12 replies to this topic

[chazzybaby]

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Please give your topic a title that quickly describes your problem. Just putting 'Help my Mini doesn't work' is useless to anyone trying to help.
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Model: mayfair
Year: 1965
Description of problem (please be as in depth as possible):

rebuild the engine and it ran perfect for 100 miles without missing a beat. suddenly started misfiring. stupidly i decided it must be the head gasket had gone. (after putting it back together i hadn't torqued up the head and before going anywhere i noticed oil leaking out the side. torque up the head and problem solved) anyway after this ran for 100 miles and then suddenly lost power and started misfiring. when i say lost power i could only get 55 out of in. the engine has a stage one kit with i have tuned the mixture on.
replace head gasket, and ground valve seats, now compression is 135PSI (don't know if this is right) timing has been set to 8degreesBTDC, i took rich needle (stage 1 kit) out and replace with the stock.

car runs but undrivable.
rev counter doesn't move when it misses. as far as i can tell there is no reason for it not to run. if anyone has any ideas please let me know!


Any non-standard parts that might be involved with the problem?
stage 1 exhaust & air filter,
engine is 998CC out of an 1986 mayfair.

[Asphalt]

Ok, let's try it:

- Is the firing order right? 1-3-4-2 (anti clockwise)?
- The stage1 kit needs the richer needle! Runing too lean a mixture may cause damage.
- Then; is there enough oil in the carb?
- Did you set the points gap??
- What about tapped clearance? Did you set it after you replaced the head gasket (needs to be done!)?
- Did you check if the head & block surfaces are not warped? If they are, the new head gasket may fail very soon again...

And last but not least:
- replace the condenser in the dizzy (or try another one). If they'r faulty it leads to all sorts of strange runing problems.
- re-torque the head in the right sequence (important!) once the engine has been fully warmed up once and re-adjust the tapped clearances!

Cheers,
Jan

Edited by Asphalt, 25 September 2009 - 06:43 PM.

[liirge]

What colour are your Spark plugs? are they oily?

[chazzybaby]

the condenser,and everything in the distrib. was replaced with new, point set right. new distrib cap,
head and block checked and not warped.
firing order is right like you said 1-3-4-2.
oil level in carb correct
tappet clearances are set right i redid those after torquing up the head and check little while after and they are correct.
new sprk plugs & leads, spark plug bit oily...

could it just be running too lean?

[chazzybaby]

thing is i started it up before with this needle in the carb and it ran a treat although bit under powered. so don't see why it should now refuse to run! unless some piston rings have burnt out

[Nightrain]

could it just be running too lean?

Most definitely, possible burn't a exhaust valve out, reset the rocker clearances and do the compression test again.

[chazzybaby]

hold up...
why do I need t reset the tappet clearances if I've already done that... they are a mechanical linkage and shouldn't/can't change themselves?
also valve have only just been ground in the seats and refitted! there was nothing on them then and engine hasn't run! how could an exhaust valve go?

I'll try a richer needle and see what it think of it! will let you know if any changes.

Accidentally what do you guys think about fitting an Metro turbo engine in a mini and leaving it without turbo? (want to supercharge but as only 20 insurance issues).

[lynnloz]

Hi,

This may be a long shot, but i had exactly this sort of problem on my sons mini today. he replace the head gasket and the carb and inlet manifold gaskets a few weeks back.

Problem: not firing on cylinders 2 and 3

Checked the following:
Compression test: all at or around 200psi
Changed, plugs, points, condenser, still no change
Removed plug leads one at a time while engine was running and noted that when removing number 2 or 3 leads there was no change in the engines running.

Then he said he had a slight popping down the exhaust, which rang alarm bells of an air leak on the inlet manifold.

Sprayed some brake cleaner around the inlet manifold, revs then picked straight up as it started running on the brake cleaner.

Changed the inlet/exhaust manifold gasket and bingo, runs on all cylinders no problem.

Regards
Loz

[chazzybaby]

that's a good point! may change that as well pitty it's such a bugger to do with stage 1 kits!

cheers guy's, got loads of things to try now!

[Nightrain]

hold up...
why do I need t reset the tappet clearances if I've already done that... they are a mechanical linkage and shouldn't/can't change themselves?
also valve have only just been ground in the seats and refitted! there was nothing on them then and engine hasn't run! how could an exhaust valve go?

I'll try a richer needle and see what it think of it! will let you know if any changes.

Accidentally what do you guys think about fitting an Metro turbo engine in a mini and leaving it without turbo? (want to supercharge but as only 20 insurance issues).

Because it's running weak and the compression of 135PSI is way too low. So seeing as you said the head gaskets fine etc, it's leaking somewhere ! Or the tappets are set wrongly !

Leaking inlet manifold will make it weaker, but won't effect the compression ratio.

[samsfern]

if your doing the manifold gasket, undo the manifold nuts, undo the top steady bar, stick a ratchet strap around the oil filler neck and the slam panel, ratchet it up, that way you can get the manifolds off easier and you have more room to get the new gasket on., it also saves a lot of awkwardness and skin if you take the bonnet off

Edited by samsernie, 27 September 2009 - 09:30 PM.

[chazzybaby]

ok so if when i recheck the tappets with a clearance of 12thou and they come out correct what then if the compression is still low? would i have to do a leakage test to see if its leaking past the rings?

[bmcecosse]

As above - that compression figure of 135 psi is far too low - suggests a totally knackered engine !
But rev counter not reading tells me there is a bad connection somewhere in the ignition circuit! Concentrate on that before fiddling with the carb - which WILL need an AAA needle.