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Chinese 6.5 block

93detroit

93detroit

Well-Known Member
Messages
311
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877
Location
central PA
I almost hate that I have to ask this, but does anyone here have experience with the Chinese 6.5 blocks sold on Alibaba? I am having zero luck finding a known good used 6.2 or 6.5 block. No one who has one to sell is willing to pull the pan and main caps to look. I refuse to pay $4500+ for an Optimizer block that I know I will break unless I invest a significant amount to modify it. The modifications are going to have to be done regardless of what block I start with (not going p400) and $3k will go a Long way towards the mods I need to make.
 
I was looking for 6.5s, and an Alibaba add popped up. Just go to their site and search for them. I imagine vendors here won't be pleased about me bringing this up, but I know that even an Optimizer will break if pushed hard enough, long enough- if it isn't modified- and maybe even if it is.
 
93detroit said:
I was looking for 6.5s, and an Alibaba add popped up. Just go to their site and search for them. I imagine vendors here won't be pleased about me bringing this up, but I know that even an Optimizer will break if pushed hard enough, long enough- if it isn't modified- and maybe even if it is.
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I think among the remaining members, the era of testing the 6.5 to the point of breakage is over. What’s left is a bunch of old men hoping to still do it without the purple pill.
 
Big T said:
I think among the remaining members, the era of testing the 6.5 to the point of breakage is over. What’s left is a bunch of old men hoping to still do it without the purple pill.
Click to expand...
No. I think there are some of us still trying to find a high power point that has a long life. We have just realized it takes a little more cash, and invest in strength over power on the 60/40 scale rather than 50/50.
 
Big T, The problem I'm facing is in the design of the block itself, not who makes it. Eighty years ago engineers figured out that the nexus of power and efficiency for a diesel was a compression ratio of about 17:1. Look where all modern diesels are at. This is where the heat problem of a 6.5 originates. The problem with the main webs cracking at the outer cap bolts is due to the extreme undercut of the main webs to make the block as short as possible. I have a n/a 6.2 with 120hp with a cracked web. No need to bore them 3mm and add the smallest turbo ever to get them to fail eventually. Many members here that are smarter than I am have figured out that compression must be reduced and the bottom end reinforced AND a turbo with a bigger hot side must be considered anywhere beyond stock power levels.
I would gladly attempt what I want to do on a seasoned 660, 599 or 506 (Navistar) block if I could locate a proven (magnafluxed) good one. Right now, I can't.
 
This is why there is only a couple of ways to attack the 6.2/6.5 problem.

Find cheap used engines and just replaced them as they blow up. We used to be able to do this all the time easily those days are gone.

Buy a used engine, hoping for the best. Rip it all apart and make the necessary changes so that it will remain a good reliable engine.
Buy a brand, new engine, rip it all apart and make the necessary changes.

Buying a military takeout engine is not necessarily the right answer. Many of the times the military took it out because something went wrong with it.
This is where you’re better to buy a hmmwv Engine from someone who bought the entire hmmwv at auction and is putting in a Duramax or an LS engine.

Otherwise, getting one of the California Sold HMMWV‘s at auction that is under 10,000 miles. Pull it out and make all the necessary changes.

Otherwise it is a large gamble.

I have an optimizer I bought new and the original plan was run it for 100,000 miles, then rip it all apart and make all the changes. I wish I had just made all the changes when it was brand new. That’s why that has become my new standard, I have seen too many brand new 6.5, including P 400, that have failures in under 100,000 miles. I am of the opinion now that all brand new 6.5s MUST BE disassembled and make the changes required.
 
My understand is that compression design is a balance between the amount of turbo boost. The higher the boost, the lower the compression. Many of the modern diesels run 20+ psi boost, but do so with 17:1 compression ratios. 6.5 ran 20:1 compression ratio with 7.5 psi limit through a wastegate.
 
I coincidentally wrote to the ebay seller of bare blocks in Virginia a week or so ago just out of curiosity to see where they are cast. I was told that the supplier of the blocks is Canadian, but that they are cast in Mexico. Was curious if anyone on here had ever seen one in person, I also agree that an optimizer bare block is super expensive as- is.

@93detroit I have a 599 block from my '93 dump truck with only ~130k that I'd part with for pretty cheap if going to a member on here. No cracks as far as I can tell but hasn't been magnafluxed or anything. Engine had crazy blow by so I'm planning on having a machine shop measure the bores to see if it was just smoked rings or overheated enough to distort the cylinder walls. I don't know how much appetite there is for the earlier non- squirter blocks but if it at all interests you let me know, I plan on getting it checked out by a machine shop here soon regardless
 
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