Gremmlin in GT

[GTtoo]

Blue Beastie not running since May. Here's the scenario : Turned the G161 off after yet another great fang. Went to start it 12 days later. All i could get is backfiring ( like a shotgun) and coughing through the second Stromberg.

What was tried ? (everything). Changed points, coil, leads.....etc. Still no cure. Eventually took the dizzy out. It was knackered. I had it reconned and I put it back in yesterday, but still has the same problem. The timing is eratic, and the timing light dies every so many rotations. So frustrated after months of f...ing around, I drove around the block. It was a drive from hell, and the G161 would'nt pull the skin off a rice pudding.

Theory : Did some research on "dwell angle". Possibly there is a short in the earth (negative) somewhere, which is not allowing for the dwell to build up enough current for the next millisecond of ignition. Hence the eratic firing.

Can anyone shine some light on this ? I'm sure someone has seen this problem before. Should have stayed connected to B'net and only have myself to blame for not staying connected to the people who count.

B.

[mrflibbles]

dont sound to good, sorry im not much help!
I have seen the dwell set properly on mine and she ran like a charm after, maybe some electronic style set up instead of points?

[oz_toffa]

try running it at night with no lights and see if there is a tracking to earth. stuff can often be seen in dark but daylight hides much. you have isolated dizzy, leads plugs and points so it has to be wiring


OZ

[oz_toffa]

i am assuming you did replace the distributor cap and rotor and that they are correct. like the rotor can be short by 1mm and will overheat the coil and cause a poor, weak spark. always keep the old ones for comparison purposes.

OZ

[GTtoo]

Thanks Oz, Never thought of in the dark diagnostics. (even though I might not be exactly sure what I'm looking for ). Also will check length of rotor, match it with the old one....etc. Yep, new dizzy cap and rotor in there, doh.

Might not happen for a day or two at this point. Slightly busy for a couple of nights, also got Vic weather here, and I need a break from trying stuff on the GT, cause it's....DRIVING ME LOOPY !!!!

Cheers Mr. Flibbles. Can you explain how the dwell angle was achieved. Can anyone tell me the relevance of dwell angle, in relation to points gap and how it is set. I'm definitely missing something here.

B.

[mrflibbles]

some friends had a dwell angle measuring thingo (possibly not the correct technical term) and whilst they were adjusting points gap, it was hooked up to measure dwell angle at the same time. Its possible they could chime in on how its done as i watched whilst they tweaked!
This was the first time i had actually seen the dwell angle taken into consideration, and have set up several cars points without giving it a second thought.
i might have to go look into my technical books to give you a better idea of what the dwell angle is!

[oz_toffa]

Dwell Angle is a clever way of measuring the points gap electrically.
and probably more accurate as gaping with a feeler gauge is very open to personal bias. some people like it to grab quite a bit while others use the it feels freee so must be right. i digress

to explain further..

a 4 cylinder car is therefore going to divide the total 360 degree travel of the rotor into 4 quarters.
each quarter is 90 degrees and the Dwell Angle meter is calibrated to measure the amount of open time compared to close time of the points. you have to choose if the car your working on is 4,6 or 8 cylinders and set the Meter to the correct setting.
most 4 cylinder cars have a Dwell Angel of 49 to 55 degrees. the car is turned over with the rotor, distributor cap and spark pugs removed and the Dwell Angle meter connected.
then the points gap is adjusted as the car is cranked over so the reading is within the 49-55 range. it is better to adjust closer to the 49 as the points will wear and the Angle will increase towards the 55 with time.
re-secure the two point adjusting screws and double check the angle has not changed as in locking down the points can influence this. so if angle moves to 55, adjust to 45 and when you lock down it should move to 49-50
then continue with the rest of your service, plugs, oil etc.
Remember to check your timing as points setup will effect it.
Your new points are set for 6-12 months of happy motoring

hope its not to technical



OZ

[mrflibbles]

thanks oz, i have an idea of how it works but no good explaining it as i generally can/will confuse myself!
hope this helps you gttoo?

[GTtoo]

This helps heaps guys. Were you a mechanic in your former life Oz !?! What this tells me is the problem I'm having is more likely to be an electrical short than dwell angle, as the reconned dizzy should let the engine fire up in any case with the points gap adjusted at 0.4 of a mm. And yes, feeler gauge adjustment is open to interpretation. Personally, I believe there must be some grab on the guage, as any slop indicates a wider gap, albeit by some millie-thaou. (is that a technical expression!?!)

Oz, still can't thank you enough for the specs sheet which mysteriuosly appeared on all our Bellett seats at the last All Jap Day. I've refered to it alot and has helped already on many occassions with gaps, settings, disposable parts etc...! Dwell angle for the GT is 53 degrees with a points gap setting of .018 of an inch (0.4mm).

B.

[Glenn]

CAPACITOR !

glenn

[GTtoo]

Hi Glenn,

Thanks for the tip, BUT...got to 'fess my mechanical ignorance here........capacitor !@#$!.........Do you mean the condenser which hangs off the dizzy or something else ? What does it look like and where do i find it on a Bellett ?

