TR6 TR6 TIMING QUESTION...............................

veale001

Senior Member

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• Jul 21, 2009

• #1

Hey guys,

Took some great advice on here and have been tinkering with my timing and carbs. I advanced the dist. to around 18", 20" being the peak. This showed a little passed 12 ATDC on the pulley and it runs better than any other setting/configuration I have worked with... but this causes my idle speed to be around 1000-1250. Not acceptable right?

I tried to slacken the idle screws, but it wants to cut out at idle when I try to get it in the 800-950 range. Not necessarily sputtering out bad, but that uncomfortable feeling at a stop light.

I guess the question would be what risks am I taking by keeping the configuration of ~12ATDC with a idle of ~1100? Or is there something else that I should educate myself on.

Help always appreciated,
W

 

poolboy

Yoda

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• Jul 21, 2009

• #2

You're talking about 18 to 20 in- Hg using a Vacuum Gauge, right ?
If you are, that might be a bit high. In my engine 18 is as high as I want to go. Don't get me wrong when the tach cable is disconnected from the dizzy, I can go into the low 20's, but the engine seems unsettled and picks up some vibration.
Depending upon what the timing was before you advanced it, you will have to adjust the fuel/ air mixture. That's in addition to making idle speed adjustment AS you change the timing.

Another thought. When you said "18 & 20" did you mean that the needle was fluctuating that much ? If so there's a problem. A slight quiver is normal but a 2 inch fluctuation is not.

 

OP

veale001

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• Jul 21, 2009

• #3

My mistake. 20" Hg on a vacuum gauge was my peak, meaning thats as high as I could get it with advancing the dizzy clockwise. I backed it off 2", to 18", according to sevreal things I have read and the way it sounded. Anything lower, in terms of pressure, seems to feel to low. It will misfire much easier.

I am awaiting my mixture tool for the carbs this afternoon.

With my vacuum gauge reading 18" and my pulley is at 12ATDC with an idle at 1100 am I running it way too high? Or ok for a car with 80k miles.

 

poolboy

Yoda

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• Jul 21, 2009

• #4

I really can't relate to the reading on the pulley but 17 1/2 to 18 is what I run at with 107k on the engine. I am able to idle at 850 and lower, but I like about 850 for a smooth take off.
My guess is that adjusting the mixture will help your situation if your carbs are in good condition. I don't see where an idle that high will hurt although it's not giving you the same vacuum reading that you would get at 850.
I think I'd retard to 17 if my idle was that high, expecting the number to be about 18 if the idle were lower.

 

T

Tinster

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Guest

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• Jul 21, 2009

• #5

Hi Warren,

I am a non-mechanic TR6 owner but I've managed to figure
out a few things. I use my Vacuum (Hg) and fuel pressure (psi)
gauge to perform several diagnostic tests and adjustments on
my 1969 engine.

Here is a color print-out of the various meanings of the
needle reading and how to interpret flucuations in Hg".

https://www.classic-car-magazine.co.uk/articles/fault-diagnostics-vacuum-gauge.html

Back under my rock now.

Dale (Tinster)

 

Brosky

Great Pumpkin

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• Jul 21, 2009

• #6

Warren,

You should be at 10-12 BTDC not ATDC. I think that is what you meant, but just didn't state it.

Your particular engine, may need to idle at 1,000 rpms to be happy, depending on the carb settings, etc. When you adjust the idle down, you will also notice that the timing is no longer at 12 BTDC, but probably at 8-10, so you move it back up and adjust the idle back down. About three rounds of this tweaking and you will be fine. Then you can start to check the carb settings, but make sure that you don't have any vacuum leaks first, that can cause you to run too lean.

Any further questions after that, just stop back. You know where we are by now.

BTW......You do have the vacuum control(s)lines to the distributor disconnected AND plugged when you are setting the timing, right?

 

OP

veale001

Senior Member

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• Jul 22, 2009

• #7

Paul,

Thanks for the correction. When you say vacuum control lines are you referring to the vacuum retard on the distributor? It is open. I tried to tape it up but it gets to coming off after a day or so. I rigged a plug at one point but it too came off on the road.

Also, I believe it is called the Thermostatic Switch (the 3 small lines coming off near the radiator to control emissions on 73's and older models) are open/not plugged? Besides that all hoses seem to be on the up and up.

Thanks for helping a first timer. I try to do as much fact finding through the manuals and old posts as possible but sometimes the questions I have are second nature and entry level vocab for you guys :wink:

 

T

tdskip

Yoda

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• Jul 22, 2009

• #8

Warren - how are your carbs? Have they been rebuilt recently?

 

OP

veale001

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• Jul 22, 2009

• #9

Not in the 8 months I have had it, probably not a bad idea? I have cleaned it out and changed the diaphragm on both is all. I am actually trying to figure out the easiest way to change out the o-rings. Can that be done without taking it completely out?

 

TR3driver

Great Pumpkin - R.I.P

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• Jul 22, 2009

• #10

The only place the vacuum retard line needs to be plugged is where it comes off the carburetor. If you leave that open, it causes a vacuum leak that will throw off the idle mixture, making the idle rpm high and erratic. Any auto parts store should be able to sell you a rubber cap that will push over the fitting and stay there. Or use the rubber connector from the original line, and jam a golf tee into the end of it.

The distributor and TVS fittings can be left open, won't hurt anything.

