FE-FC Holden Discussion Forum

Hi I have a standard 138 grey engine with twin carbis
about 6 months ago she started missing and farting so I renewed the leads and plugs and points
still no success ,it seems to foul the plugs
So I put it in the shop ,
I had the carbies overhauled and asked to have the timing reset and have a meter put on the have the correct balance of petrol and air
all good ........... no chance
After about 15 mins driving she starts to miss again
its been back 2 more times but small adjustments havent helped 
Im at a loss
Any ideas ?
FE

You may want to check the coil as the old oil cooled versions when wearing out work OK until they get hot.

Cheers Wayne

It may also be worth checking the condenser as well.

How is it fouling the plugs? Crusty or just black. You may need a compression check.

Colin.

Hi Colin.
         A standard grey with twin carbs ( Strombergs ? )  =  too much fuel so the plugs may well foul unless you can reduce the flow on the main jets on the carbs. If the compression is ok and it's  not using oil I would suggest going to a single carby . I can't see any advantage in having twin carbs unless the motor has had some performance work done. Fitting twin or triple Stormie's to a grey can be a real pain in the ass unless the carbs are matched to the performance specs of the motor.
        Dry grey / black foulling would suggest to much fuel .  Wet black fouling would be from excessive oil in the combustion chamber. If the problem started about six months ago did the motor overheat ?  It could be the rings.
       Brad.

FE
I have run twins in my car for the past few years with no problem, improved fuel economy and performance (also have Jack Myer headers fitted). When first fitted I had the head converted to ULP and the usual porting, grinding and refacing that goes along with it.

Recently (Perth Nationals) I had to replace the motor due to unforeseen issues (keyway on crank chewed out) with the assistance of a few good friend I now have a standard FX/FJ grey 132.5 in my car and still running twins, headers. we did the trip (Perth - Adelaide) in three days and the motor ran fine.

I would suggest that it could be a combination of issues causing your problem. I totally agree with some of the comments and I would suggest that your distributor could also be causing an issue so may need to be checked and even overhauled, process of elimination

- Plugs (Done)
- Points (Done)
- Leads (Done)
- Dizzy Cap
- Condenser
- Coil
- Timing
- Carby's tunes to match (I had my car Dyno Tuned I will find out what jets I ended up with made a huge difference)
- and the other stuff suggested by others.

Had my car Dyno tuned by John Dunstan in Kent Town just before the NSW Nats and did not tough it until he did it again before my trip to Perth, Once its done right you really only need to maintain.

Cheers Jim

Jim, I have to agree about the carbies, I've run twins before and now run triple strombergs with venturi sleeves and smaller jets and yes the motor has other mods extractors, electronic ignition etc. and it runs great around town or on the highway.
 
FE, unless you want to learn to tinker yourself as strombergs are a good carbie to work on, find yourself a mechanic who is experienced with grey's to go over them for you.
Harv has put together a brilliant reference guide to strombergs that you should read through, its full of invaluable information including a section on running multiple carbs ;)

How did you end up with the twins?? were they on the car when you got it (bit hard without knowing the whole story) or were they a recent purchase (swap meet / ebay) are you running extractors or headers?? These almost go hand in hand with running twins or triples, it's all about helping the grey breathe better and once sorted I'm sure you'll be happy with the twins.

Brad, Your advice to go back to a single stromberg is sound from a quick solution perspective but I know plenty of guys running twins/triples successfully, as with any modification it's always best to do your homework (research) to gain the best results ;) and some modifications e.g. electronic ignition can only help improve the reliability and performance of our beloved grey motors. As far as running twins or triples goes I guess from my point of view this was what the hot Holdens were running when I started driving, unless you could afford to buy a red motor  ;)

I make no secret of being a "Greyaholic"  ;D ;D ;D

Mick 8)

Just reread your original post and have to lean towards the coil / condensor as the probable cause :-[ :-[ :-[ I think I got sidetracked when the strombergs were blamed.
Let us now how you get on, but if it is ignition think about an electronic conversion it really helps particularly with the quality of fuel these days.

Mick 8)

Is it missing only when the revs are up a bit?  Could be the vacuum advance on the dizzy.

Hi Guys
I received my FE back last week I had a new condenser fitted and new points
I drove it for about an hour and so far so good
when I change down to second for round a bouts it farts sometimes but overall not too bad

So my thoughts are that it was the condenser ,but my knowledge of what it does 
 so does anyone know what the aim of this device is

FE

Hi FE, good to know the car is performing better.  Rather than write my words have a look at this site.

http://au.answers.yahoo.com/question/index?qid=20080803011923AAKIebG

Keith

And yet another explanation from another web site

Technical Talk – Ignition Condensors

Basically the function of a condenser in a coil ignition circuit is to reduce the spark at the contact points as they open in the distributor and thus minimise burning and pitting of the points. Arcing is caused by the effect of self induction in the coil as the points interrupt the flow of current. The resultant collapse of the magnetic field produces a high voltage to be generated in the primary winding which then tends to flow across the points, thus causing burning or pitting. This current flows into the condenser and charges it as the points open the rapid collapse of the magnetic field produces this high voltage in the primary windings, which can be as high as 250 volts. This further charges the condenser and the consequent collapse of the field causes a high voltage to be induced in every turn of both primary and secondary windings. As the secondary winding has about 100 times the number of turns of the primary, the voltage can reach as high as 25000 volts. Normally this voltage is not reached as it is limited by various factors such as point gap, compression, engine revs. Etc. so only sufficient voltage is produced to produce a spark at the plug. As the spark is produced at the plug gap the energy in the coil, stored in the form of magnetic flux, begins to drain from the coil through the secondary circuit thus sustaining the spark for a fraction of a second or several degrees of crankshaft revolution. During this interval the condenser discharges back through the primary winding producing an oscillation of the current flow in the primary circuit for the brief interval that is required for the primary circuit to return to a state of equilibrium. The condenser DOES NOT DISCHARGE UNTIL AFTER the spark has occurred at the spark plug.

Burning of points results from high voltage, presence of oil or other material at the points, defective condenser or too small a gap in the points. High voltage can be caused from high voltage setting of the regulator or high resistance in the charging circuit or the third brush set too high. On third brush generators too small a gap at the points allows the points to stay closed longer resulting in the average current being high enough to allow the points to burn rapidly.

Contact pitting results from an out of balance condition in the system which causes the transfer of tungsten from one point to the other so that a tip builds up on one point and a pit on the other. The direction in which the tungsten is transferred gives an indication for correcting the situation. If the tungsten transfers from the negative to the positive point one or two corrections may be made. Increase the capacity of the condenser, shorten the condenser lead, separate high and low tension leads between the coil and distributor, move these leads closer to the engine block. If the transfer is from the positive to negative point, reduce condenser capacity, move low and high leads closer together and/or away from the engine block, or lengthen condenser lead.

Good luck with your trouble shooting. This information was taken from a Delco Remy electrical equipment book.

Keith