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Ignition timing

Posted: 31 Jul 2006, 08:23
by SteveW
I have also put this post on the alt. fuels forum.

I have just put a 1.9 dg in to my bus that had a 2.1 dj in. So it is running injection and gas. The replacement engine did not come with a dizzy so I have taken the one out of the 2.1 by undoing the clamp fixing rather than the clamp. This was good enough to start the engine but i feel the timing is out as I am now get a bit of a backfire both on gas and petrol.

What I need to know is what should the timing be for the 1.9 and how do I go about setting it with the 2.1 setup?

re: Ignition timing

Posted: 31 Jul 2006, 08:44
by Grun
SteveW,
It says 'ere... (Haynes)

1.9 litre engines code DG (and SP) 5 degrees (+ or - 1) BTDC at 900 rpm (+ or - 50) vacuum disconnected.

2.1 DJ for 98 octane fuel 10 degrees (+ or - 1) BTDC at 800 rpm (+ or - 50) vacuum disconnected

2.1 DJ for 95 octane fuel 5 dgrees (+ or - 1) BTDC at 800 rpm (+ or - 50) vacuum disconnected.

If the DJ was set for 98 fuel you are about 5 degrees too far advanced. Turning the distributor body slightly in the direction that the rotor arm turns will retard it, until you can do it with a strobe or something.
Gas I know nothing, (Steve at gasure? can help) http://www.gasure.co.uk/

Mike

re: Ignition timing

Posted: 31 Jul 2006, 09:09
by Grun
SteveW,

Waaaaaaaiitt a munut, as Eccles used to say in "The Goon Show" (before your time?)
If you have just swopped the distributor across without checking the basic static timing, you could be a long way out, like wrong cylinder/plug firing.
Could be dangerous, like FIRE :shock: :shock: :shock: :shock:
Be careful, I tend to assume some knowledge, but not all who post have the same level of course.
Just had a re- read, (it was panic stations, for a mo there!!!) if it is running then not so bad, still it doesn't hurt to point out possible pitfalls.
I'll cancel the Corporal Jones act, and get me coat :oops: :lol:
Mike

Posted: 31 Jul 2006, 09:35
by SteveW
I must admit that I did assume that the crank to dizzy drive would have the same timing on both engines and that if I swapped the dizzy across without moving it on the clamp I should be some where close, indeed the engine started up and ran to a nice smooth idle, after I got the oil pressure up of course. Which was flushing oil.

I will treat it to new plugs, leads, cap and rotor arm later today. My strobe is about 30 years old and conects via the plug cap and plug so will be of no use on this engine as getting to No.1 plug is not great and made worse because of the gas conversion. I will have to see if I can borrow one of those new fangeld inductive types. Not going to buy one when the 30 year old Gunson with built in Tacho is still working fine :lol:

Re: Ignition timing

Posted: 31 Jul 2006, 09:46
by Grun
Hi Steve,
I got a Draper strobe(Timing Light) online from Amazon the other day, for my Mini Cooper Mad Major the neighbour.
Nice white light (Xenon) plastic pickup seems to clamp over the pluglead. I'll get a look at it. Was not expensive and post free. Draper 52616 £18.98
Mike

Posted: 31 Jul 2006, 10:01
by HarryMann
You're also assuming that the centrifugal and vac advance required by the 1.9 is the same as the 2.1. Its highly unlikely to be... put the correct distributor on else your static setting will just be an approximation at one engine speed and load...

If the air filter is on and the system closed up, there's little danger of backfire through the inlet causing a fire, though of course anything is possible (its more likely to wreck the AFM).


The AFM is also calibrated for the 2.1, but this shouldn't be a busting lot out.

Posted: 31 Jul 2006, 10:01
by SteveW
That is cheap enough. Perhaps I should invest in one, if I remember the Gunson was around twice that 30+ years ago. :shock:

Posted: 31 Jul 2006, 10:39
by SteveW
HarryMan
You are correct the dizzy's do indeed have a different part number. I will have to have a search through my manuals later and compare the curves and total advances. The AFM I did not even think of it let alone that it would be a problem. This interim engine swap sure has started to get complicated and expensive.

Posted: 31 Jul 2006, 12:46
by SteveW
:oops: Just realised I may have No.s 3 - 4 HT leads reversed. Fairly certain when I put the leads back on I went 1-3-4-2 :oops: and not 1-4-3-2 that would acount for the backfire through the inlet. What a dipstick all I can say is I was hot and tired by the time it came to put the leads back on. If I have I will admit it for you all to take the mick out of me. :wink:

Re: Ignition timing

Posted: 31 Jul 2006, 12:53
by Grun
Steve, Clive (Harryman),
Caw 'ow times 'ave changed. Us used to time ower engins wiv bit of rizla paper in the points, and a bit of straw , or summat like that there stuck in a plug 'ole to find where the piston was to.
Advance and retard was a big lever on the steering wheel boss, and the only vacuum I remember, was the autovac fuel system, leastways till they new fangled Fords came along with windscreen wipers you didn't have to work by hand. :lol: :lol:
Mike

Re: Ignition timing

Posted: 31 Jul 2006, 13:01
by Grun
SteveW,

Mickey taking, on 80 - 90. surely not :roll:
I hope plug leads are all you need to get you rolling but do let us know about dizzy numbers and advance curves etc. please.

Mike

Posted: 01 Aug 2006, 14:38
by SteveW
Not had a chance to check the advance curves yet for the DG and DJ, but when you get the correct leads on the correct plug the engine runs well, with no real difference between petrol or LPG

DH engine is 5 deg ATDC with total advance of 33 - 41 deg @3800 rpm

MV engine is 5 deg BTDC with total advance of 35 deg @ 3000 rpm

So a big difference between these two. When I get some time I will check out the DG - DJ