Symptoms of distribution problems.

[Mr Ed]

Hello everyone. :salud Amigo

I am reviewing my brother's Land Rover Series IIA 1964 2 1/4 engine,

some time ago I noticed it with very little force and over 1200 rpm black smoke,
it has Sniper injection and it seems to work very well,starts fine, at low RPM it runs very smooth and does not you can see smoke.

 I have checked several things without finding anything strange, the spark plugs get dirty with black soot very soon.

 We have never disassembled the engine, so we do not know how it is inside, the compression is very even in the 4 cylinders (125 PSI),

 it is not very high, but it is very even... I suspect that there is a problem with some component synchronization.

Could someone tell me what symptoms it produces when there are problems with the chain, or distribution tensioner?
 
 Grateful for any comments, Have a nice weekend!   

[Mr Ed]

When the timing chain is loose, what symptoms occur?

Or is nothing appreciated until disarming?   

Thanks

[diffwhine]

¡Buenos días!

I'm not familiar with the Sniper injection system, but everything your are describing seems to me to point to over fuelling. How much adjustment do you have on the sniper injection system for mid range load and power demand?

A slack timing chain usually rattles quite a lot - can hear a noise like a bag of loose nuts rattling around in the timing cover. I would guess that you could possibly compare the amount of backlash using a dial gauge between a known god engine and the suspect engine. If there is a wide variation between the readings of the rocker on a given cam lobe between the two engines, that would suggest slack in the timing chain. I suspect the only answer would be to remove the front cover.

In theory, your slack timing chain (unless drastically loose), will not impact timing when the engine is under load - it will be more evident on overrun I would suspect. A basic check of the valve timing can be done with a DDI gauge on a rocker using TDC as a reference point on either the front timing pointer (late 2A / S3) or on the flywheel pointer (earlier S2 and 2A).

My money is on an injection issue though. How does the sniper system identify the correct moment of injection?

[ChrisJC]

It's made by Holley, and it's a carburettor replacement.

Reading about how it works, I suspect the Lambda Sensor is broken.

Chris.

[diffwhine]

OK - so single point then. That makes sense. If no lambda feedback, it won't know what its supposed to be doing.

[Mr Ed]

First, thanks for your answers, they help me....

At idle the engine runs quite well, without smoke and smooth,
 the problem is when it requires force, when rolling on the street and passing second or third, there it begins to cough up black smoke and work very unevenly, it is not capable of exceeding 40 k/h h.

With the information that they have indicated to us, we will continue reviewing,
THANKS again diffwhine and ChrisJC  :salud Amigo