Flywheel/crankshaft dowel

[promotor]

I have bought a new flywheel and thought I may as well have one with a dowel, as the crankshaft has a hole for a dowel. Ignoring my own advice on all things Lotus, check and measure everything, I assumed the hole in the crank and flywheel would be the same diameter. The dowel I bought is 3/8” as is the hole in the flywheel, but the hole in the crankshaft appears to be 7/16”. I say appears to be because I have always struggled to measure internal diameters.

Has anyone else come across this? Which diameter is correct? Do I need a stepped dowel?

Richard Hawkins

Richard, do the dowel holes in the flywheel and crank line up?

[alan.barker]

Just a thought if there was no Dowel and you fit a Dowel you need to rebalance the Crankshaft
Alan

[RichardHawkins]

Promotor,

Without the correct dowel, I am not sure, but they appear to.

Richard Hawkins

[StressCraxx]

Just a thought if there was no Dowel and you fit a Dowel you need to rebalance the Crankshaft
Alan

For best results, two plane balance the crank first. Then assemble the flywheel with dowel and bolts to the crank. Two plane balance again. Install the clutch cover, two plane balance the clutch/flywheel assy, and index the clutch to the flyhweel.

[2cams70]

If it's just a road car I would not be to worried about the effect on balance of that dowel. It's not located very far from the center of rotation and the increase in weight due to the dowel is offset to a significant extent by the drilling of a hole in the flywheel.

Also if you are replacing the original bolts with ARP ones do not use washers under the ARP bolts. This is the advice from ARP themselves.

[RichardHawkins]

2Cams,

Thanks for the advice, it is a road car. As it appears that I will have to make a dowel do I need to bother?

Richard Hawkins

[Craven]

I had a look at the dowels that I have 7/16” 0.437 and 15/32th 0.468 so I think they are for a 4 bolt crank.

[StressCraxx]

@RichardHawkins,

For a road car, need not bother.

[promotor]

Promotor,

Without the correct dowel, I am not sure, but they appear to.

Richard Hawkins

I wonder if using some engineers blue (or any other way of marking) to see if the two holes are concentric to each other without the use of a dowel? Perhaps the small difference in hole size might make it difficult to see, but maybe worth a try if you've got easy access to the flywheel and crank.

[HCA]

Why all the agony?

Richard, if you have dowel holes, why the doubt in using them? Order a dowel from QED. A few pounds and job done!

[RichardHawkins]

Hal,

The QED dowel is not stepped, it is 3/8” which fits the flywheel, but the hole in the crank is 7/16”. So far I have been unable to find a 3/8” to 7/16” stepped dowel that I need.

Richard Hawkins

[HCA]

mmm. I had a quick look at the bag of dowels I have and they all were stepped. As I have two dowels ordered, assumed two are for the flywheel. I do not have the flywheel yet though. I will check again.

[HCA]

Sorted my dowels into piles and have two stepped 11.17 x 11.85 that I think are for the crank/flywheel - however, these came from the US and not QED, so apologies Richard.
I await the flywheel from QED. It is ‘6B2D’, so let us see what is sent…

See this post from the archives though:

As always Gary has a photographic record showing many variants. The crankshaft to flywheel locator dowel pin seems to have been used in the Twincam from the beginning. It is shown in the Elan S1 and S2 service parts list as part number B-6387-A, a stepped-diameter dowel pin used with the four-bolt crankshaft. A different dowel pin is listed in the Elan +2 service parts list as part number A026 E 6104, this time with the six-bolt crankshaft. The later dowel pin has constant diameter along its length. The engine in my +2 certainly left the factory with the later type dowel pin installed.

[RichardHawkins]

In the end I could not find a supplier of a crankshaft to flywheel dowel, and have made one.

Richard Hawkins