Float a motors

[duke36]

The FAM's were on my car when purchased and the rubber biscuits are being replaced with new ones. The frame/ plate rubbers are OK as installed. How snug should the bolts be that go down thru the biscuits?

[Mike V. Florida]

Tighten the nylon nuts just enough to secure them and slightly compress the "biscuits". Too much and you eliminate the vibration reduction.

[Art Newland]

WOW, I was going to post this exact question this morning.
I replaced the doughnuts at the bellhousing, and the rubber at the rear cross-member. Mine just had regular nuts/bolts and was planning to pick up some "ny-lock" nuts today so I can adjust the tension. The old rubbers are hard as a rock and the ones on the bottoms were compressed quite a bit. I'm hoping for some vibration reduction happiness.

[duke36]

I assume there should be no bulge in the biscuits. It would appear that perhaps tightening just enough so that the top "metal" retainer plate under the bolt head should just not move. Does that make sense ?

[Art Newland]

I'm going to start loose and slowly tighten until I find a happy spot. My front mount (by crank pulley) is really sensitive to how tight it is. A quarter turn can make a big difference in vibration. I put a ny-lock on it to so I wasn't restricted in adjustment by needing a cotter pin.

[BILL WILLIAMSON]

Sponsored Links (Register now to hide all advertisements)

Run the nuts down & just BARELY compress the "biscuits".
Bill W.

[Art Newland]

Had my coupe out for a test run, did just like Bill said. It has helped alot!

[Art Newland]

Clutch is jumpier tho...

[Synchro909]

Originally Posted by Art Newland

Clutch is jumpier tho...

When I installed my first set of FAMs, the rubber block that goes on the cross member looked too small - and it was. It soon fell out and from then on, till I made a new rubber block, the clutch shuddered something awful in reverse. As soon as I cast a new rubber, the problem went away.
Maybe you should look at that rubber block.

[Art Newland]

Originally Posted by Synchro909

When I installed my first set of FAMs, the rubber block that goes on the cross member looked too small - and it was. It soon fell out and from then on, till I made a new rubber block, the clutch shuddered something awful in reverse. As soon as I cast a new rubber, the problem went away.
Maybe you should look at that rubber block.

The new rear rubber block is certainly smaller than the old one, probably 3/8 inch on each side too short. I did get it a lot better by putting a couple turns on the bolts, it added a little vibration back, but it's still a nice trade off.

[Mike V. Florida]

Originally Posted by Art Newland

The new rear rubber block is certainly smaller than the old one, probably 3/8 inch on each side too short. I did get it a lot better by putting a couple turns on the bolts, it added a little vibration back, but it's still a nice trade off.

How about using the radiator mount pads to make up the difference?

[Art Newland]

I doubt that's big enough, the one that came out is about 3/4 inch square and 4-5 inches in length.

[Mike V. Florida]

Originally Posted by Art Newland

I doubt that's big enough, the one that came out is about 3/4 inch square and 4-5 inches in length.

How about body block pads to make up the difference?

[Bob Bidonde]

When the installation of the floating motor mounts is done, you need to have a 3.5 degree angle of the engine, downward to the rear. The purpose of the angle is to preserve the float setting assuming that it was set properly in first place.

You can see this angle as it is built-in the carburetor's attachment flange of the intake manifold.

Otherwise you need to iterate a new float setting if you are running an original Zenith carburetor.

[captndan]

Does FAM effect the alignment of the crank hole? Mine does not fit.

[katy]

While we're on the subject of FAMs, should the frame mounted part of the rear FAMs have the rubber pads between it and the frame, like the originals had?

[hardtimes]

Originally Posted by captndan

Does FAM effect the alignment of the crank hole? Mine does not fit.

Hey dan,
Not at all, it properly installed. Example: B engine in my '30 A frame. I used the rear alum FAM and the 'original' A front mount (along with the trans fam mount). Crank hols lined up perfect ! IMO, anyone not knowing better, tighten down these mounts...way TOOO much that I've seen , and/or do not install these mounts properly. Improper installation will cause problems with undue vibrations , wear and crank hole misalignment, etc....

BTW..just recently (after dozen yrs running as described above), I installed one of those B front mounts that are sold by vendors. After fitting problems(from maker) were corrected, my B is held much more stable under hard acceleration This B was fully balanced when built, however I was installing a crank nose balancer and opted for the B front mount. I've never had a 'vibration' from imbalance problem...but like to run rpms up a bit..sooo.

[Curly]

I am putting in a new motor later this year. Should the rubbers be replaced whenever the motor comes out?

[CarlG]

Originally Posted by Curly

I am putting in a new motor later this year. Should the rubbers be replaced whenever the motor comes out?

That would depend on the condition of the parts in question. If they are old and hard, or if they have become oil soaked and are about to dissolve anyway, now is as good a time as any to replace them.

You will probably find a ton of other parts you want to replace "while it's apart" when you start to do the swap.

[carolinamudwalker]

where is the best place to jack up the rear to replace the FAM rubbers? does anything need to be loosened or removed?