Author Topic: Fan shroud plastic identification ???  (Read 1452 times)

DAVEN1256

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Fan shroud plastic identification ???
« on: May 17, 2020, 07:13:50 PM »
Can anyone identify the type of plastic an original '68 small block fan shroud (GM part number 3893812) is made from?

I want to attempt to repair some cracks in my original shroud. There are a lot of plastic repair products out there but they're all specific as to what types of plastic they will repair.

So before I can choose a product, I need to know what type of plastic I am dealing with.

Thanks.....Dave

169INDY

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Re: Fan shroud plastic identification ???
« Reply #1 on: May 17, 2020, 09:04:21 PM »
Yes, it can be a bear determining the base material then matching the appropriate repair method and medium.
I always hear guys talking about the 'burn' test.

http://engineeredplasticsblog.info/how-to-get-a-rough-idea-of-a-plastic-material-type-when-you-dont-know/

& then you see the Plastic Welding kits, Weller, eastwood etc,,,,,,,
Jim
68 SS/RS L35 Th-400 LOS
69 Pace Car L48 Th-350 LOS
68 Z28 M21 LOS

rare396bronze

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Re: Fan shroud plastic identification ???
« Reply #2 on: May 18, 2020, 12:06:39 AM »
That shroud is still available from gm! I checked on one for a customer about 2 weeks ago it is the only still available.

169INDY

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Re: Fan shroud plastic identification ???
« Reply #3 on: May 18, 2020, 03:20:57 AM »
Avail interesting, I wonder how it measures up to the vintage NOS and originals.?
Jim
68 SS/RS L35 Th-400 LOS
69 Pace Car L48 Th-350 LOS
68 Z28 M21 LOS

rare396bronze

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Re: Fan shroud plastic identification ???
« Reply #4 on: May 18, 2020, 03:34:16 AM »
Ordered one a year ago from gm  for a customer doing 68z28. Here was very happy with it.

169INDY

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Re: Fan shroud plastic identification ???
« Reply #5 on: May 18, 2020, 03:55:15 AM »
Does it have the curved arch in the top?
Photo please?

opps I know this is not what the op was looking for but It may be relevant?

Jim
Jim
68 SS/RS L35 Th-400 LOS
69 Pace Car L48 Th-350 LOS
68 Z28 M21 LOS

KevinW

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Re: Fan shroud plastic identification ???
« Reply #6 on: May 18, 2020, 12:39:17 PM »
ABS repair rods worked well for me on kick panels, RS shields, etc.  Pretty sure the shroud is of ABS mix (stiff but flexible=ABS :)

DAVEN1256

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Re: Fan shroud plastic identification ???
« Reply #7 on: May 21, 2020, 12:28:48 AM »
Thanks for the replies.
 
I tried a burn test with a few slivers I cut from a hidden area. That really told me nothing. What I saw could fit several types of plastic. I'm not going to cut anymore off.

I've used a product called "Plastex" by G.T. Motorsports on other plastic items and it has worked great. It says it works on ABS but it will not bond to my shroud. It does say it will not bond to polypropylene and polyethylene.

I did see that this part is still available from GM. My past experience buying old parts that GM still makes new is that they will fit and will work but are not necessarily carbon copies of what was made 50 plus years ago. Can anyone comment on how close these new shrouds look to an original shroud?

Thank...….Dave

KurtS

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Re: Fan shroud plastic identification ???
« Reply #8 on: May 21, 2020, 04:06:42 AM »
Pretty close....
Kurt S
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z28z11

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Re: Fan shroud plastic identification ???
« Reply #9 on: May 21, 2020, 10:26:23 PM »
I have a recent NOS shroud from GM, plus a used OE shroud I can compare it to - which details do you want to compare ?

