Optimizer to P400 Frankenbuild Discussion

[emmott]

P400 heads, cranks & rods, rod bearings, and standard size pistons are all still available. For now.

If one already had a 2001+ optimizer 6500 longblock, could they refit it to be on par with a p400? From what I know, you would need:

• A bedplate, custom CNC'd from scratch to fit a vanilla GM/optimizer 6.5.
• Custom oil pan
• Forged crank
• p400 rods and rod bearings,
• p400 pistons
• Complete p400 heads

Am I missing any other parts that are different or improved in the p400, aside from the bare block itself?

Most importantly, would the retrofit described above have 98-100% of the durability and power potential of a virgin p400?
I'm particularly interested in the structural/metallurgical differences between a bare optimizer block and a bare p400 block and if machining and/or cryo treatment could make up the difference.

 

[Rockabillyrat]

I got the p400 crank, rods, pistons, and all the bearings for my optimizer build. I'm going to use my optimizer heads though because they are in great shape. So I saw no reason to upgrade.

As far as the bed plate goes. You can't purchase the p400 bed plate separately from the engine. And I don't think it will bolt onto a optimizer block anyway. Or if it does it will take some machine work. If you have the money you could have a custome bed plate made but it won't be cheap. I'd love to do that but I'm no sure it's in my budget. So I was planning a building a halo style girdle for the bottom end. Just need to see if I can get the correct length studs to make it happen. My plan was to have it cut from 1/4 on a plasma table.


Powered by design built this like 10 years ago. I wonder if he is still around and what he would charge to build one.

 

[ak diesel driver]

Didn't know anyone had built one like that before. Almost identical to the one I'm going to build

 

[n8in8or]

Didn't know anyone had built one like that before. Almost identical to the one I'm going to build

WELL HURRY UP ALREADY, PEOPLE ARE WAITING

 

[ak diesel driver]

Lol

 

[Rockabillyrat]

Didn't know anyone had built one like that before. Almost identical to the one I'm going to build

Here is the link for the girdle build he did.

6-5L-Turbo-Diesel-Project

Qualified and affordable design solutions for any business small or large. Product Design, Machine Design, Process Design, Patent Drawings, Autocad C

www.poweredbyd.com

 

[Will L.]

I never saw that one either. Very nice!

 

[emmott]

I'm requesting quotes for the p400 crank rods rod bearings and pistons. I have gotten some interesting comments from suppliers about the P400 & GM pistons oil squirters and rods.

• Source 1 says you cannot use P400 pistons with GM rods, or P400 rods with GM pistons, and the rod bearings are different (primarily in metallurgy).
• Source 2 says the P400 connecting rod bearings share all the same dimensions with GM, and P400 pistons are specific to the P400 block due to a different piston oil squirter location. They proposed selling only the crank and rods for my build, leaving me with my GM style pistons to use.
• Source 3 says the GM piston can be machined to fit a P400 rod however the durability will not match that of a P400 piston.

If you want to use p400 pistons on a GM/optimizer block, will the cooling on the P400 piston be insufficient since that piston is designed to work with a different oil squirter location? Or could the p400 piston be machined to work with the oil squirter location on the GM style engine.

 

[Twisted Steel Performance]

I have freely posted pics here showing the differences of the pistons, rods, p400 piston squirters, etc, I haven't posted ALL the differences I know of...

Believe who you want to the facts are...

Any other piston will need machining to fit P400 rods.

P400 rods & pistons are much beefier than the others.

P400 rods are "fracture fit" and use a bolt only, no nut.

P400 pistons can be used in a GM block as can the rods with no mods.

GM blocks locate the piston squirters in a different location, P400 pistons will be oiled same as GM pistons in a GM block.

GM pistons will need machining to work in a P400 block.

The P400 rotating assembly is heavier so balancing is recommended if mixing parts, NOTE, current aftermarket flywheels & flexplates are manufactured for GM rotating assemblies NOT the weight of a P400 assembly..

Go ahead and use rod bearings not specked for a P400, they made changes and have a different part number for a reason, it's your motor..

I give this bit of info freely, I've only built a hand full of them this year....

Best of luck with your build...

 

[emmott]

P400 pistons will be oiled same as GM pistons in a GM block.

Ok good, that's that I was worried about.
I agree TS, definitely wouldn't want to mix and match with a rotating assembly. And if the metallurgy changed it's for good reason.

 

[emmott]

I got my info from source 2 before joining the forum, so I'm glad I posted my initial plans here and got feedback. I don't plan on using stock or marine pistons if I get p400 rods now that I know the pistons are dramatically different too. My work order is on hold with the machine shop while I decide if I want to buy the full p400 rotating assembly. Big investment when $1USD=$1.30CAD. I'm trying to learn what will/will not work and avoid burning cash if there is no net gain in reliability or power potential. So thanks for the info and the nudge.

 

[Will L.]

Having been in the build of 6 p400, and hundreds of gm 6.5, and about 6 optimizers-
If you haven’t held the p400 parts, you wouldn’t get it. Simply holding and inspection of the p400 parts opens your eyes.

If you can afford it, do the full rotating assembly. Have it balanced. The coatings that come on the p400 pistons are very nice and handle beyond what the optimizer could handle heat wise, but if you would have them coated by Chris or someone of his caliber with the techline products they would do even better. What compression you are after could determine other things also like having the piston top altered to 18.5:1or 18:1, then do the coatings.

If all that becomes to much, and you cant do the p400 pistons, find out cost of maybe a set of Chris’ pistons cot to take the p400 rod/pins. The optimizer rods aren’t known as “weak” but the p400 are SO perfect you could be assured they would not be the ‘weak link’.

Back to your desire for making the bedplate (aka full girdle) that would fit the optimizer/gm block- you obviously know the strength and longevity that adds. If you can afford to make 1, bet pricing for low volume multiple in the future. Most 6.5 truck and hummer owners wish for but cant afford- but there are some that can and very well may buy. It might be a few years, but I am sure others would buy. Depending on the price of course a few could turn into a dozen...