Saturday, February 14, 2015

Crankshaft Install

<This post is part of the 'Winter Project 2014/15 - New Engine Rebuild' project>

Now that the Camshaft bearings have been renewed and the block painted a rather fetching shade of red, the engine is ready to receive its freshly re-polished crank. This is a job I have been dying to do for ages, but as exited as I am, there are a number of things that are critical and I simply cannot ignore.

One of which is taking great care not to scratch or damage the new bearing surfaces of the crank journals during the process. The second is to make sure that everything is well lubricated and finally, it's very important to make sure that no bits of muck or debris gets in while I'm working, or we're right back to square one.


Cleaning the Crank

One thing that's worth noting before we start is that clean gloves are a must, in fact a box of disposable gloves so they can be changed frequently to minimise any cross contamination.

Back when I had the crank re-polished, I sprayed the journals with WD-40 in order to protect them from corrosion and wrapped the whole thing in a plastic bag thinking it would keep it clean. The problem is though, no matter how cautious you are, small fibers floating in the air inevitably find their way onto the sticky journal surface as soon as it is out of the bag

So the first job was to wipe the journal surfaces with some clinical alcohol wipes to get the WD-40 off. Although this cleans the journal surface really well, it does leave behind a lot of bits from the cloth which will need to be removed.



Bits

These bits are a little more troublesome that you might think. There's no use wiping them off as anything you use leaves behind more bits. After a bit of thinking, I decided to use the vacuum cleaner with a brush attachment and a new clean craft brush to tease the bits away.

Much Better
This seemed to work quite well and left the journals fairly clean and dust free.


Cleaning the Caps and Block
The next area to check was mating surface between the caps and the block. If there is any debris in between then the cap will not bolt down properly. Even 1 thou could make a difference. So using the same method of alcohol wipes and a quick vac, I made sure they were spotless.



New Crank Bearings
Carefully opening the new bearings, I separated them out into the ones that go into the block and the ones that go into the caps. They were easy to distinguish by the location of the tab.

New Bearings

Block Bearings

Assembly
Cleaning the block bearing surface with by finger first, the bearings simply press into place. I read that it is important not to touch the surface of the bearings with your finger as they scratch very easily

Radiator Side

Centre

Clutch Side


I decided to use engine assembly instead of engine oil. There are a number of opinions as to whether it's worth using. It may be just a piece of clever marketing, but I though for a few pounds, it was worth it. It goes on like treacle and does not come off the gloves very easily, so changing the gloves often helps to not get it everywhere.






Now the crank can be lowered in to place, I was a bit paranoid about fitting it the wrong way so had to check several times to make sure. I also used the lube to hold the thrust bearings in place as the crank was lowered in.



Now the caps can be sorted out. They too were cleaned and the bearing pressed in and lubed with the red treacle. Again the thrust bearings were 'stuck' in place to help with assembly.




I did initially have some confusion as to which way round the caps sat, but I read that they always go tab to tab.


Once the caps are seated, I torqued the centre first then the two outer caps. The Haynes manual states the torque setting to be 85 Nm, which is 63 lbf ft. So I did them up in three stages. First at 20lbf ft, then at 40 lbf ft and finally at 64 lbf ft. Each time checking the crank still turned by hand.



Checking End Float
Once the caps are torqued down and I was satisfied the crank rotates freely, the last job is to check the crank end float. The specs are in the Haynes manual



Using a large screw driver, I levered the crank as far to the left as I could in the block, then using a feeler gauge, check the gap between the thrust bearing and the crank on the right side. I could only just fit the 0.05mm in there whereas the 0.1mm had no chance at all. From that I can conclude that the end float is just over 0.05mm so just in spec.




And that is done. I'm pretty pleased to finally be in a position to put things in the engine, next up is the pistons...



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