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6.5 Na Max Potential?

Ah yes, thanks, I forgot about the googler thing. I talked to Ken, and a regrind is really reasonable only about $95. By tightening the lobe centerline, we can generate a little overlap, then say HELLO to the header scavenging effect.

Heath used an electronic pump and custom program on the Bonneville racer. Will a mechanical pump allow higher engine speeds? I want it to run strong to 4k.
 
scottm said:
Ah yes, thanks, I forgot about the googler thing. I talked to Ken, and a regrind is really reasonable only about $95. By tightening the lobe centerline, we can generate a little overlap, then say HELLO to the header scavenging effect.

Heath used an electronic pump and custom program on the Bonneville racer. Will a mechanical pump allow higher engine speeds? I want it to run strong to 4k.
Click to expand...

Might look into a custom pump that can fill the ports quick enough at that rpm.

Source Unknown
 
If you can find the numbers to successfully get it to scavenge I'd love to hear about it. Going n/a you want to bring up the compression numbers, which makes that scavenge time even tighter. I kept getting crossflow due to the obvious lack-o-vacuum generated in diesels compared to gas engines and chucked in the towel after the 8th grind. 6 of the 8 were asymmetrical, and maybe that was my errror. My days of trying for good numbers from this are gone, just interest in "the one that got away".
 
That's a component often overlooked. Diesel engines are full throttle all the time as far as 'air' goes.. For N/A maybe implement a throttle body tied to the throttle position of the IP... Hmmm he says.
 
3500GMC said:
That's a component often overlooked. Diesel engines are full throttle all the time as far as 'air' goes.. For N/A maybe implement a throttle body tied to the throttle position of the IP... Hmmm he says.
Click to expand...

The throttlebody wide-open would just give you what you have now- full air supply. Closing the butterfly partway is going to restrict the volume of air flow going in but doesn't increase your vacuum on the intake side it lowers the rate of acceleration of rpm faster than creating the pressure difference from what I've played with... (Hence the introduction of a vacuum pump on everything diesel but not gasoline engines). Unless you find a way to force the air through to keep the volume same. Then you can increase the pressure difference as it goes through throttle body, but that's the forced induction which takes you right back to a turbo, blower,or supercharger.

That was the reason so many two-stroke diesels failed or had major problems with running away is because the inability to generate a vacuum to have Reed's function. (Detriot's famous 4-71,6-71,8-71 series The non-spring-loaded air dam doors cause the engine took smoke heavy from all the excess fuel before blocking off airflow and finally shutting down the engine. Check out videos of run away diesels and you'll notice the mass increase in exhaust right before the get shut down or pop.

That's just a nasty side of the slower burning fuel which is why I mentioned propane. The quicker your fuel can burn off in the cylinder the sooner & the more you can scavenge in the engine. Ever ran an alcohol engine using a hi scavenge rate long duration to push out quicker and then tried to run it on pump gas? Lower octane causes a lot of backfire because you can't get burned out quick enough.

Don't take me the wrong way, somehow someone will figure this out. Hopefully one of you guys, then you can explain to me why i never got it right.

Trick intakes: We never played with it for n/a, just tuned air horn was the best result we got, but the improvement was so minor compared to no intake that it just wasn't worth it, so we just went back to gasket matched and polished. Anything in mind here?
 
Ya, scavenge effect (cam overlap) and rpm is where its at with N/A. The burn rate of diesel will come into play here. No 'fan' to fan the fire.
 
I know he wants an n/a diesel for his rules but n/a diesels to the public should be banned, lol. I hated my van n/a and will never ever go back to an n/a diesel again, its too painful to drive.
 
Will L. said:
Trick intakes: We never played with it for n/a, just tuned air horn was the best result we got, but the improvement was so minor compared to no intake that it just wasn't worth it, so we just went back to gasket matched and polished. Anything in mind here?
Click to expand...

I work at a precision laser cutting and sheetmetal shop, so I have lots of ideas here.. I am thinking a sheet metal tunnel-ram, like the trick old Reher-Morrison pro/stock engines. The runners would funnel directly into the ports, and would just need to clear the ip. It would automatically flow better than the 6.2 manifold. And if you get the volume and length right - look out. Combined with a cam and real headers, it would have to make power, right up til the shortblock comes apart. Here is an artists' rendition, if it will upload.

Nope, I still can't upload, the little arrow in the upper right corner just spins and nothing happens.
 
The project is officially underway. I went by a wrecking yard at lunch hour today, and found a goodwrench 6.5 in a 90-something one ton. The intake and turbo was gone, but everything else, including the pump, was there. My cost $350, and they will pull it for me. Were the goodwrench replacements any better/worse than the oe engines? Also I found a 6.2 in an 80's suburban on CL, and I might just get that one too. I am going to measure the pizz out of these things, everything from stock to modified head flow to rod weight to cyl wall thickness, and put together the ideal combo for Project NA.
 
scottm said:
The project is officially underway. I went by a wrecking yard at lunch hour today, and found a goodwrench 6.5 in a 90-something one ton. The intake and turbo was gone, but everything else, including the pump, was there. My cost $350, and they will pull it for me. Were the goodwrench replacements any better/worse than the oe engines? Also I found a 6.2 in an 80's suburban on CL, and I might just get that one too. I am going to measure the pizz out of these things, everything from stock to modified head flow to rod weight to cyl wall thickness, and put together the ideal combo for Project NA.
Click to expand...

That would be nice data to share.

Source Unknown
 
Here is my $350 core engine, a goodwrench replacement, found in a 1990 1 ton pu. It is a na setup with mechanical pump, which gives me hope that it might have had an easier life. The block casting ends in 506, which is not the good one, right?
 

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I have yet to see solid evidence that one block is stronger than the rest. Except for the p400 and amg blocks. You will be just fine with a 506 block.
 
Wouldn't that be sweet? It doesn't have the back-to-back triangle marks though, just a small mark with two parallel bars at the bottom of the valley. It has several rows of dots on the valley walls.
 
Later gm parts replacement 6.5's were optimizers from GEP. When gm signed over the production to amg, part of th deal was they would provide gm with replacemet engine for thier parts program.

Unfortunately, without the "endless roads" symbol in the intake valley (two triangles) it's highly unlikely its a navistar block. The "gm" stamped in the valve covers also supports this. GEP valve covers only had a part number stamped in them simce it was not longer a gm product.

Still, post up the year code stamped on the block behind the passenger head and it can be decoded to know just what you got.

Very doubtful it's a navistar casting, but 350 bucks for a running development mule is a bargain.

Ride 'er till she bucks I says!

:)
 
Yes I am going to flog it hard and often. Wait, that doesn't sound right..

Is a goodwrench replacement I could buy today going to be an optimizer? That would be great unless they are $15k.

Naturally I wanted to know how much it weighs, so I picked it up with a calibrated Interface load cell. "Only" 642 pounds, with ex manifolds, but no intake or starter. Actually less than I expected, but still too much for my engine stand! I need to upgrade the rest of my shop equipment to work on this pig.
 

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scottm said:
Yes I am going to flog it hard and often. Wait, that doesn't sound right..

Is a goodwrench replacement I could buy today going to be an optimizer? That would be great unless they are $15k.

Naturally I wanted to know how much it weighs, so I picked it up with a calibrated Interface load cell. "Only" 642 pounds, with ex manifolds, but no intake or starter. Actually less than I expected, but still too much for my engine stand! I need to upgrade the rest of my shop equipment to work on this pig.
Click to expand...

Yup, gm parts replacement engines are gep optimizers.

Thats where i got mine from. Was around 7 grand at the time.
 
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