Original battery hold down bolt

[Scott69Z]

Could someone please help me by posting a picture of a correct battery hold down bolt. When I purchased my 69 Z28 it was missing the battery hold down and bolt. I purchased an original gm battery hold down and an amk under hood detailing kit which includes the battery hold down bolt. The bolt in the kit seems to be too short. I purchased a sealed R59 battery and I cannot seem to get this bolt to work. Thanks for the help.

[lakeholme]

http://www.camaros.org/forum/index.php?topic=2899.0

Maybe JohnZ can re-post the pic. I couldn't get it to open.

[JohnZ]

Here's the bolt on mine.

[Scott69Z]

Thanks for the pic. Does anyone know how long this bolt is suppose to be? Mine seems too short.

[68camaroz28]

http://www.camaros.net/forums/showthread.php?t=182584&highlight=3881339&page=35
Open up this team camaro link to our build thread and at the top of that page I have posted pics of original hold down clamps and a bolt. I have four original bolts (all in use) and they were all RBW with an oversize captured washer which makes it unique. Do not remember the length.

[68camaroz28]

http://www.camaros.net/forums/showthread.php?t=182584&highlight=3881339&page=35
Open up this team camaro link to our build thread and at the top of that page I have posted pics of original hold down clamps and a bolt. I have four original bolts (all in use) and they were all RBW with an oversize captured washer which makes it unique. Do not remember the length.

Update: I found one of my bolts to be a anchor supplied bolt. The large captured washer is approximately .85" in diameter and thread length is just under an inch.

[big iron]

Seems to be two points of view here and in other threads I have looked at.
Let's look at the facts as presented in the AIM's
Same part number 3758783 and torque used in all three years of production for this particular bolt.
Why would the torque of 60-80 in lbs (6.6 ft lbs) be applied to this bolt when the same size bolts in the same area have 120-180 in lbs (12 ft lbs) applied to them.
I believe that the toothed conical washer was specified and thus the lower torque value.
If anyone has ever tried to change a battery in a first gen then you know why the lead point on the bolt was specified, especially with AC (67-68).
I bring these points of view, not to start an argument, but to reason why this particular bolt does not have an accepted specific style and measurement.
Thanks,
Bob

[JohnZ]

Same part number 3758783 and torque used in all three years of production for this particular bolt.
Why would the torque of 60-80 in lbs (6.6 ft lbs) be applied to this bolt when the same size bolts in the same area have 120-180 in lbs (12 ft lbs) applied to them.

On the battery hold-down application, the bolt is bearing down (through the clamp) on a molded tab that's part of the plastic battery case - a "soft make-up" application; too much torque, you break the case and have acid everywhere. Other applications using the same bolt join two steel parts, with "hard make-up" joints.

[big iron]

Same part number 3758783 and torque used in all three years of production for this particular bolt.
Why would the torque of 60-80 in lbs (6.6 ft lbs) be applied to this bolt when the same size bolts in the same area have 120-180 in lbs (12 ft lbs) applied to them.

On the battery hold-down application, the bolt is bearing down (through the clamp) on a molded tab that's part of the plastic battery case - a "soft make-up" application; too much torque, you break the case and have acid everywhere. Other applications using the same bolt join two steel parts, with "hard make-up" joints.

John,
How would the bolt stay tight at half of it's recommended torque?
Is the plastic case compressing and compensating for the lack of bolt stretch or are the teeth on the conical washer keeping the bolt tight?
Bob

[JohnZ]

John,
How would the bolt stay tight at half of it's recommended torque?
Is the plastic case compressing and compensating for the lack of bolt stretch or are the teeth on the conical washer keeping the bolt tight?
Bob

"Recommended torque" on a fastener is determined by Fastener Engineering based on the type of joint and the joint materials involved; the fastener's job is to establish and maintain clamping force in the joint, and the torque required to do that is a function of the materials in the joint.

[big iron]

John,
How would the bolt stay tight at half of it's recommended torque?
Is the plastic case compressing and compensating for the lack of bolt stretch or are the teeth on the conical washer keeping the bolt tight?
Bob

"Recommended torque" on a fastener is determined by Fastener Engineering based on the type of joint and the joint materials involved; the fastener's job is to establish and maintain clamping force in the joint, and the torque required to do that is a function of the materials in the joint.

In this case was the conical toothed washer used to maintain clamping force because of the soft joint? If not, why was toothed washer specified in this case?
Bob

[68camaroz28]

John,
How would the bolt stay tight at half of it's recommended torque?
Is the plastic case compressing and compensating for the lack of bolt stretch or are the teeth on the conical washer keeping the bolt tight?
Bob

"Recommended torque" on a fastener is determined by Fastener Engineering based on the type of joint and the joint materials involved; the fastener's job is to establish and maintain clamping force in the joint, and the torque required to do that is a function of the materials in the joint.

