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Topics - COPOZ/28

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1
Maintenance / 302 Z28 Divorced Choke Rod Adjustment
« on: January 28, 2024, 12:01:05 AM »
The '69 Chevrolet Service Manual provides information on how to adjust the divorced choke rod on Z28 302's (and other Holley 4 barrel equipped V8 engines) on pages 6M-3 and 6M-7.  As written, the procedure is unclear.  On page 6M-3 it says:

    "On all engines except L6 and 2 barrel V-8 engines, hold the choke valve closed and push the rod downward to contact stop -- the top of the rod should be even with the bottom of the hole in the choke lever.  On L6 and 2 barrel engines, hold the choke valve closed and pull rod upward to end of travel.  The bottom of the rod should be even with the the top of the hole in choke lever."

There is no specific reference to Holley 4 barrel equipped engines in the 6M-3 page write up.  Therefore, should the choke rod be adjusted (bent) in the same manner as the above description for the L6 and 2 barrel engines, so that the bottom of the rod is even with the top of the hole in the lever?  I ask this because the 302 choke rod operates similarly to the L6 and 2 barrel engines -- namely, the choke rod is pulled upwards to hit the end of its travel.

Then, on page 6M-7 it says:

    "With Rochester 4MV and Holley Carburetors, install the choke rod and adjust as necessary.  Be sure choke valve moves freely from full open to full closed position."

I assume the instruction on page 6M-7 refers to the procedure on page 6M-3 which, unfortunately, does not mention Holley 4 barrel equipped engines.

Is the L6 and 2 barrel V8 procedure the correct choke adjustment procedure others have used on faithfully restored 302's that results in clean starts when the throttle is pumped just once to set the choke, without having to pump the throttle multiple times, before turning the key to start the engine? 

If anyone can shed more light on this maintenance/adjustment procedure for 302 z28's , I would be very grateful.

2
Does anyone know where to obtain the thin, stamped "guide" (or support) that go onto the ignition coil + and - primary terminals?  If I recall, GM used these items on each terminal of the ignition coil for most of their cars from the mid '50's thru the '70's.  These "guides" are the first thing that go onto each coil terminal, followed by the negative wire (from the distributor) and the positive wire (from the harness), and then followed by the #10-32 nut and lockwasher.  These "guides" were made from thin sheet metal (~ 0.020" thick) and had two opposite ends turned up as flanges (about 0.035" high).  These two upturned flanges on the "guide" served to prevent the legs of the wire harness terminals from spreading apart excessively when tightening the #10-32 nut.

I've tried AMK Fasteners and various restoration parts suppliers of replacement coils and they do not have these "guides".  Any help would be appreciated.  Thanks.

3
Originality / 1969 Z28 302 Engine Oil Dipstick Tube Orientation
« on: March 14, 2022, 08:09:41 PM »
There is information on the orientation of the oil dipstick tube in the block published in my copy of the '69 A.I.M. (in UPC 6, Sheet B1). It shows the curved portion/dipstick handle pointing forward and slightly outboard per a notation in View A that reads: 7 deg's, +/- 5 deg's, or roughly towards the left front headlight.  However, I've come across many underhood photos of  supposedly original cars that show in most cases the tube is oriented nearly vertical, such that the upper end of the tube is positioned between the cylinder head and the air pump distribution tube assembly.  Could this be one of those cases where it doesn't really matter how it is oriented as there are many documented examples showing a variety of orientations?

Thanks for the help.

