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Author Topic: 1969 z/28 full floating connecting rods - Fact or Fiction  (Read 7459 times)
asm69
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« on: July 28, 2006, 03:33:51 PM »

After dissassembling my engine in my 69 z. I found that the connecting rods had the pressed 'O' on the rod cap. But to my
surprise they had pressed in pins. I began a quest to find out if 69 z/28's came from the factory with full floating or pressed in
pins. Since I currently work at a GM dealership, I asked the senior techs have they ever seen from the factory full floating pins
in the 69 z/28 or any other performance small block. Their response was no. An interesting response. So, I then called up to
six different machine shops and ask to speak to technicians who had been in the business since the late 1960's. I posed the
question to them as well. To my surprise every single one of them stated that from the factory they had never seen full floating
connecting rod pins in the 69 z/28 302 engine. So, I wonder if Chevrolet had originally intended for the 69 302 to come with
full floating pins but at the last minute changed their minds to save money. I also had any opportunity to look at a parts book
and I did see a listing for piston pin retainers for the 68 302, no idea if it's late or early.

So, that's my question did the 69 z/28 come with full floating pins from the FACTORY. If my research is correct they came
with pressed in pins.

Call your own local machine shop and ask for yourself. Is it fact or fiction?

             
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william
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« Reply #1 on: July 28, 2006, 07:14:49 PM »

Nope, both of mine had floating pins.
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asm69
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« Reply #2 on: July 28, 2006, 07:51:49 PM »

You say that both of yours had floating pins. I believe you.

Were you also the original owner of both vehicles and personally dissassembled the engine where you then
found that the connecting rods were floating pins?
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Steve68
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« Reply #3 on: July 30, 2006, 08:57:01 PM »

"1965 - 69 Chevrolet by the numbers" says for 1969 302/290 piston pin was floating pin.

Steve
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RamAirDave
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« Reply #4 on: July 30, 2006, 10:33:37 PM »

per MacNeish's book, the full floating "386" pink rods were used in all 69 302s.
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jdv69z
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« Reply #5 on: July 31, 2006, 03:28:29 PM »

I have the 8 original full floating pistons from my 302 that were replaced when it was rebuilt; In fact one of the pistons is broken at the pin boss. I suspect that whoever disassembled them when I had the engine redone attempted to "press" the first one apart, and broke it! Just like the guys at the parts stores who always ask if my 302 is a Ford engine!

If you'd would be interested, I can take a photo on one and email you.

Jimmy V - 69 Z
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Jimmy V.
asm69
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« Reply #6 on: July 31, 2006, 11:26:24 PM »

 I believe you Jimmy V - 69 Z. But, I would believe you more if you were the original owner and had
torn the engine apart and discovered that the pins were floating. I really want to believe that
chevrolet produced the 69 z/28 302 with floating pins. But, my research is showing quite the opposite.
I contacted the person who rebuilt the engine from Dean Guccione's own 1969 z/28. His web site is
Camaros unlimited "www.69camaro.20m.com". The rebuilder Rick from RICK'S CREATIVE RESTORATIONS even
says that he has never seen full floating pins from the factory. Heres his phone number call him
yourself and ask 1-310-670-9575.

It would not be beyond chevrolet to say and print that these engines would have full floating pins. But,
then during production change it.

Dont believe what you always read. I say go call some reptuable machine shops that have individuals
who have been in the business since the late 1960's. And ask them yourself. Ask them if they have
ever rebuilt a factory 302 for a fact and then found that it had full floating piston pins.

If you find someone give me the number so that I can talk to them as well.

Honest, I really want to believe that full floating pins were used in production. But, I tell you. I cant
find the supporting facts from chevrolet parts managers, chevrolet technicians and reptuable
machine shops.

Help me if you can. I just want the facts.




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JohnKY
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« Reply #7 on: August 01, 2006, 05:54:13 AM »

Floating pins started in mid 68, with a piston design change. Early 68 302's used the 67 style piston with pressed pins. Late 68, an all 69's used floating pins.
My 68 (late 68) has floating pins, one of which deeply scored a cylinder wall when the pin retainer failed, requiring a sleeve. I've had this car since 1970.
Don't know which machinist's you've been talking to, but they've either forgotten, or didn't work on many 68 - 69 302's back then.
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asm69
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« Reply #8 on: August 01, 2006, 09:42:50 AM »

Yes, if you look at an early parts book it will list  pin retainers for the 68 302, no idea if it's late or early.

But, no listing for the 69 302.

I will do some additional research and post the results.
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jdv69z
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« Reply #9 on: August 01, 2006, 03:55:02 PM »

The first 302 I saw disassembled was in 1972; Saw the original Z/28 Camaro the engine came from; it had full floating TRW aluminum pistons; I now own a 69 Z/28; I have these same original TRW full floating pistons which were removed from my original 302 engine This original engine is still in my 69 Z/28 Camaro at this moment. (I've owned it since 1982; it's now .030" over) 1969 Z/28's came with full floating pistons. Check Jerry MaNeish's book; there are pictues of these pistons. My original pistons are identical to the pictures in MacNeish's book. Even in when they were new 1969 Z/28 camaros were not all that common a car. Many mechanics probably never worked on or even saw a 302.
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Jimmy V.
asm69
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« Reply #10 on: August 01, 2006, 07:50:55 PM »

I appreciate your comments. I looked at the picture of the piston in the MacNeish book. It only shows the top of
the piston and of course his comments that these pistons had full floating pins.

