Crankshaft Installation

Installing the crankshaft was mostly painless. The hardest part was lifting the thing; at over 50lb, it's not easy to maneuver.

The first step was to install the bearings into the block. The grooved bearings go into the block, while the flat ones go into the caps. The back of each bearing, along with the block, was cleaned and any oil was wiped off. Oil is not desirable on these surfaces because it reduces the heat transfer from the bearings to the block. The bearings also are not supposed to move, so lubricating them on the back makes little sense. The rear one was difficult to get in, but the rest were a joke.

Bearings installed into the block.

The rear main seal went on next. I put it in with a slight offset to prevent leaks, as seen in the drawing below.

Installing the rear main seal with a slight offset helps prevent leaks.

I then laid a piece of Plastigage onto each bearing. Plastigage is used to determine the clearance between the crank and the bearings.

A piece of Plastigage was put on each bearing in the block.

The next stop was to drop in the crank. I was careful to not allow the crank to touch the main studs, but I should have put rubber hoses on each one, or better yet, taken them all out while I put in the crank.

Crank dropped in.

I then put the caps on the block, making sure that they went back where they came from, and in the correct direction. Each cap was torqued to 85 lb-ft in three stages, using motor oil on the threads. I did the centre (#3) cap first, and then worked my way to each end of the crank. It probably doesn't matter which order they are done in, but I figured I'd do it that way.

After each stud was torqued, I undid each one and took the crank out so that I could get a look at the Plastigage. Every single bearing showed a clearance that was within the tolerance, with a bias toward the 'tight' side.

Using Plastigage.

I actually did the Plastigage step twice. I misread the instructions which said to put the Plastigage on the 'bottom'. Because the engine was upside down, the 'bottom' is actually the bearing caps, not the block. I did the procedure again, and luckily all of the readings were the same. Maybe it does not matter.

When I was done with the Plastigage, I put some motor oil on each bearing and a lot of RTV sealer around the outside of the rear main seal. I installed the crank one last time, torqued it down real well, and then tried to turn the crank with my hand. It turns freely and has no hard spots. I also checked the end play of the crankshaft (the ability to move fore and aft) by placing a feeler gauge between the thrust bearing and the crank. It was a very tight fit, but still within spec, which is what I want it to be.

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Page last modified on July 17, 2010 11:28:22. (ID=382)