4
Maintenance / Head Gasket Steel Shim Style
« on: February 24, 2021, 09:08:03 PM »
This is a head gasket preparation question.  I've received all my OEM '69 302 parts back from the machine shop and the block decks required about 0.008" to clean up, with the resulting deck height coming in at 9.011".  For head gaskets, I can choose between the modern Fel-Pro 0.038" composition part, the Chevy p/n 10105117 0.028" composition part, or the '69 OEM 0.016" steel shim part.  Knowing a tight piston to head quench distance (i.e.: "squish") of 0.036"/0.038" helps to fend off detonation, the 0.016" steel shim gasket gets me to this nice 0.038" squish, but the final actual compression ratio comes out to 11.08:1.  Stepping up to the thicker 0.028" Chevy '117 gasket drops the true CR down to 10.8:1 but increases the squish to 0.050".  Since I have used (and plan to continue to use) ACES IV mixed with 93 octane fuel successfully, I believe I can tolerate the 11.08:1 CR the steel shim gasket gives and plan to use it for this assembly.  My question has to do with how best to prep the "old fashioned" steel shim head gasket to avoid long term future coolant leakage.  Back in the day, the only steel shim head gasket prep I am aware of was spraying a light coating or two of aluminum paint on each side of the gasket, letting it dry and then installing/torquing the heads, followed by a retorque after it's first hot start/cool down.  I've heard of some folks laying on a very thin coating of Perma-Tex Gasket Maker (p/n 51813) around the gasket's coolant holes in addition to the aluminum paint spray.

What have others found that work long term for prepping the old style steel shim head gasket?  Thanks a bunch!

I forgot to mention all the "internals" are OEM '69 302 -- the cam, pistons, intake, carb, etc.
Chuck B.


5
Decoding/Numbers / Oil Pan Ident/Date Code Stamping?
« on: April 04, 2020, 11:24:15 PM »
While in the process of refreshing the 302, I stripped the paint off the oil pan and discovered these characters - 2252W, located on the underside of the pan, about 2" back from the front face of the pan.  Does anyone know what this code refers to? 

6
General Discussion / Block Search -- ebay Advertiser
« on: March 30, 2020, 08:06:17 PM »
Is anyone familiar with this ebay advertiser?:  thegmparts <thegmp_mu3847nffg@members.ebay.com>

In my search for an appropriately date coded block to replace the '010 CE/NOM in my '69 Z, I've made contact with him -- Gregory is his name.  He's located in Angola IN and apparently has been servicing the Corvette/Camaro guys with his blocks, engines, etc for many years.  When I called and asked him about a casting date coded block I was looking for, he stated he currently has a couple appropriately date coded '010 block that would go with my mid-May '69 POP date.  He also stated he has correctly gang re-stamped blocks to match both the POP code and VIN stamp for many collectors around the country.  Not sure I would go that far, but I would like to know what the "skinny" is on this fellow and if he's an honest businessman who represents his products legitimately.  Thanks.

7
Decoding/Numbers / Block Casting '010 -- 1969 vs. 1979 Casting Date
« on: March 30, 2020, 04:07:40 PM »
Since the 3970010 block casting was used from 1969 thru 1979 or so, is there a definitive way to determine if a 3970010 block casting with date code of E-9-9 is a 1969 block and not a 1979 block?  Are there other cast-in features or numbers that will prove it is a 1969 block?  I'm about to drive 200 miles to look at a 4-bolt block and would like to know how to confirm this E-9-9 date code '010 block is actually a '69 casting.  The deck and oil filter boss stampings (engine code/VIN) might have been altered, so that isn't going to be a guarantee.  Thanks.

8
Garage Talk / Chevy II / Nova Forum -- Orphans Category
« on: March 23, 2020, 03:10:09 PM »
Does anyone know of a Chevy II/Nova forum that has a section dedicated to "Orphans", like the CRG has?  I'm asking because a friend has a VIN stamped M21 that belongs to an early Nova and together we're trying to find the car's current owner.

Thanks.

9
Maintenance / Grease for Hurst Shifter
« on: March 12, 2020, 07:39:05 PM »
Have my '69 Z's OEM Comp. Plus shifter disassembled and flushed clean of all grease -- and there was quite a bit of it present.  I left the pivot lever and springs assembled but did drive out the two roll pins to allow the plunger to be removed for cleaning/inspection.  Before re-assembling the shifter, I checked various sources to see if there was a recommended grease to use to pre-lube the components, including the Holley/Hurst website, but couldn't come up with anything definitive for the proper grease.  Given how much grease was still present after all these years, but only about 20,000 miles, it's obvious these shifters were well greased by Hurst when shipped to Norwood/LA.  My post-teardown inspection showed next to zero wear on all the lever plates, divider shims, pins, etc.  I'm reluctant to try some of the suggested lubes I came across in my search (such as dry film spray, wheel bearing grease, PAM -- yes, PAM!, etc).  Given the nature of the shifter mechanism, with the sliding of mating parts involved, I'm guessing a conventional, heavy bodied moly infused EP grease would fit the bill.  What have others used?  Thanks.

