Introduction and Cylinder damage

[pD510]

Hi all, my name is Paul, I'm 23, and I'm new to the forum (obviously). I own a 1972 Datsun 510 sedan with a L20B and 5-speed conversion. The car has been parked for some 20 years +-3. 

The car belonged to my father's cousin who sold it to my father after it was hit on the left fender. The damage was slathered over with bondo and the car repainted.  :no:  :no:  :no:  :no:  and the car has been tinkered with only a little until the 20 or so years ago.  Until recently, I have not done much to get her back on the road as it has played storage table and space-taker for many years because I was never into cars/car culture until about 7 years ago. It has become my project as my father has passed away.

 

Progress up until now involves primarily the removal and disassembly of the engine and head. The block awaits hot tanking and searching for cracks, the head cleaning, and the valves and valve train parts cleaned.

 

The big question I have at this time is this: the #4 cylinder on the block has some damage on the back lip which is approximately 1mm in height and depth (same size as the bevel of the lip), so it essentially can be removed with an overbore of 1mm which I think is unnecessary at this time as I simply want the car to be able to be driven in the "near" future.

 

Will this be a problem if I were to reassemble the engine without removing the damaged section? What would your recommendation be in regards to this, I have read up on a L20B  being bored 2mm over and using a Z22 crank, rod and piston assembly but as stated before, I want to keep it simple at least for now.

 

Thanks ahead of time!

 

IMG_20140514_150237_313[1] by pad510, on Flickr

 

The damage is "visibile" (blurred by terrible focus on old phone) near the top. And that is surface in the passages from having drained the coolant a while ago.

 

[MicroMachinery]

As long as it isn't far down enough for the rings to contact it, I think it should be fine. Just make sure there are no sharp edges that will heat up and cause preignition.

 

Welcome to the forum, and my condolences for the loss of your father.

[datzenmike]

Have the cylinders measured for wear, taper and oval. Now's the time to bore to the next oversize piston if needed. Do all four and replace pistons. You have to get the rings anyway so get the oversize. This is a reasonable expense and you will basically have a brand new L20B. 

 

Giving it a quick hone and ring job is a toss of the dice. It may have burned oil before or overheated. That slight damage looks like it's above the top ring

[ggzilla]

That nick won't hurt anything.

 

To make sure the engine is OK, have the cylinders measured for wear, taper and oval. If it measures within specification, give it quick hone and new rings and you will basically have a brand new L20B.

[pD510]

Thanks guys. Needed that assurance and information. I'll have it dipped this weekend and pay the machine shop to do the measuring, crack testing and such since they'll already have it and will be better suited to doing that work.