The NOS shroud is really close - not much difference in any details -

Regards,
Steve
1968 Z28 M21/U17 BRG/W
1969 Z28 X77/M20/VE3 LeMans/W
1969 L78 X66/N66 Cortez/BVT
1969 Z11 L48/M35/C60/C06  1949 3100 5wd 235/6

169INDY

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Re: Fan shroud plastic identification ???
« Reply #10 on: May 21, 2020, 11:28:43 PM »
Does it have the curved arch in the top? or comparison of both; top view side by side pics or two pics so we can look down on both
Jim
68 SS/RS L35 Th-400 LOS
69 Pace Car L48 Th-350 LOS
68 Z28 M21 LOS

z28z11

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Re: Fan shroud plastic identification ???
« Reply #11 on: May 22, 2020, 01:57:34 AM »
Kurt is right (as usual) - pretty darn close. The OE is on the left, NOS on the right. Details right down to the "staple" marks are exactly the same in my view. Looking at the part numbers, you can tell they were made by the same suppier, if not the exact same mold. I may have labeled the part number pics wrong - the one listed as OE is probably the NOS - I think that's a '95 date stamping you can see below the part number.

Same weights, same materials. They are both heavy ABS, or whatever combination of plastic. The only thing I can't guarantee is if they made any vendor changes in the last year or two -

Regards,
Steve
1968 Z28 M21/U17 BRG/W
1969 Z28 X77/M20/VE3 LeMans/W
1969 L78 X66/N66 Cortez/BVT
1969 Z11 L48/M35/C60/C06  1949 3100 5wd 235/6

HOGDADDY

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Re: Fan shroud plastic identification ???
« Reply #12 on: May 22, 2020, 02:23:48 AM »
Here is one I purchased around 1990 IIRC. Hope to use it one day.
I also bought the other for a/c too at the same time just in case.

It has 2 dates '93 & '94.

DAVEN1256

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Re: Fan shroud plastic identification ???
« Reply #13 on: May 23, 2020, 05:00:38 PM »
Thanks for the replies and info so far.

The pictures posted by z28z11 and Hogdaddy have raised new questions for me about my shroud.

Look at the areas circled in red in the first three pictures. The first picture is z28z11's OE and NOS shrouds side by side, the second picture is my shroud, and the third is Hogdaddy's NOS shroud from the 90's Where my shroud and Hogdaddy's shroud are cut out behind the upper mounting bracket bolt hole, both of z28z11's shrouds appear to have some material there with a hole in it. I don't know if my eyes are fooling me and seeing something that's not there. On mine that cutout needs to be there for the shroud to sit on the upper mounting bracket. The fourth, fifth, and sixth pictures are also of my shroud.

I also have no part number or date code on my shroud like all the others. Between the lack or a part number and the differences in that cutout area, I'm wondering if my shroud is original and correct. My shroud has been with the car since at least 1978.

Thanks.....Dave















HOGDADDY

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Re: Fan shroud plastic identification ???
« Reply #14 on: May 23, 2020, 05:31:54 PM »
Your eyes are fooling you that is the bottom of the shroud. The difference I see compared to original is in the rear of the circular part of the shroud.

Looks like you've done a good job repairing yours I wouldn't buy another.
« Last Edit: May 23, 2020, 07:31:54 PM by HOGDADDY »

DAVEN1256

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Re: Fan shroud plastic identification ???
« Reply #15 on: May 23, 2020, 11:47:34 PM »
Thanks for pointing that out that difference in the rear of the circular part of the shroud. I hadn't noticed that.

Mine is not actually repaired yet. You really can't see some of the needed repair spots in the pictures. The ones you can see I tried repairing with the Plastex and they cracked again.

By the way, in what location on the shroud are you finding the part number stamped. I looked all over mine and see nothing.

Dave

z28z11

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Re: Fan shroud plastic identification ???
« Reply #16 on: May 23, 2020, 11:57:42 PM »
Inside surface of the shroud, upper left side if I remember correctly (could be the right, I'll have to go look again). I'd bet yours is still there unless it was sanded smooth - I doubt aftermarket shrouds were available in '78, due to the relative inexpensive nature of the parts in those years. I expect it wasn't much more than $25-$40 in those days.

Regards,
Steve
1968 Z28 M21/U17 BRG/W
1969 Z28 X77/M20/VE3 LeMans/W
1969 L78 X66/N66 Cortez/BVT
1969 Z11 L48/M35/C60/C06  1949 3100 5wd 235/6

HOGDADDY

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Re: Fan shroud plastic identification ???
« Reply #17 on: May 24, 2020, 12:49:38 AM »
Thanks for pointing that out that difference in the rear of the circular part of the shroud. I hadn't noticed that.

