Messages

1

Restoration / Re: Heater Hose Routing 69 Z28

« on: December 28, 2024, 10:16:19 PM »

Many thanks to GMAD_Van Nuys for posting the link to the earlier "heater hose clamp/alternator bracket" post -- it was quite informative.


It would appear the AIR pump hose is supposed to route between the two heater hoses.  On the other hand, the use of the alternator bracket mounted heater hose clamp beyond the April '69 timeframe remains an open question for discussion.  I've owned my Norwood 05E, offline ~6/2/69, '69 Z so long (am 2nd owner since Nov '79), I simply can no longer recall if that heater hose clamp was on the car when I acquired it or if I added it, thinking it should be there on every '69 Z28 because I saw it in an underhood photo.  Based on the info in the earlier post, I would have to guess it is more likely that I added that clamp myself at one time.


Thanks to everyone who chimed in  -- much appreciated!

2

Restoration / Re: Heater Hose Routing 69 Z28

« on: December 27, 2024, 03:54:27 PM »

Good magazine road test photos.  It's interesting that the August '69 photo (without the heater hose clamp) shows a plastic strap securing the alternator wiring to the 3/4" heater hose, while the January '69 photo (with the heater hose clamp) does not show this plastic strap.  This is just another indication of my years of experience working in the automotive industry that proves anything can and likely has happened in a vehicle assembly plant.


Although neither photo is definitive in the routing of the AIR pump hose, it leaves the door open to the possibility that it is routed between the two heater hose, rather than behind (rearward) both hoses.  Any chance there is a photo in your collection of such '69 Z28 road test photos that would allow one to draw a conclusion for the AIR pump hose routing?

3

Restoration / Heater Hose Routing 69 Z28

« on: December 23, 2024, 05:58:25 PM »

On 1969 Z28's, does this photo show the correct orientation of the heater hoses in the hose support clamp attached to the alternator bracket?  Specifically:


1.  Should the 3/4" hose from the water pump be positioned in the hose support clamp in front (i.e.: closer to the alternator) of the 5/8" hose to the intake manifold?  I believe that is the correct routing through the hose support clamp.


2.  Should the hose support clamp on the alternator bracket be bent downward a bit to give some clearance to the AIR pump hose as it traverses from the driver's side AIR pump check valve to the diverter valve on the passenger side?


I have been unable to locate a clear graphic of this issue in the '69 AIM that confirms the correct hose/support bracket condition.


I've found that the AIR pump hose will be deflected rearward, into the ZL2 air cleaner (not shown),[size=78%] [/size]by interfering with the 5/8" heater hose if the heater hose support clamp on the alternator is NOT bent downward.  But, if the support clamp is not supposed to be bent down, then the AIR pump hose assumes a more "natural" routing if it is positioned between the two heater hoses, rather than behind both hoses.


I would appreciate any thoughts on this.  Thanks.

4

Originality / Re: Fuel Tube Support Bracket 3959444

« on: December 11, 2024, 11:10:14 PM »

Thanks, Kurt, for providing that link.  I chased my way completely through it (and another linked imbedded therein) and came to the conclusion my late 05E car, with its VIN that calculates out to be an "off the line" date of Monday, June 2nd, may or may not have had this clip installed at Norwood.  So this is an easy decision for me -- I can look for a $500+ original clip, or do nothing and be correct.


Having said that, and being a retired chassis development engineer for one of what we use to call "The Big 3", I went right out and bought the $22 repro bracket the moment I discovered it in the '69 AIM.  In my experience, the right type of vibration (frequency and amplitude), for a sufficient amount of time, can loosen any joint, no matter how expertly tightened or how perfect (or imperfect) the mating parts are made.  Given the significant mass of the brass Y-block hanging several inches off the carb, I can see why the Chevy chassis engineers developed and released this support bracket for production -- to "calm" things down at the joint between the fuel tube nuts and their terminus at the carb and Y-block.  It would never have been released if they didn't eventually see actual evidence of its need.  This bracket can legitimately be called a "critical safety" part, in the same manner as the innocent looking clip that retains the brake booster clevis pin in the brake pedal.  This brake clip should rightly be considered the single most important part on the car. If it were not there, or if it failed, one's very life comes into jeopardy.  An undiscovered, top of engine fuel leak, no matter how small, is in the same category and is to be intelligently avoided, and easily can be, for a mere $22.  In my humble opinion, every owner of a '67-'69 Camaro with an engine that utilizes the brass Y-block would do well do install this support bracket.  Sorry for preaching, please forgive my impertinence.

5

Originality / Fuel Tube Support Bracket 3959444

« on: December 09, 2024, 09:44:07 PM »

The 1969 AIM on page A3 of the Z28 UPC section shows this clip, or bracket, 3959444 and screw.  It is wrapped around the fuel line going to the rear float bowl.  I assume its intent is to help control the vibration/weight of the fuel line and brass junction block ass'y.  It is attached under the rear passenger side Holley carb mounting nut.  I did a forum search of "bracket 3959444" and "clip 3959444" but no results were returned.  Even though the '69 AIM is clear in its use, and was added to the AIM in late Oct of 1968, I have not come across any photos showing it on restored cars or in posts from owners of original cars who can confirm if this clip was installed on Z28's sometime after the start of the '69 model year launch, or at all during that model year.


