Hi everyone, need your advice again. A 253 HZ with initial advance of 42 degrees at idle and 50 total with the vacuum disconnected. The engine is happy at this idle advance, stalls if its too much lower. I have fitted a new the harmonic balancer in case the balancer had moved, this did not change any of the results. Have also fitted different distributors, also no material change. Car also has the correct carby, but as I said these results are with vacuum disconnected so the carby is not the variable.
I do not know the history of the engine, could the cam timing be out and the ignition timing is trying to compensate, or any other suggestions would be appreciated. Thanks again.

Thankyou, I thought it would be best to check before I started pulling everything apart. Appreciate the advice, thanks

Thanks, the previous owner was heavily into big block chevs. I will check the cam timing tomorrow, I think Holden is 9 links. Thanks for your thoughts. Regards Dave (this is a possible duplicate reply, my last attempt seems to have disapeared.)

It was very confusing the way GMH did the V8 cam timing. What was wrong with dot-to-dot, this was the waY 6-cyls were done as were SBC V8s.

Anyway for 253/308 it's 9 links from dot to dot INCLUSIVE, not "between".

Dr Terry

Will be interesting to see how far advanced or retarded it is if that is what is done.

Hi Aussie Dave, have you anything to report back on your findings with the issue you have?
I have the exact same issue with my HZ 253, I tried a brand new balancer and still got the same readings, then I installed a new cam, with the correct timing chain alignment, still the same issue, I have now changed the distributor to an electronic one, and guess what??
Still the same issue.....
I'm going to borrow a timing light from someone to test it, that's my last resort. In saying that, the timing light I have is not a cheapo, so will be very dissapointed if it is buggered.

The temp sensor & the gearbox switch control the vacuum solenoid. Unless the engine is up to temp & in top gear, the dissy receives no vacuum to the vac diaphragm.

Dr Terry

only on a manual it wouldn't allow vac advance unless in top gear the first thing a young petrol head would do was to change that vac line so it came directly from the carby not that it achieved anything. What goes vac advance do when you have your foot flat to the floor. lol If ole mate above converted to an electronic distubtor did he get a full 12 volt to it?

This is what i thought but in regards to why the HX 5.0L 4sp were so gutless, even with dual exhaust, i know the manuals did not have EGR entering the intake to be burnt like the Automatics did.

So me was thinking, now if your foot is flat to the floor, the vacuum advance has no regards to power at all when flat to the boards, but the Dizzy should work just as a HJ one would ? with the springs and weights ! So that can not be the issue ! unless them springs and weights are the issue ?

Then i was thinking of the Blue motor dizzy has that big box on them ? now why is that so and can that bugger up or interfear with timing in anyway ! plus their is a electrical box with fins on it i think they bugger up and most mecanics gave no regard for them. I have heard of CL Valiants had problems with such things when they got old, for such just were hammered with heat that destroyed them from working.
I had a Dyno Tune dude do my car and he did not even detect that the vacuum adv was not working in fact ! i though how stupid can he be. they have no regard for that ? that's the main thing to make sure is working.

I had a mate with a WB Statesman in 1988 and it just would not perform, it was like the advance in the dizzy did not work, that's what i said to him that i think it's like and to get it cheked out, he did and said they claimed it was fine.

I know that the vacuum adance is only a fuel economy device truly.

Have to bypass the lower gears setup.

In regards EGR, that should not work when your flat to the floor ? so it should not drop max power at all when flat ! but for part throttle i believe.