Author Topic: Original long bolts for 1969 L/78 motor mounts  (Read 14877 times)

rszmjt

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Re: Original long bolts for 1969 L/78 motor mounts
« Reply #45 on: February 13, 2011, 01:58:24 AM »
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.

JohnZ

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Re: Original long bolts for 1969 L/78 motor mounts
« Reply #46 on: February 13, 2011, 04:37:32 PM »
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.
'69 Z/28
Fathom Green
CRG

rszmjt

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Re: Original long bolts for 1969 L/78 motor mounts
« Reply #47 on: February 13, 2011, 06:30:15 PM »
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?)

rszmjt

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Re: Original long bolts for 1969 L/78 motor mounts
« Reply #48 on: February 14, 2011, 04:37:13 AM »
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.

firstgenaddict

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Re: Original long bolts for 1969 L/78 motor mounts
« Reply #49 on: February 14, 2011, 09:26:09 PM »
Thanks Shaugs... that is exactly what I was looking for!
Now is anyone reproducing the correct EARLY style 69 HP mount?
James
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Check out the Black 69 RS/Z28 45k mile Survivor and the Lemans Blue 69 Z 10D frame off...
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rszmjt

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Re: Original long bolts for 1969 L/78 motor mounts
« Reply #50 on: February 26, 2011, 05:23:23 AM »
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.

mark x22

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Re: Original long bolts for 1969 L/78 motor mounts
« Reply #51 on: February 26, 2011, 02:13:55 PM »
Thanks . does any one know if on a big block if the rubber mount is thinner with the bracket ?

rszmjt

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Re: Original long bolts for 1969 L/78 motor mounts
« Reply #52 on: February 26, 2011, 07:44:10 PM »
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.

mark x22

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Re: Original long bolts for 1969 L/78 motor mounts
« Reply #53 on: February 26, 2011, 09:22:18 PM »
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 .

rszmjt

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Re: Original long bolts for 1969 L/78 motor mounts
« Reply #54 on: February 26, 2011, 09:29:22 PM »
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.

firstgenaddict

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Re: Original long bolts for 1969 L/78 motor mounts
« Reply #55 on: March 01, 2011, 07:47:23 PM »
"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? 



rszmjt

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Re: Original long bolts for 1969 L/78 motor mounts
« Reply #56 on: March 02, 2011, 12:50:25 AM »
"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.