn’t seem to be a problem.
Takes a fair amount of power to spin an oil pump: thinner oil, less power consumed.
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Regarding wires i had to cut, they were green with pink stripe, and green with grey stripe. They were wrapped in electrical tape. I very much doubt POs have redone the engine wiring, so perhaps it came from factory like this? The wires were a couple inches too short to run behind cam cover, so they ran it thru intake manifold? I’ve spliced in an extra foot so now can easily run behind cam cover.
all this dino vs syn makes my head hurt. I started using synthetic years ago and live with the weeping. I might switch back to dino, but kind of like the synthetic.
But if i stay with syn I will at least move up to a higher viscosity than the 10/40 I used last oil change.
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