ignition timing problems. Wont pink

[bmcecosse]

To determine if it is a low comp engine....

[zacseaman]

sorry, 9M-U-H 458123

[bmcecosse]

Hmmm -well the H indicates 'High' ( ) compression - so it really should get better mpg -and pink..... Does it have the original head fitted?

[zacseaman]

i am really not sure, how to i know if a different head has been put on?, is 6 degrees btdc static about normal do you imagine?

[zacseaman]

I think that i may just get a new 25d (maybe go electronic) and put this dm2 in the boot as a spare (see if the advance curves match up better)

[bmcecosse]

A DM2 is certainly not right....personally I wouldn't bother with electronic - a nice new 45D from Accuspark or Simonbbc will be the best way forward.

[Fingolfin]

That's interesting, Roy. Forgive my ignorance -- ignition is not my best subject -- but what advantage do the later dizzies offer? I ask because my Mog has a 948 engine and runs a DM2.

[chesney]

My Morris had a DM2 too (until I swapped it to match vac advance pipe). Seemed original?

[LouiseM]

A DM2 is certainly not right....

Yes it is, as the DM2 distributor was used on almost all 948cc models. It was replaced by the 25D from engine no: 604228 (1962).

[MarkyB]

What pressure are you putting in the tyres?
The numbers in the book are for cross plys and too low for radials.

[bmcecosse]

Oh well -wrong again! tzch tzch.... I thought DM2 was on the 803/early 948 only....Nevertheless - the later dizzies are improvements - firstl the 25D and then the 45D. Go for a 45D if buying a new one.

[zacseaman]

i have 33psi in the tyres, i think i will stay and get the 25d dizzy as i have read the advanced curves are modernised, and 25ds where fitted to later 948's so probably more suitable.

[bmcecosse]

Your choice - but the 45D was fitted to very similar spec 998 Mini engine.......

[liammonty]

If the vac advance is working, that's helpful for economy,as it gives much more advance at light throttle openings than would otherwise be possible, and helps pickup from low revs too. Just be aware, if you're buying a new distributor, that the ones sold as Lucas are actually 'Lucas-TVS' and are Indian. It's a bit naughty that the suppliers sell them as 'Genuine Lucas'. The one I had seemed OK, but certainly not the same quality as the original. If you're after a new one, PM me, as mine is surplus to requirements now (it's a 25d supposedly curved for a 948 engine,as sold by BM). I don't want much for it, and it was only fitted for around 5000 miles.

BTW, I could never get my 1098 Traveller to pink even when I advanced the timing silly amounts- that's an engine with good compression which has plenty of power etc. I think that modern fuel has better anti-knock properties than fuel years ago, and Minor engines are low compression by today's standards. In my case, it was possible to advance the timing way too far without hearing any pinking at all (and I'm young enough to still have a good range of hearing!!!). My point is that you shouldn't worry that you couldn't get your engine to pink. You could always check max advance if you're worried about over-advancing it and melting pistons etc- this is a better indication than static advance. Make sure it's not giving more than around 34 degrees maximum advance with vac disconnected, and it should be fine. Just rev the engine until you get no more advance- you'll need a strobe for this- I'll take shelter now before being told off for using a strobe! .

[zacseaman]

Its ok, i think i will get one from accuspark or simonbbc, they seem so cheap!! I dont have a strobe unfortunately, but she seems to be running fine so i am going to leave her how she is. it isnt kicking against the starter and starts on the first nanosecond of pulling the starter so i think all is well Thanks for the offer and advice though it is much appreciated.

[liammonty]

No probs- sounds like it is running well now!

[bmcecosse]

Oh yes - you can use a strobe for this - if you have markings for 34 degrees....... My engine certainly pinks - but it does have decent compression.

[liammonty]

You can work out the marks if you know the pulley diameter I guess. My strobe is adjustable though, so you can alter the degree setting and then just use the TDC mark to read off. It's an essential bit of kit for me, as in addition to the 3 Minors, I've got an aircooled VW (sorry..) and they melt pistons extremely quickly if the max advance is even a few degrees over what it should be, as their cooling is marginal.

[zacseaman]

Apologies about bringing this thread back up. I have found for my standard 948 the optimum power to be at 7.5 degrees advanced static for any others out there who have had problems sorting ignition out I would imagine this would be a good place to start. I can feel I have more power at this setting, the engine sits happier at higher revs and requires less pedal cruising at 60 than it did when it was at 8 degrees static and standard 5 degrees static. I have also seen a large jump in mpg to approximately 40mpg very happy

[bmcecosse]

Hard to imagine you can tell a difference between 7.5 degrees - and 8 degrees........ But if you are happy with the running - and it's not pinking - well done !