The Stovebolt Site Forums The Shop Area Engine Shop 49-53 front motor mount parts

Question about the front motor mount. There are many posts regarding the timing gear plate and poly replacement bushing, but I can find no mention of the lower bushing cover, either in the forums or the multitude of parts catalogs (they all seel the upper cover, but not the lower cover or the metal spacer)? I did find in one of the discussion threads the bitmap of the original front motor mount setup, showing the upper cover, a metal spacer, the rubber mount, and a lower cover.

Was the lower cover tacked to the frame? Does the lower cover actually exist (if so, could somebody point the direction)? Based on the response I get from the forum I will likely fabricate the lower cover and spacer myself, but wanted to check its existance first.

Here's a page with a pic of the front mount assembled. http://chevy.tocmp.com/1948_51truckshop/51ctsm0613.htm

It's been a few years, but I think the lower mount support sits on the frame, and the assembly is held in place by the two support to frame bolts

Thanks for the link. The photo in the link is the opposite of what I thought, i.e. the lower retainer is what all of the parts catalogs are selling, which I thought was on top. So, is the upper plate a seperate piece from the timing plate, or is it tacked to the bottom of the timing plate? Sorry to beat this one to glue but want to do this right the first time. I have a 59 270 going into a 49 1/2 ton so do not have the original setup to look at. I have found other references, specifically:

http://oldgmctrucks.infopop.cc/eve/forums/a/tpc/f/633004236/m/3261032931?r=4401042931#4401042931

The link above clearly shows 4 pieces, excluding the timing plate so am assuming a proper assembly is required for long life (which is actually the question). Anybody now where to get the parts in the photo (I have found the lower cover and the bushing)?

Thanks in advance.....

The upper part is called the oil shield and just sits on top of the mount plate. It just keeps any leaking oil from destroying the mount. I got one from Jim Carter a couple of years ago.

Thanks for the feedback... Ok, so the top piece is what the parts vendors are advertising (the oil sheild, or upper plate). Most all of the parts catalogs only sell the upper, but not the lower plate. Just spent 20+ minutes on the phone with Jim Carter's and after sending them a picture (taken from stovebolt, thanks) the light came on. They had all of the parts either new or used. Still trying to get my hands on the poly mount.

Once again, thanks for the help.... On to the next mystery!

I just recently installed my rebuilt engine into my 54 truck and to reinforce Murphy's law....I got it backwards! Not the engine...the front motor mount insert!!!!

The lower portion...1/8" steel box without a top, holds the rubber insert that you can buy from most any of the suppliers. I haven't found anybody that sells the lower box assembly or the steel plate that goes on top. The rubber cushion has 2 bushings.....the larger, longer part of the bushing goes on the TOP. A steel plate sits on top of this rubber bushing and 2 carriage type bolts drop down through the cross member and are secured with a nut and cotter key. The light oil shield sits on top of this assembly and is secured with a couple 3/8" grade 5 bolts with lock nuts that tie the main motor plate to the center bushings that you can also see from the underside of the cross member. This whole assembly can be installed with the engine in place but would be better installed before the harmonic balancer.

NOTE: There are some clearances and torques that must be maintained as noted in the Fred T's link. However, if you don't have the rubber insert oriented properly you'll have a serious vibration. I used a folded cloth pad, 3/4" plywood pad on top of floor jack...loosened rear mounts and headers and could jack the engine up enough to remove the assembly, flip the rubber insert and bolt it all back together. It was not a pleasant task as there wasn't really any totally effective way to block up the engine while I was making the change. Better to note that it CAN BE DONE WRONG and to get it right before you bolt on the balancer and get the engine lowered into place. Hope this helps prevent others from making this mistake.

Dave

Dave,

Thanks for the info. There seems to be some disagreement regarding the existance of the steel portions of the front mount. First question is, has anybody ever found ALL of the pieces for sale. I can only find 2, regardless of what you call it (Jim's said it was the oil shield, but was on the bottom, why would the oil shield go on the bottom?). The 49 GMC I purchased had a Chevy 216(?). I am replacing with a 59 GMC 270. Neither had the correct mount for this year so have nothing to go by.

Your info regarding proper setup will be valuable as I prepare to install the rebuilt 270. Jim's stated they had the parts, used and new, but now I question that they had the correct parts (told them to send them all and I will sort out the mess when it gets here). There was no mention of the bushing or the steel plate. If ANYBODY could supply dimensions of these two items (bushings & upper plate) I would be in your debt (I will fabricate). Also, you mentioned proper setup. I hope this is covered in writing somewhere, or as your signature states, "Experience, test first, lesson comes later".

Thanks......

