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Missy and DaHoooley, the SAGA continues

buddy said:
well, he used a 6.5 crank that has .02" more stroke, than that 6.2 block was meant for. The later 6.2s used the same block as the 6.5, and same crank.
Click to expand...

How detrimental would that .02 be with a set of heads that were heavily ported?
 
dragogt said:
How detrimental would that .02 be with a set of heads that were heavily ported?
Click to expand...

I wouldnt worry about the power difference between the 6.5 and older 6.2 displacement. It will be different, but ported heads may help get the same fresh air into there, and the turbo becomes kind of an equalizer. Get some roller rockers on the ported heads while youre at it :)
 
Do they even make those?

I remember one thread where a guy had adapted a set from a 454, but from the comments it sounded like a 1 off..
 
Harland Sharp makes roller rockers for the 6.2-6.5s. They are a higher ratio than stock. $$$$$$$$ but very nice.
 
I have seen some alternative stuff online, but not ready to try something thats not proven.

Get a set of factory buttons and replace your old ones. CHEAP INSURANCE

Missy
 
Stopped off at the STEALER tonight after I got in with the rig, picked up my care package of goodies.

Oil filter bypass valve
Cooler bypass valve
8 oil squirt nozzles
and a couple other tid bits to the tune of $65.40

Then I remembered that the GEP block did not come with the bellhousing dowels, the timing cover dowels and the lifter gallery plugs for the front end.

Got those ordered now

later troops

Missy
 
These buttons are the only thing that keeps the rocker assembly aligned with the valve stem and the push rod aligned within it's bore.
 
Not my favorite way to keep such an important part doing its job, but they seem to work OK.

I have seen a few aftermarket rocker refits that used a BRONZE button that was Pop riveted into the shaft in place of the plastic button.

New buttons are a good idea on any high mile Overhaul.

Missy
 
buddy said:
I wouldnt worry about the power difference between the 6.5 and older 6.2 displacement. It will be different, but ported heads may help get the same fresh air into there, and the turbo becomes kind of an equalizer. Get some roller rockers on the ported heads while youre at it :)
Click to expand...

Power difference between a 6.5 DB2 turbo and a 6.2 Military spec engine from the 80's with the 6.5 turbo:
3 miles an hour slower for the 6.2 around 65 MPH with a 28' trailer up a good hill at WOT.
Reasons for the difference include slightly smaller 6.2 military emission precups.
MPG working that hard is identical to the 6.5.
Tested with 1/3 to 1/2 turn of the IP screw and 14 PSI max boost on same 1993 GMx turbo.
 
The UPS man just came in and he had a Large Heavy BOX for me. :D

The scat crank arrived about 5 minutes ago.

Ripped the box open and that crank is a beauty.

Missy sits drooling all over the place.

Yeah buddy, thats going to make a nice addition to my 6.5

Really going to be a warm and fuzzy feeling having a good piece of iron down in the basement of this new engine.

Missy
 
Spoke with the outfit I got the crank from (C&P Machine) and they tell me that the cranks are plenty close for these engines.

My machinist has done a couple Scat cranks for 6.5's and they were all plenty close, but once you get to the point of checking, you might as well finish it.

I am going to check the pistons to be sure they are all the same weight and probably go with the crank as it is from the box.

Scat says they are spot on for the average use.

An engine that runs only 3500 at the absolute max will do fine with a crank thats in the ball park.

With the input from C&P machine, I feel comfortable with the crank right from the box.

A cast crank is nowhere near the same item as the forged unit that the P400 is getting.
I dont know who is casting the scat cranks and have no idea of who casts the Optimizer cranks.

I have seen a couple of the old GM 6.5 cranks that had been sectioned and they had porosities in them in the areas that do break.

A casting thats good, will last a long time without any issues.

Nodular Iron (6.5 cranks) are generally fine, but sometimes they can have issues.

The Scat cranks are made from a material Scat calls 9000 series.

I dont know if its cast steel or nodular iron.

They have a great track record, so its off to the rodeo with it.

Missy
 
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