Old block in a newer Truck ?

[CleviteKid]

Dr. Lee,

Hi, In the everlasting quest for ultimate power I have finally finished my engine off. It is a 93 Chevy 6.5 turbo model. It is intercooled and has a larger non-wastegated turbo. At 135,000 miles cylinder taper in cylinders #'s 7&8 became so excessive that the affected cylinders ceased to fire.

I have a lead on a 6.2 out of a 82 burb with 35,000 original miles on it. I have heard that they are the blocks with high nickel content and bigger valves. As I understand it the higher nickel content makes the block stronger and more resistant to wear. If true, I believe this to be a bonus.

However if I understand correctly the bigger valves cause cracking between the valves due to there being less material there to take the heat. Taking all of this into consideration if I get this motor bought:
should I put my 6.5 heads on as well as my 6.5 injection system consisting of a DB2-4911 pump and stock 6.5 injectors?

Also thanks to the help of another Diesel Page member I have a lead on a machine shop that will CNC my pistons down to my desired compression ratio of 18:1. If the block and pistons aren't worn excessively should I have this procedure performed on the pistons and have them ceramic coated?

Any advice would be apreciated.
Thanks, dieseldummy


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Hi dieseldummy (an undeserved modest name!),

I am not sure the '82 6.2L engine can be safely bored out to accept your 6.5L pistons. Also, if the bores in 7 and 8 are as worn as you say, the ring grooves in the pistons are probably in sad shape also. It seems like new pistons are called for. Peninsular Diesel is supposed to have low compression pistons for 6.2L diesels at a fraction of the price of those for 6.5L diesels. Give them a shout. Your 35K high nickel block may still need to be overbored 0.010" or 0.020" to clean it up for a fresh surface, and the pistons would need to be specified to match. You cannot just chuck pistons in a lathe and turn them down to size. The skirts are actually barrel-shaped axially for oil control and oval, not round, for thermal growth control across the pin versus parallel to the pin. You need a huge computer-controlled piston lathe, and the correct specifications to do this.

By all means move your heads and fuel injection system and anything else you want to the '82 block, but read all the info on www.TheDieselPage.com (http://www.TheDieselPage.com) about heads, and changes in coolant passages, and what needs to be plugged, etc.

As a point of interest, what type of oil were you using in your engine, what oil filters were you using, and how frequently did you change oil? Another point of interest, what was your procedure and frequency for maintaining your cooling system - cleaning it out - changining coolant? One theory about the 7 and 8 wear is that crud collects in the back of the block and causes those two cylinders to run hot, thinning the oil and increasing wear. And further, what did the rings from those two holes look like - worn to a frazzle?

Keep us posted on your new project. You should end up with the hottest TRUE 6.2L engine around.

Dr. Lee

[dieseldummy]

Dr. Lee,
Thanks for the responese. I should have made my self a little more clear as to what pistons I wanted to put in. I didn't intend to put the standard 6.5 pistons in it, but rather hone the block out, re-ring the 6.2 pistons and reinstall them. I found out this morning that the motor has been sold, so this particular motor is out of the equation, but would still like to find something similar.
A little history on the motor I pulled: I bought the pickup with 115,000 miles on it and imediately flushed the cooling system with Preston cleanser. I followed the directions on the bottle and tried some of the techniques I have read here on the page. I always used Texaco Ursa 15W-40 oil accompanied by a AC Delco filter. I usually changed the oil at around 3000 miles since some of the miles were towing and a lot of start and stop running errands around town. The rings on all cylinders including #7&8 were shot. They were fairly scratched up, but somehow on the other 6 cylinders the cross hatching is still visible.
Upon further examination of the block I can see where the pistons sat and "heat soaked" to the block on one occasion leaving a bronze colored mark the shape and size of the piston. I don't know if it was my doing, or from a previous experience. I always try to shut it down only after the pyrometer is below 300 degrees and water temp is around 190-195.
I think I can rebuild my '599 block for around $1500 which seems more than resonable, but I figured if I was going to do it I would do something a little different. I will continue my search for a good used 6.2 just because I think it would be unique and would really give those Ford and Dodge guys something to look at as I pass them going down the road pulling a trailer. :D I appreciate the advice.
Thanks again,
Justin

[CleviteKid]

dd: As you know yourself, you were doing everything right for routine maintenance. The previous owner is the one who cooked your engine.

The -599 block is worth keeping. Build it right and run it right and you can go 300,000+ miles with it.

Dr. Lee :cool:

[bio-diesel]

I have a good complete 1982 6.2 with a rebuilt pump, redone heads but with very bad blow-by for $525 you can here it run or even drive it.