Mine is not actually repaired yet. You really can't see some of the needed repair spots in the pictures. The ones you can see I tried repairing with the Plastex and they cracked again.

By the way, in what location on the shroud are you finding the part number stamped. I looked all over mine and see nothing.

Dave


The numbers are on the inside upper driver's side of the shroud.

Sauron327

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Re: Fan shroud plastic identification ???
« Reply #18 on: May 24, 2020, 11:23:26 AM »
I have an NOS one in storage. I'd have to get it for comparison to the assembly line ones I have. Plastic type info is on the SEM Products site and Body Shop Business publication, among others. Buy the right product for repairs. You'll need a POS donor shroud to verify the proper method and product. By the way, body filler is a poor choice to repair plastic. After you repair the damage, how are you going to exactly duplicate the original mold finish? If you use an AP(adhesion promoter) and paint it, the factory correct finish goes out the window.

HOGDADDY

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Re: Fan shroud plastic identification ???
« Reply #19 on: May 24, 2020, 08:01:16 PM »
Here is both 67/68  NOS SB radiator shrouds side by side, 3893812 and 3893814 while were at it.

« Last Edit: May 24, 2020, 09:26:21 PM by HOGDADDY »

HOGDADDY

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Re: Fan shroud plastic identification ???
« Reply #20 on: May 24, 2020, 10:12:34 PM »
This one still has the GM pick tag plus a Year One stickers on top.

HOGDADDY

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Re: Fan shroud plastic identification ???
« Reply #21 on: May 25, 2020, 01:13:36 AM »
Interesting that the 2 posted here in Chicks thread don't have that cut-out in the circular section.
The service replacement there looks a lot different.

https://www.camaros.net/forums/3431153-post1087.html

z28z11

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Re: Fan shroud plastic identification ???
« Reply #22 on: May 25, 2020, 02:52:28 AM »
Thanks for the replies and info so far.

The pictures posted by z28z11 and Hogdaddy have raised new questions for me about my shroud.

Look at the areas circled in red in the first three pictures. The first picture is z28z11's OE and NOS shrouds side by side, the second picture is my shroud, and the third is Hogdaddy's NOS shroud from the 90's Where my shroud and Hogdaddy's shroud are cut out behind the upper mounting bracket bolt hole, both of z28z11's shrouds appear to have some material there with a hole in it. I don't know if my eyes are fooling me and seeing something that's not there. On mine that cutout needs to be there for the shroud to sit on the upper mounting bracket. The fourth, fifth, and sixth pictures are also of my shroud.

I also have no part number or date code on my shroud like all the others. Between the lack or a part number and the differences in that cutout area, I'm wondering if my shroud is original and correct. My shroud has been with the car since at least 1978.

Thanks.....Dave









Dave,

Appears to me your shroud has been trimmed both at the top and the bottom of the circular portion of the shroud (engine side, your #4 pic) - if it were mine, I'd order a new one from GM as long as it's available, which it is. There is no discernable difference in the early and late versions that I can see (only the date codes, or die rebuild codes on the shroud interior). That large of a repair is gonna be tough to fix to any degree of cosmetic appearance - you'll end up with more time and money in repairing than a NOS will cost you. JMO -

Please don't do what I have occasionally done in the past - wait too long to visit the dealer and have it discontinued while you're thinking about it. Drives me crazy to have that happen -

Regards,
Steve
1968 Z28 M21/U17 BRG/W
1969 Z28 X77/M20/VE3 LeMans/W
1969 L78 X66/N66 Cortez/BVT
1969 Z11 L48/M35/C60/C06  1949 3100 5wd 235/6

DAVEN1256

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Re: Fan shroud plastic identification ???
« Reply #23 on: May 25, 2020, 06:51:50 PM »
I actually see three differences now between my shroud and all of the other shrouds pictured here. Besides the two cut outs that have already been mentioned, one at 12 o'clock and one at 6 o'clock on the engine side, I also noticed the cut out that the top mounting bracket slides under is wider on mine.

I Googled images of '68 Camaro fan shrouds and engine compartments and did not see a single shroud with cutouts like mine. This is a mystery to me. This is the shroud that was on the car when I bought it 1978. It was a mostly an unmolested original car in stock condition. Nothing had been hacked. I doubt anyone was making reproductions at the time when you could just go to the dealership and buy a new one. I can't figure out either what would be accomplished by trimming out those small sections...….Another thing is that the edges of the cutout areas look very "factory." There's no evidence of any cutting like saw marks.  The cuts are straight as an arrow too. Anyone who was not familiar with how one of these ought to look would never look at it and think it didn't come from the factory that way.

