CRG Discussion Forum
Camaro Research Group Discussion => Originality => Topic started by: nuch_ss396 on February 14, 2009, 04:49:56 AM
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Big block Camaro's had a unique motor mount that used a threaded receiver on one side. This meant that a nut was not required to secure the long bolt.
(http://i244.photobucket.com/albums/gg15/nuch_ss396/original69BBCmotormounts3.jpg)
I have an original pair of these rare motor mounts and I will be hunting the correct original bolts that were used in conjunction with these mounts. Can anyone
post information on these bolts? I need to know correct head markings, overall length, bolt head style, etc........ An image or two would be fantastic.
Can anyone shed any light?
Nuch
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Just a follow-up to my original post on this topic. I was surprised by the number of views, but
no responses. ??? I did get a few PM's though. Many thanks for those. Maybe the correct original
setup is more rare than I thought. In any event, I have been eagerly looking into this on my
own and I've purchased several original correct items ( I believe ) over the past two weeks.
Shortly, I will post more images to show all of the original components in the original big block
motor mount setup. These will include frame mounts, motor mounts, stop bracket, standard
long bolt & washer for passenger side and odd-ball longer bolt, lock washer, flat washer, bushing,
flat washer setup for the drivers side. I'll have some questions for the group once I post everything.
Through all of this I was able to finally make sense of the AIM page on this topic as well. ;D
Steve
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Thanks Steve, interested to see what you came up with! Please keep us posted :)
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Here is the AIM page pertaining to the big block left hand motor mount assembly.
The part highlighted in red is the odd locking bracket I referenced initially.
(http://i244.photobucket.com/albums/gg15/nuch_ss396/scan0003-mod.jpg)
Parts List:
(http://i244.photobucket.com/albums/gg15/nuch_ss396/bbparts-1.jpg)
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Here is the AIM page pertaining to the small block ( Z/28 & SS-350 ) left hand motor mount assembly.
The part highlighted in orange is the small block version of the locking bracket.
(http://i244.photobucket.com/albums/gg15/nuch_ss396/scan0002-mod.jpg)
Parts List:
(http://i244.photobucket.com/albums/gg15/nuch_ss396/sbparts.jpg)
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Here is the AIM page pertaining to the standard 8-cylinder right hand motor mount assembly.
(http://i244.photobucket.com/albums/gg15/nuch_ss396/scan0001.jpg)
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I will be posting images of the motor mount components shortly.
Nuch
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Original big block left hand motor mount assembly:
(http://i244.photobucket.com/albums/gg15/nuch_ss396/DSC00041.jpg)
(http://i244.photobucket.com/albums/gg15/nuch_ss396/DSC00042.jpg)
Close-up view of bolt & locking bracket assembly:
(http://i244.photobucket.com/albums/gg15/nuch_ss396/DSC00044.jpg)
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Original 3950113 left hand engine frame bracket:
(http://i244.photobucket.com/albums/gg15/nuch_ss396/DSC00045.jpg)
(http://i244.photobucket.com/albums/gg15/nuch_ss396/DSC00056.jpg)
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Original motor mount ( NOS ) 3920627:
(http://i244.photobucket.com/albums/gg15/nuch_ss396/DSC00049.jpg)
Close-up of threaded receiver:
(http://i244.photobucket.com/albums/gg15/nuch_ss396/DSC00050.jpg)
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Original stop bracket 3977983:
(http://i244.photobucket.com/albums/gg15/nuch_ss396/DSC00046.jpg)
(http://i244.photobucket.com/albums/gg15/nuch_ss396/DSC00047.jpg)
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Original big block right hand motor mount assembly:
(http://i244.photobucket.com/albums/gg15/nuch_ss396/DSC00051.jpg)
(http://i244.photobucket.com/albums/gg15/nuch_ss396/DSC00052.jpg)
Close-up view of bolt:
(http://i244.photobucket.com/albums/gg15/nuch_ss396/DSC00053.jpg)
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Original 3950114 right hand engine frame bracket:
(http://i244.photobucket.com/albums/gg15/nuch_ss396/DSC00054.jpg)
(http://i244.photobucket.com/albums/gg15/nuch_ss396/DSC00055.jpg)
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3950113 & 3950114 engine frame bracket comparison ( notice the height difference - left side is taller ):
(http://i244.photobucket.com/albums/gg15/nuch_ss396/DSC00057.jpg)
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Original long motor mount bolt components ( SEE PART LIST FOR NUMBERS ):
(http://i244.photobucket.com/albums/gg15/nuch_ss396/DSC00058.jpg)
(http://i244.photobucket.com/albums/gg15/nuch_ss396/DSC00059.jpg)
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Original motor mount to engine block bolts:
Note that the left side bolts ( 3768390 ) are longer than the right side bolts ( 3748038 )
to compensate for the thickness of the stop bracket.
