TR2/3/3A TR3 Timing gears

[TRclassic3]

I need some sage advice on this. I'm in the process of changing the timing gears. Prior to removing the old ones I turned the crank so that the key was at 6 o'clock, the dizzy rotor was pointing in the general direction of #1 piston and the lines on the gears were "close" to being in alignment. My question is, do I put the new gears back on in the same position, as was my original intent, or do I attempt to align the marks on the gears more closely. Per the Bentley you should be able to draw a straight edge through the center of both shafts and have it go through the lines on the gears. This is not currently the case. So, do I mess with it or leave well enough alone and slap it back to togther the way it is? The car ran well, although I always felt it lacked some of the responsiveness of a friends I have driven.

TIA

 

[PeterK]

Put the new ones in exactly the same position as the old ones. Do not turn the engine once the old ones are removed. Once back together, you can set the ignition timing advance at the distributor.

 

[hondo402000]

adjusting the distributor only advances the timing, if you purchased the vernier timing gears I have read you can move the gear and that will advance the valve timing or retard the valve timing, depending on which way you go. which(and I could be off here)moves the power band up or down. valve advance and spark advance are two different things.

Hondo

 

[TR4nut]

I agree completely with Peter - I would consider still putting on some scribe lines to make sure it goes back on the same way. I've done this twice, 1st time was perfect, 2nd time I moved the crank accidentally and I spent a lot of time to get the marks lined up. Of course nothing is fatal but you might have to go all the way back to setting TDC and dialing the cam back in if you lose your reference completely.

 

[startech47]

How confident are you that this installation is the original one from the factory? You are correct the lines must line up with the center of the shafts. You do not want to continue a former repairers mistake and not have full performance.

Hap?

 

[TR3driver]

you might have to go all the way back to setting TDC and dialing the cam back in if you lose your reference completely.

Personally, I would do that anyway. As Hondo correctly notes, you are setting the valve timing (ignition timing is irrelevant at this point) and it makes as big a difference in engine performance as ignition timing does, maybe more. Even one tooth off will really mess up the engine's performance.

Although I've heard that some replacement cam gears are not cut correctly; you are supposed to be able to make 1/4 tooth (which is about 4 degrees) adjustments in cam timing by turning the gear back to front, and using the other pair of holes. If the cam timing doesn't come out exactly on the money, then set it slightly advanced (ie somewhere between 0 and 4 before; rather than -2 to +2) as the chain will stretch just a bit under load.