Looking for a Motor Mount DIY
Thread Starter
Instructor
Joined: Aug 2008
Posts: 146
Likes: 0
Looking for a Motor Mount DIY
I'd really like to get solid motor mounts. I found them for $40. However I don't want to pay a lot to have them put in. I was wondering if it is a difficult job. I would like to do it myself. I am by no means a mechanic, however I do consider myself to be a competent "Do it yourselfer". So I was wondering how to swap them. If I could see the procedure then I could determine if this is something I could do myself. Also, for those of you whove had this done, what did the labor cost you? Any input is greatly appreciated. Thanks.
Melting Slicks
Joined: Jul 2000
Posts: 2,541
Likes: 0
From: Chicago
Solid motor mounts won't do anything for throttle response, that is all in your tune. If you go to solid motor mounts then the weak link or sloppy link becomes the rear differential mount. Changing the motor mounts will not address wheel hop. As far as the install goes it isn't very hard. You basically need to remove pass and drivers side headers. Lift up the engine (watching the firewall for interference). Remove the old mounts and replace with new. I think the torque on the bolts is like 49ft/lbs (check that).
Thread Starter
Instructor
Joined: Aug 2008
Posts: 146
Likes: 0
Thanks for the input Nassy. I do plan on changing the rear mount as well. I don't feel confident doing a header install myself. So it seems that my best bet is wait until I get my headers, then have a professional install both at once.
Melting Slicks
Joined: Jul 2000
Posts: 2,541
Likes: 0
From: Chicago
I think the biggest limiting factor for most people is a lack of proper tools. If you have the right tools for the job and patience, you can learn/do pretty much anything.
Best of luck
Racer
Joined: Jun 2007
Posts: 468
Likes: 15
From: Jupiter FL
As far as the install goes it isn't very hard. You basically need to remove pass and drivers side headers. Lift up the engine (watching the firewall for interference). Remove the old mounts and replace with new. I think the torque on the bolts is like 49ft/lbs (check that).
I checked the shop manual and it talks about unbolting the shocks, pop the tie rod ends and other simple by time consuming
bolt remova itemsl. Then securing the engine and dropping the cross members.
Now if your solution of unbolting the mounts and raising the engine works, it will be much easier. Have you ever replaced
the mounts using this method?
Thanks
Jay B
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Melting Slicks
Joined: Aug 2006
Posts: 2,205
Likes: 2
From: port monmouth nj
mine were changed when stroker went in. used pfadt mounts. reason drive train shake. on a real good launch the stock mounts would allow motor to twist from the excessive torque and car would go left and make a rumbling type sound would ruin a good launch. happened 3 seperate times in about 30 launches. with pfadts havent had it happen yet 10 launches and im now running a 383 stroker with 10 per cent more torque as compared to the last setup 346.
Burning Brakes
Joined: Mar 2010
Posts: 1,189
Likes: 4
From: Freeport, FL
Oh, have you found solid tranny mounts or are you going to run polyurethane mounts? I've always opt'd for solid up front and poly in back. Dunno, just figure the poly mounts will hold the rear just fine with solid up front, but if there is chassis flex it wont strain the rear end.
Tech Contributor
Joined: May 2008
Posts: 2,843
Likes: 16
From: Howell Michigan
St. Jude Donor '09-'10-'11
What would cause the flex?
Burning Brakes
Joined: Mar 2010
Posts: 1,189
Likes: 4
From: Freeport, FL
example, if the crank spins clockwise, then when you rev the engine you'll see the car lean counter-clockwise.
That gives a very rough idea of what forces are doing what. And when you have a moving force of any kind and a less powerful holding force, the holding force will be overcome. Thus the need for increased holding force, i.e. the solid motor mounts, or frame connectors, poly bushings and mounts, etc.
Not the best reply I'm sure, but hopefully it helps.