(http://i244.photobucket.com/albums/gg15/nuch_ss396/DSC00060.jpg)
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WHEW! :o ;D Glad that's over with. ::)
OK, now for some observations & questions:
1) Were the motor mounts assembled to the block prior to the BB painting process at Tonawanda?
Would there have been any orange over spray on these motor mounts ( see the original mounts at the beginning of this thread )?
2) Were the BB motor mounts 3920627 ( 3937930 ) used throughout the 1969 production year?
When were these mounts discontinued from production use? Why do these mounts have two different part numbers molded on them?
When was the left side stop bracket assembly discontinued from production? Did it make it into the 1970 model year?
3) When did the BB engine frame brackets 3980941 & 3980942 replace 3950113 & 3950114?
4) Using the AIM as a reference, no part number could be found for the right hand long motor mount bolt.
Extrapolating on the information I could find, it appears that possibly the standard 8 cylinder long motor mount bolt: 3980716 appears to be
the correct part number for use on the passenger side motor mount of the 302, 350, 396, and 427. See AIM – page 87. Can someone
reference a 1969 parts manual and tell me if I am correct in my assumption?
So sorry to all the Z/28 & L/48 guys here. Until I got into the research on this topic, I didn't know that the these cars used a similar stop bracket. Odd that
a thru bolt and nut assembly was used on the Z & SS and the big block used the threaded receiver. Are there any Z/28 or L/48 owners here that can post images of
their motor mount components? I'd like to see them for comparison purposes.
OK - I welcome responses.
Nuch
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Nice job Steve! I think your ready to write a CRG report on this topic... ;)
Paul
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Ok, so obviously this is a 69 only thing so I can't offer any help specifically to the parts. Was is interesting to me though is upon looking in my AIM for 68 there is a little bracket 3945413 listed as STOP-ENG MOUNT L.H. & specific bolt called out for it 3786494. It was added 3-5-68 so I guess that why I don't have it on my car (12D) Assuming these things (stop brackets) were GM's first attempts to cure the breaking mounts? I clearly see how the 69 mount worked (although think it would have just ripped the bolt out as there's really not much thread contact in that 69 mount) but what the heck was that little bracket supposed to do in 68???
(http://i33.photobucket.com/albums/d80/pex68/ScannedImage.jpg)
Also, Steve, I beleive if the AIM shows an assembly process, then it was done on the engine dress line and at that point the engine would already have been painted so no overspray on the mounts. I looked at this way when doing mine, NO AIM process for valve covers, distributor, or bell housing and they all had overspray on them.
Wish I could help more with this...69 guys need to chime in!!!
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Also, Steve, I beleive if the AIM shows an assembly process, then it was done on the engine dress line and at that point the engine would already have been painted so no overspray on the mounts. I looked at this way when doing mine, NO AIM process for valve covers, distributor, or bell housing and they all had overspray on them.
Wish I could help more with this...69 guys need to chime in!!!
That's correct - anything illustrated in the Assembly Manual with a part number callout was installed at the car assembly plant; that's the easiest way to determine which part was installed where.
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Makes sense - so how did they keep orange paint from clogging the threaded bolt holes for the motor mounts?
Steve
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Makes sense - so how did they keep orange paint from clogging the threaded bolt holes for the motor mounts?
Steve
They didn't - there was no attempt made to mask any of the threaded holes in the block during engine painting - only the fuel pump attaching area was masked.
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John,
Got it - thanks.
Did you ever see the engine painting process using the reported vac-forms that masked the aluminum intakes from paint?
This topic has long been talked about over on the NCRS.org forum and is one of those research topics I am quite interested in.
Steve
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Did you ever see the engine painting process using the reported vac-forms that masked the aluminum intakes from paint?
