Does 1/2 in. matter for a BB motor mount?

[Barth C.]

Hello,

I am getting close to setting my rebuilt big block back on the chassis and have taken the advice of many on this forum to install locking type motor mounts. I don't care about originality here; I just want safe, functional mounts for my 66 roadster driver.

Not knowing one brand from another I purchased a low cost set. My concern is the new mounts are a full 1/2 inch thicker than the ones I took off and am wondering if this will lead to some clearance or alignment issue. The picture shows an old and new mount side by side. The old mounts are not original to the car either.

Any advice or words of wisdom would be appreciated. I've benefitted many times in the past from this forum.

thanks

Barth Canfield

[Joe L.]

Re: Does 1/2 in. matter for a BB motor mount?

Hello,

I am getting close to setting my rebuilt big block back on the chassis and have taken the advice of many on this forum to install locking type motor mounts. I don't care about originality here; I just want safe, functional mounts for my 66 roadster driver.

Not knowing one brand from another I purchased a low cost set. My concern is the new mounts are a full 1/2 inch thicker than the ones I took off and am wondering if this will lead to some clearance or alignment issue. The picture shows an old and new mount side by side. The old mounts are not original to the car either.

Any advice or words of wisdom would be appreciated. I've benefitted many times in the past from this forum.

thanks

Barth Canfield

Barth-----


First of all, the old mount you show is an old-style, non-locking type mount. However, it does not appear to me to be an original-type Corvette mount. I cannot see it real well in the photo, though.

Second, the new mount does not look, at all, like a Corvette mount to me. Are you sure they sold you a Corvette mount and not one for some other Chevrolet application?

[Barth C.]

Re: Does 1/2 in. matter for a BB motor mount?

thanks for the response

I know the old mount is not Corvette.

The new mount was advertised as "correct in fit and function" for 1966 Corvettes but I suspect it is a generic mount for Chevrolet applications. which is the reason for my concern.

The old mount sets the center of the frame bolt 1.75 in from the backing plate. The new mount sets 2.25 in. I don't know what a correct mount would be or if it matters. Any recommendation for a correctly functioning mount would be appreciated.

regards

[Joe L.]

Re: Does 1/2 in. matter for a BB motor mount?

thanks for the response

I know the old mount is not Corvette.

The new mount was advertised as "correct in fit and function" for 1966 Corvettes but I suspect it is a generic mount for Chevrolet applications. which is the reason for my concern.

The old mount sets the center of the frame bolt 1.75 in from the backing plate. The new mount sets 2.25 in. I don't know what a correct mount would be or if it matters. Any recommendation for a correctly functioning mount would be appreciated.

regards

Barth------


The dimension does matter. On a Corvette mount, I measure the dimension you described to be right at 1-13/16" which is pretty close to the old mount you have.

I would not use that new mount you have. I don't think it's right and even if it turns out to be the one that's cataloged for the Corvette application by the manufacturer, I still wouldn't use it.

1963-82 Corvette mounts are no longer available from GM. When they were available they were expensive but just about the last American-made mounts on the market. I know of no American-made mounts currently available for 1963-82 Corvettes. So, all things considered, I'd recommend that you go with an Anchor brand mount. Their part number is 2285. Many parts stores should have this mount and they should sell for less than about 15 bucks, each. A photo of one is attached.

[Jake D.]

Re: Does 1/2 in. matter for a BB motor mount?

Barth- I have 2 - 2285 motor mounts in stock from a previous project. We went with polyurethane motor mounts, so these were not used. Send me your address, and I'll ship them to you free! They are brand new in the box never used.

[Jake D.]

Re: Does 1/2 in. matter for a BB motor mount?

Barth- The mounts are on their way. You should receive them Wed. 3/30/11. Mailed 'em this morning 9:00.

[Domenic T.]

Re: Does 1/2 in. matter for a BB motor mount?

For what it is worth, I am using the original style (dangerous) mount with the cable that was installed from frame mount bolt to engine block bolt.

Yes, I installed a number of these on cars at the dealership and was told that it was a safety strap offered by GM because there were a number of cars that were involved in accidents due to a stuck throttle when the mount broke and pulled the throttle linkage wide open.

As I remember the cable was about 6" long and one end went on the long bolt that held the mount to the frame and the other to 1 of the 3 that held the mount to the engine.

We only put them on the left mount because all the failures that caused the engine to lift and bind the throttle linkage open were when accelerating forward. That's why the left mount always went first.

This may raise a few brows but I didn't dream this up. I just installed them and they were not customer pay jobs.

DOM

[David D.]

Re: Does 1/2 in. matter for a BB motor mount?

Barth------


The dimension does matter. On a Corvette mount, I measure the dimension you described to be right at 1-13/16" which is pretty close to the old mount you have.

I would not use that new mount you have. I don't think it's right and even if it turns out to be the one that's cataloged for the Corvette application by the manufacturer, I still wouldn't use it.

1963-82 Corvette mounts are no longer available from GM. When they were available they were expensive but just about the last American-made mounts on the market. I know of no American-made mounts currently available for 1963-82 Corvettes. So, all things considered, I'd recommend that you go with an Anchor brand mount. Their part number is 2285. Many parts stores should have this mount and they should sell for less than about 15 bucks, each. A photo of one is attached.

