Optimizer Engine

[Sharecropper]

Here’s a very informative article on the Optimizer engine -

GM 6.5 Diesel Engine - The Optimizer 6500

The 6.5L GM diesel engine was introduced in 1992 to replace the 6.2L diesel engine and was in turn replaced by GM’s Duramax 6600 in 2001. On the surface it would appear that the story of the 6.5L diesel would end here, right? Well, that wouldn’t make much of an article. Related Articles - Expanding

www.enginebuildermag.com

 

[LT67]

An Optimizer will drop into a cucv and bolt right up with a different oil pan correct?

 

[Sharecropper]

Yes that is my understanding. Not sure about the oil pan. It may fit just fine. Maybe someone with specific experience can chime in.

 

[Barrman]

The HMMWV oil pan will clear the stock Chevy cross member on a CUCV. The engine above the Optimizer 6500 is the one with the girdle and oil pan that won't clear the stock CUCV crossmember.

 

[cucvrus]

I never knew if the stock 6.2 HMMWV oil pan would fit the CUCV. When I used HMMWV engines in CUCV's I just changed the oil pan. I have a few extra oil pans either way CUCV or HMMWV. Good to know they fit but I would still stay with the CUCV in a CUCV and HMMWV in a HMMWV. Never know I may flex it pretty hard at Rausch Creek. Take Care and Good Luck.

 

[Sharecropper]

The engine above the Optimizer 6500 is the one with the girdle and oil pan that won't clear the stock CUCV crossmember.

The "engine above the Optimizer 6500" to which you refer is the P400. If I can ever get through these darn surgeries, I plan to install my P400 into my M1028. And I can almost guarantee that I will need to modify my engine crossover frame to accommodate the P400 girdle and oil pan. The P400's cast iron girdle itself adds 3", and there is no way to modify the heavy cast aluminum oil pan. I fully anticipate having to fabricate a new engine crossover frame, I'll just have to get the P400 hovering above its nest to see what I will have to do. Should be fun.

 

[Barrman]

I couldn't remember if it was P40 or P400 so I wrote it the way I did.

I have an optimizer 6500 with the HMMWV oil pan in my 1987 Suburban. Plenty of clearance all around. The 1 piece rear main seal on those engines means if you swap the oil pan, it has to be from a 6.5 with the 1 piece rear main.

 

[Sharecropper]

Not that I am in the market for an Optimizer 6500, because I already have my new drivetrain assembled, however for the benefit of other SS members, I wonder where the best place to purchase a NEW Optimizer long block?

 

[Keith_J]

Cast aluminum can be welded..cuts like hardwood with carbide tooling, if you don't mind the glitter bomb.
I suppose the additional capacity is for cooling since the engine has piston cooling jets.

 

[Skinny]

There are some aftermarket crossmembers for duramax and cummins swaps. I'd bet they are pretty close to fitting that cast aluminum pan. I would take a look if I was trying to fit a P400.

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[Sharecropper]

There are some aftermarket crossmembers for duramax and cummins swaps. I'd bet they are pretty close to fitting that cast aluminum pan. I would take a look if I was trying to fit a P400.

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Thanks Skinny. ORD has one I might look at once I get the P400 swinging over the frame. If necessary I’ll just fabricate my own. Whatever it takes, that P400 / 700R4 / NP241 will be bolted up.

 

[Skinny]

The ORD is a nice piece. I have one on my Suburban. It clears a big 8.1 aluminum pan.

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[chevymike]

I thought at one point one of the bigger aftermarket companies (like Holley, Moroso, etc.) made an aluminum replacement pan for the P400 that would fit a truck without any mods. Not sure if it is still being made.