I am not trying to say that someone didn't trim it. I have to figure they probably did seeing as I can't find another one that looks it. If they did though, they did a great job! Oh, and for what it is worth, I looked again and there is no part number stamped or molded into my shroud.

I guess I'm on the fence now whether to repair this shroud or go after a new GM. I wouldn't try to fill in the cutouts, just repair the cracks. And I knew all along that if repaired it, I was going to have to paint it. So that brings me back to my original question.....What kind of plastic is this? Whether you're buying a plastic repair product or filler material for plastic welding, you have to know.....and maybe no one will ever know. :)

I appreciate all of input on this and all of the pictures posted.

Dave




KurtS

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Re: Fan shroud plastic identification ???
« Reply #24 on: May 26, 2020, 09:20:03 PM »
If you want the original look, go by a new GM part. You'll never get the original look with paint.
Kurt S
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169INDY

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Re: Fan shroud plastic identification ???
« Reply #25 on: May 29, 2020, 04:37:51 AM »
GM part number 3893812 on order via my local dealer, While he was working the computer he indicated Discontinued yet still in stock at some warehouse. Hefty discount and one on the way, I will post pictures of what is received.
Jim
68 SS/RS L35 Th-400 LOS
69 Pace Car L48 Th-350 LOS
68 Z28 M21 LOS

KurtS

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Re: Fan shroud plastic identification ???
« Reply #26 on: May 29, 2020, 09:30:52 PM »
I would have bought two then.... ;)
Kurt S
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DAVEN1256

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Re: Fan shroud plastic identification ???
« Reply #27 on: May 29, 2020, 11:38:15 PM »
I made a decision and just ordered a new GM shroud also.

Between never being able to make a positive ID on the type of plastic the original shroud is made from so I could buy the right repair product, and then finding out my original shroud had been trimmed, I gave in!

I bought mine from GM Parts Giant for $153.77 + $18.14 shipping and handling.   ( https://www.gmpartsgiant.com/ )

I also checked these other places:   GM Parts Direct…..$148.20 + $28.06 shipping

                                                    Local Chevy dealership.....$227.80 plus local tax


HOGDADDY

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Re: Fan shroud plastic identification ???
« Reply #28 on: May 30, 2020, 05:03:46 AM »
Fyi, it seems  PN #3893814 is no longer available but I see that Heartbeat City still has some.
I should have bought 2 of each!  ;)

169INDY

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Re: Fan shroud plastic identification ???
« Reply #29 on: July 03, 2020, 04:22:01 AM »
Local dealer met internet pricing.
Photos attached.
Better than what I had - Nothing.
Swap meet searches have proofed nothing but Junk.

I was surprised at the shelf and manf blemishes, but might have to high expectations. Scuffs, plastic riser sprue trimming cuts overall a nice part. better than the shiny OER yellow and black box items I have seen at the reseller vendors.

Jim
Jim
68 SS/RS L35 Th-400 LOS
69 Pace Car L48 Th-350 LOS
68 Z28 M21 LOS

DAVEN1256

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Re: Fan shroud plastic identification ???
« Reply #30 on: July 03, 2020, 05:58:28 PM »
I received my new GM shroud a couple of weeks ago and it has almost identical scratches and blemishes as 169INDY's. The worst of which is on the top passenger side. This is not a scratch, it's a gouge at least a 1/16 inch deep. Nothing you are going to polish or buff out. If it was in the inside or the bottom, I wouldn't mind so much, but not on top where everyone will see it.

After going through the trouble of contacting GM Parts Giant, writing a letter of explanation, sending them photos they asked for,  and obtaining an RMA number, I sent it back and they are going to send me another one.

I was hoping that I just got a bad one and that the replacement would be better. After seeing what they sent 169INDY,  now I'm thinking they're are going to send  me the same as what I got originally or maybe worse. I'll just have to wait and see.

And 169INDY, you're expectations are not too high! When you spend good money for a brand new item, it should not come to you looking beat up.

Dave