1969 Z/28 motor mounts

[bertfam]

I didn't even mention items 5 through 10 (UPC Z28, sheet A4), which were added to the AIM on 6-2-69 (?). I believe these were a stop gap measure before the locking mounts were available. In fact, item #5 is called a "STOP"! It's a LEFT HAND item only, so it kind of adds to the above chart. Note the P/N 3886466 shows A.R. (As Required), and the P/N 3939728 shows only 1 being used.

For service requirements, I believe the 3886466 (non-locking mount) was attached to the right side of the engine and the 3939728 (locking mount) was attached to the left side of the engine!

For production, I have a feeling (no proof) that locking mounts were never used on the 302, but a stop gap measure was applied at some point during the production run. My copy of the AIM shows the date, but the month is kind of light and I can't be sure it's a 6 (June). Does anyone have a better copy that shows the month?

Ed

[1968RSZ28]

Here's a few photos of a NOS 3886466 mount that was sold on Ebay last month...

http://www.ebay.com/itm/NOS-1961-1966-CHEVROLET-IMPALA-PASS-CAR-CORVETTE-409-396-427-MOTOR-MOUNT-3886466-/160952620273?pt=Vintage_Car_Truck_Parts_Accessories&vxp=mtr&hash=item25798614f1&nma=true&si=ISS%252BUXUgyJIHq7fDO3Dqcu0xHtk%253D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557

Paul

[tmodel66]

The 466 is the wrong mount. It's too wide for the engine stand and flops like a fish when you put it on.

[69Z28-RS]

The two photos below are of:
1)  the 3886466 mounts,  
2)  a top down view of three different mounts showing the width across the frame stand:
     On Left)  parts store mount for 302 (3" wide),
     in middle)   3886466 mount
     on right)  The 3962478 mount

The 3886466 mount is only maybe 1/8" wider than the 3962478 mount, but the parts store mount is WAY wide (3").
The 3962478 mount has a round hole for the attachment to the frame stand, the other two mounts have oblong holes.
The 3962478 mount is approximately 1-1/2" high/thick, the other two are almost the same height, or thickness, about 1".

[lynnbilodeau]

I am more confused then ever.

According to the GMparts wiki, the stop was not discontinued until 1975:

http://www.gmpartswiki.com/getpage?pageid=23193

dealer cost was $1.02

[lynnbilodeau]

Chuck has a pair from a low mileage Z on epay.  I asked him if he knows the build date on the car they came from.

http://www.ebay.com/itm/1969-Camaro-Z28-original-GM-motor-mounts-302DZ-/330683645335?pt=Motors_Car_Truck_Parts_Accessories&hash=item4cfe47fd97&vxp=mtr

[69Z28-RS]

From the photo, I think the width of that motor mount on the left is TOO wide for the Z28 frame stand...   Can't quite tell with the one on the right; it could be the right width..?

[Fred Mertz]

I don't know what the practice was in '69 but today when a part number changes and they are physically still the same, the change is due to a change in vendors.  The number change is how they keep track of inventory when a vendor change is made.

(34 years Mercedes Benz parts experience at the dealership level)

Just my 2 cents,  Dave

[firstgenaddict]

This is the correct non locking motor mount, there was an extended discussion on this a couple of years ago, it showed the extra parts that were added later in the year in order to keep the motor mount from separating.

[69Z28-RS]

Trying to read the part number:   Is it 3939728?  do you recall how they ascertained that was the production PN?  Is there factory documentation?

[JohnZ]

I don't know what the practice was in '69 but today when a part number changes and they are physically still the same, the change is due to a change in vendors.  The number change is how they keep track of inventory when a vendor change is made.

That's not the case with GM parts; drawings may show "optional constructions" to accommodate different vendor tooling or facilities constraints, but part numbers are unrelated to vendors.

[firstgenaddict]

3939728 GOLD
xxxxx07  GREEN
xx22302  AU

Is what is molded into the rubber -

This is the original passenger side motor mount for the 51 k mile Norwood 10D Early Z I have which was taken off the road in 1973.

[rszmjt]

Heres the drivers side - Note the moulded in nut
Moulded in numbers-
3939727 Pink
3943218 Lime
3931892 Coral

[rszmjt]

additonal view

[69Z28-RS]

In the last photos posted, the 'nut' appears to be 'welded' rather than molded in.   Wouldn't a molded in nut be on the opposite side where all the rubber is located?    What is the purpose of all the rubber on the side of the mount?  the holes (for the large bolts) in that mount appear to be round, rather than oblong.   Correct?