Join Date: Jul 2006
Location: Northfield, Illinois
The double mount is a preferred mounting method as it eliminates some balance link wear. It was used by Alfa on some Euro variations, but can be used with older US imported cars IF originality is not a concern. I use this center mount on all race engines using 40DCOE's. It works well.
There are some variations in lengths of the individual rubber insulators / isolators that have been available in the past. I have not checked length variation in new Pirelli insulator / isolators in either 40 or 45 mm sizes, nor have I compared the latest Pirelli offerings to old Pirelli supplied to Alfa years ago.
It is important that insulator / isolators be approximately the same length to avoid stressing Weber bodies. This would include the double center rubber. In the past, some of the individual I/I units were so poorly made that steel insert plates at either end were not even flat. One needed to remove studs and mill file the steel inserts flat, then make 4 the same length before reinstalling studs.
Many years ago, the only gaskets supplied were thin yellow gasket paper and these worked fine with original, matched length, old style Pirelli I/I units. Thicker greyish black gaskets are now commonly supplied. The thin yellow were sealed to manifold I/I, and I/I to Weber with "Gasketcinch" sealant with no issues. The thicker greyish black sandwiched between NON-FLAT I/I's will oftern burn through and leak air. A bad situation. If the I/I steel plates are flat, close to the same length, they will work fine with the thicker gaskets, but some gasket sealant should be used. I have had no problems using the double center I/I and close to the same length front and rear I/I assemblies, sometimes mixing thick and thin gaskets to get everything matched up to length, then using a sealant to be sure there are no leaks over time.
Below are pictured 4, tired 45 mm used yellow paper gaskets. The thin ones.
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Illinois SNO Alfa Chapter Director
Illinois SNO Ferrari Chapter Director
and sometimes, CONFUSED AND INCORRECT, but Larry helps me out.
Illinois Chapter Director AND Charter Member of THE CONFUSED AND INCORRECT
Last edited by Gordon Raymond; 12-02-2015 at 02:59 PM.