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TR6 TR6 lacking power when I accelerate.

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I

ichthos

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I decided to start a new thread since what I need is very specific now. I had my carbs and head rebuilt. I also rebuilt the rocker assembley. I took my car out for a test drive. When I try to accelerate, it makes a put put sound and lacks power. I also have some white or grey smoke coming out the tail pipe. My wife said the smoke smells like gas to her. Is this a carb adjustment problem? I have not touched the carbs up to this point. I am always leary about touching something and making it worse.
Kevin
 
Did you install new plugs at that time? Did you check their gap? Is the ignition tuned properly, from the point gap setting to the timing? Are all of the plug wires on tightly? What is the condition of the cap, rotor and wires?

90% of all fuel problems are electrical, so before touching any carbs (as you rightly decided not to do) let's get answers to the above.
 
First things to check:

1) Is the timing correct?
2) Are the carbs receiving fuel?
3) Is the fuel filter clogged?

You always want to dive into the carb as a last restort. One you've established that you are getting the right spark and timing at the plugs and the fuel delivery is correct, then, and only then dive into the carbs.

Jody
 
I checked the plugs. I checked the point gap. I static timed the engine. The wires are on tight. The cap, rotor, and points are in great shape. I don't know if the fuel filter is clogged. How would I be able to tell? Since the smoke smells strongly like gas, they must be gettting gas, correct? Could my problems be related to the valves at all-should I recheck them?
Kevin
 
Hi Kevin,

If all you have done is static timing, I would start there. A few questions:
1. Has your harmonic balancer been rebuilt? If not, it has slipped and your timing marks are inaccurate.

2. Did you replace the crank, cam gear and chain? If not they have wear and slack that contributes to timing issues.

3. Is the distributor gear new or original? If not, wear on those teeth will contribute to timing errors.

An old or original cam will also contribute to false timing, especially if you use the traditional timing light method. I would get a vacuum gauge and time your engine with that. If you are stock, try to get a reading of between 17-18 on the gauge. Poolboy can fill in more technical details with this method.

Hope this helps.

Greg
 
Luckily I had an extra fuel filter, so I just replaced it. The engine will be cold tomorrow, so I will check the valves then. To answer some of your questions, I did not touch the lower engine, only the head and carbs. My car is completely stock. I had thought about rebuilding the whole engine, but I just don't have the money right now. My distributor was recently rebuilt, so that is not a factor. I will try advancing the timing towmorrow and let you know what I found. The only reason I have not done the vacuum timing is that basically I didn't understand what benefit it had over other timings, nor did I really understand how to do it. By the way, can someone tell me the significance of white/grey smoke? Thanks.
 
That's just the problem, white/gray doesn't clearly point at anything. Oil smoke is normally blue, but sometimes comes out a lighter color; steam (water) is generally pure white. Fuel smoke is normally black, but might be white if one (or more) cylinders is not firing at all (which would explain the put-put sound).

What happens if you remove the air filter, and watch the carb pistons as you rev the engine up? Does it run smoothly then? Do the carb pistons rise together?

The main advantage of vacuum timing, IMO, is that it does not rely on timing marks (which may be inaccurate).

Some other points to consider :

Occam's Razor only says "usually", meaning the problem may not be related (or related only indirectly) to the work you've just done. Carbon-core ignition wires are particularly suspect in this regard, since flexing is what kills them, and you have to flex them to R&R the head.

All of the high tension components (cap, coil, rotor, wires, plugs) can fail without any visible indication. I have seen a brand new Triumph rotor fail within an hour of being installed ... and the rotor was NOT defective when it was installed. It still looked brand new, but was leaking enough spark to ground to keep the engine from running at all. In that case, the root cause was a bad plug wire, plus a Lucas Sports coil that would put out more voltage than a stock rotor can handle.

My point is not that your problem is necessarily ignition; only that it's time to start actually troubleshooting rather than guessing.
 
Is the firing order correct??? 1-5-3-6-2-4...rotor turns CCW...
 
I am just now getting ready to go back out to the garage. I did check the firing order and it is correct. I am going to recheck my work one more time, and then check some of the other items mentioned. It's funny you mention a piston not firing. The engine is behaving like it did when I had the burnt valve. When a valve burns, doesn't this basically knock out a piston from firing? Couldn't I check this problem by pulling the spark plug wire off each plug one at a time and see if there is a difference in how the engine runs? That would at least limit what could be wrong. I will try the vacuum method if I can find my directions and understand how to do it. I will get back once I know a little more. Thanks.
Kevin
 
If you have a burned valve, the spark plug still fires, but the combustion chamber will not hold the compression, and the piston will lack power or at least it will not contribute it's share of power to the engine.
A vacuum gauge can also diagnose a burnt or sticky valve along with a few other things, but it won't narrow it down as to which cylinder is acting up.
Check out the scenarios at the bottom, particularly Scenario 6
https://www.secondchancegarage.com/public/186.cfm
And for ignition timing:
https://automotivemileposts.com/garage/v2n8.html
Use the vacuum fitting on the intake manifold, either one, or the one for the servo.
 
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