Z28tt Project: April 2006 Archives

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April 28, 2006

3 link measurements, night one

One of the constraints to fabbing the 3 link is the gas tank directly above the rear axle. With the axle at ride height (car on jackstands, front frame and Ford 9" rear axle), there is about 5-6" clearance directly above the back edge of the rear axle tube, but this increases towards the middle for pumpkin clearance. The distance from the bottom of the rotor to the ground is 15.375" on both sides.

Next, time to set the rear jackstands on the frame, and remove the springs so the axle can be moved through it's full range of travel. The bumpstops have been removed, but the previous travel was 3.375" until the bumpstops touched the top of the axle tube. They were about 2.5" thick. Bottom of the rotor is 17.75" from the floor at full bump, which is 2.375" of bump travel.

The clearance at full bump is 4.5" (6.25" from axle horizontal centerline, and about 30" from the concrete floor) from the top of the axle housing (about 8" right of center) to the bottom of the gas tank. Clearance goes up to about 6" at the middle of the housing.

Approximate length of the center of the rear axle to the roll bar hoop is 20".

Posted by Z28tt at 11:06 PM

CCW rim specs

17x11 Rear, 8-3/8 Backspacing, 12-3/8 Total width with sidewall bulge
17x10 Front, 7-1/2 Backspacing, 11-1/4 Total width with sidewall bulge
Originally for a C5 Corvette

Dbl spacer (.140 each) still too tight, leaves 3/16" clearance against trailing arm.

With one washer and two plates, it barely clears the top. 7/16" total. This has 5/16" clearance to edge of wheelwell.

Need:
9/16" thick spacer
5x4.75" Bolt Circle
70.3mm centerbore, at least .350" deep
70.7mm wheelcentric lip (verify with CCW)

Specs from CCW, if they are the T1 race wheels
2.785 centerbore
Non-stainless hardware (gold colored coating) with nuts on the outside
Wheel halves welded together
Front - 17x10, 7.5" backspace, 50mm offset, 18 lbs
Rear - 17x11, 8.25" backspace, 56mm offset, 19 lbs

Posted by Z28tt at 2:58 AM

April 27, 2006

Sealing the intake rocker studs

The plugs have always been a little oily, so in the quest to cure that, I'm sealing the intake rocker studs with Permatex Aviation Form-A-Gasket sealant liquid, also know as 3H.

With a firing order of 18436572, you can lash:
0 Deg, 1 TDC - 1, 2 & 8
180 Deg, 4 TDC - 8, 4 & 3
0, 6 TDC - 3, 6, & 5
180, 7 TDC - 5, 7, & 2

Tools needed: 7/32 allen key and 5/8" wrench for the Comp ProMagnum rockers, deep 11/16 socket for 7/16" rocker studs

Rocker Stud torque is 55-60 ft-lbs.

Posted by Z28tt at 11:56 PM

Distributor gear shims

The old HEI distributor has about .040 vertical play, so I'm on a quest to find some shims to take out some of the slop. The existing shim has an OD of .982", and the shaft OD is .425"...

Posted by Z28tt at 4:21 PM

April 26, 2006

Saginaw M16x1.5 power steering fitting

The oring for my power steering box was lost in transit. Finally found someone (in Eaton industrial fittings) that was able to find specs on that o-ring. Earls cross referenced it to their -3 o-ring, which is part number 176003. The Parker number is 3-903 N0552 for NBR rubber.

From McMaster-Carr:
Part Number: 9751K113
SAE Specification SAE J200
AS568A Dash Number 903
Type O-Ring
Cross Section Shape Round
System of Measurement Inch
Width .064"
Inside Diameter .301"
Outside Diameter .429"
Material Buna-N
Buna-N Type For Boss Tube Fittings
Fractional Tube Size Outside Diameter 3/16"
Durometer Extra Hard
Durometer Shore Shore A: 90
Temperature Range -35° to +250°F
Color Black
Specifications Met Society of Automotive Engineers (SAE)

Posted by Z28tt at 1:01 PM

April 25, 2006

Rear axle bearing specs:

Bearings from Moser Engineering (260.726.6689):
9508T Big Ford & Olds/Pontiac Ball Bearing
1.562 ID x 3.150 OD, with O-ring
Green Bearing Company, RW508ER1562 A1021A

Axle ends shown on p.4 of Wilwoods brake install manual:
www.wilwood.org/ds113.pdf

The flange dimensions are close to the Chevy bolt pattern, in the above link.

O-ring on bearing goes toward outside of flange.

Posted by Z28tt at 10:56 PM

April 23, 2006

April 5, 2006

Valley drain back testing

Today Mark & I tried a few different oiling tests... First we just spun the oil pump with an old distributor to see how much oil flows through the heads and lifters - not too much with cold 20W50. Next we disconnected the -12 feed, and had that dump right into the valley. Than pan pumped dry quickly, and then started pumping aerated oil spurts. We noticed the oil drained through the Moroso valley screens much faster when the pump was moving, creating suction in the pan. Otherwise it was fairly sluggish, taking a minute or two to drain down, filling the valley with about 1/2" deep oil. Blowby pressure probably does the same thing. Final test was pumping the oil through two -4an lines into to see how much that flows. The oil was already partially aerated, so the dense fluid emptied from the pan fairly quickly. We're just going to put the intake manifold on, and see how much of a difference the .125 restrictors make. If that doesn't help, next step is to remove the valley screens.

Posted by Z28tt at 4:25 PM

April 4, 2006

Measuring the oilpan

We're reassembling the engine tonight, and did a few more measurements on the Canton pan. The side kickouts are about 2.5" deep as measured at the bottom of the pan. The bottom of the windage tray is 3.375". We measured the oil level at 2.5" in the pan, and it came to about 2.75" on the dipstick. The dipstick is notched at 3.625, which corresponds to just above the bottom of the windage tray.

For future - the dipstick is loose, and must be tightened before running the engine.