The 'E' Type Forum

Why do you think it is 7.8:1? My '72 US spec was 9:1. What is the engine number? If the last character is "L" it would have been 7.8:1. If it is "S" it would have been 9:1. If 9:1 your cranking cylinder pressures should be around 160 psi. I was 12 deg BTDC at idle, 36 degrees BTDC @ 3000 rpm, 98 RON...

We could open a book on this, my bet is broke piston. Because there is plus minus half inch movement stopped by thunk at the rear of the engine

With OTS the cockpit is connected to the boot by passages on each side, over the rear wheel wells to where the hood bows are mounted. There is suction from the boot into the cockpit. The expansion tank is at entrance to the left passage, if there is even the slightest leak from this, if there is not...

I was going to do the Lutz mod also, till I learned that for the last V12 (X305) Jaguar eliminated the rear two head coolant ports and the water rail entirely?

Suitable mechanical seals are very commonly available from almost everywhere. Google “Mechanical Seal”. All you need to know is the shaft and casing diameters and the height. There are very sophisticated types available, Jaguars use the simplest, most basic. Some, like Tadek’s pics, are just a stati...

Surely they'd have to be restorations, otherwise, wouldn't they need to comply with modern emissions and safety stds?

If you want to make it original instead of the SU's, I have a complete intake system packed away in deep storage ...

I would be concerned that a sudden step change in temperature might exacerbate the issues you are trying to avoid?

Handbook says 98. Like you I wondered about it. Used 95 if was 98 n/a, no side effects. My compression was >160 psi.
SA or SB. The "S" is the compression ratio (L = low, S = std, H=high). A and B are the piston/sleeve manuf'g tolerance.

Also sealing. Taper male into parallel female will give good seal with minimal torque without Teflon HOWEVER, if the female is aluminium, need to be very careful not to over-torque and damage the aluminium, imo this is why taper is not recommended. Taper into taper will also seal without teflon howe...

Regarding the air intake/trumpets - don’t assume the V12 arrangement is somehow a cold air intake system due to the inlets being forward of the radiator. By design it is a “constant temperature intake”; target temp is 43 degC, this being the temperature at which the flap valves become fully open. Th...

Steve, imo Polybush type 31C (lower wishbone) cannot be installed correctly by design. Early failure is inevitable. I bought a set ~7 years ago, didn’t use them due to the obvious flaws. The material is very soft, like silicone. It tears relatively easily, like silicone. Softer than rubber, weaker t...

I have started fitting Superflex bushes which work in a different way, they are meant to rotate about a st/steel center but they are giving problems as they are rotating in the housings but that's for a other time. Hello Neal, rotating bushes, same as sheared flanges, is due to excess torque being ...

Here is photo of one of the orifices I was referring to. Orifice diameter is 3.7 mm.

I bought this kit a long time ago, from Jaguarspares in UK. When trying to fit the wishbone bushes, so many issues that I basically junked them, bought a SuperPro kit instead. All I used from this Polybush kit were the roll bar bushes. I could write a book about what is wrong with these wishbone bus...

Perhaps efi or "carbs out of loyalty" may be question for S2, weren’t S3’s slated to be efi till Brico pulled out? Maybe the question should be whether to finish the job, or to struggle on with the sad, messy and temporary compromise that Jaguar was forced to make? Imo the comments in this post are ...

You are correct, I have deleted the misinformation from my earlier reply. I blame the fog of time since I considered fitting exhaust valve seals. Some cars have seals on inlet and exhaust valves, Jaguar V12 didn’t, had seals on the inlets only. On inlets the differential pressure tendency is to comp...

UNC.
The original (flat) heads used unified imperial threads. The later (dished HE) heads used metric threads.