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Decisions on engine options

SnowDrift

SnowDrift

Ultra Conservative. ULTRA!
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I'm trying to make the decision on whether to buy a new Optimizer or a long or short block Optimizer take-out (from a HMMWV) or as of tonight, a "low mileage" 6.5 also out of a HMMWV (late 90s model). As that list is read, the prices descend greatly. It sounds like the heads are different from a truck engine to a HMMWV engine, so it's likely I'll need to make a decision on those unless I buy the new engine. What are the recommendations on heads for whichever combination? It looks like Leroy has a good selection to choose from. Maybe others? Cost is obviously an issue or I wouldn't be asking. I'm open to opinions and suggestions, though.

Just some background, it's for my '95, but it's not a typical '95 truck from Ohio. It's worth saving in my estimation.
 
New is best, a take out optimizer block is better, a 90s block will be the worst as it won't have the upgraded casting metallurgy. If possible to inspect a used take out for cracks and whatnot absolutely do it before purchasing. The newer blocks can/ will still crack

Any engine with a centermount turbo like the HMMWV will have heads with a different angle so you can't run the side mount turbo & intake on them. Hence the need for different heads

P400 heads are the best hands down and worth it if you can afford it.

I haven't heard the greatest things about ProMaxx heads and would not recommend based on the word of others more experienced and knowledgeable than yours truly

What is the truck being used for? Your application and power goals will greatly affect how much you invest. If for a fart around daily driver, then yeah sure a 90s engine that will never see more than 8-10 pounds of boost will probably last ok. If you want to do any kind of serious towing be it for equipment or a camper/ trailer then it quickly turns into spending up front to avoid catastrophic circumstances down the road. Just my .02
 
My concern is that if I go with the older engine, then I've put a lot of work into something and am really no better off to where I end up with a truck I still don't trust. If it was a beater, it would be one thing, but it isn't. I put around with it from time to time in the summer when I have nothing else going on, but generally speaking, when it rolls out, it is usually because there is a need. It spends a fair amount of time with a trailer hooked to the ball in the bed or bumper and often times, it's on a run where my time isn't due to leisure.

The more I type, the more I am talking myself into new iron.

The dilemma is if I buy the short block Optimizer, I'm putting many other components onto it that seem like they'll yield the same cost as a new one I pick up in southern Ohio. The upside is that I can stretch it out if I wanted to.
 
it's funny I was just reading up on an old thread from 2012 here in TTS last night where guys were talking about replacement engines. @WarWagon and I think @Will L. had mentioned in that thread about a place called Ted's used engines where this guy would get used opimizers and sell them. aparently these engines only needed minor work like re-ringing and the most, maybe even having the pistons coated too. not sure if this guy is still around or is still selling them. I would be one to be curious on the price they go for.
 
Ted's doesn't sell military engines anymore, and the last several years of engines offered were all boat anchors in the experience of users on here

A military take out is really hit or miss; I've seen them as low as 2k and has high as 4-5k. When that high you may as well go new in my opinion

I decided to go new because I had 2 GM 6.5s blow up on me in the span of 3 years and was happy to pay for the peace of mind and longevity

In my opinion the best reason for going new is longevity and the ability to keep all things mechanical. With a new engine running a mechanical pump your powertrain will outlast any chassis and will be transferable to another good shape GMT400 platform. With the move to everything electronic, computerized and tracked, you best believe I'll be running my 6.5 as long as humanly possible
 
DieselAmateur said:
Ted's doesn't sell military engines anymore, and the last several years of engines offered were all boat anchors in the experience of users on here

A military take out is really hit or miss; I've seen them as low as 2k and has high as 4-5k. When that high you may as well go new in my opinion

I decided to go new because I had 2 GM 6.5s blow up on me in the span of 3 years and was happy to pay for the peace of mind and longevity

In my opinion the best reason for going new is longevity and the ability to keep all things mechanical. With a new engine running a mechanical pump your powertrain will outlast any chassis and will be transferable to another good shape GMT400 platform. With the move to everything electronic, computerized and tracked, you best believe I'll be running my 6.5 as long as humanly possible
Click to expand...
My 6.5 came from Ted's (late '15,early'16). It is an '07 military motor (n/a). All I did to it was swap the oil pan and install my pump,injectors, intake and exhaust. 30k hard miles so far.

