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TR6 Ignition Timing with a timing light on a a TR6

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SCguy

SCguy

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I'd like to check the timing on my TR6 with a timing light but it's been a long time since I've done it (I was 18). My book says that I should be at 40 degrees ATDC (after top dead center or to the right looking at the engine from the front?) but the scale doesn't go that high. /ubbthreads/images/graemlins/confused.gif

What I need is someone to walk me through timing (timing for dummies) with timing light. Any takers? /ubbthreads/images/graemlins/rolleyes.gif
 
The number you quoted is probably the MAX advance and would be BTDC. Even that is probably too much , my guess is closer to 34* or 36*. Never having worked on a TR6, the static or beginning timing, at idle, (with the vacuum advance disconnected) would be around 10* BTDC. Bob
 
Larry,
The timing for my '74 is 4 deg. AFTER top dead center at idle according to the sticker on the inner fender and in the Bently manual. I believe it was set this way to minimize emissions. You will find however that it may run better at 8-10 deg advanced with the vacuum andvance (if equiped) and the vacuum retard disconnected. You will just have to experiment for yourself on that one.
Hope that helps some. /ubbthreads/images/graemlins/smile.gif
 
I agree with Roman ... 4 degrees ATDC at idle (Haynes Manual, Bentley Manual and inner fender). I also run mine at 10 degrees BTDC. The retarded spark was to help keep the exhaust hot to lower emissions in the days before catalytic converters.
 
when I checked mine I found it at spec but I advanced it some (about 4 degress) and it starts easier but it idles higher (about 1100 rpm). What is the best way to bring down the idle in this circumstance? Thanks for any ideas.
 
The best way to bring down the idle is to go through the carb balancing procedure. To do this you need a synchronizing tool.
Decouple the carbs so that you can adjust the idle screw for each carb. Back off the idle screw on each carb an equal amount until you reach the desired RPM. Next, check them with the synchronizer to see if they are balanced and adjust the idle screw on each carb until they are balanced keeping an eye on the RPM. It takes a bit of fiddleing about but its not bad. Once everything is set, tighten the coupling and your good to go. /ubbthreads/images/graemlins/driving.gif
 
For what it's worth,

My 71' was tuned by a Guru in Texas. He set the timing "Static".
I returned to Maryland with the car. I proceed to make myself familiar with the car. I wanted to check the timing to see where it was set so I would know for future reference. I tried to check it several ways with my old Craftsman timing light. That did'nt go too well. A TR Club member told me I needed a Timing Light with "Advance". He said "Set it like you drive it". Meaning to raise the RPMs to about 2500 with all the hoses, and stuff connected.

So, off to Sears I go.

Got a new Craftsman Light with Advance.

Fire up the car, I pull the trigger on the light. I reach accross the engine and manually raise the rpms until the timing mark stabilized(reached full advance). I turned the advance dial on the timing light until the timing mark on the engine was at 0°, with the rpms keeping things at full advance the whole time.

(BTW: I noticed the timing mark was noticably larger at 0°. My guess is that someone enlarged the mark at 0° to make it easier to see.)

anyways,

So now I've got the mark at 0° at full advance. Guess where the Advance Dial on the timing light is set now????

40°

That's where the timing was set when I had it tuned(by a TR Guru), and that's where I keep it.

So with that expierence under my belt, maybe SCGuy is onto something with that 40° figure.
 
My comments are similar to those of Tom (a.k.a. Stinky). On my LBCs I bring the RPM up to around 4k and use an advance timing light to set the max advance to about 32 BTDC. (Set the advance on the timing light to 32 degrees and then align the "0" degree timing marks on the engine at 4k RPM). This is followed by drive testing (listening for pinging and knocking). If any is heard I back the timing off by an additional 2 degrees and repeat the driving test until no bad noises are heard.

I run regular gas in my cars so 32 is probably the best I'll ever get. On a well prepped engine running premium you may be able to run 40 BTDC max.
 
I thought static means the vacuume line(s) are disconnected from the distributor (the vacuumed lines to the carbs are then plugged during the test) then the timing is set at idle RPM's. I don't have a book at hand but static should be some where around 8 to 12 degrees BTDC on a '74 TR6. You are measuring the full centrifugal advance at 4000 rpm; I just never thought of it as static. I like to set the advance at idle w/o vacuume, and then check to see if full centrifugal advance was coming on. I seldom did the full test becauseI all ways had to take the dizzy to a "Sun" ignition machine that would actual spin the distributor and dwell could be set and you could see the centrifugal advance working (changing springs if necessary to get the right advance) That is a nice timing light you have and probably did not cost as much as my 20 pound chrome ray gun /ubbthreads/images/graemlins/cool.gif
 
Hello all,

to me 'static' means the engine not running, and setting the timing with a meter or lamp to see where the points open, using marks on the pulley.

Alec
 
pieman:
I did it that way too (engine off) when I did not have a strobing type of timing light. I do not take exception with your definition of static as the language is UK and I still have not recovered from the definition of paraffin /ubbthreads/images/graemlins/laugh.gif
 
Static means "not running" whether you're using American or U.K. "English". The opposite is "dynamic". Setting dynamic timing can be done at idle or after the dizzy has delivered its max advance. The reason you may wish to consider setting the advance at 4k RPM is that you will be setting the timing after your dizzy had added all it can. Generally this means more power and efficiency. The caveat is you must watch out for detonation and retard the timing from textbook figures to something allowing smooth operation. Every engine will be a little different and the quality of fuel you burn also affects this.
 
Hello VD,

"I still have not recovered from the definition of paraffin"

I must have missed that somewhere?

By the way I am not a purveyor of foodstuffs!

Alec
 
Well I think I've got it. I don't know where I got the idea that static was directed toward the vacuume or mechanical advance, not the turning of the dizzy. Obviously being self taught is not the best way to learn /ubbthreads/images/graemlins/tongue.gif
 
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