What you're talking about is a unibody sub-frame that has been designed and
developed by a major auto manufacturer who spent millions of dollars along the
way to ensure it works as advertised. The system has been extensively tested
and the design was modified as problems surfaced over it's development cycle.
That's why factory designed bolt on systems are safe for the vehicles they've
been designed for.
However this is not necessary the case with aftermarket IFS systems. Virtually
none of the small shops that manufacture these kits have the money or
capability to completely test a bolt on design. As an example, when you adapt
a IFS like the Mustang II to an old frame, the conditions and stresses the
suspension system is subjected to are different with each and every vehicle. It
all depends on what modifications have been done to the original frame and how
they have effected it's overall condition. Things like boxing and crossmembers
that may have been added for transmission, engine, or rear suspension mounting
will all add to or subtract from the frame's strength, and they all effect it's
rigidity and how and where it flexes. Mods to the frame, the age of the metal,
and its general condition are all factors that change the way the frame reacts
under stress. Flexing and vibration are the two major culprits that loosen
bolts, and they don't discriminate as to which bolts !
they decide to covertly back off for you. Because each of these installations
is subjected a unique environment there is really no way to accurately predict
the installation integrity (over time) of any of the aftermarket bolt on IFS
systems. Therefore, in the case of Mustang II and similar kits, it will almost
always be safer to weld these systems in place rather than trust your life to 8
small bolts.
Bill Whittaker
'53 3100 Hemi
Built Like A Rock
With Mopar Stock
-----Original Message-----
From: Brian _ [mailto:pkupman57@hotmail.com]
Sent: Thursday, September 14, 2000 6:53 PM
To: ryan_border@hp.com; oletrucks@autox.team.net
Subject: RE: [oletrucks] RE: IFS, but not to open any can or worms again
list,
i work for the ford dealer in town. ive changed several engines in vehicles
and most all FWD cars and vans use a bolt on front sub frame. the ford
windstar for example, uses 4 bolts to hold the front sub frame, engine,
suspension, steering, tranny, everything onto theh body. makes it EZ to
change engines tho, as you only undo 4 bolts, brake lines, and steering and
shift linkage, and the whole shabang drops out from under the van. so i dont
believe that the majority of bolt on front suspensions are unsafe.
Brian M
Atwater, CA
'57 Chevy 3200
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oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
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