Engine rocking and Motormounts question.

Hi everyone. I drive 1998 Buick Park Avenue Ultra Supercharged with 156k mi on the clock. At about 152k mi I changed 2 mounts: the front of the engine near the radiator and the rear one near passenger compartment to prevent huge engine rocking when shifting to reverse from any gear. At first there was some improvement, but now it's almost the same, like I didn't spend $700 to change 2 mounts. What could be the problem? When the mounts were changed my mechanic showed me the old mounts - all torn and overused. My concern is because I drove my friends 1999 Oldsmobile 88 with the same engine (no supercharger) with 215k mi and shifting between gears is flawless - no noise, no boom sound like I hear in my car.
Any input will be appreciated.

Thank You.
Yuri.

I have been through the same thing with my Ultra. The additional torque and HP contribute to the problem, over the standard version 3.8. What kind of mounts were installed? Never use "Anchor" brand, (made in China) on the left front transmission. I tried that already, it broke within a week! Pioneer and GM brands seen to last longer, however with a lot of miles and abuse, they will also break. I consider these mounts as routine maintenance now!
If you want them to last longer, be easy on the throttle from a start, and once the car starts moving, gradually open it up to full throttle.


By the way, if you paid 700 bucks to replace two mounts, you need to do some competitive part & mechanic shopping in the future.

I have been through the same thing with my Ultra. The additional torque and HP contribute to the problem, over the standard version 3.8. What kind of mounts were installed? Never use "Anchor" brand, (made in China) on the left front transmission. I tried that already, it broke within a week! Pioneer and GM brands seen to last longer, however with a lot of miles and abuse, they will also break. I consider these mounts as routine maintenance now!
If you want them to last longer, be easy on the throttle from a start, and once the car starts moving, gradually open it up to full throttle.


By the way, if you paid 700 bucks to replace two mounts, you need to do some competitive part & mechanic shopping in the future.

Thank you for the reply. The price was that high because I got genuine GM AC Delco mounts from dealer.
Also the side mounts, will they help easing the engine rocking?
One more question: I have to rebuild my supercharger. It's making a growling noise when it's in any gear and standing still, when moving - no noise is coming out. I did some research and found that the price is $450 for a rebuilt unit (with your core return). Maybe you know any other places where I can get better price.

Thanks.

If you will notice the engine rotates back toward the fire wall when you accelerate in forward gears and in reverse it would be the opposite. The only mount that seems to take the abuse from hard acceleration is the left front transmission mount. The others just sit there and float. The dog bone on the front, holds that end very well.

It seems that 400-500 bucks is the going rate on a SC rebuild. Have you changed the oil in the snout?

If you will notice the engine rotates back toward the fire wall when you accelerate in forward gears and in reverse it would be the opposite. The only mount that seems to take the abuse from hard acceleration is the left front transmission mount. The others just sit there and float. The dog bone on the front, holds that end very well.

It seems that 400-500 bucks is the going rate on a SC rebuild. Have you changed the oil in the snout?

You mean the mount on the driver's side of the engine bay?

Oil, no I never touched the supercharger, how and where do you change the oil? Is it a special oil? Where to buy this oil?

By the way where did you get 2.2" suprcharger pulley? How many horses do you have with a current set up?

Thanks.

You mean the mount on the driver's side of the engine bay?

Oil, no I never touched the supercharger, how and where do you change the oil? Is it a special oil? Where to buy this oil?

By the way where did you get 2.2" suprcharger pulley? How many horses do you have with a current set up?

Thanks.

Yes, the left front transmission mount, is on the drivers side front of engine and bolts to the block on one end, and the front crossmember on the other end.

GM supercharger oil can be purchased at any GM dealer or;

zzperformance.com http://zzperformance.com/products1.php?id=154

gmpartsdirect.com http://www.gmpartsdirect.com/ on the main page, type in 12345982 in the part number box.

http://www.pulleyboys.com/ Pulley Boys - -

It takes about 1-2/3rds bottles to refill the snout. Price range from $3.50 - $7.50 a bottle, depending on where you get it. Some people pump the oil out with a little drill type oil pump and others use a small turkey baster to suck it out. Just remove the plug and suck the used oil out, then refill to the threads on the fill hole.

I got the 2.2' pulley from Pulleyboys.com, (link above). With the 2.2' on the 1992, your boost will be in the 10-11 lb range. The custom prom alters fuel and timing curves, to accommodate the extra boost. I would guess with both changes it gained 25-30 HP. Keep in mind that you will also need a CAI to allow the SC to get the extra air it needs.