Northstar rebuild: Will style (Page 95/119)
eph_kay APR 30, 11:01 PM
Will, I’m gonna shoot you my info, I will want to talk more, I was planning to adapt one of the super chargers from a 4.4, and just got it in the mail today actually, but I will want to talk about other details too

Thanks for the help so far

Chris
Will MAY 05, 11:12 AM
Soo... Promar said that blocks are their shortage. I said I have one each of '93, '00-'04 and '06+ blocks. They said they aren't interested in bartering. I replied with a more polite form of "you sure about that?" They can still hone whatever block I provide, even with the torque plate.

They use Federal Mogul "rebuild" bearings, which are +0.25mm on the OD and -0.50mm on the ID. That is the only size those are offered in. My last experience with cutting a crank didn't go well, so I'm no wild about those. Owing to the change of shape of the main bores, I'm wondering if I need to get mine line honed with the heads on. I did that on the '93 block by skim cutting the lower crank case. The surface finish on the top of the '06 lower crank case is VERY coarse... I wonder if this has anything to do with GM's swap to RTV as the sealant of choice for the case halves, although this block still had GM's case half seals.

Anyway, since a solution wasn't forthcoming there, I bought this: https://www.ebay.com/itm/133340495195
It's what I was looking for in the first place, but it wasn't listed when I started looking... besides, seeing how the '06's worked in different ways would have been harder without taking one apart. At least that's what I'll tell myself as I pay the credit card bill.

EJC Performance is an interesting outfit... they do business with a bunch of junk yards around them, taking damaged engines that the yards can't sell as running engines, then breaking those down into major components (blocks, cranks, cylinder heads) to sell. They have stuff from a whole lot of MFGs covering US, Japanese, German and whatever else. Sometimes the engines they get have damage as light as a cracked oil pan, but the yards just don't want to mess with them. EJC also scraps damaged components (spun bearings, etc.) as their business model is to sell usable parts and not have come-backs. I found their website and called them. The guy I spoke to actually went to the block on the shelf while I was on the phone and looked at it for me. No scoring or pitting, just normal wear. Decks didn't look like it had a head gasket problem. I threw down. He said they ship Duramax blocks freight, but the Northstar block would just go UPS ground, which is also pretty wild.

I'll still go to Promar to have the bores honed, but may have it line honed locally... WITH the heads bolted on. I need to get the lower crank case decked a smidge, but prototype guy is trying to invent himself as an engine machinist, so I'll let him take that on.
Will MAY 05, 11:13 AM

quote
Originally posted by eph_kay:

Will, I’m gonna shoot you my info, I will want to talk more, I was planning to adapt one of the super chargers from a 4.4, and just got it in the mail today actually, but I will want to talk about other details too

Thanks for the help so far

Chris



Received; will respond.
sourmash MAY 05, 06:45 PM
It has to be an '06? Is that due to the head bolts needed for the heads you're using? And its the FWD block you're using?
Will MAY 06, 10:13 AM
The '06+ has the crank sensor in the valley to work with the 58x trigger wheel.
The early heads have better balanced port flow for N/A performance, and bolt to the later block using the 11x2.0 head bolts with the addition only of the spacers I showed. I also have reground cams for the early heads, which are not available for the roller cam heads.

Yes, everything is FWD. The RWD waterpump and VVT actuators would be tough to fit in a Fiero.
Will JUN 03, 10:51 AM
The Colorado block arrived... I spent the prior weekend deburring, porting the bay-to-bay breathing windows, had it cleaned at the local basic rebuild machine shop during the week, then shined it up last weekend.













Right now it's at the local custom gun shop getting Cerakoted.

My plan is to have the local race shop line bore it with the heads on, going for minimal change to the crank centerline, then take it up to ProMar in Jersey to have the bores honed and inserts installed. I'm not sure if I'll have the race shop or ProMar clean up the decks.

Then I can assemble the short block!
Will JUL 16, 11:36 AM
I was playing with the Cerakoted block last weekend... I'm seeing some weird **** .

I torqued up the bottom end and measured the main bores.
Then I bolted on the heads and measured the main bores again.
Then I split the bottom end, installed the replacement bearings, retorqued the bottom end and measured the bearing IDs.

I pulled the new set of Clevite bearings out of the box and found that the shrink wrap had ruptured and the bearings had been banging eachother up in shipment for who knows how long. They looked like they'd been media blasted in places. I polished them carefully on a veratex wheel, then cleaned and installed them. They measured out weird with a bunch of out-of-round and poor consistency from one to the next.

