For those of you who've done it, I'd appreciate any advice you may care to share about using a scissor jack to change the 2GM engine mounts, especially the front ones. I've got plenty of clearance under my engine but not much access from above (1995 Hunter 29.5). I'm tempted to place the jack under the oil pan with a piece of 1/2" plywood to help distribute the load. It'll work but I figure that I also stand a good chance of bending the pan and messing up the oil pan gasket. Where did you position your jack?
Using scissor jack to change 2GM engine mounts
- Thread starter chitradurga
- Start date
You go around the engine and remove/replace only one mount at a time. Do not jack up the engine.
First, check the radial and angular alignment of the shaft flanges so you'll have a rough idea of where you want to get back to. Next, measure all existing motor mount vertical and horizontal locations (before anything else is touched) so the new ones can go back in the same location.
The attachments to the engine block are removed in order to remove the mount without lifting the engine. This is where some gentle lifting is required to remove the attachments. I used wooden wedges to lift the block just enough to take the shear load off the attachment bolts.
I had the unfortunate job of replacing one rear starboard mount several years back and it was not fun by any stretch of the imagination. The front ones look like they may be a little easier but again, no picnic.
First, check the radial and angular alignment of the shaft flanges so you'll have a rough idea of where you want to get back to. Next, measure all existing motor mount vertical and horizontal locations (before anything else is touched) so the new ones can go back in the same location.
The attachments to the engine block are removed in order to remove the mount without lifting the engine. This is where some gentle lifting is required to remove the attachments. I used wooden wedges to lift the block just enough to take the shear load off the attachment bolts.
I had the unfortunate job of replacing one rear starboard mount several years back and it was not fun by any stretch of the imagination. The front ones look like they may be a little easier but again, no picnic.
Attachments
Agree with Ralph, don't jack to the pan. do each mount individually. With that said, you will need to unload the mount to get it out. the primary jack replaces the mount so just take the load off with it. a secondary jack (or helper with big muskles, don't use your wife or GF!!!) can be used to actually lift the motor so you can maneuver the mount out and the new one in. Then lower the secondary jack onto the primary and adjust the mount to take the load.....
Ya have to disconnect the coupling before doing anything else .. I did jack my 3 gmf up to replace two mounts at a time. The oil pan is a nice aluminum casting and with a piece of 1X6 between the jack and the pan to spread the load, there was no problem.. Your engine weighs 220 pounds; not that much. You'll have to evaluate whether jacking or removing the brackets is better in your case. You'll have to re-align the engine-to-coupling when done in either case..
Motor Mounts
I had my raw water leaking a few years ago and the mounts got very rusted so
removed the mounts to clean rust off them by using a small scissor jack with blocks of wood on a part of the engine where it was solid and just lifted a little to release pressure and unbolted from the engine plate and reinstalled.
Nick
I had my raw water leaking a few years ago and the mounts got very rusted so
removed the mounts to clean rust off them by using a small scissor jack with blocks of wood on a part of the engine where it was solid and just lifted a little to release pressure and unbolted from the engine plate and reinstalled.
Nick
I did mine with the scissor jack and piece of wood. It worked fine. As said you need to disconnect the coupling and it is wise to measure the height of the mounts all around to get you back in a general area before you do a realignment. On my 29.5 I was able to get all four changed in a few hours, not that big of a deal.
Many thanks to you all for your very helpful advice. I hadn't thought about unloading the engine brackets and swapping out the mounts that way. Now to pull out the calipers and measure where the engine currently sits on the mounts. Thanks again.
What we finally did: Raised the engine using a full size basketball and an old school bicycle pump. we prepped the task by uncoupling the shaft, applying penetrating oil to each mount nut, used calipers to measure the elevation of the bottom of each engine bracket to the base of the threaded mount shaft, and backed out the nuts on the old mounts most of the way. To replace the aft mounts we removed their mount nuts, deflated the basketball, slid it under the engine far enough aft that it would mostly bear the load of those mounts, and slowly pumped up the ball. After the engine brackets were raised above the mount shafts, we removed the old mounts, cleaned the rails upon which the mounts sit, bolted each new mount to the rail but did not tighten, and gently deflated the basketball as the engine settled onto the new mounts. Repeated for forward mounts and then aligned the engine.
I went with the basketball approach (suggested by a friend at the marina) because I felt it would treat the oil pan and underside of the engine more gently than a scissor jack and some wood blocks. I was a wee bit skeptical at first, enough so that I threw a scissor jack in the truck when we went to work on the mounts. It stayed in the truck. I will definitely drag out the old basketball if I ever need to raise the engine again.
I went with the basketball approach (suggested by a friend at the marina) because I felt it would treat the oil pan and underside of the engine more gently than a scissor jack and some wood blocks. I was a wee bit skeptical at first, enough so that I threw a scissor jack in the truck when we went to work on the mounts. It stayed in the truck. I will definitely drag out the old basketball if I ever need to raise the engine again.