29 replies to this topic

[b80ven]

something else worth mentioning, my distributor is a 41404 - 43D4 type.

[lrostoke]

lrostoke - regarding your comment about advancing until reaching the highest revs. This is fairly difficult because each time you adjust the timing, the mixture and the idling point needs to change as the vacuum created in the cylinders changes. I can't see how this will work unless you keep adjusting the mixture and idling at each point.

surely that is true however you set the timing, you have a modified engine, an old engine an one designed to run on leaded fuel, so using original factory settings will never work.

The highest revs is just an observation from when I've used the vacuum guage method of timing setting.
When I've turned the dizzy to give maximum vacuum reading, this as normally corrisponded with higher tickover, the vacuum method then states retard the timing so the vacuum reading drops 1/2" of vacuum, this also corrisponds with a drop in tickover.

you will also see bmc stating many times on here advance the timing in a similar way test run it listen for pinking, if pinking retard until pinking stops, he actually says just about stops.

[b80ven]

Thanks IRostoke!
SO I presume the vacuum is measured at the inlet manifold ?
I appreciate this info. I'll give it a go when I get a chance and keep you all posted.
I think I am hearing pinging but I'm not sure. From descriptions ive read online, pinging is more of a violent chain sound, which I can't say I'm hearing, however there is a bit of a rattling sound..

[Carlos W]

The green coolant on the plug and smoke on start up, along with rough running may be indications of a head gasket blown

Edited by Carlos W, 01 July 2012 - 01:13 PM.

[b80ven]

Yes - just as I presumed Carlos - thank you.

[Carlos W]

This needs to be sorted before worrying abut timing and mixture!

[b80ven]

yeh I agree.

[b80ven]

I decided to repost a larger version of the same image.
Could anybody please tell me, if this ISN"T the TDC mark on my flywheel, what is it. Next to the vertical notch, there is a smaller, round looking notch.

Attached Files

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[lrostoke]

Why are you still worrying about the TDC mark, you've mentioned you seem to have bigger problems with coolant in your Number 2 bore...

Best bet now is remove the head, If your still wondering about the TDC mark turn the engine over till No 1 piston is at the top (easy to see when at the top with head off), then look which mark is showing through the inspection hole. The head needs to come off to find the source of the coolant

Edited by lrostoke, 02 July 2012 - 05:25 AM.

[b80ven]

Yes, I realise this, eventually when it's all put back, I'll have the same problem. the fact that there is a certain range in motion in the flywheel, when it appears that a piston is at TDC.
Engine manufacturers put a notch on the flywheel for a reason, to show precise TDC, based on crankshaft position / piston position.

[lrostoke]

yes and with the head off you will be able to find TDC very easily, borrow or buy a dial guage. you can use this to find exact TDC.

Then look what mark is showing...you could even make up your own point by the crank pulley and notch the pulley to suit.

[b80ven]

beautiful, this is what I needed, thanks again Irostoke !

[Ethel]

You wouldn't even need a dial gauge, just something to touch (and stop) the piston before it reaches tdc. Mark the points where it touches the piston before and after tdc on the fly wheel, or pulley, and tdc will be half way between them.

[b80ven]

that makes sense.
thanks.

[Ethel]

It's probably just where a lump has been removed when balancing it.