• The Roadster Factory Recovery Fund - Friends, as you may have heard, The Roadster Factory, a respected British Car Parts business in PA, suffered a total loss in a fire on Christmas Day. Read about it, discuss or ask questions >> HERE. The Triumph Register of America is sponsoring a fund raiser to help TRF get back on their feet. If you can help, vist >> their GoFundMe page.
  • Hey there Guest!
    If you enjoy BCF and find our forum a useful resource, if you appreciate not having ads pop up all over the place and you want to ensure we can stay online - Please consider supporting with an "optional" low-cost annual subscription.
    **Upgrade Now**
    (PS: Subscribers don't see this UGLY banner)
Tips
Tips

TR2/3/3A Timing with Electronic Ignition

frankfast

Jedi Trainee
Offline
I recently install a Flamethrower distributor with electronic ignition. I can time it statically with a light at TDC but since there are no other marks on the pulley other than TDC advancing the timing seems like guesswork. Has anyone marked their pulley and used a timing light or is this just a trial and error exercise?
 

Geo Hahn

Yoda
Country flag
Offline
Many strobe timing lights have an advance dial on them -- you set the desired advance and when the ignition is there the TDC timing mark on the engine is at the pointer.

These are especially useful for checking advance at high RPM (when centrifugal advance is 'all in').

Alternately you can do some 6th grade arithmetic and figure out where the static timing should be relative to the TDC mark. I seem to recall that 5° BTDC was about ¼" on the pulley.
 

JFS

Jedi Warrior
Bronze
Country flag
Offline
I use a timing light that has dial that you turn to match the pulley mark with the pointer. The dial shows the degrees as you turn it to match the marks. You determine what advance you want at what RPM and set the distributor accordingly. I run a Mallory dual point with mechanical advance only and am basically interested in setting the total advance at 3500 RPM.
 
OP
F

frankfast

Jedi Trainee
Offline
"Alternately you can do some 6th grade arithmetic and figure out where the static timing should be relative to the TDC mark. I seem to recall that 5° BTDC was about ¼" on the pulley."

That's a good start since my timing light is from the sixties.
 

TR3driver

Great Pumpkin - R.I.P
Offline
One thing to watch out for: The TR2-4 have a timing curve that starts at a very low rpm. The book allows as much as 2 degrees advance even at 400 rpm! So if your idle is a bit high, and you set to 4 BTDC as the book says, you'll wind up with retarded timing.
 

6TTR3A

Jedi Warrior
Country flag
Offline
I went with a Pertronix, with an original Lucas 3 ohm coil in a Lucas DM2 distributor. AT 3000 RPM advance is
"all out" at 31° BTDC. I did the math, marked 31° in the pulley, set the distributor using an old-fastened timing light.
Car runs great! I noticed at 800RPM (my comfortable idle) the light shows about 10° advance. That seems to correlate with what Randall says.
Frank
P.S. I was a little nervous running at 3000 RPM at no load, but it only took about 5 seconds to get the distributor set.
 
OP
F

frankfast

Jedi Trainee
Offline
"I did the math, marked 31° in the pulley"

If 5 degrees is about 1/4" on the pulley, does that mean that 30 degrees is about 1 1/2"?
 

Geo Hahn

Yoda
Country flag
Offline
That ¼" was a guess. To calculate 31° (or whatever you want for total advance) measure the diameter of the pulley, multiply by 3.14, divide by 360 and multiply by 31.

I will then tell you what card you selected.
 

TR3driver

Great Pumpkin - R.I.P
Offline
According to my notes, the pulley is 5.50" in diameter, which means 31° is about 1.488" measured along the edge of the pulley (the formula Geo gave above).
Or, if you want to measure in a straight line, the formula becomes diameter times sin(angle/2), which is about 1.470"

YMMV
 
OP
F

frankfast

Jedi Trainee
Offline
3.14 = pi I haven't had to use that since high school geometry. Seems like the original guess of 1 1/2" was pretty close. Anyone confirm that full advance is 31 degrees at 3000rpm? Thanks everybody for all the help.
 

Geo Hahn

Yoda
Country flag
Offline
There is a 5-digit number on the body of the distributor... possibly begins with a '40'. That will tell you distributor you have.

Here is some data, formatting is crude but hopefully you can follow. 'All-in' advance is in distributor degrees, double that to get crank degrees then add static setting to get total advance.

Pulley: Diameter = 5.5”
Circumference = 17.279”
1° = .048”
4° = .192” (13/64”)
24° = 1.15” (1 5/32”) – Paint mark added to TR4 pulley
32° = 1.54”
34° = 1.63”


Service................RPM/Adv1
Number...Model......(all/in)

40480A DM2P4 2700 15

40698A DM2P4 2700 14

40795A 25D4 1200 10


Triumph TR3 – TR4

Year Vehicle Dist # Vac Unit
Later 1956-61 40480 421953 4-11-7 Hex / spring
1960-62 TR3 40698 A/B 54411480 4-11-7 cap /screw / spring
63-64 TR3-4 86mm 40735 A 54413565 2-6-3 cap /screw / spring
1963- 65 TR4 40795 A 54413565 2-6-3 cap /screw / spring
 
OP
F

frankfast

Jedi Trainee
Offline
  • "Tailored advance curve for optimal performance and drivability."

