What did you do to your Z this week?

Turn & Burn

Club Member
Mmmm..now I’m confused (easily done, admittedly) but my speedo has two wing nuts on the back, one low down next to the brake warning light and one tucked right up at the top to the left of the main beam warning light. (As seen from the rear) Are you talking 260Z with the screws, or...??
Agreed there was a change between early 240z and later 240z / 260z. Can u not access these either then?
 

Sam_C

Club Member
Agreed there was a change between early 240z and later 240z / 260z. Can u not access these either then?
I can get the lower one, not the upper one. And even if I could get it off it would be near-on impossible to refit. In reality, if I could get my hand onto the upper one, I could get to the main beam light holder as it’s very close to it. Sadly, there is so little space to work in and an almost impossible angle to get your arm up and around the wires braces etc between you and the holder that, like the wing nut it might come out but if it did it would probably be staying out
Dash out would be a solution of course, but that seems like a lot of work to change one bulb! (Although I have done it before)
 

Turn & Burn

Club Member
I can get the lower one, not the upper one. And even if I could get it off it would be near-on impossible to refit. In reality, if I could get my hand onto the upper one, I could get to the main beam light holder as it’s very close to it. Sadly, there is so little space to work in and an almost impossible angle to get your arm up and around the wires braces etc between you and the holder that, like the wing nut it might come out but if it did it would probably be staying out
Dash out would be a solution of course, but that seems like a lot of work to change one bulb! (Although I have done it before)
Just had a quick look on ClassicZCars, it seems that mini eagle beaks or long nose pliers are the best approach. It must be why they redesigned the later cars. Good luck!
 

clandon

Active Forum User
Changed the oil and replaced the fuel pressure gauage. I also ordered Pirellis from 4wheelonline because one of my tyres got a puncture near the sidewall.
 
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racer

Club Member
I haven't done one, but actually they did one at Northampton Motorsport while we were trying to figure out where the misfire was coming from.
It was 220 - 240 for 4 of the cylinders and 0 for cylinders 4 and 5. I'm pretty sure it'll be 220 - 240 across the board now - I know there was no valve/piston contact.

What are your piston to head clearances these days Jon??
 

jonbills

Membership Secretary
Site Administrator
What are your piston to head clearances these days Jon??
about 0.55mm Matt.
Not sure if I've shared this pic already - the head keeps the piston surface nice and clean where it can :)

Edit: actually, probably nearer 0.58mm

BK560009 (2).JPG
 
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jonbills

Membership Secretary
Site Administrator
So about 0.0002" under 23 thou in old money......that's very tight!
I read quite a lot about it on Hybridz.org and it seemed in line with what some knowledgeable people there said.
Clearly the photo shows it gets very close, but no real contact.
 

AD240Z

Club Member
I ordered all the parts for my brake refurb - will start stripping things down soon on the white car , particlarly after cycling last night through the newly laid road salt/grit.....................
 

Mr.G

Club Member
I read quite a lot about it on Hybridz.org and it seemed in line with what some knowledgeable people there said.
Clearly the photo shows it gets very close, but no real contact.
Hi Jon I couldn't quite work out what was touching what in the photo, is the valve touching the piston or is the piston just touching the quench pad? Did you have to go for a custom headgasket to get your clearances so tight? Have you tested it with the engine hot? I am sorry if i have missed this somewhere.
 

jonbills

Membership Secretary
Site Administrator
Hi Jon I couldn't quite work out what was touching what in the photo, is the valve touching the piston or is the piston just touching the quench pad? Did you have to go for a custom headgasket to get your clearances so tight? Have you tested it with the engine hot? I am sorry if i have missed this somewhere.
Hi George, yes, its the piston coming very close to the face of the head - so close deposits can't form there.
Its a standard 0.8mm Kameari gasket.
If Kameari didn't offer a 0.8 I'd be using 1.0 and the clearance would be 0.78.
so it's really just happenstance that the clearance is as tight as you could want to go.
 

Mark N

Club Member
Hi George, yes, its the piston coming very close to the face of the head - so close deposits can't form there.
Its a standard 0.8mm Kameari gasket.
If Kameari didn't offer a 0.8 I'd be using 1.0 and the clearance would be 0.78.
so it's really just happenstance that the clearance is as tight as you could want to go.

Is that clearance likely to change when it is hot after some spirited driving?
 

johnymd

Club Member
Most of what i've read says 0.5mm or 23-25" is optimal but other head further towards 1mm just to be safe. Obviously the bigger you go the less effective it is to reduce detonation.
 
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