First of all, are you referring to the single front mount (fig. 20) that is shown on Fred T's link? If we're all on the same page here...then that base and cover are what you're going to have to hunt up. The rubber insert and the thin sheetmetal dust cover are available from most vendors. LMC shows #34-031 "base plate" for $9.95. However, they don't show a "sheet metal dust cover" or the 1/8" steel plate that has the square holes and bolts through to the cross member. You might give them a call at 1-800-562-8782 to get some clarification. I have a feeling that it will be the thin sheet metal cover that fits down over the top of the mount assembly to protect the rubber insert from oil spray.

With all the engine swapping going on there should be somebody in the forum that would have the 1/8" thick base box piece, the 1/8" thick top piece with the square bolt holes and possible the carriage type bolts that tie the mount to the cross member. The 2 bolts that bolt the mount to the engine are just 2-1/2" grade 5 bolts with lock nuts.

BTW....I had the entire front mount in my hand this morning to correct my above mentioned bout with Murphy's law!!!

Dave

For what it is worth the top part or grease shield, and the rubber insert can be had at most part suppliers. The bottom cup, and the sheet steel cover are very very hard to come by. You might give Barry Weeks a holler. He had NOS front motor mount parts I needed for my 52. You might also put an ad in the parts wanted forum. Also don't get discouraged. It took me about a year to assemble the whole mount. Jimmie.

Jimmie,
I think that I may have found the correct parts, or so said Jim Carter's. They had the top and rubber new, and the other two used. If it turns out they are not correct then I will make them. I contacted AD-Engineering about the poly bushing and he responded that he no longer makes them. This issue is working itself out slowly but surely.

Thanks for the feedback.

This is explained above but let me go thru it once more.

From the cross-member up. There is the steel pan with sides on it which holds the rubber mount. Then there is a flat steel plate next and a stamped metal pan (oil shield) which follows.

The rubber mount in that steel pan bolts to the cross-member. The engine bolts to the rubber mount with bolts which go right thru the cross-member BUT do not touch it. If you look at the cross-member from below you will see that two of the holes are bigger and that is so the nuts/bolts do not touch the cross-member. You may ask why are there holes in the cross-member if the engine bolts are not attached to it. The holes are there so you can access the nuts.

The steel plate sits on top of the rubber unit and there should be a gap between the steel parts and the oil shield pan sits on top of that. It will take a few fingers to get everything lined up but its quite simple.

In theory what you have is a unit that holds the engine to the rubber mount with two bolts and two other bolts which hold the rubber to the cross-member without a direct connection.

I cannot tell you where to get the steel pan which holds the rubber mount but can offer two tips. AD Engineering make a replacement mount for the rubber one which is impervious to oil and should last forever. Secondly before you put the bolts thru the oil shield, put a dab of gasket cement around the hole to help prevent any oil seeping through the bolt holes.

Hope this helps although it might sound complex. Any questions you can get back to me directly if you want.

Bill

Did anyone ever find a source for the lower steel pan and the steel plate that was discussed in this thread? Jim Carters is out of the used parts business now.

Thanks,

Don

Here's what I came up with. The nomenclature is not the same with each vendor and does not coincide with the Manufacturer's parts listing. Olblu49 has tricked it out for us with a very good description.

Here's the skinny from the 1929 - 1957 Master Parts & Accessories Catalog: (Thanks to Keith Hardy) Note - Italics and bold mine and are representative of description in the Master Parts Catalog.
Engine Mounting Parts

Complete Front Mounting Assembly Breakdown see Front Motor Mount Assembly photos here

3656502 Shield, Frt Mtg, (7 15/16 x 2 1/2 wide)
3657522 Plate, Frt Mtg, Top, (7 7/16 x 2 wide)
368449 Retainer, Frt Mtg, (7 7/16 x 1 5/8 wide)
3657520 Mounting, Engine Front

JC Carter -- ME533 Motor Mount Shield (3656502 Shield) They do not carry the plate or retainer

Obsolete Chevrolet -- ME533 Motor Mount Grease Shield 6 CYL FITS ABOVE ME216 this is actually the(3657522 Plate). There is some confusion in part numbers but it appears that Obsolete Chevy carries everything but the retainer. Call them to sort it out.

American Classic -- MM-12 Motor Mount Front Shield this is actually the (368449 Retainer). They do not carry the plate or shield. Their MM-12 is only about 8 bucks but they have a $20 minimum order which is the only vendor that has this restriction to my knowledge.

Why no vendor carries the complete assembly or doesn't use the proper nomenclature is beyond me.

Don

I eventually found out the same thing you just described, and came to a similar conclusion, "why no single vendor has all these parts when they seem vital, yet simple to remanufacture?".

JC Classic Truck parts delivered on all of the required pieces: A new grease shield (ME533 is the sheetmetal grease shield), and a used top cover plate and lower mount (the rubber fits into this).

The poly bushings are not longer made, by anyone to my knowledge, so had to go with the soft rubber that everybody else is selling.

You together our two posts help others solve this puzzle.