The car just won't run right.

Post by **bmcecosse** » Sun Oct 19, 2008 10:30 pm

The fumes come back into the car - no matter what.

Post by **Lukey** » Mon Oct 20, 2008 2:28 pm

I took the dizzy out, it was very worn. My friends dad gave me another Lucas 25D from a shot 1000 engine, we swapped the vac advance unit over all was going well until we tried to put the cap on and the rotor arm was stopping it from fitting properly. The unit that my I was given appears to be a little longer too. Does anybody have any idea why they won't fit?

Post by **eastona** » Mon Oct 20, 2008 5:50 pm

aren't there 2 different types of rotor arm?

I seem to remember the mini ones being slightly shorter?

is that the difference between a 25D and a 45D?

BMC?

Andrew

Post by **bmcecosse** » Mon Oct 20, 2008 5:59 pm

Well a 45D is a different beast - but if both dizzies are 25D the cap should fit!

Post by **Lukey** » Mon Oct 20, 2008 6:27 pm

Took it to my motor factors, they showed me that that cam was sticking up a good 5mm taller than the other and that the points weren't sitting on the cam correctly. We tried putting a side valve cap on because it looked as if there was more clearance but that didn't fit. Everyone there was stumped, they said there's defiantly something not quite right with it and that I'd need to take it to Lucas (my local Lucas was sent in to administration two weeks ago doh!)

Took it apart again put it back together same problem, I've given up and bought a new one from bull motif.

The other distributer was very worn the springs were so loose you could just pull them off with your finger, almost just balanced on there. The shaft was making a clunk and moving so this has got to cure my idle.

Post by **eastona** » Mon Oct 20, 2008 6:51 pm

The shaft was making a clunk and moving

doesn't sound normal!

no idea why the other one doesn't fit.

Are you sure your engine/distributor are standard?

Andrew

Post by **Lukey** » Mon Oct 20, 2008 7:00 pm

As far as I know yeah, the history of the car is very patchy though with me buying it from a breakers not being able to ask the previous owner any questions.

Post by **bmcecosse** » Mon Oct 20, 2008 11:53 pm

The springs should be loose - the only worry really on a 25D is side play in the shaft bearings. If that is excessive then the points gap varies and so does the timing!

Post by **Lukey** » Wed Oct 22, 2008 10:04 pm

New dizzy came today, it runs so much better I can't tell you. There's still not something quite right there but that's one major bit out of the way.
Should the engine have been pinking at 5 deg before tdc on regular unleaded?

Post by **bmcecosse** » Wed Oct 22, 2008 10:18 pm

You need to retard it until there is just the slightest trace of pinking - AS YOU ACCELERATE - then the pinking must die away. You must NOT let the engine pink continuously.

Post by **Lukey** » Wed Oct 22, 2008 10:36 pm

I set the timing to 5 deg btdc. The engine ran beautifully but pinked like crazy so I retarded the timing until the pinking went but it didn't run as well.

Basically is it normal to set it to 5 deg btdc then retard it, or set it 5 deg btdc then advance it until it pinks?

Post by **PSL184** » Wed Oct 22, 2008 10:41 pm

What gap did you set the points to?

Post by **bmcecosse** » Wed Oct 22, 2008 10:51 pm

The new dizzy may not have the correct advance curve for your engine. Ideally you want it to be such that it idles well AND runs well! You can look inside and see what the mechanical advance is set to deliver - overall the engine needs ~ 30/35 degrees advance at speed. The mech advance may be marked say '13' - which gives 26 degrees of advance (2 x 13) and so static advance of around 5 or 6 degrees may work well. If however it's marked '11' - then much more static advance ( ~ 8/10) will be needed, and vice versa if it's marked '15' then less static advance ( ~ 0/2) will be required to stop it pinking - and then it may not be ideal at idle speed! Although it's a new dizzy - just check the vacuum advance is working properly because that comes in to play at idle speed and if it's not working then that gives poor idle.

Edit - The ideal dizzy is a '123' which comes with a complete range of advance curves which are selected at will. Snag is a cost of close to £200, but it does include electronic ignition built into the dizzy. If I could afford one - I would have it! But it would be for my TR7 - not the Minor, which goes well enough on my home-modified nos dizzy bought at a jumble for £5!

Post by **Lukey** » Wed Oct 22, 2008 11:10 pm

Points set to 14 thou. I checked the vac advance before I put it on, worked fine. I'll check the dizzy tomorrow. How strong should the vacuum coming from the nipple on the inlet be? (the nipple that attaches to the vac advance)

Post by **bmcecosse** » Wed Oct 22, 2008 11:15 pm

The vacuum varies with engine speed and throttle opening. If you rev up hard and then close the throttle sharply - the vacuum will be close to 30" Hg.

Post by **Lukey** » Fri Oct 24, 2008 4:26 am

Drove it to work and back and realized it was still pinking, in 4th going up an incline mostly and at high rpms in 3rd. I retarded the timing a bit more and the car wouldn't start with that much retard.
There's something seriously not right with it.

I'm about to give up now, I've spent a whole evening trying to stop it pinking, I've done everything short of a decoke. Even put some colder plugs in there. Is it worth trying a decoke before I throw in the towel find a decent mechanic?

Post by **alex_holden** » Fri Oct 24, 2008 8:42 am

Try a compression test. One of my cars sounded like it was pinking when actually the head gasket had partially failed.

Post by **rayofleamington** » Sat Oct 25, 2008 9:46 am

Should the engine have been pinking at 5 deg before tdc on regular unleaded?

Basically that should work well for a first set up.
When you have full throttle the vac advance can be ignored. Vac advance is only there for fuel economy and will advance the timing at low throttle.
If you are getting pinking at partial throttle - something very not right, as the cylinder compression value is lower with part throttle.

If the engine wont run when retarted to 0 degrees BTDC then this also indicates a serious issue. The average Minor engine will run almost normally (with a fraction less power) at 0 degrees.

Post by **bmcecosse** » Sat Oct 25, 2008 1:19 pm

There must be something seriously amiss with that 'new' dizzy -it must be going to full advance as soonas you rev up. Maybe a spring has come off - or the springs are far too weak. Try another dizzy - it's not going to be decoke etc, no need for that! Strange it wouldn't start - they usually start ok even with impressive amounts of 'retard' - too much advance of course makes it 'kick' against the starter and then it won't start and may break the starter bendix!
Don't be offended, only trying to help - but are you turning the dizzy the right way to retard the ignition - not by any chance advancing it by mistake ? Retard is anticlockwise turn.

Post by **Lukey** » Sat Oct 25, 2008 5:36 pm

Solved it, the cylinder head wasn't torqued correctly! Thanks for the help everybody, It runs beautifully with the new dizzy too!