Can anyone provide some insight on this?  Thanks.

6

General Discussion / Re: Donating to the CRG

« on: December 08, 2024, 07:57:05 PM »

Setting up this donation route was an excellent move!


Here's a thought:  Like many of us have, I just recently had some automotive related parts I no longer needed listed for sale on Marketplace and/or Craigslist.  I was prepared to accept a modestly lower offer price for my items but the purchaser was so pleased with what I had for sale, he gave me my asking price -- so I donated the difference to the CRG.  A win/win if there ever was one!

7

Maintenance / Re: Survey Request -- Z28 302 Cold Engine Starting Procedure

« on: December 06, 2024, 03:11:31 AM »

Dave69x33:  Very interesting.  Of the responses posted to this survey request so far, your Z is the only one that actually fires up (even though it may not be "clean" running right away) with just one pump of the pedal after sitting for a day or two.  You mentioned your car is "stock restored", so I assume it has all the correct carb, manifold, camshaft, distributor, etc. pieces for a '69 302.  The rest of us stated that we have to go through multiple pumps before we turn the key to get it to fire up on the first attempt when cold.  If I were to give my car just one full pump and then turn the key, it would literally crank without firing for as long as I chose to keep the starter turning.  Has your car always behaved this nicely for you on cold starts, or is there something regarding its tuning spec's that you've done to enhance its ability to cold start on just one pump?

8

Maintenance / Re: Survey Request -- Z28 302 Cold Engine Starting Procedure

« on: November 14, 2024, 08:11:48 PM »

Thanks for your info, Tim.  Your info on your L88 is applicable to this survey, given those engines had similarly "long-winded" camshafts and big CFM carbs to those found on the early Z28's.  And thanks for mentioning your engine starting process includes waiting 10 seconds after pumping the throttle before turning the key.  I should have included that as a question to ask in the list of survey questions.

Is the carburetor on your L88 a Holley with mechanical secondaries (meaning, it has an accelerator pump on both the primary and secondary float bowls)?  If so, that may help to explain why you’ve had success starting your cold engine after giving it only 2-3 throttle pumps.  I recently had a 413 small block with a solid roller cam that had the same int/exh durations at 0.050" as the ’67-’69 302 cam.  It had a Quick Fuel mechanical secondary 850 CFM carb with no choke system on a dual plane intake.  Like your L88, it would always fire right up after only 3 throttle pumps when dead cold.  The key thing here is that any mechanical secondary carb puts the same amount of fuel into the manifold with only 3 throttle pumps as a roughly equivalent vacuum secondary carb does with 6 pumps.

I am hoping more 302 Z28 owners respond to this survey.  If they do, owners of these, and similarly spec'd, cars will gain information about how they can best be "coached" to reliably cold start in a more consistent manner.

Thanks to all who respond.
Chuck B.

9

Maintenance / Survey Request -- Z28 302 Cold Engine Starting Procedure

« on: November 04, 2024, 06:58:29 PM »

This survey request is for those owners of well-maintained survivor, or authentically restored, 1967-69 Z28’s having the following correct 302 engine components:  ignition system (Pertronix conversion OK), carburetor and fast idle system, intake manifold, camshaft, pistons, spark plug wires, starter, etc., and is in a proper state of tune, without exhibiting any drivability issues once the engine is running.

If your 1967-'69 Z28 is in this category, I would be interested in hearing from you about the process you go through to start your cold 302 engine in typical summer temperatures (60-80 deg’s F) providing it has been at least 24 hours since the car was last driven.  Thanks in advance to everyone who participates in this survey request.

Could you please answer the following questions:

1. Before attempting to start the engine, have you found the fuel level in the primary float bowl is considerably below the bottom of the sight plug threads, with no signs of external leaking?  About how far below?

2. Do you routinely add any fuel to bring the float level in the primary bowl up to spec, to replace whatever fuel may have evaporated, prior to turning the key? (by way of an electric fuel pump or manually adding fuel to the bowl by another means).

3. Do you pump the accelerator pedal one or more times before turning the key?  If so, about how many “pre-cranking” pumps do you give it?

4. Do you pump the accelerator pedal while the starter is engaged?  If so, have you experienced the engine backfiring while doing this?

5. How far open do you hold the throttle when you turn the key to engage the starter?  Is it just cracked a bit?, about 1/2 of the way open?, all the way to the floor?, or ?

6. When the engine first fires, does it typically run "clean" on all cylinders, or does it need a few seconds and/or some throttle movement before it runs clean on fast idle with your foot off the accelerator?

7. With whatever process you’ve found that works best for your 302 engine, do you find you have to repeat the entire starting process from scratch more than once in order for the engine to start and continue running?

