Float-A-Motor Questions
 

I am chasing some vibrations getting into the frame from the motor. I bought the car with the Float-A-Motor rear engine mounts. I bought new rubber pads for the mount and also the rubber sheets that normally sandwich the frame. I thought that that would help. I took the mounts out and the rubber on the outside of the frame was original and hard as a rock. The previous owner had installed the Float-A-Motor with a new rubber sheet on the inside of the frame but the Float-A-Motor bracket was resting on the frame at the bottom. He had used the sleeves that go inside the rubber sheets.

Now, the instructions for the Float-A-Motor show no rubber sheet between the mount and the frame but a new rubber sheet on the outside and the normal steel plate on top of that. It shows the sleeves which I think are shorter than original and shorter bolts than original.

Is this correct? If I put the rubber sheet between the frame and the Float-A-Motor mount the top and bottom parts of the mount, where the rubber disk goes, are not in alignment.

Will putting it together as the instruction show help to reduce the amount of vibration transferred to the frame?

By the way, I loosened the bolts for the Float-A-Motor and that helped the vibration transfer. How tight should these bolts be?

Re: Float-A-Motor Questions
 

The 2 big bolts are just snug. I loosen them until I start to pick up a little clutch chatter and then tighten them just a little.

Chris W.

Re: Float-A-Motor Questions
 

I recently went through this very puzzle. Brattons and Snyders diagrams both show no inner pads but an outer pad and the outer plate. I bought mine from Bert's and I was sent both inner and outer pads plus spacers that were definitely made for two pads with the frame sandwiched in between.

I called Steve at Bert's and questioned him about this and he told me to use both of the rubber pads, the spacers and the steel plate. This seemed logical because the original firm mounts also had both inner and outer pads. I did have to cut the "L" off the inner pad soi it was flat.

It was a struggle to start the nuts on the bolts and squish it all together, but in the end, I got it.

I still do not know why Snyder's and Bratton's instructions omit the inner pad.

Re: Float-A-Motor Questions
 

The way I did it was to measure the total width of the mount, "biscuit-to-biscuit," with no tightening of the bolts, and then incrementally tighten the bolt until I was able to measure 1mm of compression in the biscuits, and then I stopped.

Re: Float-A-Motor Questions
 

Neil,I used the full set,front,rear and transmission, used a balanced flywheel and clutch assembly,static balanced rods and pistons to .5g..but the biggest thing I did really shouldn't matter.I installed a harmonic balancer to reduce main bearing wear with a stock crankshaft..as an added unexpected benefit, vibration at certain cruise rpm's was gone.

Re: Float-A-Motor Questions
 

Thanks everyone for your comments. Believe it or not it helps.

I have the dynamic balancer. It came Saturday. I am waiting for some 5/8 - 18 bolts from McMaster Carr to push the balancer onto the shaft. I don't want to hammer it on for fear of damaging the thrust bearing for the crankshaft. I am planning on reporting the results when done.

Re: Float-A-Motor Questions
 

I bought my set from Mac's, and the instructions showed no inner pads but to use the existing outer pad and the outer plate. No spacers were provided so I assumed I was supposed to install the originals...then I later read forum opinions that the spacers should be omitted, but that bothered me since the frame holes are then too large for the bolt diameters. The castings for the new mounts are flush with the bottom of the frame, and everything works well (the new mounts fixed the misalignment of the crank start with the access hole). Vibration is not a problem, but I'm thinking about pulling the original spacers (or perhaps shortening them) when I remove the engine in a few weeks. Any thoughts?
Tom


PS, regarding the use of the inner pads...it seems unnecessary as the new mounts provide plenty of isolation without them.

Re: Float-A-Motor Questions
 

Correct, the FAM mounts *move* the inner pad, that's the whole point. Instead of being a flat pad, crushed between the motor mount and the frame, it's a pair of rubber biscuits; half the mount is mated to the engine, the other half is mated to the frame, and the biscuits dampen vibrations being transmitted between the two. Most vibration is going to be vertical rather than horizontal, so aligning the biscuits vertically works better than the original horizontally-aligned pad.

Re: Float-A-Motor Questions
 

Does anyone know why they countersink the holes on the rear mount? The bolts they provide are not countersunk. I installed the countersunk holes facing down.

Re: Float-A-Motor Questions
 

That's technically the transmission mount, but anyway I'm not sure why they'd do that. The kit I got from Bert's does not have countersunk holes and it looks like the Bratton's kit doesn't either.

Re: Float-A-Motor Questions
 

Yea, well the picture from Bert's doesn't even show all the parts you should get with the kit, the rubber piece for the "transmission mount" for example.

It is good to see Bratton's includes the side pads, bolts and spacers.

Re: Float-A-Motor Questions
 

You do get those pieces from Bert's, but I agree they should post a better pic. They both use the same supplier; the instructions at Bratton's are nearly identical to the printed instructions you get at Bert's.

Re: Float-A-Motor Questions
 

I think the spacers are needed when you use the rubber pad on the outside. However, the original spacers are too long. I chose to use both pads on the outside, thus the original spacers and bolts still work and frankly, it is hard to even notice that the rubber pad on the outside is double. It seems to work well. I did have to cut the leg of the "L" off of the inner pad.

Re: Float-A-Motor Questions
 

I agree with you...shortening the original spacers (with just the single outer pad) is what I am going to do while the engine is out. Unfortunately, the inner pads on my beast were completely worn out and in pieces.

Re: Float-A-Motor Questions
 

Don't under estimate the value of one of those New Zealand harmonic balancers in eliminating vibrations. I've had one for a year or two now and that is the smoothest running of my 4 cars but wasn't always that way.

Re: Float-A-Motor Questions
 

I put my FAM mounts in without the inner pad but with both pads on the outside plus the steel plate. I used the spacers without shortening them. I used new pads. I tightened up the bolts until the plate and FAM mount were tight against the spacers. I just snugged up the bolts that go through the FAM which worked the best before. The upper and lower halves of the FAM were in alignment without the inner pads.

I installed the harmonic dampener and will report how well it works when I get the car running again. I am waiting for parts, mostly the crank guide that was missing the upper half.

Re: Float-A-Motor Questions
 

This thread is discussing whether 6 of one is better than a half dozen of another,
but it's actually about either side of the same piece of paper.....
You're talking about a "FAM" kit, so you can use just the outside rubber pad,
only the inside rubber pad, you can use BOTH the rubber pads, or you can leave them
out and use neither rubber frame pad; you're isolating the "FAM" frame bracket from the "FAM" flywheel housing bracket by inserting the rubber biscuit between the two
cast "FAM" kit brackets an you have accomplished what the kit was originally designed to do! True, individual results may vary based on your ability to turn a wrench and
align things up so that the center lines of the two brackets allow the mounting bolt
to pass through the center holes of the mounting brackets and the center hole of the rubber biscuit and not have the mounting bolt touch either of the brackets.
Without addressing the original issues of what the kit was designed to do, you're

all just creating problems that don't exist if the basics of the kit are observed and it's installed correctly. JMHO

Re: Float-A-Motor Questions
 

"JMHO"? Really? ;)

Re: Float-A-Motor Questions
 

OK so JMHO is a stretch, I was just trying to focus on the solution and not the problem.

Every response kept bringing up the WHAT, but not the WHY.

Re: Float-A-Motor Questions
 

Steve, You have a good point. Just line things up. Without the rubber sheets and the inserts, the holes in the frame are large enough to move the FAM forward and back to get the holes in the FAM to line up fore and aft. I would still use the steel plate. Because I used the rubber sheets and the inserts, my FAM is slightly misaligned fore and aft.