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Ignition timing TR5 CP.


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I have a question perhaps somebody may have an answer,

Lucas 22D6 distributor, 41219B, timing set with a strobe gun, at 10 degrees before TDC at about 850 erpm, if I accelerate the engine, and still with the strobe light shining on the timing marks the timing shows about 5 degrees retarded, and then will increase above the 10 degrees as the engine speed is increases, I have the correct springs fitted as supplied by DD, I questioned this with him also, and said that its normal, is this really true, all other engines I have checked not TR's, mostly BL's always increase the timing but never dip below the set amount, can anybody enlighten me on this please.

It doesn't seem to detract from the performance, so perhaps I shouldn't  be looking for things that are not important!

How much advance can I go too, without it pinking?, as this dizy is easy to just keep turning the wheel. I have got up to about 16 degrees so far, and wondering how much further to go? Using 98e5 regular.

Any suggestions would be welcome please.

John

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Hi John 

I had a Lucas distributor with a badly worn rotor arm on my TR4a which gave erratic timing.

Try removing the distributor, gently clamping the drive dog, then trying to turn the rotor arm. As you know all you should get is return spring action up through the drive.

Kevin

 

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2 hours ago, John L said:

I have a question perhaps somebody may have an answer,

Lucas 22D6 distributor, 41219B, timing set with a strobe gun, at 10 degrees before TDC at about 850 erpm, if I accelerate the engine, and still with the strobe light shining on the timing marks the timing shows about 5 degrees retarded, and then will increase above the 10 degrees as the engine speed is increases, I have the correct springs fitted as supplied by DD, I questioned this with him also, and said that its normal, is this really true, all other engines I have checked not TR's, mostly BL's always increase the timing but never dip below the set amount, can anybody enlighten me on this please.

It doesn't seem to detract from the performance, so perhaps I shouldn't  be looking for things that are not important!

How much advance can I go too, without it pinking?, as this dizy is easy to just keep turning the wheel. I have got up to about 16 degrees so far, and wondering how much further to go? Using 98e5 regular.

Any suggestions would be welcome please.

John

More important is the light steady? Also that can happen with wear in the drive dog normally the pin

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There is something wrong.

Timing @1500 about 15degrees, @3000 about 30degrees

 

So the culprit maybe the dizzy itself or the drive allthrough the machine like timimg chain.

Easiest way to find out is to fit a fresh dizzy. For that I always have cheap item from SimonBBC at hand, what cost me about 70GBP.

I use that with a new set of wires and plugs and a fresh Lucas Golden coil.

 

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Is there vacuum advance John ? If so a changes in vacuum as you open the throttle might account for some initial retardation. 

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I've always ran my PI with vacuum advance permanently disconnected, 11deg BTDC at idle , then creep the timing forward until I get pinking just starting at WOT , 4th gear low speed, then retard it a tad.

Are you sure you don't have a US distributor with the extra anti-smog advancing and retarding gear?

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Please excuse the low level of my understanding on this, but looking for some help on this subject. I have got my TR6 running well after doing some work cleaning the throttle assembly. I have an early 1969 TR6 and gone thru checking spark plugs, HT leads and timing. The car had no bushes in the throttle assemblies, and there was a lot of free play in the throttle both in the accelerator pedal and the throttle spindle. I think I have corrected this, and then had problem with high idle. I looked at changing timing but when I checked vacuum I was changing timing back to what it was. I disconnected the throttle assembly so the butterflies were at their most closed, and then spent several hours getting the assemblies to open simultaneously and close completely. I did not clean the internal butterflies. Reasonable amount of crud / carbon in them but not too much. Anyway the butterflies are now set so the idle is around 800 rpm. The question I have is the base timing (sorry long way to get here). With timing strobe I have got timing at 4 deg AFTE. This does seem to give the car the best performance/acceleration and smooth running. It’s taken awhile to get here but the car is running well. This maybe a fluke. My question is in the above the timing mentioned is significantly different. What am I doing wrong. Why do I have 4 deg AFTE and car running well? I don’t think I can go 10 deg Before TDC or am I missing some understanding. Again appreciate any help.