Pistons (I'm not saying all) come with the ability to have piston pin retainers for full floating pins or use no retainers to
have pressed pins.

I'm just looking for more hard facts. The Chevrolet parts books dont even list retainers for the 69 302. As I said before
there is a listing for the 68 302 (unsure if it early or late model year).

Being an enthusiats you surely must know someone that is a technician or works for a machine shop. Ask them what
they have found, call up your local Chevrolet dealer and tell them you want to purchase some piston pin retainers
for your 69 z/28. They can either tell you there is no such listing, (which may mean they were never made) or they
may tell you that it's no longer available (which may mean that it has been produced at one time as a service part
but is now discontinued).

As I said before I really want to believe they cam with full floating pins, I just need some more facts.
If you know of any one that I can call or contact please respond. And I will call them or email them.

The answer for my questions will continue until I get more concrete evidence either way.

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jdv69z
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« Reply #11 on: August 01, 2006, 08:49:00 PM »

You can call Jerry MacNeish at 410-781-0418; Or e mail him at z28camaroman@juno.com if you want.

But based on what I've read so far, you wouldn't believe him anyway!

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Jimmy V.
asm69
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« Reply #12 on: August 02, 2006, 09:43:35 AM »

Yes, thank you. I had plans to contact him as well as the gentleman who wrote the chevrolet by the numbers book.

I will also be contacting some additional well known machine shops as well as those people who were racing
in the trans am circuit during the day.
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Classicgary
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« Reply #13 on: August 03, 2006, 03:21:09 AM »

here's some fuel for the fire:  Piston pin retainer part number: 3946848  (.042 thick)
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asm69
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« Reply #14 on: August 03, 2006, 02:49:34 PM »

Thank you for your comments Classicgary. That is the correct part number for
a 1968 302 (unsure if it's late or early), not a 1969 302.

If you find an original parts book that has not gone through a revision. You should check that
out. In the meantime I am trying contact some of the companies or individuals who were
involved in the trans-am circuit racing during the late 1960's.


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red69
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« Reply #15 on: August 03, 2006, 10:22:50 PM »

Have to throw my two cents worth in here. In 1972 I purchased a 1969 Z-28 with 50,000 miles on it. The motor needed freshinging so I pulled it down, the pistons had full floating pins. In 1975 I purchased my second 1969 Z-28 with 66,000 miles on it. When it was pulled down for rebuild it also had full floating pins. I assumed with all I had read about 1969 Z-28's being produced with full floating pins, that these two cars came from the factory so equiped. But it is possible that both these engines were torn down before I bought the cars and full floating piston pins installed. Could have been a full foating pin legend conspirousy.
          Pat
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jdv69z
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« Reply #16 on: August 08, 2006, 08:25:29 AM »

I pulled out my 34 year old copy of "How to Hot Rod Small Block Chevy" published in 1972, and "viola", it lists the part no.'s for 69 302 engine's full floating pistons; not only standard 4" bore, but .010, .020, and .030 over as well. Aslo listed is the spirolox retainer no. This conspiracy goes way back. May be related to Kennedy assasination??

Jimmy V
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Jimmy V.
asm69
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« Reply #17 on: August 09, 2006, 12:38:32 AM »

Thank you for your response.

If you have the opportunity could you please post the part numbers for the standard size piston as well as the oversize pistons.
I would like to cross reference those numbers. As I said before. I prefer to believe that the 69 z came with full floating
pins during factory production.

Thanks again. Please post those numbers as soon as possible.
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asm69
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« Reply #18 on: August 09, 2006, 09:44:59 AM »

While I continue my research into this matter I would like those of you who have 1969 z/28's and who have pulled their
engines out and who also have found that the bottom of the connecting rods had the cast letter 'O' and who also
have found that the connecting rods had pressed pins to post to this thread and say so.

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jdv69z
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« Reply #19 on: August 09, 2006, 09:05:41 PM »

From "How to Hot Rod Small Block Chevys", authors Fisher and Waar published 1972:

3946841 - Connecting Rod 1969, floating pin
3946876 - Piston & Pin Assembly 302 Std, 1969, forged, floating pin
3946878 - Piston & Pin Assembly 302 .001 OS, 1969, forged, floating pin
3946880 - Piston & Pin Assembly 302 .020 OS, 1969 forged, floating pin
3946882 - Piston & Pin Assembly 302 .030 OS, 1969 forged, floating pin
3946848 - Retainer, piston pin, Spirolox for floating pins, 0.042 inch thick

Jimmy V
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Jimmy V.
Classicgary
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« Reply #20 on: August 10, 2006, 10:36:14 PM »

my copy of Chevrolet Power copywrite 1980, has the same numbers for the std. 302 and the .030 302 forged pistons.
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