In this case was the conical toothed washer used to maintain clamping force because of the soft joint? If not, why was toothed washer specified in this case?
Bob

Are you referring to the battery hold down bolt #3758783 Bob? It did not have a conical toothed washer that I'm aware of, just that oversize captured washer.

[big iron]

Chick,
Yes.
The questions I have asked have arisen from reply #1 which indicates two types of bolts being used on survivors but only one type was factory specified.
Just trying to find an engineering answer to my reply #6 and now reply #10.
Bob

[JohnZ]

John,
How would the bolt stay tight at half of it's recommended torque?
Is the plastic case compressing and compensating for the lack of bolt stretch or are the teeth on the conical washer keeping the bolt tight?
Bob

"Recommended torque" on a fastener is determined by Fastener Engineering based on the type of joint and the joint materials involved; the fastener's job is to establish and maintain clamping force in the joint, and the torque required to do that is a function of the materials in the joint.

In this case was the conical toothed washer used to maintain clamping force because of the soft joint? If not, why was toothed washer specified in this case?
Bob

I guess you'd have to ask the responsible release engineer about the specifics.

[KurtS]

Clamping force required, that's all. They worked out the force required for the battery and generated the spec. Sure don't want to have the battery loose or crack the case.

[big iron]

John,
How would the bolt stay tight at half of it's recommended torque?
Is the plastic case compressing and compensating for the lack of bolt stretch or are the teeth on the conical washer keeping the bolt tight?
Bob

"Recommended torque" on a fastener is determined by Fastener Engineering based on the type of joint and the joint materials involved; the fastener's job is to establish and maintain clamping force in the joint, and the torque required to do that is a function of the materials in the joint.

In this case was the conical toothed washer used to maintain clamping force because of the soft joint? If not, why was toothed washer specified in this case?
Bob

I guess you'd have to ask the responsible release engineer about the specifics.

John,
Thank you for your input to my questions and as always I usually learn something from your replies.
Any DRE engineers out there that could respond to my final question would be appreciated.
Bob

[big iron]

Clamping force required, that's all. They worked out the force required for the battery and generated the spec. Sure don't want to have the battery loose or crack the case.

.
Kurt,
I can agree with you fully if the bolt 3758783 is as Chick described from his 68 survivor. But if we assume that the bolt 3758783 is a lead point with a toothed conical washer as on other survivors, we have to ask, which style bolt is correct? If they are both correct then the AIM's are incorrect and can be noted.
Bob

[KurtS]

I'm missing how which bolt affects the torque question.

btw, I was a D&R engineer.

[68camaroz28]

Guess I'm trying to know more about the washer being a conical toothed washer as I've not noted one of those. JohnZ's seems to be the same as the examples I have but maybe something is different below. The clamp is not what I'd expect to see as correct as most originals have two indents.

Here is what I deem an original off one of our cars with the original battery hold down clamp (has two indents).

Large type captured washer approximately .87 thousands of an inch in diameter.

The underside of the washer-

[big iron]

http://www.camaros.org/forum/index.php?topic=2899.0

Maybe JohnZ can re-post the pic. I couldn't get it to open.

To All,
Before we go further, please read Phillip's attached thread as we seem to have a communications gap.
Two different style bolts and two different style conical washers = my questions. Which style and if both ( AIM indicates only one), then why the lead point and conical toothed washer?
Bob

[68camaroz28]

http://www.camaros.org/forum/index.php?topic=2899.0

Maybe JohnZ can re-post the pic. I couldn't get it to open.

To All,
Before we go further, please read Phillip's attached thread as we seem to have a communications gap.
Two different style bolts and two different style conical washers = my questions. Which style and if both ( AIM indicates only one), then why the lead point and conical toothed washer?
Bob

JohnZ posted his bolt on this thread reply #2 so that answered or took care of what Phillip was referring to, i.e. "maybe JohnZ can re-post his pic", or at least I thought it did Bob. And I do not see a conical toothed washer on his bolt he posted, only a captured washer the approximate same size as what we both have communicated but maybe John can clarify. 
The only thing I've noted unique on this part # is the large diameter of the captured washer which I'm not aware of it being used anywhere else on the car as I went through all screws, bolts, etc. in my 68 AIM looking for similarities back sometime ago.  Here is one more original exactly like others except for supplier name.

[KurtS]

I would agree these bolts all appear the same. 7/8" washer.

[Marty]

My original bolt was missing but I have one off a 68 full size car from the junkyard. It's the same as those shown, 0.87" diameter captured washer, 0.060" thick, tapered tip, length about 29/32" length from washer to tip. Mine has the RBW head markings with the three lines and dot under the B, so a little different than the one already posted.
Martin

[big iron]

Mine, which I believe to be original, is a 5/16"-18 recessed hex head with a captured conical washer and a reduced-diameter round flat point (we called them "dog-point" bolts in the plant).
[/quote]

Washer is 7/8" in diameter, and it does have serrations ("teeth") on the bottom.

John,

Two different styles of washers and two different styles of bolts = ?
Bob