Yes - I worked at the Chevrolet Pilot Line, almost next-door to Flint V-8, from 1966-69 (a friend of mine ran the Flint V-8 Piston Department); Flint V-8 made the vacuum-formed plastic masks in their toolroom.
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John,
To the best of your recollection, has anyone ever documented that process
with pictures taken during the engine painting process? Did any of these masks
make it out of Tonawanda and into someones collection? I'd love to see one...... ;D
Steve
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Did you ever see the engine painting process using the reported vac-forms that masked the aluminum intakes from paint?
Yes - I worked at the Chevrolet Pilot Line, almost next-door to Flint V-8, from 1966-69 (a friend of mine ran the Flint V-8 Piston Department); Flint V-8 made the vacuum-formed plastic masks in their toolroom.
John
were several different motors built at the same time? for instance the Corvette motors alongside the Camaros?
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John,
To the best of your recollection, has anyone ever documented that process
with pictures taken during the engine painting process? Did any of these masks
make it out of Tonawanda and into someones collection? I'd love to see one...... ;D
Steve
If I had known 40 years ago it would be important today, I'd have taken pictures :). No, I don't have any photos of the Flint V-8 paint process, have never seen any, and the GM Media Archives doesn't have any either. The only photo I have is of the Tonawanda paint line, but it doesn't show the masks - the only engines Tonawanda built that used intake masks were tri-power and solid-lifter big-blocks.
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John
were several different motors built at the same time? for instance the Corvette motors alongside the Camaros?
Yes. Both Flint V-8 and Tonawanda built 300-320 engines per hour, 16-18 hours per day (one every 12 seconds), and they typically ran 30-40 different suffix codes every day, with a mixed schedule.
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What's the correct finish for the motor mount through bolts and nuts? I always thought they were black phosphate but just ordered a set from AMK and their both clear zinc!!! Is that right??? Also just have a simple "A" on the head with GR 5 marks...what's correct? Speaking of 68 396 application.
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Here is an Original Early 69 Z Engine Mount, this was on the right side of the 10D 69 Z I am restoring now.
I assume the left would have originally been the same with the limit assembly including the long bolt and spacer, however this car had a later interlocked one on the left.
It also uses a threaded reciever which is blind so I have no idea what the nut reference is in the AIM.
(http://inlinethumb19.webshots.com/36370/2304767950059464720S425x425Q85.jpg)
(http://inlinethumb08.webshots.com/31239/2562289760059464720S425x425Q85.jpg)
The difference from the BB is the chunk of rubber with the threads is opposite and the BB doesnt have the elongated cutout along the bottom where the lower hole is.
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Since the AIM shows the mount as a production part that would mean it would have been oversprayed with the engine paint... correct?
And the limit bracket was installed at the assembly plant so it would not have been painted.
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Are thse mounts L-78 specific?? AIM says L-34-35. I just looked at mine & I have nothing but a 3 one half inch bolt X 7\8 with a lockwasher,no spacer ect! My engine is L35 04C
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No the ones in the beginning of the thread apply to all 69 Camaro BB's L34 L35 L78 and L72.
Yours most likely is the replacement style with the Interlocking tabs so the engine will not come off the mount when the rubber deteriorates. The originals broke because the L braket with the long bolt and spacer were not introduced until later in production.
If I am not mistaken Chevrolet changed to the interlocked style (safety mount) in 1970 which is the one pictured below which is still sold by GM.
(http://i174.photobucket.com/albums/w112/68zproject/IMG.jpg)
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Since the AIM shows the mount as a production part that would mean it would have been oversprayed with the engine paint... correct?
Nope. "Production part" means that it's the same part used for the base engine condition, installed at the car assembly plant; anything that was part of the engine from the engine plant would be normally be called out as "part of engine assembly".
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No the ones in the beginning of the thread apply to all 69 Camaro BB's L34 L35 L78 and L72.
Yours most likely is the replacement style with the Interlocking tabs so the engine will not come off the mount when the rubber deteriorates. The originals broke because the L braket with the long bolt and spacer were not introduced until later in production.
I had not heard this before. Anyone know if this is accurate and more importantly when exactly "later in production" came to be for the '69 BB Camaros?