Not sure which O-ring you want to change. The ones that let the damper oil leak out can be changed by just removing the top housing from the carb body (like you did to change the diaphragms). But the ones that let fuel leak out the bottom require removing the float bowl, which is probably better done with the carbs off the car if you haven't done it before.

Sometimes you have to adjust the bowl vent valves to get the idle rpm down. The details vary by which ZS carb you have; on my Stag (with '73 carbs I think) I had to undo the vent adjustment screw, pull the clip off and bend it to get enough adjustment range.

 

TR3driver

Great Pumpkin - R.I.P

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• Jul 22, 2009

• #11

Lots of good TR6 tech articles on the Buckeye Triumphs website, including this shot

of one style of vent valve.

 

poolboy

Yoda

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• Jul 22, 2009

• #12

I have a couple of things to add. When your engine is running, pull the vacuum line fitting off the dizzy retard unit. You will notice a change in engine speed. Put your finger tip over the opening of the fitting that you just pulled off. The engine speed will return to "normal". That's what you need to plug, that hole in the fitting.
Also If you get into dealing with the float chamber vent that Randall wrote about, check the movement of the brass plunger that the vertical leg of the L-shaped lever rest on.
With the engine not running, work the carburetor linkage in the way that it does when you accelerate and see if the plunger moves toward the engine. A lot of times, the plunger gets fouled and sticks.
If it's stuck, it can be freed quite easily. Repost about that if you need to.

 

OP

veale001

Senior Member

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• Jul 22, 2009

• #13

Thanks guys,

In regards to the o-ring Randall, I am trying to stop the leakage of damper oil. I looked down the shaft after emptying each and I didn't see an existing o-ring in either carb? But only one seems to be loosing oil at an accelerated rate. So I looked in the bentley manual and the only referenced one shown was the one near the bottom?

I took your way of going about things poolboy, Im sorry I dont know your real name , with covering the small hole. I didn't hear/feel any real difference in the rpm's? It hasn't ever been connected to anything since I have had it and I never felt any blowing or suction coming from it? Could it not be properly secured to the dist.?

Thanks for the help
W

 

TR3driver

Great Pumpkin - R.I.P

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• Jul 22, 2009

• #14

For some reason, most manuals don't mention the O-rings for the damper oil. The ring is actually around the adjustment screw, which is in the bottom of the sliding shaft. There is a good section on them near the bottom at
https://www.buckeyetriumphs.org/technical/Carbs/CarbsII/CarbsII.htm

Rather than hunt down a suitable steel rod and hammer, I used an unsharpened wooden pencil and just rapped it against the bench (effectively making the piston a slide hammer) to tap the screw & retainer out.

 

TR3driver

Great Pumpkin - R.I.P

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• Jul 22, 2009

• #15

<span style="font-weight: bold">AUGH!</span> In the post above, I meant plug the line off the <span style="font-weight: bold">CARBURETOR</span> not the distributor.

Mea Culpa, I'll fix it.

 

poolboy

Yoda

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• Jul 22, 2009

• #16

veale001 said:

Thanks guys,
I took your way of going about things poolboy, Im sorry I dont know your real name , with covering the small hole. I didn't hear/feel any real difference in the rpm's? It hasn't ever been connected to anything since I have had it and I never felt any blowing or suction coming from it? Could it not be properly secured to the dist.?
Thanks for the help
W

Click to expand...

Just "poolboy" or PB is fine with me, Warren.
I guess what I am unclear about at this point is, do you have a small plastic tube (line) connected to the nipple on the retard unit that is attached to the Dizzy ? I guess what has me confused is that you say it was not connected to anything.
Was the metal nipple part of the retard unit not connected to any thing or do you mean that plastic vacuum line was never connected to anything ?
What did you cover with your finger ?

 

Brosky

Great Pumpkin

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• Jul 22, 2009

• #17

Re: TR6 TIMING QUESTION...........................

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]BTW......You do have the vacuum control(s)lines to the distributor disconnected AND plugged when you are setting the timing, right?[/QUOTE]

That's why I asked this question early on.

 

poolboy

Yoda

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• Jul 22, 2009

• #18

Re: TR6 TIMING QUESTION...........................

Paul, I guess we need to ask Warren if he even has a vacuum line from the bottom of the rear carb to the dizzy retard. It sounds like he doesn't have the vacuum line. Hopefully he'd have the nipple on the bottom of the carb plugged if there's no vacuum line connected to it.
What you say Warren ?

 

OP

veale001

Senior Member

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• Jul 23, 2009

• #19

Re: TR6 TIMING QUESTION...........................

The module has never had anything connected to it. I would place my finger over the output nipple of the module and there wasnt any change in the engine. The module feels loose or not connected firmly in the dizzy, so I am not sure what my strategy should be for it?

In regards to the carbs, there are vacuum lines that start from the bottom of the carb closest to the cockpit that connects, via a t-bar, to the second and leads to the emission canister near the radiator. When I disconnect those as well there is no real change. When I remove a line from the top of the manifold to use my vacuum gauge I hear a definite change in rpms, but nothing remotely noticable from the dizzy's retard module or from the vacuum lines underneath the carbs?

Thanks for your help.
w

 

T

tdskip

Yoda

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• Jul 23, 2009

• #20

Re: TR6 TIMING QUESTION...........................

Warren -any chance you can post some pictures? It can be a big help on remote diagnosis!