Lack of Performance/backfiring/wont run properly!!

[moggymaniac]

hey guys bit of a problem. Just got the moggy back on the road after putting in a new gearbox successfully solving the last problem, was driving home and all of a sudden the engine stopped performing properly, revs increasing very slowly/no acceleration lots of popping/spluttering/backfiring from exhaust and i'm pretty sure its not ignition system as ive replaced basically everything but the condenser and coil. Getting a bit of a tapping from inside the rocker box so maybe something there si the problem. any suggestions? iv also put a 1275 mini rocker cover on it, shouldnt make a difference to tappetts clearing the cover should it?

[hotrodder13]

mine did a simular thing, wouldnt go very fast and a tapping and backfireing, no acceleration might be your head gasket check your water level in the rad

and if it is that dont drive it at all, i did and put a hole in my block

tom

[moggymaniac]

ok tom, thanks for the advice, my dad and i noticed she seemed to be running hot but the gauge said otherwise, maybe thats stuffed too...the rad was almost empty but that seemed to be where i hadnt tightened the bottom hose up properly after having the engine out last time. so i cant be sure. thanks though i'll try the obvious stuff first like consender need a new vacuum pipe and possibly coil lead, if not will have the head off!

[mickm]

Just an idea, but before lifting the head try a compression test first!!

[moggymaniac]

ok will do thanks,
jamie

[PSL184]

Compression test will confirm (or not) if HG is blown immediately. Condensor would be my first chioce for trying to fix but after that it sounds like HG....

[bmcecosse]

Compression test????????? Do you have a 'scientific' reason to back up that suggestion PSL .....

It does sound a bit like head gasket problem - if the water level falls below the temp gauge sensor -it will not read high. The warning sign is loss of heater - when that happens - always stop immdiately.

[PSL184]

Nope - just a degree in "bulls..."

[bmcecosse]

Excellent - just the right requirement to deal with some of the characters on here! And NO - this is not in any way aimed at you moggymaniac - it refers to another recent argumentative poster who reject the idea of a comp test 'out-of-hand' - he knows much better!

[Kevin]

...the rad was almost empty but that seemed to be where i hadnt tightened the bottom hose up properly after having the engine out last time.

Many years ago I had a hose split and ran rather low on water and my performance not only went off but the engine noises became much louder especially the tappets, I would try topping the water up first (making sure there are no leaks) and see what happens first in case that's all it was.

[bmcecosse]

It could just be an oiled up plug - or some similar simple problem. Have a look at the plugs anyway.

[moggymaniac]

thanks for the advice guys, basically i came home saturday lunchtime to find my dad uunder the bonnet with the idea that its an ignition system problem, so he replaced the condenser, the coil and the lead from the coil and put in 4 new plugs. The running of the car improved dramatically to the point where i can hardly feel the loss of power now but it's still not quite as responsive as before, and when you rev the engine it seems to misfire and pop on the way back down to tick over, but then ticks over ok. The leak was found and sorted, radiator had a slight leak. the only ignition things i havent replaced are the points (a new set went in just a week before this problem started so i thought it cant be) the rotor arm, dizzy cap, and plug leads, which are only 6 months old. Should i replace these or suspect exhaust valve wear and tear? sorry for the essay

Jamie

[PSL184]

Just tweak the timing first and see how she runs then.....

[bmcecosse]

So - this problem has come on a week after changing the points ?? That's EXACTLY where to look for the problem then! Either refit the old points (why did you change them ?) - or clean these ones and re-gap them.

[moggymaniac]

i have checked/regapped the new points to no improvement, i changed the old ones as part of a standard kind of service whilst the engine was out/oil filter too etc. bought new points again today will fit and check tomorrow as i'm not sure where ive put the old ones! will keeo you posted!

[moggymaniac]

also, if it was the points...would i not have noticed the engine running poor immediately rather than a week down the line? kind of strange dont you think?

[bmcecosse]

Not strange at all! Some of the points sold these days are 'not the best' shall I say! But it may not directly be the points - you may have disturbed something else while fitting them. In any 'fault finding' process - always take a step back to what was done last.

[moggymaniac]

great will do! thanks

[nigelbainbridge]

do compression test,some garages have a thing called a sniffer ,it takes two minuites to check if your head gasket is gone for definate.just a long shot check you tappet gaps if you have a tapping .elimination is the word i think.

[moggymaniac]

done a compression test, its all good. changed the points, hell of an improvement proves they make rubbish points nowadays be careful out there! however still backfiring on deceleration at 3k revs and above and slight delay on acceleration just after changing up a gear from higher revs. will check the tappetts next! thanks, jamie