Author Topic: Why is there some Z28's with 3908326 Rear Proportioning Valves and Some without  (Read 8988 times)

dannystarr

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Hey Guys, anybody know why there is some car's that are equipped with the rear Proportioning valve and some car's that are not? You know, the one on the drivers side frame rail. I see lot's of car's with and without. The old story used to be that the car's that got it had A/C. And so the extra weight needed to be controled so the rear wheels would not lock up during hard braking. But that's on SS big block's and such. Z/28's never had the A/C on any of the 28,103 first gen cars. Why do I keep seeing some cars with them and some without? I met a guy back east who has 6 Z/28's all original. He might even hang out on this site. He said 4 of his car's have it and 2 don't. I just seen another car certified by Jerry M. in PA and it's ALL there, but has no valve. I'm gett'in pissed. What the hell is the deal with these valves. I also have seen them on some 68's but not other's. And if a 68' doesn't have it it scares me into think'in it ain't the real deal. Could Chevrolet really come up with this system and then just say to the guys on the assembly line... put them on when ya want? I have seen probably a hundred of 69's with it, and just as many without. Jerry never really decided to put this info in his book's??? It even show's it in the assembly manuals. Ok, I have rambled enough ???.......Danny

77thor

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Let me start off by saying that I'm no expert.... I'm sure one of them will chime in....

My understanding is that all Z28's and SS's had the rear Prop valve on the frame under the drivers seat.
I'm not clear on the reason for the valve.... something to do with the higher horsepower/performance of those models??
1969 Camaro SS350, M21, 12 Bolt, 01B LOS Build

JohnZ

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What we know about the valve's usage is summarized here:

http://www.camaros.org/suspen.shtml#valve

Research continues on exactly what the vehicle configuration criteria were that required it and why it changed.
'69 Z/28
Fathom Green
CRG

1968RSZ28

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Let's all post whether or not our cars have a rear brake line pressure regulator valve.  Once we have enough data, Kurt will figure it out!    :)

I'll go first...

68  02C  LOS  Z22/Z28  NO rear brake line pressure regulator valve

Paul

1968 Z28

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No valve.....see signature for vehicle.
Jerry G.

Z28-1968-07C-Norwood
Ermine White, Red Std. Interior
2nd. Owner, 38,000 miles

Gramps69Z

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My 10E Norwood 69 Z has it.
Captain John Wykoff
Destin Fire     5 months  to go

I'm sick and tired of mismanagement and disappointment. 
I'm a COWBOYS fan.

fireZ

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My 02E Z28 from the LOS plant has it,I think it dates about 54 days before the car was built. ???
1968 Z28 LA Built
LIC # RPO Z28

dannystarr

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So there it is, I guess that's the latest. Just frustrating. And as some of you know, I collect these valves for fun. I know....I know....I think I am up to about 20 or so. In fact that reminds me, I need to get John Z and or CRG a new front and back picture of all of them. So if ya have any of these valves LMK. I may purchase them from ya.
Sure would be nice to know if Jerry M. kept track of all the cars he inspected, had the valve or not. AND what the julian date was on each valve. Maybe he did. Anyway to go to the registry of all these cars on the list for 67' 68' and 69'.....and email or contact them and ask? Takes about 30 seconds. Not like ya have to take any components off to find out. Then at least we could have the info on ALL remaining cars? I talked to some guy a while back and he said he wouldn't own a car if the valve date went farther back then 35 days from build date. What's the deal with that? I have seen them on original 23,000 mile cars with full doc's and it was 62 days back. Even FIREZ mentions his car at 54 days. I think everybody should add the date along with the info. Good idea??...Danny

X66 714

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My 02E 68 z/28 from Van Nuys does NOT have that valve....Joe

CNorton

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My late '69 (10C) X11 non-SS car that had J52 brakes had no valve.

jacmac

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My 69 Z10  O4C L35 w\AC has one
69 Z10,72 corvette

Marty

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My 01C LOS 68 SS-396 has the valve, date is 3447. The car has front disc brakes.

Martin
Martin Foltz
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68 Van Nuys Camaro

68Zproject

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05D 68 Z no valve.  I had a 68 SS that had it and I have no idea of it's build date.
68Z28

dutch

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  My 02D '68 Z 2/8 does NOT have the valve...