In looking at the numbers, I see that the Colorado block main bores are ~0.002 larger than the rusty bore block main bores in which the bearings ended up at -0.0025 main clearance. I figured that was a step in the right direction, so I split the bottom end again, installed the coated bearings and measured them. They still come up with negative bearing clearance, but it's improved from -0.0025 to about -0.0012... which is effing weird, because that's an '06 block and '06 crank... why are the bearings coming in like that?

Between the beat up set and the coated set, subtracting the bearing ID from the bore ID gave me a total shell thickness number. This is 0.3164 for the beat up bearings and 0.3170 for the coated bearings, so there's not enough variation between the bearing sets to account for the delta in bearing ID.

Once I had installed and measured the coated bearings in the Colorado block, I pulled the heads and measured them again.

I need to bolt up the bottom end on the '93 block that came out of the car and see WTF it does. I took those measurements when I built that engine, but they didn't get into my Google drive, so I may not be able to find them now. I need to check for the hard copy notes in my filing cabinet.

I also need to measure the thickness of the factory bearings that came out of the rusty bore block to see if they are different from my coated Clevites

//

When I measured the rusty bore block with and without heads, the average main bore and average out of round each increased by 0.0001. The average out of round increased from 0.00026 to 0.00038, which seems a little high.
In the Colorado block, the average main bore increased by 0.0001 and the out of round was consistent at 0.0001.

The rusty block deltas are barely worth considering and the Colorado block numbers are in the noise, so I no longer think that the mains should be bored with the heads on. If the situation evolves to the point of boring the mains 0.002 to get the bearing clearances right, this will be handy knowledge.

The average main bore in the rusty block is 2.8523 and the average main bore in the Colorado block is 2.8542. Both blocks are 2006 units. 0.0019 difference seems like a lot of variation in what should be a very consistent and precise feature.
Will JUL 16, 11:52 AM
Oh wait... I just compared the journal ODs of the cast crank that came out, the forged crank I bought new and the forged crank that came out of the rusty bore block. The crank from the rusty bore block came out at 2.5385 average, while the new forged crank and old cast crank came out at 2.5335 and 2.5338... so my used crank, that came out of a running engine is 0.005 larger than the other cranks.

That's fishy... I need to go back and make sure I didn't blow those measurements by reading the mic wrong.
Will JUL 17, 10:13 PM
I'm reasonably lucky that I have access to this place to work on precision stuffs.



Coated block:



The luster of the surface is "deeper", like it has been clear coated, but that does not show up well in photos. The whole coated surface of the block looks like this... you can see that the side of the cylinder and the head bolt boss tube looks "wet", like it has a sheen of oil... or has been clear coated. That's the coating. That a surface has been coated is immediately obvious to the touch. The coating is hard, very smooth, and actually quite slippery. I need to evaluate what the coating looks like under the heads of the "outside" crankcase to block bolts.



Mic'ing a whole lotta bores...



Valley as I was putting the (ugly, filthy) heads on my bright shiny block



Forged crankshaft with RMS weighs 50.25#, so the bare forged crank should be right at 50#.

[This message has been edited by Will (edited 07-20-2020).]

Will JUL 19, 04:16 PM

quote
Originally posted by Will:

Oh wait... I just compared the journal ODs of the cast crank that came out, the forged crank I bought new and the forged crank that came out of the rusty bore block. The crank from the rusty bore block came out at 2.5385 average, while the new forged crank and old cast crank came out at 2.5335 and 2.5338... so my used crank, that came out of a running engine is 0.005 larger than the other cranks.

That's fishy... I need to go back and make sure I didn't blow those measurements by reading the mic wrong.



My prior cranks were 2.533x on the mains. I thought the used forged crank I'd settled on using was 2.538, but it's actually 2.533. I asked the racing machine shop guy to put a mic on the crank; he called me back Saturday with the results.

So when I measured that crank, I had just finished measuring the main bore IDs in one of the blocks. Since those are 2.85XY, I was reading X off the mic barrel and Y off the vernier. I then went to the crankshaft and instead of reading 2.525+.00XY, I read 2.53XY... So I got 2.538 when I should have gotten 2.533.

So there are actually zero problems there.

HOWEVER, that means my main clearance is 0.0035ish... which is not horrible, but definitely on the wide side. Now I'm looking up bearing build-up coatings...