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ZDDP Anti Wear Oil Additive
OK, that's very helpful. I was going to add Lucas stabiliser when servicing. What do you think of it?
Also can I ask you to clarify does the result on the vacuum gauge mean the vacuum is good on the car?
And does it say anything about the engine condition/wear?
I don't have a timing gun, but let me look into it. I watched a few youtube vids, so have an idea of it now.
No ZDDP in Lucas Stabilizer. The Lucas ZDDP additive "TB Zinc Plus" is P/N 10063 - but I think the Classic Pre-formulated 10W40 oil I linked to above is all that you need, and it seems to be fairly reasonably priced for the UK.

Vacuum is good on the car. Good vacuum implies that all cylinders are contributing well to engine performance, not much more. Good vacuum doesn't say much about engine condition/wear, other than nothing catastophic appears to be going on (so onward and forward - no smoking gun found). If you really want to diagnose, that will take compression and leak-down tests and possibly other work. But I think you probably would prefer to just make it run good, put spark plugs in it, drive it, and see if oil consumption improves (or at least becomes acceptable). If oil consumption is still too high or if the spark plugs foul again quickly, you can always do the testing and the repairs later. Does this sound like a decent plan? If so, go ahead and source a dial-back timing light to use next. We will be doing much more than just checking initial timing.
 

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Discussion Starter · #123 ·
Hi,
I got that Timing Gun with the dial for advance timing from the USA, Amazon.com.
Took a while to arrive but have it now. Also Santa brought me some other goodies.

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So now we use the dial-back timing light to map the advance curve in the distributor. Timing is read by turning the knob on the timing light to align the balancer mark with zero degrees on the timing tab. Then read the number of degrees indicated on the timing light dial. We will check timing at points increasing in RPM, starting at low idle. So it is best to have a helper that can sit in the vehicle and hold the throttle to various steady RPMs, while you run the timing light and record the ignition timing at each RPM. However, for RPMs 2000 and below, you can use the throttle adjustment screw to fine tune the RPMs and read the timing without the helper's involvement.

Unplug the vacuum advance line from the distributor and plug the end of the hose for the first series of tests.

Starting at 600rpm (if it will Idle there). Record timing and RPM. Then repeat at 700, 800, 900, 1000, 1500, 2000, 2500, 2750, 3000, 3250, 3500, 4000 RPM. Do it a second time to make sure your readings are repeatable. Once we have those readings we can decide what RPM to test the vacuum advance (which will be a one and done)

That oil should be just fine! At 2100 ppm ZDDP its a bit higher than I have read is necessary, but Lucas chose to formulate it that way for some reason and they should have more expertise than I do regarding oil.

I would save the spark plugs for last (as long as you're not misfiring). Then you can see any deposits after all else is optimized/verified.
 

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Discussion Starter · #125 ·
ok I will get someone to help and get it done over next day or so.
Do I cap just the hose (and leave the distributor port open)?
Or cap the port out of the distributor also?
Thanks
 

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Discussion Starter · #128 ·
There is a white mark on this, so does this mean it is how the rebuilt engine was reset?
Do i ignore the white mark?
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The white mark would be zero on the timing tab (if you look closely you can see the "0" degrees stamp next to that point, and then the "4" degrees BTDC stamp next to the point right above it). At desired RPM, turn the knob on the light to line up the white mark with the mark on the balancer. Then record the timing shown on the timing light itself. The reason timing is being checked this way is because your ignition timing will be off-scale at the elevated RPMs if a simple timing light is used. The dial-back timing light delays the flash and brings the apparent mark back onto the physical scale - so with this method you line the mark on the balancer up with zero on the timing tab and read the timing on the timing light.

Does your timing light have a knob to turn or is it electronic adjustment? Photo please.
 

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Discussion Starter · #130 ·
yes it does. ok i think i understand what i have to do now. Thank you.
I may be thick but I'm not stupid (I hope) LOL
Oh yeah, I nearly forgot to ask, which plug is no.1 to connect gun to?
Is it drivers side front?
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No shame during your first time! Your timing light has the manual dial I was speaking about. #1 is drivers side front cylinder on a SBC.
 

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Sometimes it feels like a couple of us should hop on a plane and go help him out!
But we do have this forum.
I used to mark the tab like that too. And the line on the balancer.
a good safety tip especially for you. Be very careful with the wiring of your light. Make sure they can’t contact any moving parts.
 

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Yeah, its pretty easy to lose a timing light lead in the fan, or burn them on the exhaust manifold.

For something like this, the forum format is so far superior to that of Facebook...................... Just don't understand why people choose to move to Facebook Groups and let the forums die. With Facebook, there is no way to track 132 posts on one topic, over months - and keep it all together for future reference. Once posts scroll off the screen, they get lost in oblivion.
 

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Yeah, its pretty easy to lose a timing light lead in the fan, or burn them on the exhaust manifold.

For something like this, the forum format is so far superior to that of Facebook...................... Just don't understand why people choose to move to Facebook Groups and let the forums die. With Facebook, there is no way to track 132 posts on one topic, over months - and keep it all together for future reference. Once posts scroll off the screen, they get lost in oblivion.
Exactly.

