WAWUZAT Northstar build thread (lots of pix) (Page 3/16)
ryan.hess MAY 01, 11:54 PM
You should smooth out those windage holes while you've got the block on the stands... I think Will has pictures somewhere. That's like +10hp for free.
WAWUZAT MAY 02, 09:06 PM

quote
Originally posted by ryan.hess: You should smooth out those windage holes while you've got the block on the stands... I think Will has pictures somewhere. That's like +10hp for free.


Ryan - Ya' made me go look! I did find the pix of the windage hole mods Will did on his block. While I can appreciate the purpose of rounding off those edges, I have my doubts that it's worth 10 HP ... 2 to 4 maybe, but 10? I'm also at a point where I'd have to reclean a lot if I attempted that mod now.

FWIW in the area of additional ponies, I will be doing some minor porting work on my cylinder heads. I'll contour the exhaust ports to a D-shape as shown in an earlier photo, but will not remove much from the runners. My goal is to D-shape the exhausts, knife-edge the splits between the valves, and then only smooth the cast surfaces. I think I read somewhere that CHRF removes almost 0.100" all around from the ports.
WAWUZAT MAY 03, 08:56 PM
Ryan - It now looks like I'll get the chance to deburr those edges on the windage holes. Read on ...

Tonight I was all ready to assemble the bottom end. New main bearings, crankshaft, crank case, and seal it up using information from AJxtcman's TSB document (use a GM sealant in lieu of gaskets). I had all the parts, bolts, and wrenches laid out in an orderly fashion. Also had a cardboard template pre-cut for torquing the main bolts. The GM manual calls for 15 ft-lbs first pass, followed by a second pass of another 65-degrees ... on all twenty main bolts. In lieu of a single pass at 65-degrees, I opted to make two passes at 32.5-degrees each ... a total of three passes over the tightening sequence.

Here's the lower crankcase ready to go ...


Here's the oil manifold with black RTV sitting awhile to allow the sealant to "skin" ...


Here's the block with the crankshaft in place, sitting on new bearings with a coating of assembly-lube ...


Then this happened !!! Caused me to use the French translation for "Darn it!"


Here's another shot ...


Months ago, I posed the question in this forum about inserts for the main bearing bolts. It just seemed like a logical progression if one installs inserts for the head bolts, that one should also do likewise for the mains. I was assured by some (will leave their names out of this post) that installing main bolt inserts was rarely, if ever needed. Looks like I found the need.

Anyone have any inexpensive sources before I go inquiring at a GM dealer? The manual says I'll need insert package R1084-10-20, insert length of 29.5mm, tap #2093-10, and insert tool 3747-10.

[This message has been edited by WAWUZAT (edited 05-20-2007).]

AJxtcman MAY 03, 09:35 PM
I have never had that problem. I have seen one repaired out of say 500 or so.
ryan.hess MAY 03, 09:55 PM
I would say you just got (un)lucky

Timesert sells the kit for it. Copy the part number and do a search on ebay for it. You might get lucky again.
WAWUZAT MAY 05, 09:27 PM
The Timesert kit is advertised for about $300 ... way too much $$$ for inserts that do not impress me much. Even if I did find a good deal on them at eBay, I'm reluctant to buy them. I already have the NS300L inserts installed in the head bolt holes, which means I already have all the tools on hand to install inserts with the same external thread (external thread is 5/8" x 11 TPI). I'll have a machinist friend of mine make me some shorter inserts with M10 x 10.5mm internal threads, then drill and tap the block to install those. Being that they're replacing aluminum threads, I would think that I could make the new inserts from Grade 2 threaded rod.
WAWUZAT MAY 06, 07:46 PM
Ryan (and anyone else that's interested) - I got the block apart again this weekend, AND did the bay-to-bay window deburring treatment today as was discussed on page 6 of Will's N* thread ...
http://www.fiero.nl/forum/F...2/HTML/044924-6.html

I did not break out the carbide deburring tips and pneumatic die grinders. All I did was run some strips of emory cloth through the holes to round-off the edges. Also used a small rat tail file to get at some edges. I believe the advantage of the rounded edges is to allow oil to weep down the walls easier, without accumulating inside each "window ledge" to eventually meet with a fast turning crankshaft. With the sharp edges removed, it's less likely the oil will experience liquid adhesion in close proximity to the crankshaft.
WAWUZAT MAY 08, 09:24 PM

quote
Originally posted by WAWUZAT:I already have the NS300L inserts installed in the head bolt holes, which means I already have all the tools on hand to install inserts with the same external thread (external thread is 5/8" x 11 TPI). I'll have a machinist friend of mine make me some shorter inserts with M10 x 10.5mm internal threads, then drill and tap the block to install those.



Well, I changed my mind after checking some dimensions, and decided against a 5/8-11 external thread. I'm going with a 9/16-18 external thread. First I looked at several aspects of the lower crankcase & block.






One thing I noticed is that the cast oil passages around the main bolts are not centered with the bolt hole.


So out comes the Dremel tool and an appropriate bit for the task. This little bit of surgery is done so the 1/2" drill bit will not get hung up on the sides of the oil passages, and will allow the drill bit to stay centered.


Actually, I drilled the holes open in three passes ... first with a 3/8" bit, then a 7/16", and finished with a 1/2" bit. Drilling the holes in steps allowed for much easier self-centering of the bits. Here's a shot after the first pass with the 3/8" bit ... barely removed the threads. You can also see my "poor man's" drill-stop (tape wrapped around the bit).


And here's a shot after the last pass with the 1/2" bit ...

[This message has been edited by WAWUZAT (edited 05-08-2007).]

WAWUZAT MAY 08, 09:31 PM
Before running the 9/16-18 tap into the holes, I need to make a guide block so the tap will remain square with the surface. Since I was finished using the guide block that came with the NS300L head bolt insert kit, I opened up the smaller hole in that block to 9/16" diameter.


Here's the guide block in use while tapping ...


And the guide block comes in handy as a small square to ensure the tap is going into the hole at the correct angle ...
WAWUZAT MAY 09, 09:06 PM
Finished tapping & bottom-tapping the main bolt holes tonight. The inserts should be in my hands early next week. So the next step is to roll this block outside, spray some degreaser on it (and in it), hose it off and blow-dry with compressed air. While waiting for the inserts, I can start making my own tool adapter to use with a valve spring compressor. I need to get the heads disassembled so I can do some minor porting work. Removing N* valves looks like it can be a tedious task. I tried to buy the GM tool adapter, but was told it's not available.