BlackoutSteve

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Everyone here with Zs are responding.. What about SS 350/L48 owners? That's the chapter in the AIM where the valves are listed (L48-B3). One would expect 100% of those cars to have the valve..
Restoring my RHD 69 Jane in Melbourne, Australia.
http://www.usmuscle.com.au/Forum/showthread.php?t=2840

dannystarr

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Hey Blackout Steve, I was just talking about the Z28 of the first Generation. But I think it would be great if we could have every first gen Camaro chime in. Cause we know alot of big blocks were supposed to have them and many others. I am sure this thread will die off long before we have the info we need. But a guy could dream I guess.........Danny

BlackoutSteve

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Sorry, I guess I forgot the title of the thread was asking about Z28s in particular. ;)

However, aren't the results of SS/L48s just as consistantly inconsistant?
Restoring my RHD 69 Jane in Melbourne, Australia.
http://www.usmuscle.com.au/Forum/showthread.php?t=2840

dannystarr

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Hey Steve, I can't tell ya anything about any other Camaro's. Only Z/28's and not past 1969. Any info is of course useful. But I sure would like to be able to have someone contact all registered owners of first Gen Z/28's and ask about the valve. Got a good start here I guess.......Danny

Camaro Billy

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    • 1969 RS/SS
I'll chime in.
1969 SS/L48    11D (1968) build date
Has the valve. 275-8 date code on valve. Oct. 1st 1968
Billy
1969 RS/SS 350/300 Rallye Green . Black Vinyl Top

LB68SS350

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 '68 SS350 (L48)  w/12bolt and no AC   03D build date    Has the valve   Larry

westonz28

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Ok heres mine. 1967 RS 327 L30/M20 with the valve, 1968 SS/BB with valve, 1968 coupe 327 210hp no valve, 1969 LM1/350 auto with valve. Only one of them is an SS Camaro. Hope this helps.

sam

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1969 Z/28 (11D-1968) has no valve. Still has original brakes lines.

tinman75

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Have a 68 NOR built 10D car. L48 rs-ss, P/S, Non power drum brakes, 12 bolt  and no A/C and it HAS the valve. I believe it is stamped 285-67 or something like that, I would have to look.
« Last Edit: December 26, 2009, 01:29:17 PM by tinman75 »

KurtS

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My 02E Z28 from the LOS plant has it,I think it dates about 54 days before the car was built. ???
I just stopped by and looked in the garage for you. :)                         Well, in the db actually.....
It's dated 038 8, so about a month ahead.
« Last Edit: December 27, 2009, 06:15:28 AM by KurtS »
Kurt S
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69 skunk

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My 06A x77 car has the valve. Stamp is 108-9

Dave69x33

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My Norwood 05A Z28 has the valve, date stamped 108-9, or April 8th, 1969. 

I was going to post a question to confirm the date coding on these valves, but it appears from this discussion that they are stamped with a Julian date code.

The valve is also stamped "KH" and "R" (see picture attached).  I assume the “R” indicated the rear or outlet side of the valve; however, the tab and hole in the bracket position the valve in one position.

Does anyone know that the “KH” stamp indicates?  Is this the manufacturer?

KurtS

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Kelsey Hayes.
Kurt S
CRG

dannystarr

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Hey Dave thanx for the info. Look's like we are on our way to gett'in some more good info. And as Kurt mentioned I also believe it is Kelsey Hayes that made them. And I am assuming also that the little "R" does stand for rear. The bolt's that hold them down are a different story. They are specific and as far as I can tell not your basic fender or common body bolt. There was I think 3 manufactures of bolts. But not sure about the one that made the bolt that held these valves to the frame. Maybe somebody else knows for sure. But lets not get off track. Still need people to chime in on their cars and these dang valves. Over and out for now.......Danny

Pex68

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68SS 12D LOS L35 HAS valve 283-7 date.

Danny, could you post or PM me the info on the bolts?  I'm not sure if I put the right one back in there.  Has RBW headmark with 3 lines and star lock washer.  Haven't looked to see if this info was in your original post or not.
Thanks!
Chris P
1968 Sequoia Green SS 396/325 M20

Dave69x33

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The bracket on the valve on my car did not have witness marks that a lock or toothed style washer was ever used.  This is not to say that a lock or tooth washer was NEVER used.  However, based on page 302 in the ’69 AIM covering the L48 pressure regulator valve, it calls for a #3958062 screw with no washer called out.  Using AMK Products catalog as a guide, I used the 8062 screw shown in my pic to attach the valve. 

There where often several suppliers for a common used hardware.  The 8062 screw is called out for 6 – 7 various applications in the ’69 AIM (brake and fuel line clips, etc., to mention a few) so we can expect some variation on the manufacturer’s bolt head markings.

jdv69z

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Oct 68 10B  build Z/28; no valve.

Jimmy V.
Jimmy V.

SEK Z28

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03A 68 Z/28 does not have it.

Pex68

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The bracket on the valve on my car did not have witness marks that a lock or toothed style washer was ever used.  This is not to say that a lock or tooth washer was NEVER used.  However, based on page 302 in the ’69 AIM covering the L48 pressure regulator valve, it calls for a #3958062 screw with no washer called out.  Using AMK Products catalog as a guide, I used the 8062 screw shown in my pic to attach the valve. 

