Spark plugs last a lot longer in the unleaded fuel era. You suffer no lead erosion of the electrodes.

I know you are pulling plugs to evaluate mixture Huey.

 

Does this engine need to have Zinc added to the oil?

 

No...
A modern synthetic or non-synthetic oil with todays superior anti-friction additives far surpass old technology when it comes to Zinc in oil.

Read post #2, here's a link.

https://www.jaguarforums.com/forum/m...3/#post2761153

I've run 10/30 in both my 340 Jaguar and my MK VI Bentley for decades, and all the mechanicals are in good condition.
I just fitted a reconditioned cam shaft to the Bentley, and all the lifters are in good condition; that was after 21,000 miles from a complete engine rebuild.

 

Never add anything to the oil. Shell, Chevron, BP/Castrol, ... spend a fortune developing and testing their products. They employ world class tribologists, chemists and engineers. They know what they are doing.

Apart from that, Jaguar made a big effort to ensure a more than adequate supply of lubricant to the camshafts of their engines unlike some other manufacturers for whom adding a tube or drilling a hole adds too much to the cost.

 

No ~ never from a major with the huge development budgets as Peter correctly comments.

 

Well, I've got a new issue, something with the transmission/overdrive. I drove it a little over 10 miles today with no issues. I just tried to drive it and it started acting like the brakes were dragging. It shifts ok, and there were no odd noises or indications of a failure. With the engine off and the clutch disengaged and in a forward gear it will roll backwards but not forwards, with it in reverse it will roll forward but not backwards. In neutral it rolls fine in both directions.
The overdrive controls are not connected and it has not been tested. The transmission and overdrive fluid levels are correct. I have to assume the overdrive engages when the solenoid is activated or possibly when the lever on the overdrive is manually engaged.

Anyone got any idea what's up?

 

I figured it out, the overdrive was partially engaged. I moved the manual lever a few times and that must have relieved the pressure in the pump assembly.

 

The oil pressure has been about 40 psi until today. This morning the pressure was down a few pounds after driving a few miles. I just drove it again, now the pressure is around 32-35 psi at 2000 rpm, and about 15 at 500 rpm.
When I assembled the engine the sump pickup tubes replacement O-rings did not fit correctly. The original O-rings appear to have been replaced when the engine was assembled by the previous owner and were a better fit than the replacements.
The bearings clearances were within spec and should not be an issue as far as oil pressure goes.

Is it possible the pressure relief valve spring is weak? Or are the pickup tube O-rings not sealing correctly?

 

it's IS possible the pressure relief valve spring is weak (i've recently purchased one and have yet to install it) but i would first suspect that it may be held open by debris as it doesn't take much. i would also HOPE that it is debris. ha

 

Faulty gauge and/or sender.
The only way to be sure is test with a bourdon tube type gauge.

When I first got my car the oil gauge would be all over the place, and sometimes would rest on "0".
I knew there was nothing wrong with the engine as an engine with zero oil pressure makes a tremendous racket.
I ended up installing a mechanical gauge from a Mini, and changed out the chrome bezel to the Jaguars painted type.
The gauge has been in there for more then 30 years, and has never leaked, or given any trouble.
I just used compression and pipe fittings to install it.
I took the original sender, removed the electrical parts, then drilled and tapped it to 1/8 pipe thread.

 

I just drove it about 30 miles. A little timing correction brought to life. The 3.4 is very impressive, plenty of power for this car. It's much more fun to drive, and the exhaust sounds like no other, it's great.

Oil pressure issue. The car originally had Auto Meter gauges, electric not mechanical. I've ordered Murphy Switch Gauge industrial mechanical gauges for coolant temp and oil pressure. They are equipped with adjustable contacts that can be used for warning lights or shut down.
I checked the oil pressure relief valve and didn't find any thing out of place. The pressure now reads 24-30 PSI no matter what RPM, and that's with the Auto Meter and a basic mechanical gauge. I'll probably try replacing the pressure relief spring.

There are a lot of little items that still need addressing, at least I can attempt to complete the engine break-in now.