Mckinney Mounts causing engine to shake?

[noodl35]

So I've had my rb26 s14 done for almost a year now and the engine runs pretty good. One big problem I have is with the mckinney mounts. During low acceleration or reverse acceleration, the engine shakes back and forth horribly causing the transmission to shake as well. I've re-tightened the transmission mount and that worked for a day but I think the 2 front mount polyurethane isolators are causing the vibrations. I have a lightened flywheel with 1 piece alum. driveshaft, which could cause some vibrations but I'm pretty sure the mounts are the issue. Anyone ever had this type of issue with Mckinney mounts?

[gawdzilla]

You might have something wrong, like an unbalanced driveshaft? Does it occur when you aren't moving too? If not, it is probably not the engine mount.

I switched to the solid aluminum pucks Mack offered about 4 years ago and haven't looked back. The poly ones always warped or got squished. Mack stands by his product and helped me out with getting some solid pucks and they've been great. Only my trans mount still has a bushing in it. Vibration isn't bad at all. Hardly noticeable for a solid engine mount.. probably because of the i6.

[noodl35]

Engine only shakes back and forth when like pulling out slowly in 1st gear or reversing out of a parking lot, situations like that. Does not shake when going full speed. It is also hard to shift sometimes when your gassin it and shift quickly. That sudden jerk causes the shifter not to go into gear smoothly. I feel like I may need solid metal mounts like you have gawdzilla. Ill contact Mckinney Motorsports and see if I can pick up some. Thanks for the feedback.

[Yellow4g63]

did you drill the front cross member and put the bolts through the mount to hold the it firm?

[noodl35]

Yes drilled the holes and bolted the blue mounts firmly. A little more background about my swap is that i used the oem rb26 cast aluminum oilpan causing the bottom of the pan to touch the subframe. I literally had to add an inch worth of big washers on each isolator for it to not touch (words from mack and other mckinney users). I feel this also adds to the flexibility of the mounts. May have to make my own custom one-piece isolators. We'll see. Definitely these mounts were made with rb25 oil pans in kind . Anyone else using cast rb26 pans chime in?

[Ramius83]

Back when I was using McKinney mounts, I had a similar issue. Whenever I bolted the bottom wing down onto the sub-frame, I would get some heavy vibrations, more than normal. I bought a 12"x12" piece of solid poly-urethane, 1/4" thick. I cut two 1" squares out of it. Then I placed each of those squares in between the sub-frame and the front lower wings, solved all issues. It doesn't make sense why I was getting the vibrations as the engine was mounted to the hockey-puck mounts and not touching the sub-frame. But it worked for me.......

[noodl35]

Thanks for replies. After looking at my passenger side isolator, i noticed a crack. Spoke to Mack and he is sending me solid aluminum isolators good customer service