There where often several suppliers for a common used hardware.  The 8062 screw is called out for 6 – 7 various applications in the ’69 AIM (brake and fuel line clips, etc., to mention a few) so we can expect some variation on the manufacturer’s bolt head markings.


Thanks Dave!

ALSO - If everyone could include the plant that would help out a lot as there are many known differences between NOR & LOS.

Happy & Healthy New Year Everyone!

 
Chris P
1968 Sequoia Green SS 396/325 M20

dannystarr

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Pex68, you are correct. I forgot about that. Knowing the plant will help in determining possible install start and stop times of the valves etc. etc. Why can't Mr. J.M. at CHP and CRG get the info for all the cars documented so far? Just wondering why that can't place...........Danny

Camaro Billy

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    • 1969 RS/SS
Good point-

1969 SS/L48    11D (1968) build date  Norwood Car.
Has the valve. 275-8 date code on valve. Oct. 1st 1968

Billy
1969 RS/SS 350/300 Rallye Green . Black Vinyl Top

JohnZ

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02D Norwood '69 Z/28 - has valve, stamped "016 9".
'69 Z/28
Fathom Green
CRG

RonM

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'68 Norwood L30/M20 07D build with disc brakes, valve stamped 157-8. Hope this helps, RonM.

Hot302

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12B LA built 69 Z/28 - Has Valve
Rick
69 RS/Z28

jmcbeth

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09C Norwood '69 Z/28 has the valve
John
1969 Camaro Z/28 RS
Numbers Matching

tom

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Just thinking, if some have the valve and some do not have it, could this be a more complicated thing than dates? Could there be specific combinations of drivetrain, and other options that determined if the valve was needed? Then again sometimes I think too much.
69 X11 Z21 L14 glide
looking for a 69 export model (KPH) speed
o

DONCZ28

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   69 NOR. BUILT Z28 O6A  HAS THE VALVE

agriwlw

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  Here is mine;  68 Z/28   Norwood   06 A...no valve.     Bill                                                                                                                                                               

dutch

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ALSO - If everyone could include the plant that would help out a lot as there are many known differences between NOR & LOS.

Happy & Healthy New Year Everyone!

 
[/quote]

 Yup - very good point... Mine is a 02D '68 Norwood 'Zed' car WITHOUT the valve...    Randy

KurtS

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Why can't Mr. J.M. at CHP and CRG get the info for all the cars documented so far? Just wondering why that can't place...........Danny
Just thinking, if some have the valve and some do not have it, could this be a more complicated thing than dates? Could there be specific combinations of drivetrain, and other options that determined if the valve was needed? Then again sometimes I think too much.
I'm keeping up with the data in this thread for the cars we already have in the database.
Have you guys read http://www.camaros.org/suspen.shtml#valve? I don't think I'm seeing any exceptions in the data that's been posted so far.

From the site:
Usage of the valve was not consistent.
•1967 Camaros that received the valve were: all models with C60 air conditioning, all SS396 models, and NOR-built Z28's (at least the later ones). However, the 1967 LOS Z28's did not get the valve.
•For 1968, only cars with 12-bolt axles received the valve. The C60 air conditioning option no longer caused use of the valve (though C60 cars could get the valve due to a 12-bolt axle). The one known exception is that NOR Z28's stopped using the valve midway through the 68 model and didn't begin again until mid-model year 1969.
•For 69, the valve was generally used on 12-bolt axle applications, except for JL8 equipped cars (which had disc brakes in the rear and didn't need the valve). As noted above, the 69 NOR Z28's did not use it until mid-year, in the late January / early February timeframe. Other exceptions in 69 include: some SS's and LM1's have been observed without the valve, and the valve has been observed on some drum brake 10-bolt axle cars.
•Note that usage of the valve on 67-69 Camaros was not apparently related to J52 disc brakes.

Oh, and JM is a part of CRG.
Kurt S
CRG

68Zproject

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My Z is 68, has a 12 bolt and is not Norwood.
68Z28

bbd564

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July 67 Build Norwood L78 has valve
July 68 Build Norwood Z28 has no valve

westonz28

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Ok heres mine. 1967 RS 327 L30/M20 LOS 03D with the valve, 1968 SS/BB  NOR 10B with valve, 1968 coupe 327 210hp LOS 03A no valve, 1969 LM1/350 auto LOS 11D with valve. Only one of them is an SS Camaro. Hope this helps. Corrected with build date and plant. Why does the 1967 RS have the valve as it does not fit the 1967 data? Any ideas Kurt? 

jdv69z

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Oct 68 10B  build Z/28; no valve.

Jimmy V.
Norwood

Jimmy V.
Jimmy V.