• Tapatalk and Mobile iOS/ Android APPs no longer supported on aussiefrogs.com. Please delete on your device. Use the web interface instead.

tuning light 15

KEVIE

New member
hi folks trying to fine tune my light 15 been through mixture setting,tappets,and timing,still seem to have a slight
miss in motor,has anyone worked out a way to use a timing light on a traction as it seems a bit hit or miss
way of tuning by just moving distributor,any help or thoughts would be great.
 

jaahn

1000+ Posts
Hi Kevie :)
Great car you have there. No there is no easy way to put a timing light on it. But if it has a miss then it will not be the timing causing that. It depends on what sort of 'miss' but usually an ignition problem. The points are not good, condensor failing or the coil not good. A proper tune should start with checking and adjusting all the ignition system and plugs. Setting the timing is the last step when all the rest is 100%.
A slight rolling or 'miss' at idle might be a lean mixture or slight air leak. Hard to say from my computer keyboard ! What sort of a miss does it have ? while idling, reving up or when driving, slowly or hard ? Slight or bad ?
Jaahn
 
Last edited:

gerrypro

1000+ Posts
If none of the above from Jaahn provides a cure, it may indicate worn valve guides and possible crook valves. If the head has never had any work the guides can be quite worn and in extreme cases the exhaust valves can be burned. It was a common occurrence on higher mileage engines!
 

KEVIE

New member
thanks for your reply's its a slight miss when idling,notice that when mixture screw is screwed all the way in engine doesn't
stall,don't think its values or guides as low mileage on reconditioned motor,its just annoying guess i'll replace
plugs,points etc to eliminate any problems cheers kevie
 

gerrypro

1000+ Posts
thanks for your reply's its a slight miss when idling,notice that when mixture screw is screwed all the way in engine doesn't
stall,don't think its values or guides as low mileage on reconditioned motor,its just annoying guess i'll replace
plugs,points etc to eliminate any problems cheers kevie
32 PBIC Carburettor?
 

gerrypro

1000+ Posts
32 PBIC has a habit of the main jet spray tower becoming loose at the base. It can get so bad the jet air correction and emulsion tube assembly (the spray tower) can drop out. ( A long cold wait on the top of Mount Dandenong expecting a tow from my father in-law resulted from this circumstance )
The first signs of this is a slow drip down the choke tube onto the butterfly valve. It can produce a miss fire at idle and would fit with the fact that the needle valve can be closed without stalling the engine. The fix is easy-- remove the jet tower from its mount and re-insert with a smear of loctite. Care is needed removing the spray jet tower not to crack the base or to break tower itself. Do not ask me how I know this!
 

KEVIE

New member
hey thanks guys ,yes carb is 32 pbic will remove carb and have close inspection of spray tower,also
have vacuum gauge can't say i have ever used one ,had a look at a few videos on you tube,so
in the case of a traction would you connect gauge hose to vacuum advance on carb using a T section
or could i connect to overflow pipe at bottom of inlet manifold ? cheers.
 

gerrypro

1000+ Posts
The vacuum gauges I have seen measure the depression at the carby throat. ( air cleaner removed)
I have never needed to use one and always thought they were for balancing multi carb setups!
 

DoubleChevron

Real cars have hydraulics
That jet in the carby throat .... if its not leaking .... DON'T TOUCH. If you must try heat cycling it ... or possibly even the candle wax trick. It take absolutely zero force to break the top off it.

The last time the blue ID19 had an expert work on it .... it came back running and idling very poorly. The carby expert had rebushed the throttle spindle and installed the flap backwards..... so it would stick and not fully close.

if your mixture screws aren't working, you have blocked passages in the carby .... or huge vacuum leaks (the base of the carby ? ).

You really need to go over everything. I've even found things like the vacuum advance hooked up to the manifold drool tube.
 

gerrypro

1000+ Posts
The carby that stuck me up on the top of Mount Dandenong was 'reconditioned ' by a reputable carby expert. They actually forgot to put back the emulsion tube in the jet spray tower. I could never work out why it would not idle down slowly and consequently I had it set at about 1500rpm. The Mt D incident revealed all. So the spray jet tower falling down the carby throat actually did me a favour in a round about way!
 

jaahn

1000+ Posts
The carby that stuck me up on the top of Mount Dandenong was 'reconditioned ' by a reputable carby expert. They actually forgot to put back the emulsion tube in the jet spray tower. I could never work out why it would not idle down slowly and consequently I had it set at about 1500rpm. The Mt D incident revealed all. So the spray jet tower falling down the carby throat actually did me a favour in a round about way!
Hi :)

