chevy 229 odd fire distributor

[zzzzz]

hi the anyone help this pooroldpom out with a problem the motor is a chevy v6 oddfire and i for the life of me cannot stop it missfiring just rebuilt the heads and replaced the dissy cap and inbuilt coil plus the rotor. have double checked the firing order #165432 # and still it will ide well but under power will missfire like a gun going off.have been unable to find much info on the net about these distributors and setting them up so now i need help,

[intelliGEORGE]

Those are notorious for misfire generally at the higher end of the RPM scale approx 5000 rpm. I'd say replace it with a newer dizzy, there are a lot on the market that specialise with this motor as enthusiasts that race them have found that they combat common issues such as cross fire, misfire, burn out, rotor bounce etc.

Aftermarket dizzies can have several advantages;

1. Up to 9000 RPM operation (twice as much as standard)
2. Optimum advance curve
3. Low amperage use
4. Twice the fire over magnetos
5. Improved throttle response

[Godzilla]

Did the misfire start after the work you did?

Have you read the plugs to see if their all uniform, or that 1 or 2 are different?

When you say misfire you mean a plug not firing, many not firing, backfire inlet or exhaust?

Can you post a pick of the engine or explain what type of ignition system, magneto or coil, crank sensor and so on to give me am idea of the set up.

Have you tried to close the plug gaps by .1mm-.2mm to see if the misfire goes away?

I did have something similar a number of times, it normally comes down to a number of ignition problems.

Points gap, leads, plugs (hotter, and/or less gap), bad earth for dizzy or engine, cracked cap or bad centre contact, dirty rotor, crank sensor playing up, coil with crack.....the list could go on.

Id read the plugs, even pull leads while it misfires (be careful to insulate yourself) to see if i could isolate it to a particular cylinder.

One other thing you could try is to spray your high voltage leads, dizzy and coil in soapy water while the engine is running. Use dishwashing liquid.

If you have leakage you will see a nice lightning show at night.

Edit; the last time i saw something like this it was just a ignition lead, passed enough spark at idle but couldnt at 2000 rpm+

[intelliGEORGE]

This guy explains the oddfire in laymans terms.



Read the part about the dizzy cap, it points out that GM in their infinite wisdom used the one cap to work on all of their engine configurations. Have a read, got some pics to explain the way the dizzy works too.

[Godzilla]

Good link George.

One thing i picked up on is if the dizzy was, put in the wrong way you would have a misfire when the timing advanced as it would miss the extended terminals under the dizzy cap on certain cylinders. Hence misfire at a rpm that needed timing advance.

Another possibility.

(what a crappy tight arse design)

[intelliGEORGE]

I knew they were a problem from experience with an old Buick V6, there are far more advanced "purpose built" dizzies. I wouldn't bother with trying to fix it, I'd be looking at trying to find an MSD replacement or the like.

[zzzzz]

thanks for all the replies guys but it turned out i had miss read the pot numbers by placing the odds on the drivers side instead of realising that the yanks drivers side is on the left so once i got myself right with that it was all systems go go go

[Godzilla]

and still it will ide well but under power will missfire like a gun going off.

Im still trying to comprehend how it idled well with your cylinder banks mixed up. LOL

Never the less congrats on getting it going zzzzz.

[zzzzz]

Im still trying to comprehend how it idled well with your cylinder banks mixed up. LOL

Never the less congrats on getting it going zzzzz.

after all the reading i did it works out that as long as the timing is retarded enough it will run quite well due to the way the crank and cam are designed as it turns out all they did was cut 2 pots of the v8 version..

[problem child]

thanks for all the replies guys but it turned out i had miss read the pot numbers by placing the odds on the drivers side instead of realising that the yanks drivers side is on the left so once i got myself right with that it was all systems go go go

they are numbered from the front not left.