raylish said:Harvey, Chris, thank you for your patience and persistence.
No problem, and now I've realised this is a 4 pot not a V8, we might stand a better chance of sorting it.
raylish said:Harvey, Chris, thank you for your patience and persistence.
harveyp6 said:raylish said:Harvey, Chris, thank you for your patience and persistence.
The vacuum does rotate the baseplete (in a CLOCKWISE direction) when 'sucked'! Chris, the rotor arm (which rotates in an anti-clockwise direction when the engine is turned over) does spring back, with no slack movement when twisted in an ANTI-CLOCKWISE direction?
Ray
If this is a V8 the rotor arm turns CLOCKWISE with the engine running, and so sucking on the vac unit should move the baseplate against normal rotation to advance the timing, hence ANTI-CLOCKWISE.
harveyp6 said:raylish said:Harvey, Chris, thank you for your patience and persistence.
The vacuum does rotate the baseplete (in a CLOCKWISE direction) when 'sucked'! Chris, the rotor arm (which rotates in an anti-clockwise direction when the engine is turned over) does spring back, with no slack movement when twisted in an ANTI-CLOCKWISE direction?
Ray
If this is a V8 the rotor arm turns CLOCKWISE with the engine running, and so sucking on the vac unit should move the baseplate against normal rotation to advance the timing, hence ANTI-CLOCKWISE.
raylish said:Thanks Harvey, but this is a 2200 sc.
harveyp6 said:raylish said:Thanks Harvey, but this is a 2200 sc.
Yes. I've just realised that......
In which case if the vac unit moves the baseplate that will be in the opposite direction to the direction of the rotor arm, which makes all that you previously said correct. I don't know where I got the thought that it was a V8 from.
So I'd check with the strobe again, set the timing to 8BTDC as a starting point, and then rev the engine while looking at the timing marks with the strobe, and see what happens.
I've done a little spring cleaning to my previous posts in the hope that it will be a little less confusing if it's referred back to in the future.
raylish said:Harvey and all,
I can get it to start at 8 degrees BTDC. It starts and runs (lumpily), then the revs rise, the timing advances to 20 degrees BTDC, it falters and the timing returns through 10 degrees BTDC to TDC and it then either repeats this procedure or stalls?
Ray
chrisyork said:Mmmm. You wouldn't be able to identify any slack in the bottom chain from moving the top chain if both crank and cam are locked. BUT, if you just locked the cam, you could see how much crank movement each way you could get. That would identify total slack in the system. Then from identifying how slack the top chain is, you could infer the state of the bottom chain. It's only the bottom chain that really matters here, because the distributor is driven direct of the intermediate pulleys / jackshaft, and it's the relationship between distributor and crank position that interests us.
I suppose it could be sticking bob weights. When you initially set the timing, the bob weights being stuck with 8 advance, then a quick rev frees them off and they return to nil advance, giving you this strange effect of a retarding advance system...
So let's set the timing static. That way you can be certain that the centrifugal advance is fully home at zero advance. Then see what the strobe tells us during running.
Does feel like we might be homing in on the problem
Chris
raylish said:... stripped down the carburettor (HIF6) and all appears fine; timing is spot on.
Ray
chrisyork said:I agree with Harvey. Before you go any further you need to confirm whether the vacuum advance and the centrifugal advance are working. No matter how many times you've taken them apart that says nothing about whether they work.
To verify the function of the vacuum advance. With the distributor cap off, disconnect the vacuum pipe to the advance unit at the inlet manifold end. Suck on this end. You should see the baseplate rotate within the distributor. If it doesn't, then check that the baseplate isn't seized solid within the distributor. If free then bin the complete vacuum unit and buy a new one.
To verify the function of the centrifugal advance. With the distributor cap off. Twist the rotor arm clockwise. Does it spring back to its original position when you let g? Is there any rotational free movement when it is at the rest position before you feel the spring resistance? If any of these are faulty you need to strip the baseplate out of the distributor and find out what is going on with the fly weights and the springs.
Once these two functions are verified, only then can you move on to discuss the timing.
Chris
raylish said:How far should the rotor arm twist anti-clockwise, please? I can see a metal arm (bob weight?) moving slightly outward when twisting the rotor - But the rotor only moves about 5 mm before springing back - Is this correct?