Northstar rebuild: Will style (Page 25/119)
Will JUL 28, 10:26 PM
Drilled the oil manifold drain back holes today. Used the lower crank case as a template and just ran the drill through on a press. All the holes in the manifold can be safely enlarged to 9/16", but the one immediately forward of the oil ports on the left side of the engine is VERY close to the seal... probably only 0.020 away...

Tomorrow evening I'm going to get it clean enough to bolt the bottom end together and measure the main bearing ID's with the new bearings. The clearances were too wide with the old bearings so I ordered another set, as well as a 0.010 under set if necessary. Alan Johnson likes to see 0.0023 to 0.0025 clearance on all bearings, main and rod. It would be an absolute shame to turn that carnk though... it's absolutely pristine and within 0.0002 of spec on all journals with basically no out-of-roundness at all... after 100,000 miles.

Damn I love working on Cadillac engines.

Will JUL 28, 10:33 PM
Sealed Power at one time made rings for a 262 Chevy, but that set has been discontinued.

Hastings, however, makes a 1/16" racing piston ring in that bore size. They also have a standard cast 2nd ring as well. Hastings is the OE supplier for Cadillac oil rings, so I went ahead and ordered their oil rings as well.

Since the Northstar uses 1.5mm rings with 0.135 radial depth, and the Hastings rings are 1/16" with 0.166 radial depth, I have sent the pistons (along with the rings) back to Ross to have the grooves re-cut for the wider, deeper rings.

Should get them back in the 2nd week of August.

Erik JUL 29, 10:14 PM

quote
Originally posted by Will:

The '99 and older N*'s use a direct acting hydraulic bucket tappet. The Y2K and newer engines use rocker arms with rollers and the hydraulic lash adjusters in the cylinder head itself. Overall it should be a reduction in valvetrain mass and friction.


The cams are different as well
Will JUL 30, 12:12 AM
I had hoped it would be pretty obvious that different cams would go along with conversion from flat tappet to roller lifter
Erik JUL 30, 12:15 AM

quote
Originally posted by Will:

I had hoped it would be pretty obvious that different cams would go along with conversion from flat tappet to roller lifter


I just realised it when i was comparing my 97 motor and my "supposed" 99 motor. Apparently its a y2k so I am kind of upset that I cant swap cams if I wanted to

Will JUL 30, 05:31 PM
After dorking around with my block all morning, I've decided to have it align honed.

The front four main bores and bearings vary from 0.0002 to 0.0005 out of round. Thanks to an incident with flywheel bolts too long, the rear main is 0.0013 out of round. Numbers 5 and 4 are also tapered about 0.0004.

The clearances vary from 0.0034 to 0.0038, which is WAY too wide. Alan Johnson recommends 0.0023 to 0.0025, which I think is still a bit wide. I'm going to call him and ask him about that.

I could fix the clearance and out of round of #'s 1-4 with 0.001 shim under the lower insert...
But #5 is just too hosed to be fixed that way, so I'm going back to the machine shop with it. Might be breaking new ground align boring this engine, as it doesn't have conventional caps. I might end up doing some of the work myself--clamping the lower crank case in a mill and skimming a couple of thou off the top in order for the shop to finish with the boring.

Will SEP 09, 11:16 AM
Block is still in shop for align bore.

Rings are coming back to me. I will be hand lapping them to get the thickness tolerance where I want it, then the rings and pistons will go to Ron Baxter at Rebco in Kansas to have the grooves cut with .0001" flatness tolerance.

Just need to find a free weekend to spend on setting up the crank for balancing.

Does anyone know how to get in touch with Hank the Crank (HTC)?

[This message has been edited by Will (edited 09-09-2005).]

Will SEP 13, 03:58 PM
I was just reminded that we have a surface grinder... I'm going to save what I've learned from this build for the next, and go ahead and use the Ross grooves, in the interest of getting it together sooner and cheaper.
Nashco DEC 06, 01:22 AM
Any update on this? Sorry if there's another thread or something, I rarely have time to hang around here anymore.

Bryce
88 GT

Nashco DEC 08, 09:30 PM
Has anybody heard from Will? I sent him a PM with no response.