Nuch
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Has anyone narrowed down the timeframe when this stop bracket / bolt assembly was installed? I have the bracket and bolt from a 1969 350/255hp Impala that is identical to the 'Z/28' RPO graphic in the assembly manual that's posted earlier in this thread. Pic below:
(http://farm6.static.flickr.com/5203/5318061138_3cc7fe15ed_b.jpg)
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The 1969 z/28 left side mount is different then the right. My very original 11d 69z never had the engine removed. So I know the mount is original to the car.Only one other person that I know has one of these mounts. He also restored a very original car and the mount is the same as mine. John Allouez Restorations
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Is the mount that uses these brackets shorter than a regular mount to allow for the thickness of the bracket , or does the engine set higher ? How thick is the bracket ?
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Tony,
Do you happen to know the production date of the Impala?
Were the old type motor mounts on the car?
The one pictured earlier is on the 10D Lemans Blue Z28 purchased from you.
James
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James,
I think the Impala was an early June of 1969 build. It must have had the old style mounts on it but at the time I didn't have the foresight to check.
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The 1969 z/28 left side mount is different then the right. My very original 11d 69z never had the engine removed. So I know the mount is original to the car.Only one other person that I know has one of these mounts. He also restored a very original car and the mount is the same as mine. John Allouez Restorations
Quote - So sorry to all the Z/28 & L/48 guys here. Until I got into the research on this topic, I didn't know that the these cars used a similar stop bracket. Odd that
a thru bolt and nut assembly was used on the Z & SS and the big block used the threaded receiver. Are there any Z/28 or L/48 owners here that can post images of
their motor mount components? I'd like to see them for comparison purposes.
OK, Here you go. I am missing the bracket and spacer.
Hope this helps. Mike.
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RE: The top mount in this NEW set of photos. Is this the 69 HP Small Block Left hand (drivers) motor mount?
Shauger's L48 RS/SS with 14k miles has the original mounts on it. The right is the same as the photos above, however my photos do not clearly show the left one. I requested in the Yenko boards, however it would be great if someone could get some photos of his.
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RE: The top mount in this NEW set of photos. Is this the 69 HP Small Block Left hand (drivers) motor mount?
Shauger's L48 RS/SS with 14k miles has the original mounts on it. The right is the same as the photos above, however my photos do not clearly show the left one. I requested in the Yenko boards, however it would be great if someone could get some photos of his.
Yes this is the HP 302 left hand mount. What is weird is that if you look at the AIM sheet it shows that a bolt is used from the front and threads into the mount. This mount has the bolt comes in from the back and threads into a nut that is part of the mount.
Unless there are 2 different mounts 1 for the antilift bracket shown above and another version. It appears that if a person used the Big Block Bracket it would work with this mount. ??????????????
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It's understandable for the mount to be as shown, because if the car had power steering it would be difficult if not impossible to insert the Motor mount to frame stand bolt.
They appear to be the exact same mount, however the left has a recess for the bolt in the "chunk" of rubber and the attached nut.
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RE: The top mount in this NEW set of photos. Is this the 69 HP Small Block Left hand (drivers) motor mount?
Shauger's L48 RS/SS with 14k miles has the original mounts on it. The right is the same as the photos above, however my photos do not clearly show the left one. I requested in the Yenko boards, however it would be great if someone could get some photos of his.
I just happen to see this thread referencing my car. Anyway my car is typical in that the left MM is different from the right and the bolt is inserted from the rear. My car is a 4C without bracket. Pictures of mount below...
Link to a short write-up: http://www.yenko.net/ubbthreads/ubbthreads.php?ubb=showflat&Number=432052#Post432052
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paceme,
Thanks for posting, your mounts look the same as my original Z28 mounts, except mine have RBW bolts.
I am still puzzled by the AIM (Z28 page) and bracket shown on page 1 of this post. The mount appears to be different, unless it is just a generic drawing, it also shows the bolt going in from the front.
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paceme,
Thanks for posting, your mounts look the same as my original Z28 mounts, except mine have RBW bolts.
I am still puzzled by the AIM (Z28 page) and bracket shown on page 1 of this post. The mount appears to be different, unless it is just a generic drawing, it also shows the bolt going in from the front.
If you look closely at all the engine mount illustrations and pay attention to the change dates in the title block, you'll see that ALL the engine-side mounts for L-34/35, L-48, L-78, and Z/28 were changed between 5/29/69 and 6/2/69, and the base V-8 mounts were changed on 8/6/69. Cars built before that ALL had different old-style mounts.
