Spark Plug Bore Diameter?

[bmwman91]

Can someone measure the diameter of the bore hole which the spark plugs are installed in? I think that the holes in the valve cover are a little smaller than those in the head, so the hole diameter in the cover is probably what I need.

Thanks!

[bmwman91]

Also, can someone measure the length of the connector "boot" that reaches down the bore to the plug? Just the length of the rubber tip to the start of the big floppy seal. If you have a COP conversion, the length of the connector boot is fine too.

[roguetoaster]

Edit: Changed img link.

[bmwman91]

Hey, I know I should be thanking you (I probably will be soon), but the images you posted all show up as little error icons.

[roguetoaster]

Dang, I wish I knew why that happens to some google images for some people. If you need other measurements I can get them quickly enough.

[bmwman91]

Cool, thanks!

Any chance you can get the bore depth? As in, remove a spark plug and get depth from the flat face the plug seats on to the top of the head surface where the VC seals? Also, total depth of the "sleeved" hole in the VC, as well as how tall the "sleeves" are on the VC?

I am making BIG plans for my ignition system when I switch to Megasquirt 3 Pro, and just need to confirm some stuff before I buy coils. My car is not accessible at the moment, hence these requests!

[roguetoaster]

All measurements are approximate, but should be fairly accurate, and some, like threaded area are extrapolated from the plug itself.

Well depth head to upper well seat - 11.3cm
With VC/gasket well depth to upper well seat - 13.8cm
Gasket thickeness compressed - 3mm
Well step down/washer depth- 2mm & 1mm (NGK BKR6EK)
Threaded area used by plug - 16mm (NGK BKR6EK)
Exposed plug body beyond head - 1.5mm (NGK BKR6EK)
VC well for plug connectors base to top - 69mm
VC well shoulder height - 52mm

Some extra reference (2st image centered on plug 2 @10, 2nd 0mm at edge, last reference from when I repaired a plug threaded area):