any use these engine mounts?

[jethrow6978]

hello everyone
My 69 firebird ls2/t56 setup vibrates very bad at about 65 mph and higher. It only vibrates when it is driving/rolling. I am using the 327 frame stands and tall and narrow mounts. I am also running a BMR crossmember. I took measurements of the trans angle and it is at -6 degrees. and after doing some internet searching i found that this is alittle too much downward angle. I also recently installed the heidts four link kit with 9 in housing and coilovers. The car used to never vibrate before with the old leaf spring setup and 10 bolt. I measured the pinion angle and it was set at +6 degrees. I know this kit lowered the rear axle in the car roughly 2 inches. After having a new shaft built, rebalancing my wheels and trying to adjust the coilovers out to make the angle alittle less,nothing has changed. It still vibrates very badly.:banghead: I called "Holley" and one of their techs confirmed that -6 degrees trans angle is way to low and they suggested these mounts. https://www.holley.com/products/ls_p...parts/12618HKR (https://www.holley.com/products/ls_power/engine_and_transmission_mounts/ls_engine_mounts/parts/12618HKR). My question is has anyone used these mounts? pros and cons of each would be greatly appreciated. Also would i need to purchase the crossmember to match the mounts also or can i keep my BMR one? any help would awesome. :fart:

[OG_Racing]

mine vibrated your teeth out at 65... after I changed everything else I found out it was a bad U-joint.

[69importkilla]

I am dealing with this exact issue as well. Chris Allison Chassisworks makes a new set of mounts that are supposed to deal with this exact issue.

I was hoping others would chime in this as well, as we cannot be the only ones that have encountered this issue. Hopefully this winter I will be able to try these new mounts....

[IMPALA MAN]

Check your adapter plates if you are using them.
Bet few if any knew. Very simple pieces right? We have all thought they were simple enough to make ourselves, right. You can't get them wrong....right?

If you look closer, you will see that the plate has four holes (in a perfect rectangle) that bolt directly to the LS Engine. They also have one hole that goes through the Factory SBC or BBC engine mount and into the LS Block.
The remaining two holes in the SBC or BBC mount, bolt to threaded holes in the plate.
They can be install two different ways. One way sets the engine about 2.00" higher than the other way

This way( the single bolt on the mount on the top
http://www.autopartsdb.net/assets/images/ProductImg/A/AT1003.JPG

Or this way the single bolt on the bottom
http://www.welderseries.com/blog/wp-content/uploads/shopp/images/LS166%20(6)%20(Small).JPG

So what's the big deal right!
When you install the plates with the two bolts to the top, the engine sets a little over 2" LOWER than the other way.
http://s616.photobucket.com/user/rickpaw/media/67%20Firebird%20LS%20swap/P1010644_zpse9922b91.jpg.html
OR
http://s616.photobucket.com/user/rickpaw/media/67%20Firebird%20LS%20swap/P1010670_zps69970d6d.jpg.html

This and all of the different heights of factory engine mounts and stands may explain why it seems so hard to get headers, oil pans, steering boxes and other things to fit in these swaps.
The solution,
1. Find out what the product (headers, oil pan, etc.) was built around before generating a headache.
2. Read the instructions on the plates.....if there are any?
REMEMBER: THIS HOBBY IS SUPPOSED TO BE FUN, LET'S KEEP IT THAT WAY.

[IMPALA MAN]

In most cases you are in a catch 22. If you set the engine low you get the driveline angle you need without cutting the trans tunnel. However you have very little if any pan clearance, the pan sump may hang below the crossmember (bad plan), you may have to notch the engine crossmember to clear certain accessories, steering box issues, and some steering component interference.
The other option, setting the engine higher, and you need to cut the tunnel, however Speedtech makes a great piece that makes that the easiest way....it is a great product and kudos to Speedtech!

http://www.speedtechperformance.com/index.cfm/page/ptype=product/product_id=264/category_id=30/mode=prod/prd264.htm

http://www.speedtechperformance.com/index.cfm/page/ptype=product/product_id=386/category_id=30/mode=prod/prd386.htm

[jethrow6978]

Thanks for the info guys. I just wounder how would the carpet and interior look with the speedtech tunnel cover installed. I am not running the factory console. It would be way eaiser to cut the trans tunnel and move it up, then pulling the engine/trans and cutting xmember. Not to mention having to buy different mounts. But i dont want the car to look ghetto or anything.

