I've been looking for the right engine to turn up in our yard for a year, but no luck. I pulled this '93 3000GT engine at our Charlotte yard to see what crankshaft was in it:

I think there may be some confusion in the online writeups about which DOHC engines had the nitrided steel crankshafts. Some folks say only '95+, others say '93+ with a build date after June '92. Some say it's only in the 4-bolt main engines. This engine was a in a '93 3000GT and was a 2-bolt main block which appeared original except at least the oil pan and rear seal had been removed at some point, but the crankshaft appears to be the real deal - the holy grail of 3.0L crankshafts:

When stood on end and struck with a hammer, it rings long, loud and clear as a bell:

Note the brass color of the flange. I don't remember seeing this blue paint on the last one I had, so maybe it's a parts dealer's mark, maybe not:

There's also some brownish-red paint on the front throw:

And a stamped serial number on the front counterweight:

The journals look good - very light scoring that will polish out just fine:


So, tomorrow this crankshaft, along with a Diamante SOHC block w/ARP main studs, Wiseco pistons, 3SX rods and the rest of the rotating assembly will go to the machine shop for .040" overboring, decking, align honing, crankshaft journal polishing and balancing. <img src="/forums/images/graemlins/kewl.gif" alt="" />

Frank

SWEET!

Excellent! That's good news. Let me know when it goes back in.. I'm getting used to working on your truck, keeps me motivated for a garage in the very near future.

Here's a "Cast vs. Forged" spotter's guide photo from 3SX that shows the same paint marks, so the marks must be placed there by Mitsubishi:



Note also the lack of casting seams and the rounded center lobe on the steel crankshaft:

3SX

3SX sells these for $900 <img src="/forums/images/graemlins/scared.gif" alt="" />

Operators are standing by, but we don't double the offer if you act now

Frank

Congrats on the find, Frank <img src="/forums/images/graemlins/kewl.gif" alt="" />

After a month of gestation, the Diamante block and 3000GT crankshaft are back from the machine shop. This is a new shop to me - it's a one man operation and he has the best reputation in town among the racing crowd.

The block is cleaner than I'm used to seeing from most shops - it's been decked 0.006"..... that's more than I had hoped would be necessary, but that's what it took to clean up the etching around the fire ring areas. It's also been over-bored 0.020" and align honed. For those interested, ARP main studs do tighten the main bores a hair at the parting lines, so I would suggest align honing if anyone uses the main studs...... otherwise, the alignment of the bores was spot-on:




The crankshaft has been balanced.... it was almost perfectly balanced as it was, but it's now on-the-money and it polished out very nicely:


The 3SX rods were dang near perfect right out of the box - balanced within 0.5 grams big end/little end/total weight. We decided not to drill the oil squirter hole in the rods and I'll depend on splash lubrication for the major thrust face of the cylinders. I guess time will tell if that was a good decision.

The pistons were also spot-on - all within 0.5 grams weight difference.

The crankshaft was balanced using a new OE rod bearing for reference, but I changed to Sealed Power bearings after I saw the price of the OE main, rod and thrust bearings..... have they ever gone crazy! $400 (with a discount) is nuts when Sealed Power was less than $100. I did compare the weight of the 2 rod bearings and they're within 0.5 grams, so I should still be good on the balance job.

So, Sunday I'll wash and paint the block and get this mess started once again.

Frank

where's that popcorn?! <img src="/forums/images/graemlins/kewl.gif" alt="" />

We need to have that tv production guy from chattanooga to make a tv film of Frank doing this engine.

Are you using any piston coatings? I think Kevin had some very good things to say about the low friction skirt coating. I'm intrigued by the heat shielding for the crown, too. The longer you can keep the piston dead erect in the bore, the longer the ring seal lasts, and from Kevin's report, the coating held up very well. This might make the non-drilling of the rod squirt hole less troublesome in my mind...

Way cool to see this project come off the back burner. <img src="/forums/images/graemlins/kewl.gif" alt="" /> A fine example of never give up, never give in!

<img src="/forums/images/graemlins/cheers.gif" alt="" /> <img src="/forums/images/graemlins/rodent.gif" alt="" />

Eddy - nope, no piston coatings.

I just hope I don't have to cut the piston tops because of the .006" deck cut. I'll find out when I test fit the rods and pistons.

I've forgotten how much the heads have been cut, but I think I'm now over the .008" limit for heads and deck suggested by the FSM.

I need to do a lot of careful measuring on the combustion chambers, piston/deck clearance and piston relief because I spec'd to the low side on the piston dish...... with that, in combination with the overbore and the heavy deck cut, I'm getting a little concerned with the static CR. I was counting on 9.1:1 maximum, but I have an idea that I might be looking at 9.3:1 static CR.

Whatever...... I'll figger out something.

Frank