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Timing Mark Moving Around

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rlich8

rlich8

Jedi Trainee
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Hi all,

I'm trying to set the timing on my TR4A and the timing mark is moving around.

It is NOT the distributor - it has been fully rebuilt and re-curved by Jeff Schlemmer at Advanced Distributors. I even pulled the distributor and double checked everything and reset the points gap.

Any ideas here? I'm stumped! I hope it's not something to do with the timing chain but all suggestions are welcome!
 
Could always be the juice for the timing light is not right. Maybe a bad spark wire.
Move it to a different wire and see if it still jumps

Don't know about this , ... a bad rotor??
 
sp53 said:
Sounds like the vacuum unit on the distributor.
Click to expand...

I thought of that but the problem is, it still moves when it's disconnected.
 
Have you checked the end float on the distributor drive gear (in the pedestal)?

What happens when you rev the engine up a bit?

How's your oil pressure?
 
Have not checked the drive gear - what am I checking for here?

Oil pressure great - 70 going down road 30 at idle.

If I rev it up a bit it evens out a bit.

I'm suspecting timing chain if it is not an issue with the distributor.

I am also going to try another timing light and another power location for the timing light. When I had the car in the shop I used a really nice timing light to check the timing and it was NOT doing this. (or at least I don't remember!)
 
rlich8 said:
...It is NOT the distributor - it has been fully rebuilt and re-curved by Jeff Schlemmer at Advanced Distributors...
Click to expand...

Did he replace the bushing? I'm thinking I asked him about that and he said he prefers not to replace it.
 
Usually he does a custom shaft bushing, according to what he told me and his website says? Hmm. Maybe I'll also try another dizzy. I have a spare MGB one.
 
rlich8 said:
Have not checked the drive gear - what am I checking for here?
Click to expand...
The procedure is in the workshop manual, page 1-130 in my copy. Basically the gear should have between .003 and .007" clearance between the bushing in the block and the bottom of the distributor pedestal. If the bushing were really badly worn (or the pedestal wasn't seated somehow), the gear could bounce up and down, affecting ignition timing.

But it's kind of a reach, just something that is easier to look at than the timing chain. My first thought was the dizzy, but I guess you're not open to the idea that Jeff might have made a mistake.
 
TR3driver said:
rlich8 said:
Have not checked the drive gear - what am I checking for here?
Click to expand...
The procedure is in the workshop manual, page 1-130 in my copy. Basically the gear should have between .003 and .007" clearance between the bushing in the block and the bottom of the distributor pedestal. If the bushing were really badly worn (or the pedestal wasn't seated somehow), the gear could bounce up and down, affecting ignition timing.

But it's kind of a reach, just something that is easier to look at than the timing chain. My first thought was the dizzy, but I guess you're not open to the idea that Jeff might have made a mistake.
Click to expand...

I'm going to check that - thanks.

I'm very open to Jeff having made a simple error, I'm praying it's something with the distributor in fact. :smile: Sorry for seeming stubborn! :smile:

I just want to try a different timing light, and different power source.

Cheers, and thanks.
 
Seems to be "better" with a different timing light.

It has to be some sort of distributor or timing light issue because it was not doing this. This engine was running like a CLOCK 50-100 miles ago. Now it's running like crap. And the carbs are rebuilt too.
 
It should move if it is disconnected if it is not connected. Pull the cap and look inside to make sure the little eyelet is connected to the rod. I am working off memory here, but try and move the knurled knob with the light on pulley and see if the responds accordingly. If the vacuum rod is undone, the timing move and float around. The timing will advance with weights also. If your problem is keeping the timing set, the distributer can come lose in two places one on the block and one right under the body on the sheet metal clamp.
steve
 
Any luck finding the cause?

Scott
 
Hey Guys,

Yes, I've found the cause. It's definitely inside of the distributor. I was reluctant to think so, but I swapped it out with a different distributor and alas, the timing mark is dead on. It's just a bad advance spring.

Weird problem because the distributor was new, and the motor is really fresh...it's been rebuilt and the components are just too new to be doing something like this.

I've sent my 25D back up to Jeff to have the spring replaced, so it should be sorted out pretty soon!

Roy
 
And that's why I always cringe when the owner of a car I'm thinking about buying says something was "just rebuilt". There's a lot of latitude in the definition of "rebuilt"!

Glad you figured it out...

John
 
CJD said:
And that's why I always cringe when the owner of a car I'm thinking about buying says something was "just rebuilt". There's a lot of latitude in the definition of "rebuilt"!

Glad you figured it out...

John
Click to expand...

John,

I have those same sympathies, however, Jeff's work is top notch and he is thoroughly backed by many enthusiasts. It's not Jeff's fault, it's just a faulty spring. But nonetheless, it's very rare for that to happen. He's done like 6 distributors for us.

On an engine or transmission or something, the "just rebuilt" thing is often times bogus.
 
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]And the carbs are rebuilt too.[/QUOTE]

Once again, 90% of all carb problems are electrical......

Glad that you got this sorted out before you began playing with the carbs. Jeff will make it right. Over the MANY distributors that he's done for this forum and for the people who have gone to him from the write-ups on my website, this is the first problem that I've seen come from his shop. And it could be a defective new spring that he bought in good faith of having no erratic timing issues with old weak ones.
 
To Jeff's credit he's corrected the 2 or 3 distributors that I know of that were sent back to him.
 
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