It's incomprehensible how FB is popular.
 

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Facebook is great for broadcasting and looking at photos of the grandkids, and hearing from otherwise silent family members because everyone is on it and all friends can see what you post. Also Marketplace is a good replacement for Craig's List. But for me that's as far as the usefulness of Facebook goes!! Facebook Groups suck!!

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The reason behind disconnecting the vacuum advance is that with no load on the engine (no vehicle resistance to movement) it takes very little throttle opening to get high RPM where the mechanical advance is working. But the problem with a lot of RPM combined with very small throttle opening is that the engine manifold vacuum remains quite high which if the vacuum advance is connected it is actuated by high manifold vacuum so your timing light is reading the sum of the mechanical and vacuum advances not just the mechanical. This condition does not exist out on the street!

The carburetor port is plugged as that is the vacuum source, left open it becomes an air leak into the engine that upsets the mixture ratio and the idle speed. The vacuum can is on the receiving end and is benign in this regard. Things to check with the hose loose is for a vacuum leak in the diaphragm which can be done by sucking on the tube, if you can (essentially) breath through the tube the diaphragm is ruptured and is not functional, it has become an air leak into the carb as previously discussed on mixture and idle effects. Yes the tube tastes like gas and oil, if you want to be a mechanic it’s something to get used to.

You need to figure out what the white mark on the damper denotes which will require cleaning it and the damper so you can read the stamped numbers doing this all without removing the white mark.

- Often the Chevy has both TDC and several degrees stamped on the damper and TDC and some degrees also indicated on the timing tab but there are other configurations Chevy has used:

- An only TDC mark on the damper with a timing tab with TDC indicated along with marks for TDC and the before and after degrees.

- Another way Chevy has done it is TDC and before and after degrees on the damper with just a pointer for the timing tab. From your picture this is not what you have.

But you need to clean what you do have up to see what the white mark means whether someone marked TDC or the degrees of advance they were shooting for.

Bogie
 

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Discussion Starter · #137 ·
OK fellas,
We did it 3 times, with thermostat open, with advance unplugged and hose capped, the revs drop to a rough 500rpm.
Firstly, at lower revs (600 to 800) the light jumps around a bit, is this normal?
600-10, 700-12, 800-14, 900-18, 1000-19, 1500-21, (1750-23 extra reading),
2000-25, 2500-26, 2750-27, 3000-27, 3250-27, 3500-27, 4000-28.
What do these readings tell us? What should it be?
Thanks
 

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Yes at low RPM you will miss fires you will see this on a accurate tach as RPM changes.

If you see this with no RPM changes (drop a bit then recover) then it’s likely to be the timing light not reacting to every signal.

Bogie
 

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Great! Timing is "all-in" by 3000 rpm. It has a performance centrifugal advance curve that is all in (fully advanced and not changing by 3000 rpm). On your car, idle is not a good place to plug in vacuum advance to check how much of it there is, because the increasee in idle speed will also increase the centrifugal timing and give a false high reading on the vacuum advance. But we can get around that.

Now loosen distributor clamp just enough to turn distributor, and advance timing about 6 degrees at (slow idle). Then re-check at 3000 rpm. You are shooting for 33-34 degrees of timing at 3000 (vacuum advance unplugged). Once you have 33-34 degrees at 3000 rpm - return to idle, tighten the distributor clamp fully, and plug the vacuum line onto the vacuum advance. Record timing at 3000 with vacuum advance plugged in.

Set idle speed to desired idle - lets go with 650 rpm.

Turn each idle mixture in slowly until engine speed starts to drop and then back out just far enough to recover engine speed. Now shut off engine.

Turn each idle mixture needle in until it very lightly hits the bottom (carefully counting turns and fraction of turns). Now carefully turn them both out the average of the previously counted turns in and start the vehicle. From now on you will turn both idle mix needles the same amount in or out at each adjustment.

Begin final adjustment by turning both needles in 1/8 turn. If engine speed starts to drop right away and idle is smooth, back them out 1/8 turn and you are done. If no engine speed drop, keep turning them in together (1/8 turn at a time) until engine speed just starts to drop, then back both out 1/8 turn and you are done adjusting idle mix.

Readjust idle speed if necessary, and report timing at 3000 with vacuum advance plugged in (that you previously read). Recheck and report engine vacuum (bet it went up). Report idle mix screw position (turns out from closed). Report if PCV valve is steady (you previously had a problem here). Drive car and make sure no audible pinging (detonation) occurs.

If all is good, change the spark plugs and oil and start evaluating your oil consumption. Your car should now be running very near to the best of its ability. If the additional timing at idle causes any difficulty in cranking over while starting, let us know and we can tell you how to deal with it.
 

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Discussion Starter · #140 ·
i loosed the bolt on the ditributor but the distributor wont move.
but the plate on the bolt moves? but it seems not to be connected to the actual distributor,
just a plate on its own???
 
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