B.

[BULLITT]

mate you reckon your mechanical is zilch ..im looking for a bellett with the dealers warranty and all i want to do is armarol the seats and tyres ...........yes i am a dreamer .....but its out there waiting for me good luck with the problem ...maybee our newest member can draw some of his pictures for you all the best davo

[Farmer]

Hi B,
All good advice so far.
When I set the timing I use the 'static' method instead of a timing light. With you rotor nearing No.1 plug lead, place the timing mark on the timing chain cover half way between the 1st & 2nd pulley marks (14 deg. b.t.d.c.). (For sedan. Not sure if GT is the same)
Now turn the ignition on & turn the dizzy clockwise until the points spark. Lock the set bolt at that. This gives basic timing without any mech. or vacuum advance.

The timing light going on & off has happened to me. Could be slide contacts on coil or Dizzy- make 'em shiny & tight. OR tiny wires in the dizzy - test with ohm meter & wiggleing. Or the insulator where the wire goes onto the dizzy could have a crack which allows intermittent leakage - swap for another. OR the neg wire from the coil to the dizzy - test by running another piece of wire direct from the coil neg to the dizzy pole.

Hope this is a help, and remember to have a cup of coffee if you start to swear!
Cheers mate,
Matt.

[Glenn]

capacitor = condensor

glenn

[oz_toffa]

correct but there are often 2 on the car.

one fitted onto one side of the coil and the other fitted to the side of the distributor.

quite easy to dis-connect either or both to see if that fixes the problem


often overlook the simple things

OZ

[GTtoo]

All great info guys, but just come back from the shed with no results for my frigg'n around !! Tried looking for shorts in the dark......nothing to be seen. Then tried for TDC again just to confirm correct position, and YES, that is correct. Pulled the dizzy out again to reinsert it in case I got that wrong. I'm not so sure this is correct.
All other bits are new....Coil, points, condenser on dizzy, spark plugs, all leads. Also perusing websites on "how to" ignition timing setup.
Desperation, yeah ?

Heres a thought. The old coil had a condenser attached to it as well. The chappie at auto pro said I wouldn't need one on the new coil as they were built into them. Is that correct or should I run one anyway ?

Me thinks it's time to get the mechanic from down the road to check if i've put evrything back properly or alter the setup if needed. Then if problem still persists, it's time to get the auto electrician in to diagnose fault...........yep, more dollars !!

B.

[GTtoo]

btw, the GT is supposed to be at 11' BTDC with a points gap of 0.45 mm.

Another dumbass question. Does cylinder ignition occur when the points gap is sparking (open ), or in the closed position ?

Also Matt, my GT is set up with the positive lead off the coil going to the dizzy, and the negative goes into a wiring loom
which looks like it's going to the dash, possibly tacco, speedo. Is this correct ?

B.

[gt orphanage]

The neg from the coil goes to the dizzy. You will need a power sorce to the positive disconect the wires from the coil and use a test light to find which one lights up with the key on position? Connect this one to the positive side of the coil. I would then only connect the one wire from the dizzy to the neg for a start. The points when closed basicly earth the system and when open you have a open circuit. If the car runs ok now, the tacho will not work as it feeds from the neg side of the coil. Remember that we ony put 1 wire on the neg at this stage. It is possible that having the tacho wired backwards [if i am reading your explaination right] it may be stuffed If at this stage of reconnecting the tacho it will not run or problems start. Repair tacho.[tacho wire to neg]
you should only have three wires to the coil if standard if i recall the one to dizzy is black with yellow trace if original and positive is black with red some one may confirm as this is quoted from memory.
if you turn the ignition on after you connect it up use the test light you will have power at the positive and also the neg now when you crank the engine if all is ok the test light will flash when the points close.

[mrflibbles]

double check the new bits too, i have had failed new parts before!

[PR95]

You wouldn't by chance have the dissy timed on 4 instead of 1. When on top dead centre are the timing marks on front lined up? On new bits that FAIL, the sedan that we are doing a resto on has a GT bottom end with a steel head pulled the head off and replaced with GT head and carbs, new plugs ect, result, would not start, did everything no go would backfire and fart just could not get it to run nice,checked timing,valve clearance no go, in desperation removed head again check everything and put back together still the same, ran like a pig. In disgust walked away from it, can sit in the corner and rust.
In the mean time Lizzy,s wasp motor was being recoed, when it was placed into car and all hooked up to go we had no new plugs on hand so down to the other Bellett removed the plugs (that were brand new) fitted to the other engine, started, ran like a pig, after all else failed into town and bought new set plugs,came home and fitted them,ran as sweet as. Remaoved plugs and refitted to other Bellett and it ran just as sweet. Don't know what happend to new plugs, suspect that they had been dropped.
PS the Bellett is currently being painted and hope to bring to Coona for it's debut.