In my ’69 Z28’s case, the 302 engine retains all of its original components, with the exception of my addition of a Pertronix II to the 1111480 Delco distributor about a dozen or so years ago.  I’m the 2nd owner of the car since buying it from a friend in 1979.  It has 28,000 miles since new and it has always required more than just one pump to set the choke and start up on the first attempt.  I have checked the fuel level in the primary float bowl 24 hours after the last drive on a number of occasions and found I typically have to add 1.75 ounces of gas through an upper bowl screw opening to bring the level in the bowl up to the bottom of the sight plug threads.  Whether I pre-fill the float bowl or not, to help ensure the engine starts and continues running on the 1st attempt, I have to give the throttle anywhere from 6 to 8 pumps, crack the throttle a bit, and then turn the key to engage the starter.  Then, if it does start, it usually runs on less than 8 cylinders.  I then immediately open the throttle a bit more and the engine usually “cleans up” after a few seconds and will then run on fast idle at approx. 1,600 RPM with my foot off the accelerator.  Once running, the car has always driven like a dream during the warm up period and, when fully warm, pulls strong well past the 6,000 RPM redline.  Hot re-starting, or after a two hour soak, is always just a quick one pump, turn the key and it instantly starts right up.

Again, many thanks to everyone who posts a reply.
Chuck B

10

Decoding/Numbers / Re: Part Number Stamp or Sticker on Wiper Motor Assy

« on: October 31, 2024, 12:28:53 AM »

Just discovered this older post on Wiper Motors and thought I'd add my info.  Hadn't realized wiper motors were date code until just recently.  I'm the 2nd owner of this '69 Z28 and bought it from my best friend's older brother in 1979.  I helped him get prices on the car from several Detroit area dealers on his behalf, but he ordered from Snyder Chevrolet in Defiance, OH.  It was delivered to him on 6/9/69.  The car had 5,172 at the time I bought it from him and it had not been licensed since 1973.  I've been very familiar with this car since before Day 1.  Given all this, I'm as sure as anyone can be that this is the original wiper motor that's still on the car today.

I am not sure how this new data gets added to the wiper motor date code chart Kurt has uploaded.  Perhaps someone can do that?

Body Build Week: 05E
Assy Plant: NOR
Vehicle Type: Non-RS
Sticker p/n 5045572
Stamped p/n: Yes, also 5045572
Sticker codes: 106 9 B F
Wiper Plant: Rochester

11

Decoding/Numbers / Re: Part Number Stamp or Sticker on Wiper Motor Assy

« on: October 31, 2024, 12:27:53 AM »

Just discovered this older post on Wiper Motors and thought I'd add my info.  Hadn't realized wiper motors were date code until just recently.  I'm the 2nd owner of this '69 Z28 and bought it from my best friend's older brother in 1979.  I helped him get prices on the car from several Detroit area dealers on his behalf, but he ordered from Snyder Chevrolet in Defiance, OH.  It was delivered to him on 6/9/69.  The car had 5,172 at the time I bought it from him and it had not been licensed since 1973.  I've been very familiar with this car since before Day 1.  Given all this, I'm as sure as anyone can be that this is the original wiper motor that's still on the car today.

I am not sure how this new data gets added to the wiper motor date code chart Kurt has uploaded.  Perhaps someone can do that?

Body Build Week: 05E
Assy Plant: NOR
Vehicle Type: Non-RS
Sticker p/n 5045572
Stamped p/n: Yes, also 5045572
Sticker codes: 106 9 B F
Wiper Plant: Rochester

12

Research Topics & Reports / Re: Original cowl hood photos needed

« on: February 07, 2024, 10:09:28 PM »

If it would help, I have a cowl hood on my car that I purchased new, in primer, that has the original GM Parts sticker still on it, last time I looked before covering the car for the winter last November.  I bought this Parts Dept. hood from a private owner back in the 1980/81 timeframe to replace my '69 Z's flat hood.  Just how old this hood was when I bought it is unknown.  I never procured/attached the matching underhood insulation and would be happy to take and post whatever photos of it are desired -- please let me know if this would help and I'll do that.

13

Maintenance / Re: 302 Z28 Divorced Choke Rod Adjustment

« on: February 07, 2024, 09:45:54 PM »

Thank you, GMAD_Van Nuys, for providing the link to the Holley 4150 repair/adjustment procedures -- very informative.  In reading through it, I noticed there are several carburetor adjustments that require a specific dimensional measurement be achieved for that feature to be adjusted properly.   There is a note in several places that state: "On some models, a specified dimension will be given in the specification table."  Is there a chance you might have this specification table for the 4150 carbs and be able to share it?

14

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.

15

Originality / Re: Ignition Coil Primary Wire Connections -- Guide, Support, etc.

« on: December 24, 2023, 06:56:07 PM »

Hi Mitch,

Thanks for looking.  I was a bit surprised to see there are three upturned flanges and one long, narrow tab on the part.  I was expecting to see only two upturned flanges on opposite sides.  Perhaps my memory is failing me.  Is the one you found definitely the style Chevy used in the late 60's?
Chuck