Engine starts but will not run

[woolfie1948]

Thanks will read again, and try to digest.
I have already increased the points gap to spec (that means dwell now 30) and it has smoothed and increased tickover. It also had the effect of changing the timing to 9btdc.
I changed this to 8 and on a short test (to look at the queue at the petrol station) drove quite well but still slight pink, so must still be room for improvement.

According to Volvo book -
'Adjustment in relation to loading is controlled by vacuum regulator that has two diaphrams. During engine braking or idling it lowers the firing, the throttles in the carbs are closed so that there is no vacuum in the connection from the carbs and the return spring presses back the primary diapram against a stop. If the connection from the manifold is large it pulls the secondary diaphram from the stop and lowers the the firing.
During throttling primary diaphram is influenced by the vacuum in the carburettors and takes overthe regulating irrespective of the vacuum in intake manifold.
The positive part of the vacuum regulator is not used in cars in the USA.'

I think you are you saying it is the positive part not used in the USA that I should disconnect.
Sorry if I appear dense but still cannot get my head around whether to plug the tube from the carbs (that takes over regardless of the manifold vacuum) or the one from the manifold.

[swedishandgerman]

Ah! That kind of confirms my theory, but I'm unsure which is which without seeing your distrubutor in front of me, but I think that the vacuum advance is taken from the manifold and the advance pipe is connected to one of the carbs, right?

Do you know which is the advance and which is the retard side? If not, to find out which is which. With the engine running, disconnect the pipes at the carb/maifold end. Now suck either of them. Whichever one results in the engine speed incrementally increase is the vacuum advance. The other will reduce the speed - this is the retard unit

Now don't just leave the retard unit pipe off and don't use it again. Plug the take off and in my opinion, there's no point in ever using it again. If you want, take it for a spin to confirm - I bet you'll notice ZERO difference

For the sake of this experiment, leave the vac advance pipe off and plugged. Now drive it and tell me if how it differs, if at all

If it makes no difference still pinks, we've confirmed it's all ok and we need to look at something else. If it doesn't pink, there are other improvements to be made! We're making progres here my man!

[swedishandgerman]

That's weird about your dwell angle - does your meter have the possibility to change from 4-cyl to a 6-cyl

However, if you're telling me that it's good at 30, then that's what we should set as a benchmark, I think

[Derek UK]

Don't forget that a 4 cylinder dizzy has 4 lobes and the 6 cylinder, 6. Means that the 6 has less dwell to play with. Some 6 and 8 cyls go to twin points and coils.

This is a nice presentation http://www.orcc.com.au/Shared%20Docu...ll%20angle.pdf

[woolfie1948]

According to the diagram in the manual the pipe from the carb. (connected to the pipe furthest from the dizzy) operates on the primary diaphram and the one from the manifold (connected to the pipe closest to the dizzy)
on the secondry diaphram.
Without doing your suck test I am not sure which is retard but when I disconnect the pipe from the manifold (to set the timing) the engine speed increases.
I left this pipe off and put a plug in it this afternoon but now suspect it was the advance not the retard, anyway below is what happened.
Did not have time for a long drive (and it does need to be really warmed up to pink it's worst) so can't be sure, and remember the pinking is far better now with the wider points gap, but I din't think it improved pinking or performance but the tickover was definitely more lumpy.
I will try the suck test to confirm and if I got it wrong will swop my plug to the other pipe. I am also tempted to try pulling the timing back another degree as I feel I am so close to killing the pink now!

The dwell meter just has a different scale for 4cyl and one for 6cyl - no switch.
The book gap is minimum 10 thou (a lot less than on my 1800E 16-20 thou) it's just that it does not seem to equate with the book dwell as shown on my meter but the gap method seems to work better for me.
I hope to have time and petrol do bit more in the morning but the petrol stations were running dry one after the other round here this afternoon.
With your help we are making progress while your comment about further improvements is a real tease and aroused my curiosity so please stay with me!

[john h]

Originally Posted by woolfie1948

it does need to be really warmed up to pink it's worst

Others on this thread so far more than me about carbs and distributors, so I won't comment on that. But the quoted remark gave me another thought. The B30 is known for sludging up water-ways and having inadequate cooling, usually worst on number 6 cylinder.

If the pinking is only bad when the engine is 'really warmed up', could it be that one piston/combustion chamber is becoming too hot causing pre-ignition? Perhaps compounding another issue?

Sorry if this is an unhelpful tangent!

John

[woolfie1948]

Thanks John for suggesting another possibility.
I will put this on the possibles list for the future as i would think if it is this the cure would be far more work than the possibilites we are trying to eliminate now.
Would the condition of no. 6 plug not give me a clue if this was happening?
The cooling system was drained and refilled with fresh antifreeze when I first got the car as I did not know how long it had been in, and it appears to be clean. I suppose a can of descaling fluid may be a idea anyway.

[woolfie1948]

Suck test carried out this morning!
The pipe from the manifold, connected to the tube nearest the dizzy, is the retard. Checked the manual and this the right way round.
Confirm that this is the one that I plugged yesterday.

[swedishandgerman]

I just read the article Derek kindly put up and of relevenace is the author's explanation of how dwell angle can be calculated into a percentage of time that the points are open vs the time they're closed. On 6-cyl engines, he writes the typical dwell being 30 degs to achieve 50% open and 50% closed. So I'm trying to work out why your manual suggests 40+/-3... It doesn't calculate! So if 0.25mm gap (feeler guage) achieves 30 degs dwell, you have it spot on! The smaller points gap for a 4-cyl compared to the 6-cyl confirms this

I have to say that I'm getting confused with the differing terminology of vacuum retard and advance compared to what's in your book of primary and secondary diaphrams! But...

Disconnect and try the manifold pipe first (theory tells me this should be to the retard). Would you be kind enough to tell me what happens? Nothing at all, or does the idle speed increase a bit?

Once you've reported back (!!), we'll go on to find out what happens when you disconnect the carb pipe (theory = advance).... It may cure the pinking and seeing as your manual suggests that American cars never had it, we shoudl perhaps consider leaving it disconnected - as I said, I have some other things up my sleeve

John H's point of a cylinder overheating is extremely valid as if the chamber temperature is too high, mixture goes weak so could in theory, cause pre-ignition. BUT, in my opinion, the given symptoms mean we should exhaust all procedures with the igniton before looking at that

I love this process of elimination stuff. I've been going through the same over the past few days with my '53 Citroen which has been going down the road like a flatuating geriatric. Finally found that it was a tiny, tiny bit of something-or-other behind the idle jet in the carb. Sorted and running better than before!

[swedishandgerman]

Originally Posted by woolfie1948

Suck test carried out this morning!
The pipe from the manifold, connected to the tube nearest the dizzy, is the retard. Checked the manual and this the right way round.
Confirm that this is the one that I plugged yesterday.

Ah! You posted before I finished writing my reply! So it increases the idle slightly, does it?! Anything else?

Next, would you try 2 things?

Firstly, would you disconnect the advance, plug the pipe and re-post your findings? Does the pinking go away?

Next, seeing as you commented that the idle is lumpy with the retard disconnected, would you tell me what it's like with the advance disconnected, but the retard connected please?