Joe, I think you are going to find that the Anchor 2285 mount, that you recommended also has the wrong dimension. Most of them will measure 1-5/8", from the flat side of the metal plate facing the block, to the center of the motor bount bolt hole, not 1-13/16", like the original old style motor mount. Bottom line, to use the 2285 mount, need to use a spacer or washer, about 3/16" to 1/4" thick, between the block and back of the mount, at each of the 3 bolts that fasten it to the block. If not, you will not be able to get 1 of the frame mount bolts in. I believe you may also be able to just use the factory type "V" shaped A/C spacers. I think they are about the right thickness, but I am not sure. Also, the 2285 ears, that set over the frame mount location, that accept the frame mount bolts, are much wider apart, at the through bolt area, about 3/8" or more, if I remember correctly.
IMO, the locking mount with the 2.25 or so dimension, shown in Barth's picture, with the old aftermarket replacement mount, is for 1970 and up passenger car's. An easy way to tell, the mount ears are not be wide enough apart, to fit over the frame bracket. Hope this helps. Dave

[Joe L.]

Re: Does 1/2 in. matter for a BB motor mount?

Joe, I think you are going to find that the Anchor 2285 mount, that you recommended also has the wrong dimension. Most of them will measure 1-5/8", from the flat side of the metal plate facing the block, to the center of the motor bount bolt hole, not 1-13/16", like the original old style motor mount. Bottom line, to use the 2285 mount, need to use a spacer or washer, about 3/16" to 1/4" thick, between the block and back of the mount, at each of the 3 bolts that fasten it to the block. If not, you will not be able to get 1 of the frame mount bolts in. I believe you may also be able to just use the factory type "V" shaped A/C spacers. I think they are about the right thickness, but I am not sure. Also, the 2285 ears, that set over the frame mount location, that accept the frame mount bolts, are much wider apart, at the through bolt area, about 3/8" or more, if I remember correctly.
IMO, the locking mount with the 2.25 or so dimension, shown in Barth's picture, with the old aftermarket replacement mount, is for 1970 and up passenger car's. An easy way to tell, the mount ears are not be wide enough apart, to fit over the frame bracket. Hope this helps. Dave

Dave-----


I've never used the Anchor mount. However, I don't know of any better mount available on the market today. The reason I recommend the Anchor mount is that at least it's a brand name piece. All the others that I've seen are either no-name or a name that I've never heard of. Anchor used to sell mounts that were American made.

[Barth C.]

Re: Does 1/2 in. matter for a BB motor mount?

The ears on the locking mounts I have are a little too narrow to fit over the frame brackets as Mr. Dezinski suggested. I'm sending them back and will go with the 2285 mounts with spacers.

Thanks again for the information.

[David D.]

Re: Does 1/2 in. matter for a BB motor mount?

Dave-----


I've never used the Anchor mount. However, I don't know of any better mount available on the market today. The reason I recommend the Anchor mount is that at least it's a brand name piece. All the others that I've seen are either no-name or a name that I've never heard of. Anchor used to sell mounts that were American made.

Joe, I agree, the Anchor mounts are about the best there is on the market, today. That is the main reason I bought them. But, I found they also have design problems. I has 2 sets of the Anchor 2285 replacement mounts. One set was purchased over 12 years ago, embossed Made in Malaysia, in the rubber. The other set was purchased about 3 years ago, embossed Made in Taiwan. So, I doubt many, if any, currently available Anchor mounts are Made in USA.
I found the problems with the Anchor 2285 mounts, when setting the 427 engine and 4speed in my 1966 convertible, to free up some garage space. The 2285 mounts just would not line up, no problem with the old original mounts. So, checkng into it, I found the difference in the mounts. Side by side, it is not real noticable, but you can see the difference between mounts. I only mention the mount difference, to save someone some grief. Especially, when trying to line up the motor mounts to the frame and find it will not drop all the way down on the frame mounts. IMO, it is better to make someone aware of the problem now, before the engine and trans are hanging over the car and maybe have to remove it again. Dave

[Joe L.]

Re: Does 1/2 in. matter for a BB motor mount?

Joe, I agree, the Anchor mounts are about the best there is on the market, today. That is the main reason I bought them. But, I found they also have design problems. I has 2 sets of the Anchor 2285 replacement mounts. One set was purchased over 12 years ago, embossed Made in Malaysia, in the rubber. The other set was purchased about 3 years ago, embossed Made in Taiwan. So, I doubt many, if any, currently available Anchor mounts are Made in USA.
I found the problems with the Anchor 2285 mounts, when setting the 427 engine and 4speed in my 1966 convertible, to free up some garage space. The 2285 mounts just would not line up, no problem with the old original mounts. So, checkng into it, I found the difference in the mounts. Side by side, it is not real noticable, but you can see the difference between mounts. I only mention the mount difference, to save someone some grief. Especially, when trying to line up the motor mounts to the frame and find it will not drop all the way down on the frame mounts. IMO, it is better to make someone aware of the problem now, before the engine and trans are hanging over the car and maybe have to remove it again. Dave

Dave------


Yes, it's fine to make folks aware of potential problems, if only to advise of the sort of problems they will have to find some way to overcome. The unfortunate thing here is that, as I say, I don't think there's any better mount available than the current Anchor-branded offering. So, unless one happens to have NOS GM, one pretty much has to make the Anchor mount work. That may involve some modification or adaptation but there's no viable alternative at the present time.

I extensively investigated available motor mounts awhile back. I figured there just had to be an American-made mount somewhere available. It turned out I was wrong. For some reason, these mounts for older applications (and, even newer applications) have all gone "offshore". Offshore does not necessarily mean bad but in the case of these motor mounts, I have not seen one yet that I'd be really comfortable with.

[Tom R.]

Re: Does 1/2 in. matter for a BB motor mount?

Barth- I have 2 - 2285 motor mounts in stock from a previous project. We went with polyurethane motor mounts, so these were not used. Send me your address, and I'll ship them to you free! They are brand new in the box never used.

Man, you don't see this much anywhere else but with this group. Way to go Jake.

[Jake D.]

Re: Does 1/2 in. matter for a BB motor mount?

Barth-- I'm glad they arrived safely. I'm sure they will do the job for you. Enjoy. I'm glad to help--we're all in this together.