Those early post war carbies on any car were made of very low quality diecast metal. Not good when new but it has aged very badly as well. i have in previous times had carby discharge tubes and auxilary choke tube supports and cast pump discharge jets and the like, just fall apart and crumble. Just no strength left. Even the carby base flange is weak and warps easily if you use soft gaskets. BE VERY CAREFUL with your old carby as Shane and Gerry have said. If it does not need fixing leave it alone IMHO.
Jaahn
 

gerrypro

1000+ Posts
There are reproduction 32PBIC carbs made in India. I do not know if they are any good though as you read all manner of comments of varying opinions!
 

Artificer

Member
The vacuum gauge mustn't use any ported vacuum [like most vacuum advances] just straight manifold vacuum from below the throttle butterfly.
Old motor mechanics & I am one of those, used vacuum gauges to diagnose & tune engines before scopes & OBD came into vogue.
On old vehicles one would hook in a vacuum gauge before tuning a vehicle.
A good reading eliminated lots of unnecessary work & replacing good parts hoping to solve problems with other new good parts [costs money].
Customers don't like paying for parts & labour that doesn't solve problems.
As for the Indian Solex carbs reviews are mixed but they can be sorted. Main issue seems to be with the nylon filter screen near the needle valve breaking up & causing flooding. The originals had brass filter screen.
 

gerrypro

1000+ Posts
The vacuum gauge mustn't use any ported vacuum [like most vacuum advances] just straight manifold vacuum from below the throttle butterfly.
Old motor mechanics & I am one of those, used vacuum gauges to diagnose & tune engines before scopes & OBD came into vogue.
On old vehicles one would hook in a vacuum gauge before tuning a vehicle.
A good reading eliminated lots of unnecessary work & replacing good parts hoping to solve problems with other new good parts [costs money].
Customers don't like paying for parts & labour that doesn't solve problems.
As for the Indian Solex carbs reviews are mixed but they can be sorted. Main issue seems to be with the nylon filter screen near the needle valve breaking up & causing flooding. The originals had brass filter screen.
How would you hook in a Vac gauge to a 32PBIC carb so that the vac can be read from below the butterfly valve. I just cannot see any way possible.
 

Artificer

Member
No argument:
This is precisely what I offered:
The vacuum gauge mustn't use any ported vacuum [like most vacuum advances] just straight manifold vacuum from below the throttle butterfly.

I have always run into vacuum gauge skeptics or modern folk who have never ever used them.
Doona Dan is probably one of them.
If any intake manifold [NOTE not carburettor] has a plug or PCV valve outlet under the carburettor that is where to plug into.
 

gerrypro

1000+ Posts
Maybe the obvious place is to make up a temporary connection to replace the manifold drain tube of a Traction Avant. It is right underneath the carb mounting and has a 10x1.5mm threaded connection for the drain tube!
I am not arguing against the use of a vacuum gauge. It is just that I have never had occasion to use one!
What sort of readings would be obtained for various engine conditions /defects?
I am always eager to expand my knowledge base!
 

Artificer

Member
I could go on for a week but this write up given as a link earlier is about as good as there is in understanding an engine is a pump/compressor & any malfunctioning part/s will show up in a vacuum reading.
The skill is interpreting that reading which will often point to simple things like a vacuum leak or poorly closing/leaking valves etc.
http://www.secondchancegarage.com/public/186.cfm
 

jaahn

1000+ Posts
No argument:
This is precisely what I offered:
The vacuum gauge mustn't use any ported vacuum [like most vacuum advances] just straight manifold vacuum from below the throttle butterfly.
I have always run into vacuum gauge skeptics or modern folk who have never ever used them.
Doona Dan is probably one of them.
If any intake manifold [NOTE not carburettor] has a plug or PCV valve outlet under the carburettor that is where to plug into.
Hi Artificer :)
I agree that a vacuum gauge is useful for old engines though I have not used one for a long time. It can be used for best idle mixture settings and timing too. That was normal in the old days. Perhaps not accurate after pollution laws came in.
I looked at your reference but could not see the table of readings. Tried again later and just now to see if I could reveal the table but had no success getting the table to open up for me. Any suggestions. It has a lot of good stuff on that site. :rolleyes:
Jaahn
 

Dapco Auto France

Top