New jackshaft spacer thickness

[TrevorJones]

Hi folks

When fitting the jackshaft chainwheel it looks to be 0.030" higher than the crankshaft sprocket. I looked up this issue on this site and this has happened before and people have discussed shimming.

However upon the checking the new Jackshaft spacer from one of our usual suppliers it seems to have a slight dome to the front machined face 0.004" and the chain wheel can be rocked on the spacer! I measured the spacer on a lathe machined bed flat surface using a DTI and the center of the spacer is 0.004" higher than the outside edge in all 4 quadrants.

I appreciate that with the chain wheel able to rock on the spacer an exact measurement of jackshaft to crank sprocket misalignment is not possible.

Before contacting our usual supplier I am wondering if the spacer thickness is also incorrect!

I would appreciate someone measuring an original Ford spacer for me if possible.

Thanks in advance.

[HCA]

I can, but it is part of a larger order from QED due in a week or so, depending on customs.

Why are you being coy regarding the ‘usual supplier’? The whole idea of a forum such as this is to assist others…

[TrevorJones]

Hi Hal

Thanks for the reply, hopefully someone may have one to hand and can measure it. If not I will have to wait.

I may be a bit coy with naming the supplier but I like to give suppliers a chance to learn from their mistakes, they probably farm out the machining of this type of spare but fail to do quality checks before selling to us. With the original spares getting thin on the ground we will need these people or start making the spares ourselves!

[Craven]

Have this Pic looks like not just thickness that could be wrong, original part.

[TrevorJones]

Hi Craven

That's the part, the spacer just prizes off the cam. I'm looking for the thickness of the spacer on the flat section (between the holes).

[rgh0]

I measured 6.41mm on a spare original spacer

cheers
Rohan

[2cams70]

Might be worth measuring the jackshaft flange thickness too if the jackshaft isn’t original. Also worth checking the crankshaft sprocket to ensure you have a LTC sprocket fitted the correct way around and not one intended for a crossflow or something else. They are different.

[TrevorJones]

thanks Rohan & 2cams70 and Lotus Elan.net

The thickest part of the spacer does measure 6.41mm so just poor machining on their lathe setup.

I will measure everything else to make sure the components are all LTC or compatible.

Thanks for the rapid responses, great site.