[andrewb70]

I am dealing with this exact issue as well. Chris Allison Chassisworks makes a new set of mounts that are supposed to deal with this exact issue.

I was hoping others would chime in this as well, as we cannot be the only ones that have encountered this issue. Hopefully this winter I will be able to try these new mounts....

OG Racing said that it wasn't the mounts that were the cause of the vibration...

The Holley mounts are very well designed and if I was building a F-body, I would use them.

Andrew

[69importkilla]

OG Racing said that it wasn't the mounts that were the cause of the vibration...

The Holley mounts are very well designed and if I was building a F-body, I would use them.

Andrew

My fault.

I didnt mean the mounts themselves caused a vibration, just the driveline angle they created is causing an issue..

[andrewb70]

My fault.

I didnt mean the mounts themselves caused a vibration, just the driveline angle they created is causing an issue..

Precision of language is important especially on the Internet where people just read bits and pieces...LOL

Andrew

[Toddoky]

hello everyone
My 69 firebird ls2/t56 setup vibrates very bad at about 65 mph and higher. It only vibrates when it is driving/rolling. I am using the 327 frame stands and tall and narrow mounts. I am also running a BMR crossmember. I took measurements of the trans angle and it is at -6 degrees. and after doing some internet searching i found that this is alittle too much downward angle. I also recently installed the heidts four link kit with 9 in housing and coilovers. The car used to never vibrate before with the old leaf spring setup and 10 bolt. I measured the pinion angle and it was set at +6 degrees. I know this kit lowered the rear axle in the car roughly 2 inches. After having a new shaft built, rebalancing my wheels and trying to adjust the coilovers out to make the angle alittle less,nothing has changed. It still vibrates very badly.:banghead: I called "Holley" and one of their techs confirmed that -6 degrees trans angle is way to low and they suggested these mounts. https://www.holley.com/products/ls_p...parts/12618HKR (https://www.holley.com/products/ls_power/engine_and_transmission_mounts/ls_engine_mounts/parts/12618HKR). My question is has anyone used these mounts? pros and cons of each would be greatly appreciated. Also would i need to purchase the crossmember to match the mounts also or can i keep my BMR one? any help would awesome. :fart:


The 12618HKR Hooker engine brackets and 12626HKR T56 crossmember for your application will put the engine/trans into your car between 3 and 3.5 degrees (that 6 degrees is killing your efforts)to give you better optimized U-joint working angles AND better ground clearance of your T56 case where it hangs down just in front of the crossmember. This was all made possible specifically due to the development of the new Holley 302-2 oil pan, which allows the front of the engine to be placed lower in the subframe than possible with just about any other pan besides the 4th-gen F-body pan. No type or brand of swap plates that install with the factory frame stands and mounts can achieve this lower height due to their discrete stacked height, which is non-adjustable.

The Hooker combination of mounting components can be installed without having to cut the tunnel at all and gives your car a lower center mass height than you get by cutting the tunnel and raising the engine/trans (read good for handling performance). Search around on LS1tech and you'll see a number of builds featured there that have used the mounts and the crossmember, so you can ask questions of the users for a first-hand experience. Feel free to PM me if you have any technical questions about the set-up.

[69importkilla]

Precision of language is important especially on the Internet where people just read bits and pieces...LOL

Andrew

I just presumed that the caliber of people here were mind readers....LOL

Let me just say Laughing Out Loud! Only joking....

[andrewb70]

I just presumed that the caliber of people here were mind readers....LOL

Let me just say Laughing Out Loud! Only joking....

No worries...:-)

Andrew