10
Decoding/Numbers / Help With Spare Wheel Code
« on: March 06, 2020, 10:53:41 PM »
The spare wheel in my 05E  '69 Z, inside a never-been-on-the-ground Sport Car 200 tire (which doesn't really prove much), has rim stamping code that is clearly "K-1-8 7 24 FW", although the "W" looks much like an upside down "M".   From older posts, I gather the "FW" code wheel is a '71 and later Chevelle & Monte Carlo wheel.  If this is true, how do we explain a July 24, 1968 date with an "FW" code?  Having spent 30+ years working for that other "C" car company and crawling all through their many assembly plants, I know first hand that almost anything is possible with parts being flown/trucked all over the country in emergency part shortage situations.   But it doesn't explain the 1968 date code on an FW wheel.  I'm confused!  The photos I have of the tire and wheel were too large to include in the post but I can attach them to an email if anyone would like to see them.  Thanks.

11
General Discussion / Original 302 TRW 11:1 Piston Dome CC's
« on: March 04, 2020, 11:46:20 PM »
Has anyone gone through the labor intensive process of measuring the cc's of the original TRW forged '67-'69 302 piston dome cc's?  If my memory serves me (as well as it does as I plunge headlong towards  age 70!), the dome on these pistons displaced 10.0 cc's.  Is this correct?  Thanks.

12
General Discussion / CE Block Documentation
« on: February 25, 2020, 05:04:07 PM »
Hi All,

As a newer member of CRG I've been reading a number of CRG posts these last few weeks to get familiar with the forum and the depth of knowledge many forum members have and I have to say I am very impressed with the content on this site and the professionalism of everyone.  I'm hoping there's someone in the forum who can provide some help regarding the CE block in my car.

Some years back, I sent the intake manifold from my '69 Z to Jerry M to weld/repair the right rear corner that had a collapsed bolt hole, which he did beautifully -- the repair matches the surrounding casting perfectly.  In that correspondence with Jerry I mentioned the 1st owner of the car had the block/fitted pistons replaced under warranty in 1970 due to a loose wrist pin retainer scoring a bore.  I also mentioned that the 1st owner did not save a copy of that warranty repair order (WRO) even though he saved almost everything else in the 10 years he owned the car.  I am the 2nd owner, having purchased the car in 1979.  Compounding the "originality/documentation" issue with my car, the 1st owner decked the replacement block shortly after getting the car back from the dealer in 1970 to prep the engine for amateur drag racing, thereby removing the CE stamping.  I mentioned to Jerry that I had managed to successfully contact an attorney in Chevrolet's Office of the General Counsel in 1980 and inquired about receiving a copy of that specific WRO and why it was important to me.  The attorney assured me that the WRO in question is definitely in Chevrolet's microfilm records but corporate policy prohibits him from printing and sending me a copy of it.  My offer to treat him and his wife/S.O. to dinner at any Detroit area restaurant of his choice was to no avail.  Jerry, having heard all this, suggested I look for a block with a casting date code that precedes my 0513 engine build date.

So, here I am today, not having pursued Jerry's suggestion.  Instead, the only "documentation" so to speak that I have is a signed and notarized letter from the 1st owner stating the block was replaced under warranty in 1970 and that a copy of the WRO paperwork was not saved by him.  The casting date on my replacement '010 block is D-14-0, 11 months after the original engine's build date. Ethically, if I had my 1st choice, I would prefer to have a copy of that WRO in hand as that would represent what the world of Chevrolet/Dealer did to the car, but it would appear that is impossible to obtain, unless Chevrolet is more willing these days to accommodate enthusiasts/collectors.  This is opposed to finding a representative casting date block and having someone take that block that has no meaning or relationship to my car and "create" what would appear to be the original CE block stamping or even the "born with" block stampings and then transferring my original engine parts to it.

Other than sympathizing with my situation (which would be appreciated nonetheless), is there any wisdom/advice anyone of you might share with me?  Has anyone had success contacting Chevrolet and obtaining a WRO or other such records?

Thanks,
Chuck

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