jonbill

TBH those values look pretty good. I wouldn't go leaner than low 14s at idle. Mid 14s at cruise, no need to go leaner unless you're doing big mileage and want to save a few pennies.

What sensor can you put in the inlet tract to measure the air/fuel ratio?

thats too far in, should sit flush with the outside face of the timing cover. I think thats in danger of falling in!

Thats partly true. as I said, if you don't have a high enough energy coil discharge, the spark won't be able to jump a 1.1mm gap. so you could buy - 11 plugs for that or regap any other plug. The heat rating of the plug (5,6,7 etc) is dependent on combustion pressure and temperature, not so much the ignition system.

In the same way that taking your temperature is a reliable indication of whether you have an infection.

The residual oxygen in the exhaust is a reliable indicator of the ratio of fuel and air at the inlet. This is true given a working and reasonable ignition and cam timing. Engine Management systems do work on this basis. I mean, as well as that being an assumption they make, they actually do work well in optimising fuel mixtures.

I think its mainly a function of the coil and the voltage. points running at only 8v, there's not enough energy to jump the gap at peak cylinder pressure. start at 1.1mm, and if you don't misfire anywhere in the rpm range, leave it there and be happy. if you misfire around peak torque, close the gap a bit until the misfire goes away, then leave it and be happy.

I guess you know the Dupuytren's is fixable, but not the arthritis. what you need is a younger keen relative who'd like to inherit it. you can be the brains and they can be the brawn.

I did read on the speeduino forum that 1 wire sensors don't work well. I think just getting a later thermostat body with more holes would be best option.

Sorry, I've never seem that system 🙂 what happens if you unplug that switch?

can you describe what you've got in a bit more detail @jas. you've mentioned EGR and water temp switch, neither of which I'd expect on a 72 carb car.

got a pic of your spark plugs?

Does your thermostat housing not have a blanked hole next to the standard sensor housing? mine does, its a standard size, m12 maybe.

The Zclub in the UK has a thread on seat upgrades at the mo with some interesting options. https://zclub.net/community/index.php?threads/seats-again.27924/

standard gasket is 1.2mm installed.

they don't have struts, but they do have strut inserts : https://www.thezstore.com/page/TZS/CTGY/classic20b04

must be an electrical problem. Maybe your alternator is over or under charging?

If it was smokey, make sure you change the valve stem seals. Maybe even check the guides aren't too worn. It won't be the compression rings.

not only will it take a lot of filing, I imagine it'll be under quite a bit of stress, being that compressed. And if the bore isn't round, it'll still not seal, as @zedhead pointed out.

I don't think there's a down side to a big cam in a Z. Mine is ~15mm lift and it goes like a normal engine below 4k rpm and a not so normal engine above. No 'driveability' problems anywhere. You wont get the full benefit without exhaust, carb, head etc improvements but it won't hurt.

is your current ring end gap 0.049"? thats 1.2mm, which is very big. my recollection of the spec is around 0.3 to 0.4mm for the top ring.

I don't think any original standard Nissan pistons have cut outs like that. on the compression rod, I have these, which are cheap and effective. https://www.thezstore.com/page/TZS/PROD/23-4190 I had poly bushes both sides before I fitted them, and I had a lot more roll after I fitted them which I think shows how much load they were taking.

I've got an e88 skimmed to 36cc chambers on a "big bore l26" and 10.5:1 CR I built recently. There's no problem with chain tension or cam timing. It hasn't run yet but it won't ping on decent fuel I'm sure.

Apologies, I misunderstood 😅

The standard gasket is 1.2mm, so you can't have a head gasket 1.25mm thinner. You can oval the mount holes in the tensioner and Slack side guide to take up the slack.