My 6.2L diesel rebuild update

[arveetek]

For those of you who have been interested and are following my 6.2L diesel buildup...

Things were going along pretty well until about a week and a half ago. I had nearly all the parts together, and all the machine work finished. I started assembling the short block, and all was going well. Crank fit perfect, had perfect oil clearances on all the main bearings, camshaft fit great, and I installed the new pistons onto the original rods. Before fitting the pistons into the cylinders, I checked the top compression ring end gap and discovered that the end gap was .032", and that's .010" too large. The max. gap allowed, according to the specs, is .022". I knew something wasn't quite right. I went ahead and installed piston #1, and then I could see that the piston seemed awfully loose in the bore.

Well, to make a long story short, the machine shop bored my cylinders .004" too big. Instead of waiting for the .030" over pistons to arrive, they bored the block by adding .030" to the stock bore measurement of 3.980". This would have been fine, except that the 6.2L stock bore is actually closer to 3.976". So the shop screwed up. I know that .004" doesn't sound like much, but that translates into a ring end gap that's .010" too large, and a piston-to-bore clearance of .007", which is well over the recommended .0035". I'm sure this engine would have run okay, but if I had assembled it like this, I would have had a new engine that was already worn out!

I have since ordered new .040" over pistons (luckily the Diesel Depot is taking the .030" over pistons back in exchange for a small fee), and am waiting for them to arrive. This time, I will wait until the new pistons are in my hands, and then I will have the shop bore the block again to fit the new pistons. The shop has agreed to do this at no charge.

If I knew then what I know now, I would have waited for the .030" over pistons to arrive before boring the block, but I didn't know any better. You live and learn, eh?

In the meantime, I sent the injection pump and injectors to Tim at accuratediesel.com to have them upgraded to 6.5L 4911 specs. Should make my 6.2L a great runner. I should receive the pump and injectors in the next couple of days.

So, that's where I'm at right now. Just waiting on the pistons. Soon as they get here, I can get the block bored again, and then start assembly, again!

One of these days!!

Casey