That is the only information Pertronix gives for their Flamethrower distributor.
 

TR3driver

Great Pumpkin - R.I.P
Offline
40480A DM2P4 2700 15

Hmm, I've got 40480 (and the previous 40403) listed as 14 degrees (± 1°) @ 2700. May I ask where you got 15?

BTW, 14@2700 means "all-in" would be total 32 degrees at 5400 crank rpm, ignoring vacuum advance. Specified advance at 3000 crank rpm would be closer to 25-26 degrees.

But it does seem that a stock engine can tolerate more advance on the fuels we have today; depending to some extent on temperature and altitude. I believe the factory numbers were deliberately conservative, to minimize problems under adverse conditions, poor fuel, etc.
 
OP
F

frankfast

Jedi Trainee
Offline
After solving a poor connection to the stater motor, the car started right up. It seems someone installed the distributor drive 180 degrees off and then compensated the distributor dogs to match in order to get the rotor pointing toward the No. 1 cylinder. That is the reason the new Pertronix Flamethrower had to be mounted with the rotor pointing away from the No.1 cylinder. I compensated by changing the wires to the plugs. The distributor and new coil work fine and now I can get down to proper timing. Thanks for all the suggestions.
 
Similar threads
Thread starter Title Forum Replies Date
T static timing with electronic ignition? Triumph 10
T MGB Static timing a MGB w/ a Crane Electronic Ignition MG 5
D Timing with an electronic distributor? Triumph 14
K TR2/3/3A How to tell if the timing chain has slipped...... Triumph 12
Got_All_4 TR5/TR250 Timing chain tensioner completely shot Triumph 11
mt10flyer TR2/3/3A Timing Chain Tensioner - again Triumph 13
M 1275 Timing Cover Vent Spridgets 2
waltesefalcon Miata Water Pump and Timing Belt Other Cars 3
Y TR2/3/3A I cannot get my TR3 in correct timing. Triumph 7
K TR2/3/3A Timing chain rattle on start up? Triumph 2
D Cam Timing question. Spridgets 11
KVH General Tech Valve Timing--No Marks Triumph 20
drooartz MGB Question on timing and vacuum MG 11
E Ignition Timing Austin Healey 14
K TR2/3/3A Ignition timing questions while I'm waiting for Spring Triumph 27
56HealeyDan 100-4 Timing and Vacuum Austin Healey 5
K TR2/3/3A Timing marks on pulley? Triumph 10
LAW75 Timing Chain Cover Gasket Austin Healey 12
Lin Ignition timing question Spridgets 2
Kolecki TR2/3/3A engine assembly cam timing issue Triumph 8
Lin Checking static timing for a 1275 with Crane XR700 ignition Spridgets 0
A Timing cover access Spridgets 6
BN6_2197 BN6 Static Timing Austin Healey 2
vette Timing Marks! Austin Healey 12
J Crankshaft dog nut and timing chain cover removal advice Austin Healey 30
J TR6 73 TR6 Static Timing Questions Triumph 6
P TR6 1970 TR6 Timing Question Triumph 2
TRclassic3 TR2/3/3A Timing and temperature Triumph 13
B TR4/4A New valve gears/timing Triumph 21
K TR2/3/3A Ignition Timing? Triumph 11
K TR2/3/3A The timing mark on the crank pulley.... Triumph 5
M 100-4 Timing Pointer Austin Healey 5
D TR2/3/3A Timing chain tensioner. Triumph 3
KVH TR4/4A No Marks on Timing Gear Triumph 30
Got_All_4 TR6 Newly purchased poor quality timing gear Triumph 5
vette MGB 74 1/2 Timing Specs. MG 16
B Timing Light question Austin Healey 0
F TR6 Timing adjustment Triumph 13
doc50 Metro 1500 Has Slack Timing Chain? Other British Cars 20
Got_All_4 TR6 Timing chain Triumph 10
Got_All_4 TR6 Double row timing chain in a 69? Triumph 2
D BT7 Timing Advance Austin Healey 17
D BT7 ignition timing Austin Healey 5
R TR2/3/3A Timing Triumph 3
F TR2/3/3A Ignition Timing - Again Triumph 11
T Even but low compression on 3.8 - timing slightly off? Jaguar 7
B Engine timing Spridgets 8
tinman58 TR2/3/3A Timing ? Triumph 21
Michael Oritt Replacing timing chain tensioner and more Austin Healey 24
DornTRoriginal TR2/3/3A Checking if Timing Chain is Installed Correctly Triumph 6

Similar threads

Top