Distributor repositioning question

[TR3driver]

Ok, I'll bite, what else causes TR6 timing marks to be wrong?

And Ed was talking about rotating the housing, whatever you were talking about.

When the timing chain stretches and the "sprockets" wear, the overall effect is that the cam begins to lag behind the rotation of the crank Simply taking up the tension has no effect on the lag. The chain in effect is longer.
In addition the gear engagement between the cam and distributor drive is subject to wear.

That is all true enough; but does not affect the accuracy of the timing marks relative to the crankshaft and therefore has no effect on the setting of ignition timing relative to the crankshaft (eg 12 BTDC).

Sometimes the camshaft is even deliberately advanced or retarded by a few degrees, but that still doesn't affect the accuracy of the timing marks.

 

[poolboy]

No, I meant Jeff's second paragraph with regard to "phasing".
However his whole reply is worth reading again and again. He sums up years worth of his experience regarding ignition timing.

 

[CJD]

Wow!! I missed a whole soap opera in a few hours!

Ed, to answer your phasing question, just have fun with the car for at least a thousand miles. Then, some time when you have time and nothing better to do, remove the cap ans see where the "fuzzy" looking corrosion is on the rotor and cap posts. If it is generally in the middle, you are golden. If it is on the edge of the rotor, then post it back here and we can go through this again in a month or so. But, if the motor is running great right now, your phasing has to be close.

I, personally, will look forward to it!

John

 

[Member 10617]

John,

Sounds like a plan! The rotor I have in the car now is brand new -- an Advanced Distributors rotor. I'll give it 1K miles and take a look. I have to think that the phasing is close to being correct now, however, because as you mention, the motor is running great.

..... better than a soap opera!

BTW. My primary source of guidance on setting the timing on this car is Lucas "Fault Diagnosis Service Manual" (Catalog No. XIA116). In it, the recommendation is to first set static ignition timing, and then "Final adjustment may be carried out using the stroboscopic timing light and the micrometer adjustment."

 

[TR4nut]

For all I know, your timing marks are wrong and 10 is actually 4, or something like that.

At the risk of adding to the mire, I'd like to point out that is unlikely on a TR2-4 motor. Unlike the TR6 (where that problem is rather common), the TR2-4 does not have the pulley mounted on rubber. The mark could be wrong by increments of 60 degrees (due to improper assembly of the pulley/hub), but not by only 6 degrees (unless perhaps the crank key is sheared or the pulley hub is badly damaged). My opinion, if one were to find a timing mark off by a few degrees on a TR2-4 motor, it's time to tear it down and find out why. It probably indicates something about to come apart.

So so true. I'm rebuilding my TR4 engine right now. When I pulled the hub and the front cover and got into the timing chain, I was shocked that the timing gear on the crankshaft actually rotated 3-5 degrees by my eyeball estimate. I missed that the last time I changed the chain because I took care to not move anything. During the current tear-down, though, I found the woodruff key to be worn, which allowed the gear to move. This basically has turned the gear into a paperweight as far as I'm concerned. Fortunately, the wear on the crankshaft nose has already been repaired by a good machinist I trust who welded it back up then turned it down to stock diameter.