What they're selling since then, I have no idea.
 
SnowDrift said:
Do the Optimizers come from the factory with gapless rings?
Click to expand...
NO
“Gapless rings” is a modified set of rings made by one company: Total Seal.
The rings used in optimizers are the best rings available for this engine- you pull the rings on a new optimizer, check/ file the rings to best fit. Then ship the second ring off to Total seal to have altered into a gapless ring. Be sure to put each ring into its own ziplock bag labeled with the cylinder it is fit to. Then reinstall back on that piston and enjoy the cleaner engine oil (more tasty!) and a slightly better compression life.
 
Will L. said:
NO
“Gapless rings” is a modified set of rings made by one company: Total Seal.
The rings used in optimizers are the best rings available for this engine- you pull the rings on a new optimizer, check/ file the rings to best fit. Then ship the second ring off to Total seal to have altered into a gapless ring. Be sure to put each ring into its own ziplock bag labeled with the cylinder it is fit to. Then reinstall back on that piston and enjoy the cleaner engine oil (more tasty!) and a slightly better compression life.
Click to expand...
I thought the gap-less ring part went on the top piston ring. I guess I have some learning to do lol
 
Roger that. You told me that, Will, but it wasn't until I read your post here that I was able to decipher the notes I had written down from when we talked. Thanks for clearing it up.

If that's the case, then the only thing I would need to take off the new engine would be the pan if I went that route since I should be able to slip the pistons out the bottom end.

I'm considering making the girdle for the main bearings, rather than purchasing. I understand the concept now, and it appears to be supporting the bearings in the longitudinal direction (lengthwise, with the crank). The material used has a higher yield before permanent deformation - likely much higher than the block material, which is cast and "brittle". I can draw the profile and cut with plasma or gas. I have a call out to a local shop to see if they can laser cut this thick of material.

The cost to balance the rotating assembly at the local shop is around $350. If I go new, I may forego this step due to the added cost/benefit.

I had a conversation with these guys today, as well.

The engine is not an "optimizer", but I was told it is the same block casting being used by AMG, which is cast in Brazil, using the updated metallurgy. The difference is that there is a warranty and all their engines are ran and dyno tested before they get shipped out. That's attractive, but also comes with an increased cost. Crank is cast, but it sounds like if the main webs remain intact, the crank is not necessarily the issue.

Regardless, I see no reason to not go with Leroy's billet lower pulley and Fluidamper. From what I've learned, those are going to be a must-have.
 
Twisted Steel Performance said:
You better do some checking, you are talking to Bostic in Nc, buyer beware...
Click to expand...
Well, that's exactly the reason I'm posting on here about what I'm considering. I didn't want to get blindsided. Warranty is nice, but how many times do I want to be stranded in a 12 month period of time and have to take the time to pull another engine? One time will be too many.
 
Well, I'll give a few things to consider knowing I'm out of your budget.

New motor - is just that, a unused version with the same flaws as what you have now, it will wind up with the same trouble spots in time and miles.

Rebuild - upgrades can be added to overcome nearly all the factory short comings and hold much better tolerance than a factory run engine and added improvements will make it last without worry.

If you plan to keep it, or even pass it down one day, spend or save to be able to build something worthy in 20 more years, much better than a truck payment.

Just my thoughts.....
 
Balance that rotating assembly. Well worth the time and money.
I do believe they have to have the pistons, rods, crankshaft, harmonic balancer, front crank pulley and flywheel or flex plate.
Someone please correct Me if I am wrong on any, or all, of this statement. 🤷‍♂️😹😹😹
 
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