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TR6 vacuum retard help, 69TR6

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ichthos

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vacuum retard help, 69TR6

I am still troubleshooting the distributor;I need more help. My vacuum advance works, but my vacuum retard does not. I checked the line where it connects to the vacuum retard unit and there is no vacuum. I followed the vacuum line back to the manifold, and there is definately no vacuum there either. What would cause this? What are steps I should take to find out what is casing a lack of vacuum at the manifold? Any suggestions would greatly be appreciated.

Kevin
 
Re: vacuum retard help, 69TR6

on later cars the retard hose goes through a thermostatic device on the top rad hose, if yours does this it could be the problem, have you checked for hose leaks/blockage?
 
Re: vacuum retard help, 69TR6

So your car has the valve operated by the throttle linkage, and gets retard vacuum from the manifold ?

If there is no vacuum right at the manifold fitting, then it must be blocked somehow. Possibly intentionally by a DPO. I'd pull the fitting off (engine stopped) and see what the problem is.
 
Re: vacuum retard help, 69TR6

My vacuum retard hose does not go through through anything, Graham; it is a straight shot to the vacuum retard. I did check to make sure the line is clear. No problem with air flow until you get to the fitting on the front carb near the butterfly (I inaccurately said the vacuum fitting was on the manifold-sorry.) I will be replacing the needles and seats in the carbs (I found that the fuel/air mixture screws have no effect, even when I totally screw them in!), so I may just check the fitting then to see if it is clogged. I am not sure if I can get the fitting off the carb without damaging it, Randall. In the meantime, would it be safe to just stick a wire or small drill bit through the opening to see if it is clogged? Either way, I will have to wait until I get home.
Kevin
 
Re: vacuum retard help, 69TR6

ichthos said:
In the meantime, would it be safe to just stick a wire or small drill bit through the opening to see if it is clogged?
Click to expand...
Better, IMO, to pull the carb off so you can see what's going on. The actual opening into the carb throat is pretty small, so you'd want to use a wire or drill that will pass through that opening. ISTR 1/16" might be too big, but I'm not sure offhand (and my carbs may be different than yours).

BTW, note that there are two different things commonly called "needles". The mixture needle is what the mixture adjustment moves; while "needle and seat" implies the float valve. I believe originally, a 69 TR6 would not have had adjustable needles ... which might explain why you can't adjust them ?
 
Re: vacuum retard help, 69TR6

I was talking about the float valve. I think you are correct about them not being adustable, but since the air/fuel adjustment screw is making no difference, wouldn't this indicate the needle is worn and gas is just flowing past it? The exhaust definately smells like unburned fuel. You're right, I should take off the carbs first, but I am just not looking forward to pulling the carbs.

Kevin
 
Re: vacuum retard help, 69TR6

Kevin, the advance comes from the front carb on top and the retard from the rear on the bottom, both at the rear of the carb, unless yours is the very early '69 and has the little vacuum switches on the bottom of the idle linkage, if so best of British luck in getting those suckers to work right. Unless you are having a big problem with the car idling down, the retard has little effect on the running and can be plugged off. I put a TR4 advance on mine and it will go in the same housing, you will need the micro adjust knob and the little spring clip to keep it in place. If you decide to do it give me a PM and with a phone # and I'll give you all the information and timing and how to set it up.

Wayne
 
Re: vacuum retard help, 69TR6

ichthos said:
I was talking about the float valve. I think you are correct about them not being adustable,
Click to expand...
The float valves are adjustable, it's the main mixture needle that is fixed on early emissions carbs.<div class="ubbcode-block"><div class="ubbcode-header">Quote:] but since the air/fuel adjustment screw is making no difference, wouldn't this indicate the needle is worn and gas is just flowing past it?[/QUOTE]Not necessarily. The air bleed on the side has almost no effect; you need an exhaust analyzer to see what it does.

Unburned fuel in the exhaust definitely indicates a problem, but usually if it's a float valve you will also find fuel running all over the engine compartment.
 
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