Burning Brakes
Joined: Mar 2010
Posts: 1,189
Likes: 4
From: Freeport, FL
An old school trick was to use a short length of chain and bolt it to the driver side of the engine block and to the frame of the car. Only was effective if you could find just the right length of chain so that there was no slack at all.
Tech Contributor
Joined: May 2008
Posts: 2,843
Likes: 16
From: Howell Michigan
St. Jude Donor '09-'10-'11
Hmmm, well, the rotating assembly spins one way and when acceleration takes place it results in the surrounding mass, i.e. engine block, to rotate in the opposite direction. Sorry, not the best explaination.
example, if the crank spins clockwise, then when you rev the engine you'll see the car lean counter-clockwise.
That gives a very rough idea of what forces are doing what. And when you have a moving force of any kind and a less powerful holding force, the holding force will be overcome. Thus the need for increased holding force, i.e. the solid motor mounts, or frame connectors, poly bushings and mounts, etc.
Not the best reply I'm sure, but hopefully it helps.
example, if the crank spins clockwise, then when you rev the engine you'll see the car lean counter-clockwise.
That gives a very rough idea of what forces are doing what. And when you have a moving force of any kind and a less powerful holding force, the holding force will be overcome. Thus the need for increased holding force, i.e. the solid motor mounts, or frame connectors, poly bushings and mounts, etc.
Not the best reply I'm sure, but hopefully it helps.
Burning Brakes
Joined: Mar 2010
Posts: 1,189
Likes: 4
From: Freeport, FL
Well, I take it that you are new to Corvettes. Our Corvettes are different than most other cars on the road. They have a propshaft that rotates in a torque tube. These to parts allows the reacting torque a direct path back to the engine without going through the engine mounts. If you would like to learn more about this I would suggest reading this THREAD starting with post #15.
I just thought you were a novice asking about a simple concept.
I realize that this forum is about Corvettes, but you asked in a manner that suggested that you had no idea as to how an engine could possibly cause "flex", so I responded in a very general manner. If you understand the workings of the Corvette, it seemed a better use of your time would have been to offer your knowledge upfront in order to help those reading this thread.
Pro
Joined: Feb 2004
Posts: 718
Likes: 1
From: barrie ontario
I replaced mine with the poly ones.
Lifting the engine did not give enough clearance. I also had to drop the front cradle a bit to get them out.
You will notice quite a bit more vibration with the stiffer mounts but you can notice a difference in power delivery.
Lifting the engine did not give enough clearance. I also had to drop the front cradle a bit to get them out.
You will notice quite a bit more vibration with the stiffer mounts but you can notice a difference in power delivery.
Burning Brakes
Joined: Mar 2010
Posts: 1,189
Likes: 4
From: Freeport, FL
I think I'm gonna install poly or solid mounts
Tech Contributor
Joined: May 2008
Posts: 2,843
Likes: 16
From: Howell Michigan
St. Jude Donor '09-'10-'11
Nope, not new
I just thought you were a novice asking about a simple concept.
I realize that this forum is about Corvettes, but you asked in a manner that suggested that you had no idea as to how an engine could possibly cause "flex", so I responded in a very general manner. If you understand the workings of the Corvette, it seemed a better use of your time would have been to offer your knowledge upfront in order to help those reading this thread.
I just thought you were a novice asking about a simple concept.
I realize that this forum is about Corvettes, but you asked in a manner that suggested that you had no idea as to how an engine could possibly cause "flex", so I responded in a very general manner. If you understand the workings of the Corvette, it seemed a better use of your time would have been to offer your knowledge upfront in order to help those reading this thread.
If you take a look at molson’s post right after your response, “you can notice a difference in power delivery”. The fact of the matter, it will increase the amount of vibration into the vehicle with no benefit. If you took a ¼ mile run with stock engine mounts and then replaced them with poly mounts and ran the ¼ mile again you would see zero benefit in track times. I see a number of folks that will make statements like this about Corvettes. Unlike the “F body” mount changes on the Corvette will not gain you much if anything at all.