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

[t rex 7]

arveetek,

Do you know of any places besides the dealership for 6.2 fender and hood emlems for the 6.2 diesel? Everyplace I have looked only has the silverado badges. Thank for the update on your rebuild I have located a turbo and plan and doing a rebuild similar to yours and look forward to seeing more.

t rex 7

[Prerunner1982]

Casey, not sure if you saw it, but there was a happy birthday post for you... but it got moved...

sorry to hear about the mishap, glad you caught it though.. keep up the good work, i know there are people here eagerly watching what you do in hopes of following in similiar footsteps..

[Prerunner1982]

nevermind, i see you found the bday thread...

[arveetek]

T Rex,

LMC truck used to carry the 6.2L emblems, but they don't show them in the current catalogues anymore. I'm not sure they still have them. I beleive that even the dealerships will tell you they've been discontinued. I haven't found any source for new badges, but I see decent used ones on ebay from time to time.

Thanks for the encouragement, Jon! It's been nearly two months since I pulled my engine....I'm going through some serious Chevy withdrawals right now! (My work truck is a Ford!! At least it's a diesel too!)

Casey

[badone07]

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?

Good thing you caught. That actually falls on the machine shop. I'm surprised they bored the block without actually having all the pistons in their hands. Maybe they learned something as well.

[Beefcake]

Hey casey! I just caught this.... was wondering how your adventure is going. Sorry about the mishap! glad you caught it though. can wait to get my 6.2 turbo'd and on the road as well.

[arveetek]

The project is completed!

Finally! This project has dragged out way too long for my tastes. I pulled the engine at the end of February in the cold weather, and now it's hot and just a few days away from June! Oh well! It's all behind me now!

I finally got the new .040" over pistons, had the shop bore the block to fit the pistons, and then started assembling the engine, again!

I got the engine assembled and installed over the past couple of weeks, and fully running on Monday night. I made a couple of mistakes that set me a back a few days, though.

My first mistake was that I managed to bolt the flexplate (flywheel) on backwards, and didn't notice until the engine and tranny were bolted up together in the truck. I tried bolting the torque convertor to the engine and noticed it wasn't going together correctly. Doh! I had to completely remove the tranny to R & R the flexplate. Not too bad, only took me 2.5 hours to do the whole job.

The other mistake was worse. I got the engine started and discovered that I had very little oil pressure, and that exhaust was popping back through the intake. I figured the two problems were related, and decided that the exhaust popping was due to lifters not getting pumped up due to low oil pressure. After some digging around and investigating, I found out that I had left the two lifter oil galley plugs out of the front the engine! This pretty much let all the oil being pumped up through the block get dumped straight back into the oil pan! Doh! I had to remove the water pump, front cover, and timing gears to get to the oil galley holes next to the camshaft. Just took a couple of minutes to install a couple of freeze plugs in the holes, but it took an entire day's worth of work to tear down and reassemble the engine. After starting the engine a second time, I had great oil pressure and no exhaust popping through the intake. I was quite frustrated at the time, but that's all behind me now. I just don't know how I skipped that step as careful as I was.

I've been driving the truck for about two days now. Runs like a champ!

Before I pulled the motor, the engine was starting okay in the morning, but the smoke screen it layed down was absolutely ridiculous! The white/blue smoke would completely envelope the truck, and it would continue smoking some even when fully warmed up.

This morning I started it up, jumped out of the truck to look at the tailpipe, and I could detect no smoke whatsoever! Granted, the ambient temperature is warmer, but still! I'm using the exact same 60G glow plugs and plug controller that I had with the old engine. They were in good shape, so I didn't replace them. I just let the plugs glow for about 10 seconds, hit the key, and bam! She's running in the first revolution of the crank with no smoke out the pipe.

I do have black smoke, though. But only when I mash on the go pedal! From a standing start I can mash the pedal and a large cloud of black smoke comes pouring out, but just until the turbo spools up, and then it's gone! And so is the truck! Man, this thing will push you back into the seat, that's for sure. I thought it was running great before, but I can't wait to get a load on this engine and see how she pulls. I didn't have any black smoke before the rebuild, and I had turned the pump up quite a bit.

I can't hear the timing gear drive set. I've read that some people think they're noisy, but I can't hear it at all unless I take the oil fill cap off, and then there's a slight gear noise.

The engine seems to be running a bit hotter on the water temp, but that's normal for a new engine. I can't detect any real changes on EGT or boost as yet. Still hitting around 14 psi, but I haven't run it really hard yet.

I'm so glad to be getting past this rebuild stage and actually having a truck I can drive again! I tell you what, this truck has come so far from it's original C code naturally aspirated days, it's not even funny. It's no longer a gutless fuel pincher, that's for sure. I just hope my mpg doesn't drop TOO much!

Sorry for the long post, but I just wanted to update ya'll!

Casey

[86 GMG]

casey the bottom line is that you got it done and it runs great from what you say as far as the mistakes hell we all do them when i rebuilt my motor i put a stus kit in the heads and bottom end by the time i was ready to put the oil pump on i was in a hurry to hear it run so domn a$$ me didnt put the connecting ron on that goes to the dizzy ha ha ha ha!
well that saved me a hole hell of a lot b\c i put oil pump on and the washer was under neith the pump instead of on top were it belongs. so what im saying is we all make them and its not that big of a deal as long as we learn from them so great great job on the rebuild.

[boxrodz]

Impressive.
Good job.
I know we're talking trucks, but a Kansas farmer once said "it not the size of the tractor that's impressive, it's the amount of black smoke that's bellowing out the stacks".