The Stovebolt Site Forums The Shop Area Engine Shop 216 Rear engine mounts, Where are they From??

I have a 1951 Chevy 3600 with a 216. The rear engine mounts and cross member are not consistent with the manuals. It appears the cross member was replaced with a different style, thus the motor mounts are different as well as the flywheel housing. Any body know where these mounts and cross member comes from. I cannot find the motor mounts anywhere.

Pictures of Cross Member/Flywheel Housing/Motor Mounts

Hy tsteckle, the only thing I don't recognize as stock is the mounts themselves. I think if you removed those mounts from the bellhousing, and purchased the stock mounts for the truck, everything would bolt together as it should, hope that helps.

These are HD mounts that were offered through dealers and FLAPS as a replacement part. I believe it is mentioned in the Master Parts Catalogs but not in the data books. I have also seen them as NOS items offered occassionally on eBay. The reason they were offered is for the reasons you see in the weld repairs on the crossmember I have not seen many trucks (47-53) that did not show evidence of stress or cracking in this area. The new 54 style is completely different for a reason and that is the original 47-53 style were sometimes a warranty/service problem. These may also be mentioned in one of the 49-53 service bulletins. I think recall seeing them but don't know which series.

A little more info:

In section 0.029 of the 29-53 Master Parts Catalog these mounts can be found on page 84. They are reffered to as 47-53 UTILITY UNIT carrying part #3689112* and the note says they are to replace rubber mounts for HD Service.

Ok, great! This helps alot. When I looked at the cross member I thought someone had replaced the original with something not. Where would a guy find these HD replacement mounts, or should I just buy the standard mount from LMC. My one questionis, I have the Factory Assembly Manual, and no where in there is this cross member and mounts depicted. All I can find is the original, which is why I raised this question? The pictures in the manual look nothing like what I have.

The 47-55 FAM contains illustrations for 54/55-1st series trucks. The frame cross member for the rear motor mounts changed in 1954 (as did the motor mounts and the clutch housing).

Brad is right on about the cracking at the upper part of the cross member. My '50 has the same problem and I suspect that it is the cause of the vibration that I've had at about 40mph. I've been chasing that for five years and haven't been able to nail it down and I probably still won't be able to test it till I do the frame off next year and can make the correct repairs.

I would really like to see some close up pictures of those HD motor mounts. I'm assuming you're going to replace them with the stock motor mount, I would really appreciate it if you could post a few more when you get them out in the open.

Denny Graham
Sandwich, IL

Yeah that is no problem, I will post more pictures Monday when I get home. I looked at the flywheel housing again, I still dont see where the stock motor mounts would bolt to it. Does anyone have any pictures/illustrations of a flywheel housing and cross member with the stock mounts, for my 1951?

Brad, Is there any site to get information on those services bulletins you mentioned?

The service bulletins may be posted online somewhere (I have not found them yet). I ordered reprints from ClassicParts or one of the other vendors so I have the 49-50 years which I will pull out and look at. I have pictures of the bell housing and stock mounts I will post some tomorrow. They will bolt right up to your bellhousing and crossmember with no problems. I actually swapped out my 50 crossmember for a 54 version/bellhousing/mounts/engine and it is night and day different on vibration, the 54 is really a good upgrade.
http://community.webshots.com/photo/2656458530102454676QmfUEF

Scroll around this picture, it shows the new rear mounts on a 1950, 216:
http://www.pbase.com/dennygraham/image/136171598

Denny Graham
Sandwich, IL

All the parts books that I look in have this listing for the rear motor mounts:

1937-53 ALL COMM (exc. ½ ton) pn 3702198 changed from pn 595741

1947-53 ½ TON (2nd design) rear mount is shown as pn 756700. What the difference was in the ½ ton rear mount I have no idea. I’ve always been under the impression that they were the same on all of them.

I see no mention of a “HD” rear motor mount in the 1929-1950 or 1929-1954 parts books. I also looked at all the indexes of the 1947 thru 1954 Chevrolet Service News and the only mention concerning the rear mount that I could find was a reference to the 30° angle change made to the rear cross member for the 1954 model year .

There is an illustration in the early parts book of a pn 598097 mount, however it isn’t listed in the text. That mount looks like it has the same mounting holes as the pn 595741 but has a thicker cross section.

It seems like I’ve seen those cylindrical mounts before but without having an original 1947-53 ½ TON (2nd design) pn 756700 rear mount and an original 1938-53 UTILITY pn 3702173 mount in front of me, I’m really wondering if those mounts in the picture just weren’t some aftermarket motor mount sold by an auto parts outlet.

Denny Graham
Sandwich, IL

Denny, I sold a NOS set of these HD mounts to someone on this forum a couple of years back so I know they are GM. They had a part number I found in one of my parts books, don't remember the number or which book though.

Denny,

I will scan in the page and part numbers from mine tomorrow. As Dave said I have also seen these NOS boxed with part numbers they are a GM part.

Thanks, they don't show up in anything I've got access to.
Denny Graham
Sandwich, IL

Denny I sent you and e-mail with the info.