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Martin- you have a PI, there should be no vacuum connection to the distributor, so I assume this refers to the engine idle without any correction to the distributor timing from a vacuum connection- " but when I checked vacuum I was changing timing back to what it was".

The car will never run properly with the timing set at 4 ATDC. You are setting the timing at low engine speeds before the distributor weights cut in ?

If you're still getting high idle speed with the timing set around 10 deg BTDC you probably still have an air leak in the inlet system and are having to correct the high idle speed it caused by retarding the timing.

Connect a vacuum gauge to the brake booster hose and check the manifold vacuum at idle- I have to get 10 inches Hg or I have a leak.

There may be leaks in the hoses connected to the manifold and in the MU that you haven't noticed yet.

 

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9 hours ago, Martin50 said:

Please excuse the low level of my understanding on this, but looking for some help on this subject. I have got my TR6 running well after doing some work cleaning the throttle assembly. I have an early 1969 TR6 and gone thru checking spark plugs, HT leads and timing. The car had no bushes in the throttle assemblies, and there was a lot of free play in the throttle both in the accelerator pedal and the throttle spindle. I think I have corrected this, and then had problem with high idle. I looked at changing timing but when I checked vacuum I was changing timing back to what it was. I disconnected the throttle assembly so the butterflies were at their most closed, and then spent several hours getting the assemblies to open simultaneously and close completely. I did not clean the internal butterflies. Reasonable amount of crud / carbon in them but not too much. Anyway the butterflies are now set so the idle is around 800 rpm. The question I have is the base timing (sorry long way to get here). With timing strobe I have got timing at 4 deg AFTE. This does seem to give the car the best performance/acceleration and smooth running. It’s taken awhile to get here but the car is running well. This maybe a fluke. My question is in the above the timing mentioned is significantly different. What am I doing wrong. Why do I have 4 deg AFTE and car running well? I don’t think I can go 10 deg Before TDC or am I missing some understanding. Again appreciate any help.

Have you physically checked the timing mark on the pulley relates to actual piston top dead centre?   The rubber bit of the crank pulley is known to allow creep of the outer pulley ring 

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Sorry John, did not mean to hi jack your original questions. But if I may just follow up with Mike and Peter.

I do get approx 10 inHg vacuum testing at the inlet manifold connection that goes to the MU. It appears quite steady at idle, but drops and comes back when I blip the throttle.  It is a PI, so no vacuum connection on the dizzy. I was expecting or thinking I should have more than 10 inHg, but put that down to age of engine. I also had checked some time ago that nos 1 cylinder was TDC when aligned with pulley marker, but haven’t done this in the recent work I did. I can re do check. All I did last time was to take the plug out and put a screwdriver into hole and turn engine. I looked for when screwdriver was pushed out at its highest on nos 1 cyl and see the timing mark came to about zero.

I’m doing something wrong or not understanding but the car / engine is running well, it is idling around 800. Not perfectly smooth but not bad and it is best once it has warmed up. The 10 inHg does coincide with the 4 degAFTE. This is using a strobe light, picking up white tipex marks on pulley and aligning with indicator on pulley. I cannot see how I can be that far out if 10 deg BTDC is the norm. Appreciate the comments, and I will check the pulley and TDC. I can see that would cause problem.

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14 hours ago, Mike C said:

I've always ran my PI with vacuum advance permanently disconnected, 11deg BTDC at idle , then creep the timing forward until I get pinking just starting at WOT , 4th gear low speed, then retard it a tad.

Are you sure you don't have a US distributor with the extra anti-smog advancing and retarding gear?

Same here, advance it till it pinks then drop back a bit.  Fuels have changed a lot since 1960s and plenty of mechanical variables too. So the "spec" is just a rough guide to get it started.

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