December 6 & 7 (3), 2007 HOME



Before we can move on to set the crankshaft in place in the crankcase half, we install the drive gear on the end (rear) of the crank.  This is the gear that will drive both the ignition and the valve timing and yep, it's pretty important.

I recall the bolt in the center of the crank holding the gear in place was torqued to 18 foot pounds and then the little tab is bent up to lock the bolt head in place.

Preparing the camshaft involves adding lubricant to the cam lobes.  The chance of cam lobe galling on startup is very much reduced with roller tappets, but the lube is a good idea anyway.  The valve springs pushing back on the pushrods still create a very high pressure against a very small surface on the cam lobe.  While there isn't the friction of flat tappets because the bearing roll, the pressure is still there and a dry start could very much shorten the life of the cam.

The cam lube is spread generously and evenly over the surface of the cam lobes.

Sealant is applied to the crankcase through bolts.

There is a very tight fit at this area in the center of the through bolts, but oil can still make its way past the walls to leak out.  The sealant needs to be spread evenly and thinly on the center section of each bolt.

Back to the case half, o-rings are placed around the studs at the back of the engine to seal between the case halves.  There is no "rear main" bearing as the closed case is open to the rear as you will see further on.

Each of the main bearings gets a spread of lubricant before the crank is set in place.  Sealant is applied around the main bolt holes to help prevent oil leaks.  In this picture you can see (upper left) the roller bearing of the lifter.

Next, the crankshaft and camshaft are set into the case half.  The huge front main bearing set is split vertically, unlike the rest of the bearing (I don't know why).  The 2 halves of the bearing must be placed on the crankshaft and set into the case half with the crank.  A little care is necessary to avoid any damage to the main seal from the sharp edges of the case half, but the task is straight forward.

It begins to look like you are building an engine when the crank and cam are both in with the rods protruding from the crank.  The yellow arrow shows rubber material placed to hold the rods in place so the second crankcase half can be easily set in place.










Notice that the silk sealing thread runs right up to the front main seal.

A small amount of special sealant is added at the main seal to ensure that the split edge at the union of the 2 case halves don't leak.   The picture shows an amount of sealant greater than is needed, but not excessive.

A quick inspection reveals that the crank is properly seated at each main bearing and that the bearings are still properly aligned.  The bearings are not likely to move, but it is a bad thing if they do, so a double check is cheap insurance.

The second case half is placed on top of the (remember, these case halves are rally right and left side - split vertically) bottom half and wiggled into place.  The fit is snug but easy to make.

When the union of the 2 case halves is made, the rods protrude top and bottom and the rubber pieces can (must!) be taken out.  The rods can rest gently against the case half.

Now it's time to insert the through-case bolts that will help pull the 2 case halves together.  They can be pushed in by hand most of the way.

Washers are placed around the bolts to protect the case halves and a modestly deep nut is screwed on the top to protect the threads.


This is a rather unceremonious event that involves pounding the long bolts into the case halves with a small sledge hammer.  It seems that a press would work for this, but getting the whole assembly into a press would be a major chore in itself.

Through bolts inserted, the nuts come off.

It's time to begin bolting the cases together.



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