please help
My grey motor has just been playin up
it is slightly worked, twin stromies
1st it was the points so fixed them
went alright for a while then:
2nd It conked out and was told could be the fuel,my carbies were a bit old so had them reconditioned
3rd put the carbys back on, started when wasnt reving properly
checked the timing..little out so tweeked that
then put in electronic ignition and new coil+leads+plugs
4th now it starts fine revs OK....but when it gets hoet after driving for about 10mins..misses farts and backfires
seems to break down under load
does anyone have a clue what it could be
please help!!!
138 grey motor bbackfiring and missing under load
Backfiring and missing under engine load only could most likely be an ignition circuit problem and most likely either spark plug/s breaking down and/or ignition leads with too much electrical resistance.
If it was an engine mechanical problem it would most likely miss and fart at all times and not just under engine load as you describe.
That said, maladjusted engine tappets may cause a problem when the engine is hot if they are too tight with not enough clearance it can actually hold the enigine valve slightly open when hot and contribute to the hot running problem especially if it's an inlet valve that is being held slightly open.
With a cold engine there is more tappet clearance and some less chance of engine problems until the engine heats up and metal expansion due to heat lessens the amount of clearance.That's why most engine manufactureres give tappet cold and hot settings.
However the problem could be elsewhere, it's hard to diagnose an engine problem without actually being there under the bonnet or actually driving the car with the problem evident.
There could be carby problems,even though they have been rebuilt.Do you run a fuel filter and if so is it in the preferable position between the fuel pump and tank line?
Have you replaced the condensor at the ignition points?A faulty condensor will allow the points to burn quickly.Although this would most likely give erratic problems across all engine RPM and loadings.
There's some things to start you off, but checking/replacing these may or may not fix the problem as its so hard to help people with engine problems via a typed out description.
If it was an engine mechanical problem it would most likely miss and fart at all times and not just under engine load as you describe.
That said, maladjusted engine tappets may cause a problem when the engine is hot if they are too tight with not enough clearance it can actually hold the enigine valve slightly open when hot and contribute to the hot running problem especially if it's an inlet valve that is being held slightly open.
With a cold engine there is more tappet clearance and some less chance of engine problems until the engine heats up and metal expansion due to heat lessens the amount of clearance.That's why most engine manufactureres give tappet cold and hot settings.
However the problem could be elsewhere, it's hard to diagnose an engine problem without actually being there under the bonnet or actually driving the car with the problem evident.
There could be carby problems,even though they have been rebuilt.Do you run a fuel filter and if so is it in the preferable position between the fuel pump and tank line?
Have you replaced the condensor at the ignition points?A faulty condensor will allow the points to burn quickly.Although this would most likely give erratic problems across all engine RPM and loadings.
There's some things to start you off, but checking/replacing these may or may not fix the problem as its so hard to help people with engine problems via a typed out description.
I can't think what to write here so this will do.
-
Sammy
- Posts: 664
- Joined: Mon Jun 26, 2006 3:06 pm
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- Location: Tenambit, NSW.
- Contact:
when you installed the electronic ignition did you get 12V for the positive coil terminal ?
normally the ignition wire has a resistor in it to limit the voltage to the coil and if this was plugged into the coil that will give it less than what it needs to run correctly.
so easy way to do it is put a relay in there, use the original ignition wire to power the relay (pin 85/86) then the other one of those two pins goes to ground. then get a nice big red wire to go from the battery +ve to pin 30 on the relay and then pin 87 to +ve coil terminal.
normally the ignition wire has a resistor in it to limit the voltage to the coil and if this was plugged into the coil that will give it less than what it needs to run correctly.
so easy way to do it is put a relay in there, use the original ignition wire to power the relay (pin 85/86) then the other one of those two pins goes to ground. then get a nice big red wire to go from the battery +ve to pin 30 on the relay and then pin 87 to +ve coil terminal.
Regards,
Sammy.
http://www.oldholdens.com
Sammy.
http://www.oldholdens.com
1864A pertonix
Ta for the help
got to the bottom of it tappets were too tight as well as not enough oil was getting over the valves-causing them too stick
However the guy that fixed it couldnt get the electronic ignition to work
kept backfiring and running rough, so Im bloody back to points
running ok though
any hints on these pertronix1864A ?
coils plugs flame thrower coil all on just like they say
got to the bottom of it tappets were too tight as well as not enough oil was getting over the valves-causing them too stick
However the guy that fixed it couldnt get the electronic ignition to work
kept backfiring and running rough, so Im bloody back to points
running ok though
any hints on these pertronix1864A ?
coils plugs flame thrower coil all on just like they say