jonbill

That's about an hour late. 11.25 is what you're looking for on #1 TDC. There are many threads here on it. https://www.classiczcars.com/forums/topic/44470-where-the-heck-is-the-1-spark-plug-wire-supposed-to-be-on-the-distributor/

I found this very interesting. The good oils in this test are expensive in the UK, if available at all, but it at least gave me values for zinc and phosphate levels I should have. (1400ppm+) I recently bought some eastwood additive and so looked it up, and it seems to have the right sort of amounts for a Z sump full. https://www.eastwood.com/ew-zddp-oil-additive-4-oz.html

I think it might be correct that the fuel pump only runs on "start". There may be an oil pressure switch that means the pump only runs when "on" if the engine is spinning.

I don't think the fuel pump is meant to run on acc. Acc is for accessory, like the radio. "On" is where fuel pump and the ignition get powered. Based on my 74 260, I wait to be corrected!

Probably either, depending which buttons you've pressed on your timing light. It sounds like you've got a dial back timing light, which might have options to either read the ignition advance off the engine or the timing gun. You'd probably need to read its instructions to be confident of doing it right.

The bolts only been in there for 100 miles! It should come out easily.

The broken bolt will have to come out. If it was recently rebuilt, that bolt shouldn't be rusted or seized into the block and you might get it out with stud extractor, with the block in situ.

Rebuilt engines need the zddp protection more if anything. Older engines I think may have a degree protection from work hardening.

Ah, interesting. Is that with that middle carb disconnected from the linkage? If so, I'd suggest something in that carb is binding as it heats up and the metal expands. Could be the throttle plates themselves (need recentering) or possibly the shaft or bearings.

When its hot and acting up, can you still close the throttle plates with your fingers?

That makes sense.

Sounds like a simple case of the map not supplying enough fuel as you start to put it under load. Increasing fuel pressure will make it richer everywhere - doesn't it offer more precise tuning?

That is a fantastic job.

Clearly the internal return spring on that middle carb isn't doing its job. Either the spring is weak or the throttle shaft or plates are binding. If you disconnect the internal spring, you'll be able to feel whether there's any binding. Even without fixing the problems on the individual carbs, the linkage with a strong spring should be able to pull all throttles closed. If it can't, and it's not a throttle stop on the linkage limiting it, then I would think the carbs aren't balanced perfectly and one of the other carbs has reached its stop earlier and is preventing further movement of the linkage.

Sounds like you just need stronger/more return springs.

I imagine Haltech are expecting it to run with paired injectors so it doesn't need to know the cam's position. AIUI there's not much advantage to sequential. A little better on economy I think. I'll be converting mine to EFI with Speeduino this winter with paired injectors.

You can get custom made springs Ali for not too much. Less than those Eibachs I expect. Springcoil.co.uk made mine. They even let me send them back a couple of times for just carriage cost (because I mis-specced them)

That sounds a good candidate to me. I've had a couple of toyota engines with stuck oil control rings that used a lot of oil, but didn't smoke. The one I had that smoked had knackered valve stem seals. Does the engine have a modified cam and big lift?

Perhaps: There was an incident in the engine that blocked something that drove oil pressure up. That caused something else to deliver oil into the combustion Chambers, even after the original high pressure incident is resolved. I can't imagine how high oil pressure could damage valve stem seals or oil control rings. I can imagine high oil pressure might damaging the head gasket and leak oil into a couple of Chambers, but hard to think how that might make all cylinders equally sooty.

I read it as: Oil pressure was observed to be "high", relief valve was removed or Modified and then it started smoking.

Does it smoke at idle or only at higher revs? What colour smoke? The idle relief should do its job before 80 psi.

Those pics don't really look like an oil burner to me, unless its only just started. It just looks like it's been running too rich.

I think that's better. The Webers will be happier with more static advance. You could go even further and take out a few mm of range in the centrifugal advance limiter.

I used to use a pertronix igniter and it had similar misfire problems over 6k. I'd try a 280zx distributor if you can borrow one from somebody near.

Thanks, very nice.