This is the type where the rubber is inside a cylindrical sleeve. I have removed many parts for repairs and access to the engine mounts is good now. If the rubber is OK I would like to just reuse the existing ones. It seems the conventional wisdom is that rubber is better than polyurethane at reducing vibration. This is not a high horsepower hot rod and I want smoothness. Are factory style rubber replacements available?
'73 318 how do you know if original engine mount rubber is good?
- Thread starter Lasalle
- Start date
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He has great OEM parts. I know he has motor mounts also. I tagged him here he will chime in. Craig is a good one!
Rat Bastid
Dunamis Metron
If they are rubber and more than a few years old they are already heading down.
You are in there. Change them out to poly and don’t look back.
I've never used poly spool type engine mounts, but I've used poly spool trans mounts, and the vibration increased a lot. When I've used the earlier biscuit-type poly engine mounts, vibration also increased.
One way to get a little more support for the engine is to use RTV silicone to fill the voids in the rubber of the mount. Let it cure for a couple of days, and install as usual. It will take some flex out of the mount, but any NVH added would be minimal. I've done that on more modern engines with good results.
Rubber inserts are available to replace the originals
1974 DODGE DART 5.2L 318cid V8 Motor Mount | RockAuto
Poly will result in less engine movement, but it does increase the vibration transferred. It's not a big deal, I run poly inserts in the spool style engine mounts with the 340 in my Duster.
I've done that before, but with windshield urethane.
Ironracer
Gearhead
No Sir, the additional material add to New Rubber will make em a Lil tighter, and stronger. At least you have the good mount set up. My 68 Coronet had the older biscuit style, kept shearing em off, even broke a torque strap! Gotta Love big block Mopar and a 4 speed!
Ironracer
Gearhead
They're really inexpensive, and the job isn't bad. A floor jack, block o wood, and think it's 5/8" maybe 11/16" on the nuts. A few of em are that "darn 1/8 th' of a turn" I did polys there and at the trans, also the rear, in my 74 Duster w a 340. It's a tight car...
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