View Full Version : Lookin' for new block, need advice...
Well, despite checking my harmonic balancer (which looked fine), my crank snapped. Now I'm in the market for a used core to rebuild.
Could some of you guys be so kind as to tell me the difference between the early '80's 6.2's and the later '80's?
I've heard some rumors that it's a better block in the late 80's, but I've found no precise info as to why. I figured I would be wise to clarify before I bought this '84 block for a hunnerd bucks.
Thanks guys.
I would check the mains out in the block before I handed over any cash. I have spent the last year looking for good blocks to build two new engines from. Have gotten quite a few with cracks in the main web area.
Early blocks two piece rear main seal,later blocks one piece seal,later,later blocks have the piston oilers these blocks are the most suspect, but not all are bad.
ALL blocks should be checked at main bearing web areas for cracks.
Odee has it right, check first pay later.
I think the pin oiling started in late 96 or so. I had a motor bought off a fellow on ebay with twenty thousand on it,the block busted about twentyone or twentytwo thousand. Pull it apart finally to check for useable parts the crack I had found wasn't the big one. It has one cylinder cracked about a quarter the way up the other crack was over half way. The early eighties red blocks have rope seals from what I've been told. That is the only series of blocks that I haven't put my hands on to find cracked.
Does anyone have a weight on a fully dressed 6.2L block? I'm buyin' an engine stand and I'm wondering if a thousand pounder will hold 'er fine.
painthorsman
08-17-2003, 21:49
Hi,
A fully dressed engine weighs just about 900 lbs. I would not risk using an engine stand with less than 1250 to 1500 lb capacity... you might also entertain the idea of putting grease fittings in the tube that the engine mounting shaft rotates in ... allowing you to rotate the engine on the stand... they are a bear to rotate with all that weight... I did it and saved a lot of worry about whether or not the whole stand would flip over before the engine rotated in the stand.
painthorsman
08-17-2003, 21:59
Opps! forgot to mention... the only blocks that I have ever seen that don't have a tendancy to crack is the early '82 "red" blocks... seems GM took a little more care in the casting of the early engines. 99% of the 82's that I've ever seen were good blocks (mine was actually cast in March of 1981!)... I've seen a LOT of 84 - 89 blocks that had web cracks. I have heard that the last series of 6.2's built had a block casting # 599... they are supposedly the best of the best but, who knows.... ask Dr Lee or Jamie at Avant for a better educated answer.
I can vouch for the 82's not cracking. I have one that I just took apart after 180k plus miles and it had no cracks. Looked really good inside. Will be a future project...
Randy
I am going to have the 6.2 block from my '93 to get rid of pretty soon but the shipping would probably cost too much. I haven't taken it out yet or pulled the pan so I don't know yet if there are any cracks.
I was talking to Benny at the Diesel Depot (Avant) the other day and he said that a 6.2 crated only weighs 700 - 800 pounds.
Dieselboy
08-18-2003, 08:02
The 599 blocks are very choice, but tough to come by when working within a budget. You might consider using a CUCV block. I remember hearing that they came with a slightly higher nickel content than regular blocks :confused: , so that may be a nice plus. I used a CUCV 6.2L as my starting point, and the engine was in great shape. Everything speced out at the machine shop; even the heads!
Larry Andrews
08-18-2003, 23:59
How bout the '83 blocks?
<crossing fingers>
-la
painthorsman
08-31-2003, 11:06
I just got off the phone with Benny at Avant. He stated that the reason that the early 1982 6.2L block castings wern't as prone to web cracking is because they had a higher nickel content than blocks of later years. Mine was cast in March of 1981 according to the raised casting numbers at the rear of the block but, according to the broadcast code letter "T" stamped in the top front of the block, by the #1 intake runner, assembly and machining didnt take place til 1982... I guess that meant it spent a lot of time in the sand, cooling off from the foundry.
High nickel content makes for a very strong block but also makes it a real bear for high speed machine work on the assembly line (high rate of machine tool wear)... Probably why the DZ-302CID engine for the 1969 Z-28 Camaro was only available for one year (high nickel content). The MO-302 block casting of the previous 1968 year model was of regular cast iron material. The 1969 DZ block offered higher strength and 290+ hp from a bone stock 302! 68&69 were the only two years GM built a 302.
I have also been told that the blocks found in 1982 and 1983 6.2L CUCV's also had a high nickel content...would be a good choice if you can find one.But, by all means pull the pan and use brake cleaner and a flashlight to look for cracks
painthorsman
08-31-2003, 11:20
Hey! forgot to mention... As I am a former Marine in a Transportation Co... You should be aware that the miltary changed out engines for all kinds of reasons... If you think you have found a '82 or '83 CUCV that you might rescue a good high nickel block from, think again! That particular truck might have needed an injection pump, timing chain or some other minor repair at some time but, if that part wasnt on the shelf at the base, they often would just replace the entire engine if they had one in stock and needed the truck back in service quickly... rather than wait on parts! It happened all the time! I know...worked there, did that! I worked in the heavy truck repair shop, next door to the HUMMV and CUCV guys and we shared the same parts warehouse.
So, always check the casting numbers to be sure# :D
Eric Deslauriers
08-31-2003, 13:05
If anyone's interested, I have a motor out of an 83. I haven't pulled the heads and don't know where to find the casting #s. It was supposed to have a broken crank, but it all spins fine, so I think it was either a misdiagnosis, or the guy's story so he could drop a BB in his Blazer.
It has a C-code intake as far as I can tell (I don't know much).
If it doesn't find a home, it's likely going to the scrapheap in the back of the 77 Blazer I'm stripping (more stuff for cheap if anyone wants).
painthorsman
08-31-2003, 17:48
Eric,
The casting #'s on your block are above and behind the oil filter housing, just foward of the mating surface where the bellhousing bolts up. There is a casting # there and also a date of casting.
Also, If you have a decent radiator and oil cooler lines for sale... I would be interested!!!!
imported_
09-01-2003, 08:09
I wonder if the 82 heads have the same high nickel content as the blocks, I have an 82 truck and an 85 motor that I am building, I still have the 82 heads. I am starting to smile now. My 85 block is not cracked and I think that my 82 is solid as well. I also have a van block but I am not sure what year, but would my 82 stuff be military spec castings?
painthorsman
09-01-2003, 08:55
I couldnt say for sure on the MIL SPEC. I would think that the heads would be of the same material as the block though... again, I wouldn't swear to it... I do know the heads have a tendancy to crack in between the intake and exhaust valves on the end cylinders of all 6.2's, all the way up to about the last couple of years that they produced the 6.2. Mine were cracked and I used a K-Line 3900 crack repair kit, to fix them... does a good job of permanantly sealing the crack from entering the drilled water passage right below and between the valves, using a bronze tube driven into the water passage.
Eric Deslauriers
09-02-2003, 06:50
Originally posted by painthorsman:
Eric,
Also, If you have a decent radiator and oil cooler lines for sale... I would be interested!!!! Looks to be 14022660 (the 1/4 are fuzzy), then a 349 on another section. Casting date 9 (8?)/1/82
The lines on it go with it. They got tweaked by the guy who yanked it. Prolly can be straightened as there are no kinks, but they're definitely not matching the bends the factory wanted. No radiator (I do have one out of a 77 gas Blazer, no oil cooling function)
Would include the intake and secondary spin-on style fuel filter, AT flywheel, some other odds and ends.
I was told it had a broken crank, but I'm not seeing it. It all spins over smoothly as I had to spin it to pull the IP.
my e-mail is:
eric at lvmt.net
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