TR2/3/3A TR3 Engine Miss

[oxendine]

Been trying to get my latest addition to the garage running correctly. It is a 1961 TR3 that had been in long term storage. I did all the basic stuff like lubing cylinder walls, cleaning points, changing plugs and wires. After a little fiddling it started but only runs on the front 2 cylinders. I adjusted the valves and check compression. Compression is all over the board between 150 and around 75. The back plug gets wet and black and #3 stays clean. I can start the engine and pull the back 2 wires with no difference in the engine sound. There is a good spark from each plug. The car had no air cleaners mounted when I pulled it from the storage locker. There is gas in the back float bowel and plenty of gas feeding it. Any ideas?

Thanks, Donnie

 

[TR3driver]

Is #3 also the one with the very low compression ? I'm guessing there is something wrong inside the engine, like a burned valve or missing cam lobe.

 

[CJD]

Or stuck rings...

...the good news, they can loosen on their own, if they aren't frozen too tight.

John

 

[oxendine]

Compression about 75-100 on each, the front 2 about 150. Even with 75 lbs. of compression the cylinder should still fire. I'm almost thinking fuel delivery? I'm not quite sure on how to proceed.

 

[CJD]

Are the plugs on the back two wet with oil or gas? A lot of oil (or gas, for that matter) can choke out the flame and foul the plugs after a few pops...especially with the narrow plug gaps we are using.

If you have access to a leak down tester, you can pressurize the cylinders and then listen for where the air is escaping. Oil filler cap and road vent...is rings. Intake or exhaust will be the respective valves. Without a leakdown tester, you can just use an air hose with a rubber tip stuck in the plug hole. The cylinder you are testing must be at top dead center on the compression stroke...and keep away from the fan when you add pressure, as the crank can spin rapidly if you did not get it dead center.

If a lobe is flat, like Randall suggests, you can check by turning the engine by hand and measuring valve lift on 3-4 compared to 1-2.

If it is rings, shoot a lot of penetrating oil down the holes and let it sit to do it's job. you'll know the rings are free when the compressions go up consistently. You don't have much to loose, as the alternative to free them is an engine disassembly.

It's a process of elimination...

John

 

[Bremer]

If your carbs are not synchronized, two cylinders will be doing the work while the other two are just along for the ride. If you then pull the plug wires from either of the two "lazy" cylinders, engine speed will not change, but that doesn't mean they don't fire.