18 replies to this topic

[chris_mg72]

I have just rebuilt my 1275 mini engine.
I am trying to petit to run properly and am scratching my head and can not fathem it .
I have installed the 286 cam with a duplex and ligned up the dots and. Checked with a dial gauge.
The dizzy drive installed and rotor arm points to no 1 plug.
I have a 59d dizzy with accu spark unit fitted.
The car starts and runs quite roughly but when I connect my strobe it shows about 40 degrees before tdc as the sparking position as my strobe has a dial I can change the advance .
When I try to move the dizzy to about 10 degrees it stalls and stops.
Any ideas of what I have done wrong before I burn it

Chris

All help accepted

[KernowCooper]

You dont have the vac advance pipe connected when checking the timing do you? the idle will need to be 1100'ish rpm with a 286 cam maybe a hundred rpm more

[dennismini93]

286 cam doesnt have standard cam timing. i dont know what it is but its not in line with what a standard one would be

[KernowCooper]

OP posted said its checked with a dial gauge so assume its set correct at Inlet 106 Deg ATDC

[chris_mg72]

Yep set at 106
Dizzy does not have vac advance fitted as got it made to match cam and head.

[dennismini93]

ok sorry missed that

[lrostoke]

this isn't another one of those accuspark weird advance issue problems is it.

There's another topic going where somebody can't set an accuspark to run right

[chris_mg72]

Will try it with faithful aldon yellow and dlb 105

Chris

[jaydee]

You have to check it with vacuum disconnected at about 1500 rpm.

You need fairly aggressive advance curve with a 286 cam, whats the curve for your 59d? Becuse if standard curve, switch to aldon yellow.

[chris_mg72]

Right . Set cam timing to 106.. replaced points, checked they open and close when they should.
Set dizzy to correct place to spark at no1.
Battery on charge and will start it in the morning! As dont think neighbours would appreciate it now!

Chris

[KernowCooper]

Be interesting to see the outcome, I have a aldon in mine but use a aldon igniter kit

[Pigeonto]

What is actually troubling you here? When you say the engine starts but runs rough, would this not be down to the 286 possibly...have you experienced the idle quality with a 286 before?
40 degrees gives the best idle: nothing unusual about that with a cam like you have, you'll need a lot of idle advance due to such poor cylinder filling at this speed,valve overlap etc and it wont want 10 degrees. My 276 will idle much better at 35 degrees than it will at 20.Never been brave enough to try 40 but it will probably be better still though. I have been told that the hydrocarbon will be horrendous at this setting but with a 286 you probably wont be overly concerned about that. Of course you cant do this because you have a dizzy and you'll end up with over 60 deg at high rpm and horrendous pinking on the way there. This is why I had to go to Megajolt as you can do anything you like to get both a good idle, max power output, economy and no pinking.
**** PS, edit, When I had a dizzy,I locked off the centrifugal advance ,set 30 degrees with the vac connected and had to accept that. This way, under acceleration the vac system backed it off to stop the pinking and it had 30 deg everywhere for reasonable idle and higher speed performance. All good fun

Edited by Pigeonto, 05 August 2013 - 06:17 AM.

[Guess-Works.com]

I'd be checking the measuring equipment.

 

My rule of thumb is 10 degrees btdc will get any mini engine running.

[jaydee]

What is actually troubling you here? When you say the engine starts but runs rough, would this not be down to the 286 possibly...have you experienced the idle quality with a 286 before?
40 degrees gives the best idle: nothing unusual about that with a cam like you have, you'll need a lot of idle advance due to such poor cylinder filling at this speed,valve overlap etc and it wont want 10 degrees. My 276 will idle much better at 35 degrees than it will at 20.Never been brave enough to try 40 but it will probably be better still though. I have been told that the hydrocarbon will be horrendous at this setting but with a 286 you probably wont be overly concerned about that. Of course you cant do this because you have a dizzy and you'll end up with over 60 deg at high rpm and horrendous pinking on the way there. This is why I had to go to Megajolt as you can do anything you like to get both a good idle, max power output, economy and no pinking.
**** PS, edit, When I had a dizzy,I locked off the centrifugal advance ,set 30 degrees with the vac connected and had to accept that. This way, under acceleration the vac system backed it off to stop the pinking and it had 30 deg everywhere for reasonable idle and higher speed performance. All good fun

 

Hes got a non-vacuum dizzy, he cant set it this way

[Pigeonto]

 
Hes got a non-vacuum dizzy, he cant set it this way

Aha, yes. Well he may have to look into getting one, but I concluded that by the time I'd done that and then it still wouldn't be spot on, maybe got another, it would be cheaper to go mappabble and be able to alter it to suit future mods for free. The joys of modifying/optimising engines eh.