• Hi Guest! Being a Paying Supporter is NOT a requirement to participate at BCF. However, subscribing will help ensure we can continue to serve the LBC community for years to come. If you enjoy BCF and find our forum a useful resource...Please consider supporting us by **Upgrading**
    (PS: Subscribers don't see this banner)

TR2/3/3A TR3 Missing [running rough not stolen!]


Senior Member
Just came in from the garage trouble shooting the TR3's rough running engine.

The engine is missing at low RPM (900 to 1500)consistently High RPM (3500+)intermittently
Cold high RPM smooth
Warm high RPM rough <span style="text-decoration: underline">sometimes</span>
Acceleration is always smooth

The step by step actions are listed below. I'm making a change one at a time to ID the problem. I'm stuck on the ignition system and will try the carbs next.
1. Replaced wires- no fix
2. Replaced MGB cap with correct cap - no fix
3. replaced Rotor - no fix
Next steps:
1. Replace points
2. Replace coil
3. Move to carbs.

The plate that the points are mounted to wiggles. It moves up and down making the little red plastic cam follower face change from being parallel to the cam to being at an angle.
[img:left]C:\Documents and Settings\Duke\My Documents\My Pictures\58' Triumph[/img]
Is this correct? Seems that should be a constant "flat" against the cam.
How can this movement be taken out of the points if it not to be there?
Any suggestions on where to go next?


Jedi Knight
Re: TR3 Missing

Have you checked the timing? Also check to see if there is one of the spark plugs that may not be firing properly.


Country flag
Re: TR3 Missing

Phew! from the title of the thread I thought your car had been stolen....
Anyhoo... I think you're on the right track. Do the points and condenser (although a bad condenser usually kills acceleration). the plate tends to have some play in it, usually it dosen't move that way when in use. don't let that get you bent out of shape.
Make sure that the flexible ground wire from the moving part of the points plate to the dizzy body is in good shape, in not, that can cause intermittant ground issues as that plate moves back and forth.
good luck Guv'na


Senior Member
Re: TR3 Missing

Sorry about the title, I'll try to change that.

Timing checks OK and the 4 spark plugs look the same in color, originally had some differences in the #2 cyl but with the changes it seems to have resolved some of those. I'm still thinking there are a couple of issues here I'm trying to purge. New plug wires have made the high RPM roughness intermittent. Others have told me the carbs need cleaning. I'll try that while I'm waiting for the back ordered coil.

Going for a drive, maybe it'll work itself out :smile:


Great Pumpkin - R.I.P
Re: TR3 Missing

What does the timing mark look like under the timing light, as you rev the engine up? If the point plate is wobbling around, it will show up as spark scatter.

There needs to be some play in the upper plate, so the vacuum advance can turn it; but not a lot. Remove the assembly from the dizzy, disassemble, clean and lube; then you can see how to bend it slightly to reduce the clearance if necessary. While you are in there, inspect and lubricate the mechanical advance as well, including where the cam turns on the inner shaft.

Banjo's remark about the ground wire is on-target as well. I like to check both wires (both the ground and the hot wire to the side terminal) by connecting an ohmmeter, while I gently tug on the wire, to ensure it's healthy under it's insulation (never did understand why they put insulation on a ground wire).
Similar threads
Thread starter Title Forum Replies Date
S TR2/3/3A missing problem with this tr3 Triumph 10
luke44 TR2/3/3A Help - TR3 Wiring Harness - Horn Wire Missing? Triumph 16
F TR2/3/3A TR3 missing Triumph 17
newmexTR3 TR2/3/3A TR3 missing at high speed / load Triumph 6
M TR2/3/3A Fuel line missing [ TR3] Triumph 13
1 TR3 Fender spats sold on EBay. Triumph 0
J TR2/3/3A What size speedi-sleeve needed for pinion seal on a TR3? Triumph 6
T For Sale Free - Body Jig for TR3/TR3A Triumph Classifieds 0
J TR2/3/3A TR3 engine cylinder top clearance Triumph 22
BillyB62 TR2/3/3A Looking for the Owner of a TR3 Triumph 5
Pool Dad 1960 TR3 engine serial number Triumph 14
T TR2/3/3A TR3 coolant hoses Triumph 2
T TR2/3/3A Has anyone designed a hand brake warning light for the TR3? Triumph 3
J TR2/3/3A "TR3" painted on the engine block Triumph 13
J TR2/3/3A TR3 Rear seat Triumph 11
D Socket for TR3 Gear box drain plug Restoration & Tools 6
J TR2/3/3A TR3 gas tank mystery Triumph 5
T Wanted Wanted - 1956 TR3 Crankshaft Triumph Classifieds 0
jfarris TR2/3/3A Venture into the "dark side," Miata seats in a TR3 Triumph 2
T TR2/3/3A Question on old radio from my TR3 Triumph 9
T TR2/3/3A tr3 front carpet replacement Triumph 5
T TR2/3/3A Should there be a body ground strap to battery on TR3 Triumph 7
G For Sale: Triumph TR2, TR3, TR3A Sheet Metal Body Parts – Front Apron (valence) with grille, Bonnet (hood), Doors, Boot (trunk) Deck Lid Triumph Classifieds 3
G For Sale: Triumph TR2, TR3, TR3A, TR3B Factory Steel Hardtop, New Rear window, Partial Bracket Set Triumph Classifieds 2
A TR2/3/3A Early TR3 starter (bomb style) bushings sizes Triumph 5
T For Sale TR2 - TR3 Gas Cap for sale Triumph Classifieds 1
B TR2/3/3A TR3 Hard Top Triumph 2
D TR2/3/3A TR3 throttle linkage bell crank. Triumph 13
M TR2/3/3A Defective master cylinders Tr3 Triumph 13
BarryO TR2/3/3A setting up a TR3 clutch slave Triumph 5
M master cylinder brake/clutch Tr3 Triumph Classifieds 6
C TR2/3/3A TR3 Gearbox Problem Triumph 10
Tr3aguy TR2/3/3A Started a Car revival channel for the TR3 Triumph 12
J TR2/3/3A Any advice for new floor install on my TR3? Triumph 9
D 1957 Triumph Tr3 Triumph Classifieds 2
P TR2/3/3A tr3 side curtains Triumph 4
banjojambo Triumph tr3 vertical link wobble Triumph 2
S TR2/3/3A purchased a box of tr3 parts this weekend, Triumph 1
C TR2/3/3A TR3 close by Triumph 2
D TR2/3/3A Tr3 horn testing and wiring Triumph 8
J For Sale Triumph TR2 TR3 TR3A New Moss Motors Black Karvel Style Carpet Kit Triumph Classifieds 0
B TR2/3/3A TR3 sag to the left [port sag] Triumph 10
K For Sale Triumph TR3 Bullnose Starter Triumph Classifieds 0
K For Sale TR3 rear rebound brackets Triumph Classifieds 0
K For Sale TR3 Radiator Guard Triumph Classifieds 0
S TR2/3/3A TR3 has me stumped, it runs then dies over and over and the exhaust system was pulled Triumph 9
D TR2/3/3A TR3 Headlamp Rings Triumph 8
O For Sale New Member from NJ 1960 TR3 Triumph Classifieds 1
K For Sale Rare TR3 Folding Lug Wrench Triumph Classifieds 1
A TR2/3/3A TR3-A replacement top Triumph 7

Similar threads