Changing motor mounts

Don't lift on the oil pan.

Probably pretty obvious, but.....

Rocky

Mike , I did one side at a time. Found a broken bolt in the right upper motor mount. Snapped off in the block. I have a grease pit in my garage. Carried the trolley floor jack down in the pit , loosed the lower mount , 3 bolts. Loosened the ZF mounts. Loosened the through bolt. With a ~6 foot 2x4 jacked against the oil pan rail and rocked the engine about 1/4 inch to the left. I was able to pull the pieces out.
I acknowledge any thing moves and you could get hurt bad , so don't work alone , some secondary support for the engine.
Was able to get the broken bolt out of the block with a Harbor Freight left hand drill bit and extension.
The old mount went right back in and new grade 8 fasteners from Tractor Supply.
Left side was able to replace fasteners with out jacking.
The engine was pro built but the previous owner had used a small import repair shop to install the engine and they went cheap on the fasteners.

Mike , last night there was a reply to my post , don't see it this morning. The short answer is you can change one motor mount at a time. That should keep things lined up and the power train is still supported at three points.
Working from a hoist or pit some variation of what I did would be employed. Not sure how well a transmission jack would work in this case.
The post suggesting a Darwin Award didn't set well. I am nether stupid or cavalier about safety. It would have been justified if I used a "bottle jack" or anything that could kick out or didn't use secondary support. A clear 2x4 should take half the dressed weight of the engine as compression loading on axis.
Be careful and use your good judgement.
What I did is now I did it and not an endorsement.
If it is any comfort to the forum, I chlorinated my own gene pool , got a vasectomy at 21.

True confession time, I guess.

On several occasions I have supported the engine with a full coverage three-quarter inch piece of plywood and a floor jack, lifting under the oil pan sump.

Changing motor mount insulators does not require lifting the engine very much. Snug the plywood up against the oil pan sump but do not apply any pressure. Create some slack in the motor mount system by loosening the bolts of your choice. Lift the engine maybe one quarter of an inch and then proceed to loosen and remove all motor mount bolts, replace both sides and reverse the process.

Now I obviously agree that placing a 1 inch diameter bottle jack underneath an oil pan sump and lifting the engine in that manner is not a wise move in anybody's book of tricks. But I have used the above process without any apparent repercussions.

YMMV

Larry

Use a cherry picker.

David, now that you have the broken mount bolt replaced, let's think about WHY it broke. The usual reason is, the rubber isolator discs tend to collapse more on the inside than the outside, from the weight of the engine, age and heat from the headers. That puts a bending-strain on the bolts and after awhile, one or more will break. The time-honored way to temporarily fix this is to rotate the rubber isolators 180 degrees while ordering new discs. Occasionally, old collapsed isolator discs will loosen a bolt enough to have it fall out. Sure, gr-8 bolts or tapping the block to the next larger size also stops the breakage temporarily, but the real fix is new rubber.

Thank you Bosswrench for the kind response! I always read your and George's words of wisdom. I wish I knew what you 2 have forgotten!
I have read lots of auto engineering books but lack the hands on experience.
One item on the invoices that came with the car was a helicoil repair to the block's motor mount. Kind of funny Precision Performance had a order mix up and had shipped 2 replacement motor mounts.(hockey puck) I returned them.
I had written the bolts off as cheap un-graded hardware. I do not put shock loads on the ZF.

Thanks everyone for the replies. I think I have a plan worked out now and will give it a try this weekend.