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TR2/3/3A Engine shakes as it is accelerated.

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DavidApp

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Working on a TR3B for a friend and have got it running after its long rest.

Went through the carbs and did a seal kit. Adjusted the jets to all the way up then down 10 flats as a starting point. I think the rear carb is a little rich at the moment.
Replaced everything on the ignition side. Coil, condenser, points and plug leads.
Replaced the fuel line from the tank to the fuel pump.
Checked and reset the timing to 8 degreed BTDC static. It was 8 degrees ATDC. Ran but not well.
Replaced exhaust down pipe.,

When I accelerate from idle slowly the motor shakes all the way to about 3000 rpm. If I accelerate quicker it seems to stop shaking sooner.
The TR has the Monza Free flow exhaust system on it so it sounds very different to my TR3A
What am I missing.

David
 
Interesting.
I have very little to no knowledge on the history of this engine. It is not the original engine in the TR3B going by the engine number.
It does have good oil pressure to the point that I had to adjust the PRV as it was getting to 90PSI when I drove up the road today. I have it set to 70PSI now.

David
 
Apart from the shaking does it pull all right or does it sound like it is missing, have you got the firing order set right, did you check the tappets are all the valves opening and closing?

Graham
 
Hello Graham
Thank you.
It does pull OK. The exhaust has that Monza system so it has a different sound to mine but I do not think it is missing. Have considered trying my spare distributer on it.
Firing order is correct 1 3 4 2.
I have not checked all the tappets yet.

David
 
David - could you make a video showing the engine at idle, and shaking as you slowly open the throttle?

I'm still thinking worn main bearings, especially as you don't have a history of the engine.
Tom M.
 
Might look at valve adjustment as it stops at about 3000, might be tight do to old stiff oil. Will not be hard to check after rocker cover of.
 
I am curious as to why you started the process of adjusting the carbs and then quit before you actually adjusted them?My suggestion is to get a manual and finish adjusting the carbs. Until you do that I believe you are chasing ghosts.
Charley
 
Charlie.
I had them adjusted to basic settings. Balance and the jet height (10 flats down from the top). Choke working both pulled and choke off both jets go to the adjusting nut.
I was trying to get them fine tuned and got the front one to give a tannish plug but the rear one kept looking rich. I leaned it and leaned it then it would spit back through the carb as I revved it. So I went back to the basic setting on the rear carb then leaned it a couple of flats.
That is when I started to try to get to the bottom of the shaking.

Just got an INNOVA timing light with the dial back feature.

I did a bit of work on the engine today.
Checked the valve clearance and had to reset a couple of tappets a few thou. All the valves open and close.

Used my new timing light but got inconsistent results.

Swopped the distributer and got somewhat better timing light results. Took the distributer apart and found the cam and weights were not connected. I had noticed the center screw was lose and the cam would lift up so I tightened the screw not realizing the weights were probable out of position. The springs look a bit tired. I got the weights back in position and tightened the center screw.
Replaced the original distributer on the engine and set the timing to 8 degrees BTDC.
Using the new timing light set to 8 degrees I expected the timing mark to line up with the pointer. It did not so I dialed in more and more advance till it did. It read 27degrees of advance??
The timing position does move now when I rev the engine.

It may have run a little better.

When I started on this engine it was set to 8 degrees ATDC

I am going to check to see if the mark on the pully is true TDC..

David
 
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Sounds like you are you close to getting the optimal performance out of the tr3 David. Heck maybe rings and a valve job might give you some more even power and stop the shaking. Once I had a problem with the front carb jet assembly moving back when I pulled the choke. The needle would start to drag after the choke was pulled and that stopped the piston from falling with that click, but after driving a little the needle would re-center most of the time and run better, I guess from moving up and down. I fixed it by changing the angle of the clamp that held the choke outer cable just a little and tighten down the big holding nut more.

it does sound like a carb problem because you have done so much everywhere, maybe a weird coil.

maybe the choke is not fully returning

Have you guys taken the car out for 50 mile drive and see how it runs and perhaps do some tuning on the open road?

steve
 
After thinking about it over night I took a look at the distributer in my TR3A and checked how the rotor and cam returned after being turned CCW. It sprung back quickly but on the on the TR3B I am working on it did not spring back very forcefully and did not get to the stop.
I dismantled the distributor and noticed the springs has some slack at the mounting points when the rotor was turned back CW.
I learned from a you tube video that the heavier spring should have some slack but not both springs. This is to allow for a progressive advance or the advance curve.
I carefully shortened both springs making sure the stronger spring still had some slack in it.
Reinstalled the distributer and reset it to 8 degrees BTDC. When I checked it with the timing light set to 8 degrees it was just about dead on the mark and as I revved it up to 2000 rpm the timing advanced to about 35 degrees BTDC. with No shaking. Going back to idle it returned to 8 degrees.

I hope this is the solution to the shaking problem. I will go up the road in the morning to give it a road test.

David
 
Great attention to details. Excellent!! Taking a chance adjusting the springs must have been very satisfying to see it running better. Frank
 
Took it for a short run today. It did far better on the road even kicked up some gravel as I left the driveway.

David
 
No shaking now. So it must have been the disconnected mechanical advance weights and lose springs. That was all I changed to enable me to get a good timing result and no shaking.

The owner has decided to order a new distributer from The Roadster Factory. Did not want to rely on my shade tree Distributer Advance curving.
Must say I do not blame him as there was more wear in the parts that I could not address. At least I did identify the problem.

David
 
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