Over 100,000 miles on my rebuilt 6.2L diesel!!

[arveetek]

Well, yesterday I had the transmission flushed and serviced, and while recording the information in my maintenance logs, I looked back over the years to see when I started keeping records. I was shocked! I have put over 80,000 miles on my truck since 1998. I installed the 6.2L sometime in 1996.

Here's the story: in 1995, I was driving a '77 Blazer that I had converted to a 5.7L diesel, strictly for fuel economy (I was going to college at the time). That engine blew in early 1996. I then went to a salvage yard, and picked up a used, '82 model C code 6.2L for $400. It was locked up due to rust in the cylinders. I rebuilt it, though the lower half looked like new. It was in good enough shape, that I retained the original pistons, crank, lifters, etc. I installed new rings, bearings, timing chain, injectors, and had the pump rebuilt. I installed that engine into the '77 Blazer.

At the time, my '81 3/4 ton had a 305 and a TH350 tranny. Later that year (1996), I decided I didn't need two vehicles any more, so I swapped the 6.2L into my '81, along with a used 700R4 tranny. I put the rebuilt 305 into the Blazer and sold it.

I don't have any real good records between 1996 and 1998, but that truck was my primary vehicle. So I know I have at least 100,000 miles on that 6.2L since I rebuilt it to stock standards in 1996! Again, it has the original pistons, didn't bore it out. A simple honing took care of the rust. I polished the crank, didn't grind it. So the bearings are stock size. The engine has never given me a moment's trouble.

Also, I don't know how many miles were on the 700 when I got it, maybe 50K or so. So my tranny might have 150K on it!

I sure wish I knew how many miles were on the engine to start with.

Here's looking at the next 100K!

[LOHRTBT]

whoo hooo!! congratulations!!

[79BIG10]

I hope my engine will last like a Diesel

[c10scotty]

im sure you've got another 100,000+ ahead of ya too! diesels last forever...just look at the big rigs, 1,000,000 miles while pulling 80,000 lbs behind em!

[Tom]

I just dont understand it. Deisels have enormus cylender pressures, and create tons of torque. This should mean they wear out quicker, and they should eat up trannys like the 700r4. At least thats what I thought it would mean?

[arveetek]

Tom, tear apart a 6.2L and you'll see how beefy these things are. They have 4-bolt mains, roller lifters, and tons of steel. They are way overbuilt. True, they do run at 21:1 compression, but they are almost over-built, as far as the structural block is concerned.

Another thing to remember, is that diesel fuel is just one step up above crude oil. Diesel is very oily, very slick. It lubes the internal parts of the engine every time it's injected into the cylinders. It's extra lubrication that gassers don't have.

Also, diesel fuel ignites much slower than gasoline, so the combustion isn't as harsh, even though it has much higher cylinder pressures. As diesel ignites, it continues to burn and push down on the piston while it's already moving down. This is one of the reasons that diesels don't rev up very fast. My 6.2L has a redline of 3600 rpm. Any fast than that, and it just won't burn right. That's why diesels have so much more torque than gassers. My 6.2L really doesn't have much more stroke than most small-blocks, but the diesel fuel continues to work after the initial explosion. That's why they're so effecient.

[swervin ervin]

I thought diesels had a lot more than 21:1 CR. I was thinking way over a 100:1? Are you sure on the CR?

[Tom]

Thanks arveetek, that makes sence.

Yes mike hes right about the compression. Turbo deisels usally run around 17-19:1 and NA are usually between 20-23:1

[swervin ervin]

OK

[arveetek]

Yes, Tom is correct.

In fact, the 6.2L is on the high-end of compression ratios. The Cummins and other diesels typically have 17 or 18:1. A popular performance mod for the 6.2L and 6.5L is to install lower compression, 18:1 pistons. This is good for a turbo. Lets you add more boost and fuel without blowing the heads off.

I've got a turbocharger sitting in my shop just waiting to go on. I can't wait to get to that project. But I'm going to retain my stock 21:1 ratio for now.

[u2slow]

I had to come over here and post

After a metric-to-imperial conversion, it looks like I have 170,000 miles on my diesel Burb.

Only had the thing 4 months, and I'll never go back to gas....

[79BIG10]

21:1 That's some compression.

[swervin ervin]

Thanks for the explaination Casey. Goes to show you how much I know about diesels.