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paceme,
Thanks for posting, your mounts look the same as my original Z28 mounts, except mine have RBW bolts.
I am still puzzled by the AIM (Z28 page) and bracket shown on page 1 of this post. The mount appears to be different, unless it is just a generic drawing, it also shows the bolt going in from the front.
If you look closely at all the engine mount illustrations and pay attention to the change dates in the title block, you'll see that ALL the engine-side mounts for L-34/35, L-48, L-78, and Z/28 were changed between 5/29/69 and 6/2/69, and the base V-8 mounts were changed on 8/6/69. Cars built before that ALL had different old-style mounts.
Thanks John, So if I am understanding correctly the mounts shown that I posted were used until 6/2/69? ( June?)
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paceme,
Thanks for posting, your mounts look the same as my original Z28 mounts, except mine have RBW bolts.
I am still puzzled by the AIM (Z28 page) and bracket shown on page 1 of this post. The mount appears to be different, unless it is just a generic drawing, it also shows the bolt going in from the front.
Never Mind, I answered my own question tonite. I was looking in my own AIM and mine shows the bolt going from the back on the drivers side mount, there is a revision on my page.
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Thanks Shaugs... that is exactly what I was looking for!
Now is anyone reproducing the correct EARLY style 69 HP mount?
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Is the mount that uses these brackets shorter than a regular mount to allow for the thickness of the bracket , or does the engine set higher ? How thick is the bracket ?
The Z28 frame brackets are different heights to compensate for the additional thickness of the antilift bracket, their difference is exactly the thickness of the bracket. Here are some shots of my Z28 mounts with a Heartbeat Repo antilift bracket. Hope this helps.
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Thanks . does any one know if on a big block if the rubber mount is thinner with the bracket ?
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Thanks . does any one know if on a big block if the rubber mount is thinner with the bracket ?
I think Steve shows that the 396 RH frame mount is taller on page 1 of this post, I think all the engine insulators are the same physical height, the anti lift bracket thickness is equalized by the frame mounts.
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The big block frame stands are different to offset the engine to the right . I was wanting to know if the rubber mount was different on the left to allow for the anti lift bracket thickness .
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The big block frame stands are different to offset the engine to the right . I was wanting to know if the rubber mount was different on the left to allow for the anti lift bracket thickness .
Not sure on the big block mount but the small block rubber mounts I posted pictures of, are the same hite.
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"The Z28 frame brackets are different heights to compensate for the additional thickness of the antilift bracket, their difference is exactly the thickness of the bracket."
Here is my opinion on the frame stand height difference...
This, I believe, is merely a coincidence, as the retrofit was more than 2/3 of the way through 1969 production.
Why, if the safety stop was taken into consideration when the frame stands were designed, were they not installed until after 9-10 months of production?
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"The Z28 frame brackets are different heights to compensate for the additional thickness of the antilift bracket, their difference is exactly the thickness of the bracket."
Here is my opinion on the frame stand height difference...
This, I believe, is merely a coincidence, as the retrofit was more than 2/3 of the way through 1969 production.
Why, if the safety stop was taken into consideration when the frame stands were designed, were they not installed until after 9-10 months of production?
Hi James,
You might very well be correct, never thought about it that way. I have changed lots of engines in first gens in the last 40 years and I have never had trouble getting the engine to sit level, but I guess that is why both engine frame stands are slotted. I probably just assumed the hite difference was because of the antilift bracket, mainly because of this post. I ran a Corvette/Camaro restoration shop for 18 years (1987-2005) and I have only seen these anti lift brackets a few times, last 1 was in a 69 Corvette 350/300hp car.
It would be interesting to know how many cars originally had them, I wonder if lots of them were removed under the engine mount recall program.
The mystery continues.
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Have these long bolts and spacers along with correct engine mounts been reproduced by anybody yet?
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As far as I know the motor mounts are not reproduced. Originals are very $$$$. I have original motor mounts in good condition.
I have a 69 396/375 and I purchased the support from HBC. For the bolts, washers, spacer you can look in the AIM for part numbers and then in the AMK Products catalog and cross reference GM numbers to AMK hardware. You can find most of the hardware. I think the long bolt was listed as a Pontiac part. For the bushing I cut down the length of a generator spacer with the correct ID and OD. You can get a good idea of lengths, etc. by looking at the photographs. The hardware was placed on marked background. I hope this helps.