Engine rebuild - pt.1

So I started rebuilding my L28 this weekend and can honestly say that without this book, I would be straight up guessing at what to do.

From Z2

If you want to rebuild an L series motor, you can do no better.

Luckily, I had the foresight to bag and mark all of my nuts and bolts from the disassembly so it was very easy to take inventory before getting started.

From Z2

I pulled my L28 block out of storage and gave it a good cleaning before doing anything. Brakleen loves me.

From Z2

My first order of business was to hone my cylinder bores.
I strongly recommend watching a video on how to do this to get an idea of the speed of plunging and spinning that is required.

From Z2

As for honing oil, everyone has a different opinion. Some say kerosene is the best, some say to use a mix of 20w motor oil and kero, some say to never use motor oil, etc etc..

I found one site that said that they had the best results from using WD40. So I picked that one cause it was easy. :)

From Z2

Attach the spring loaded cylinder hone to your favorite drill and get to work, making sure that you clean the bores thoroughly, and keep them well oiled. I had bad results from honing while the block was upside down. I recommend that you hone with the block right side up.

From Z2

If all goes well, and you are a master of doing things, your hone job will be perfectly crosshatched. A quick google will show you that machine shops can get a much nicer cross hatch than this, but since I completed this job for about $20 (including the WD40), I am happy with it.

From Z2

Next you have to clean the bores three times with WD40 and Brakleen and check the bores thoroughly for any deep scratches or anything at all that you can catch your fingernail on. If you can catch your finger nail on it, it's no good and you have to re-hone it.

From Z2

Sweet.


Next up is test fitting and gapping your piston rings. I bought mine from Rock auto and got the cheapest ones I could find. The "Economy ring" by Sealed Power.

From Z2

They ship the rings in separate compartments because each ring is different, and needs to be an exact length for each ring's specific job and heat tolerance requirements.

From Z2

Keeping tabs on which rings will be where in relation to the piston and their specific cylinder bores, you have to test fit them in the block.

From Z2

The top or primary compression rings need to have a total ring gap of .014 inches (0.36mm). With the use of the proper feeler gauge, I was able to determine that my "Econo" rings and my Craigslist L28 were exactly perfect with all rings on all bores.

From Z2

I continued this process with the bottom or secondary compression rings. They required a total ring gap of .012 inches since they are subject to less heat and subsequent expansion, they require less overall clearance tip to tip.

Every single ring in every single bore measured out absolutely perfectly (lucky mofo), so I did not have to shave any of my rings.