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Will optimizer 6500 heads fit on a 6.2L diesel?

Will optimizer heads fit on a 6.2 diesel

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K30Diesel

K30Diesel

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I have an 82 k30 with a 6.2 diesel. I was wondering if the optimizer heads would fit on a 6.2? I am planning to shave off the piston tops to achieve 17:1 compression, and then install an hx35 turbo. After 38 yrs of pretty hard use, the heads on this truck have never had a problem, but I doubt they would last very long with the turbo. My goal is to have approx. 300hp and 550-600 ft/lbs of torque. Please excuse any typos or messups as this is my first time posting on the truck stop20200510_164525.jpg
 
The more important aspect of the heads are the precups. Small NA precups don't like lots of boost and fuel as they turn it into rolling coal. Been there tried NA precups with a big turbo... Turbo precups and esp. the diamond precups are the best choice.

6.2 and 6.5 heads are identical "bolt on" other than injector angle. Except the early 1982 6.2 heads you may be dealing with for injector threads and valve train. I will assume you are changing the injectors to 6.5 style and rockers to match the heads. This general difference causes 6.2 head injectors to nearly hit the GM 6.5 turbo manifold the airflow abortion it is.

If you are using your 6.2 block I have some parts you may be interested in from heads to 6.2 gapless rings with coated pistons.
 
If you want that kind of power get the properly machined and coated 18:1 pistons from @twistedsteelperformance and a hot rodded DB2. An intercooler will also be a must.

Don't know what the +/- tradeoffs are in using a 6.2 block vs 6.5, but it's the general consensus that the new optimizer blocks have better metallurgy and can make the kind of power you're looking for. @n8in8or has a military optimizer that dynoed at 350 hp, check out his build thread(s) to see how he got there. As my name states I am no expert, but think that refreshing a 6.2 with optimizer heads would be a great way to add more longevity to a reliable 6.2 platform, but perhaps not the best route if you're looking to build more of a power plant.
 
I apologize for not responding sooner. I couldn't find this page after I had posted the question. After talking to a few people at a diesel injection shop, I realized that 17:1 most definitely too low compression. I was thinking that by bringing the compression to 17:1 that I could increase reliability(not thinking of carbon buildup). Starting the truck is not a problem for me as we don't experience much cold weather and I do have a good block heater. I know that on the p400 they added a 3" girdle. There is a shop in town that can build a girdle for me. The only problem with that is the price (about 2,000). I'm planning to use the omega moose injector pump, pushing 130cc of fuel. And if i can find them, the diamond pre cups
 
I know that the optimizer block is a better foundation to build. However I would like to keep my mechanical lift pump. I have not been able to find out if the optimizer has that option . also, I plan on using a center mount turbo setup(humvee exauhst/intake manifolds, and custom piping to bring the turbo more forward and up out of the valley). I know that an intercooler is a must especially with 130cc of fuel but I haven't done much research in that area yet. Although 600ft/lb is my goal, I am more concerned with making a reliable motor even if it means less power. Another thing I've been thinking about is a forged crank and balancing the rotating Assembly. Also, another question. Are timing gears better or worse than a timing chain? I read somewhere(I can't remember where now) that the timing gear set contributes to crank failure do to extra vibrations.
 
All the blocks have the provisions for a mechanical pump, trouble is they won't feed a hungry motor.
And 2k isn't bad if its a full girdle. A forged crank is that much alone.

If you aren't prepared to spend 6-8k, then you may want to reconsider the plan, reliability does cost as the hp goes up.
 
I would be hesitant to do any machine work on IDI pistons. The relationship between the precup and piston is responsible for proper combustion due to the dual swirl it creates in the main combustion chamber. If you change the design of the piston bowls or deck the piston you might negatively affect the combustion process. When GM dropped compression to 20.5:1 they accomplished that by increasing the volume of the piston bowls.

You can see the dual swirl in his picture of the IDI combustion process from a research paper
Screenshot_20190324-084221_Messenger.jpg
A guy installed a piston backwards in a 7.3 IDI build years ago. He quickly caught it and after pulling the head back off you could see the large amount of soot concentrated on the backwards piston. The lack of the piston bowls caused incomplete combustion in the main chamber
Screenshot_20190324-085338_Messenger.jpg

As far as precups go I have a less popular opinion on cup sizes. I dont view the precup as "air flow" but more as part of the injection process. Fuel is still being injected after TDC so the pressure differential at the cup throat is going to farther atomize the fuel as it moves through the cup and into the main chamber. On paper the smaller cups should do a better job at atomizing the fuel. Not only that but it physically matches the ramp in the piston better in my opinion.
20190606_201656.jpg
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No one has proven which cups works better and why so at this point it all based on personal experience. More testing is needed for us to farther understand the affect each cup has on performance of the engine.
 
Glad you re-found us.
Like mentioned- forget the mechanical lift pump if you want anything near that fuel volume. There are other problems with mechanical pulps too- but point is moot based on power requested.
Maybe take the time to read N8in8or’s build thread. It will walk you through hitting those numbers.

300/600 is not hard with modern diesels- but the 6.2/6.5 platform is designed for fuel efficiency (mpg) not power. There is not a lot of people that hit those numbers and get over 100,000 miles on that engine.

Yes you NEED to find a set of timing gears instead of chain pushing those numbers and wanting longevity. Leroy Diesel was the last one making them and he is out of stock iirc. So you ought to start putting out the word you want a nos or used set and figure the pricetag isn’t low. Either that or get used to swapping timing chain every 30,000 miles because you need the clearance for the valves and when that chain stretches out with the valves opening that far...
so definitely you want the 18:1 pistons with the valve reliefs cut in them from Twisted Steel Performance imo. (Thats what I have for my current build).

Rockabilly has a ton of info on the precups and has many valid points to his argument. Some of us that went to the bigger is better theory on precups is from swapping them out and notice way more smoke with smaller cups and bigger turbo/fueling that gets dramatically eased with larger cups. You will not find new diamonds. You can find other new cups and have them machined out to diamond spec (something I’ve also done).

Hopefully with AM General just being sold the new owners will (through GEP) put the p400 back in production. It is of course possible they will kill the 6.5 all together. We probably won’t see any actual changes until 2021.
 
You piston design is the best I've seen for a 18:1 6.5. I'm not a fan of decked pistons on an IDI. It looks like yours will still retain some of the mixing properties the stock pistons provide. I'd love so be able to take some high speed pictures of the combustion process with your pistons like the ones I posted above. It would be cool to see what changes it makes.
 
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