 

[Sharecropper]

I purchased my P400 long block from LeRoy Linza (LeRoy Diesel) in 2017. I believe I may have gotten the last one GEP released to the public. Around the same time LeRoy was in the process of tearing down another new P400 long block to see what made it tick. He was documenting his “rebuild”on his YouTube channel, which I was watching, and I noticed that he had Moroso build him a shiny new oil pan for the project. I asked him what he planned to do with the OEM oil pan, and he offered it to me for $100. I bought it immediately so that I would have a spare, and it is currently in my spare parts rack. So I am probably the only guy on the planet with a new P400 and a new oil pan for a spare.
Back to Moroso, they will indeed build a custom oil pan for any engine. All it takes is money.
I welded in heavy aluminum bungs on each side of the spare oil pan, one for the oil temperature gauge thermocouple and one for the suction line for my aircraft pre-oiler pump. I then dropped the original pan from my P400 and replaced it with the pan with the bungs. While I had the pan off I got a close-up of the inner workings of the P400’s girdle and massive main bearing assembly. It was then that I realized that the design and shape of the cast aluminum oil pan could not be modified due to the P400’s bottom end. I feel blessed to have a spare pan on hand.

 

[Keith_J]

I wonder if any P400s are going to be surplus sold with red tags..or if they are scrapped?
I know they won't bore and upsized so it might be worth it to buy a junker and sleeve it..

 

[Sharecropper]

I wonder if any P400s are going to be surplus sold with red tags..or if they are scrapped?
I know they won't bore and upsized so it might be worth it to buy a junker and sleeve it..

I've watched Ebay for the past couple of years for P400 engines and/or parts. It's like watching for parts for the Space Shuttle - there just is nothing there. Although I cannot confirm, but I have heard that only 400 of the P400 long blocks were released for civilian consumption. My only regret was not buying more. When I purchased mine, I had the opportunity to purchase ten (10) at $7500 apiece. I wish that I had gone forward with the purchase and just stored them here in my warehouse. But I didn't. Its that freaking hindsight 20/20 thing. Oh well, at least I got mine. And I am looking forward to installing it and the entire drive train into my truck. I have one more serious surgical operation coming up in May, and if I survive it, I plan on beginning the installation process. I will document the entire process in my rebuild thread.

 

[Sharecropper]

Dayum. Just found this -

Hummer H1 P-400 Long Block

Only one left!! Thinking about doing an engine conversion? You might want to consider the P-400 first for the following reasons; Produces 250 hp & 550 ft/lb of torque stock (without any performance modifications) That is a 30% increase in HP and 22% increase in torque over the stock 6.5 A full...

www.rubberduck4x4.com

 

[chevymike]

Dayum. Just found this -

Hummer H1 P-400 Long Block

Only one left!! Thinking about doing an engine conversion? You might want to consider the P-400 first for the following reasons; Produces 250 hp & 550 ft/lb of torque stock (without any performance modifications) That is a 30% increase in HP and 22% increase in torque over the stock 6.5 A full...

www.rubberduck4x4.com

Really wish these would have made it into the consumers in large quantities and they would start popping up used. I would love to have one and would likely keep me staying with the diesel. As it is, I will be moving to a 454 I have.

 

[Skinny]

Anyone willing to spend $14,500 on that should seek help. Amazing no one taking my tax dollars felt ashamed for doing so.

Yeah I like my mechanically injected 6.2 mostly because it hasn't exploded yet. But $14,500 gets you a nice Duramax that will literally eat a 6.2 for lunch while getting a 1/4 better fuel economy. Sure it takes more then one wire to run but that engine should be like a third the cost.

So where exactly is the P400 pan hitting? The factory crossmember is way out front. Im guessing unless you are still on a factory sag springs it should fit.

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[LT67]

Anyone willing to spend $14,500 on that should seek help. Amazing no one taking my tax dollars felt ashamed for doing so.

Yeah I like my mechanically injected 6.2 mostly because it hasn't exploded yet. But $14,500 gets you a nice Duramax that will literally eat a 6.2 for lunch while getting a 1/4 better fuel economy. Sure it takes more then one wire to run but that engine should be like a third the cost.

So where exactly is the P400 pan hitting? The factory crossmember is way out front. Im guessing unless you are still on a factory sag springs it should fit.

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My DD is an 04 Duramax truck. No way I want that much power in a CUCV truck. Lol, the warmed up 406 in my K20 is enough