Interesting... but parts are readily available at any FLAPS for the Pacer
front end.
On Fri, 10 Aug 2001, Bill & Pam Whittaker wrote:
> The ongoing discussion surrounding the virtues of IFS made me think (and
> that's dangerous) that maybe a broader discussion of all the options is
> in order. The following are my personal observations and I'm not going
> to make any judgments one way or the other about which is better. Ill
> just offer them up to stimulate thinking and a discussion of some of the
> options that are available to the average backyard mechanic.
>
> Ive always felt that when making the decision on what type of front (or
> rear) suspension to use one must first decide how they intend to use
> their car or truck once its on the road. In the case of old trucks, if
> you want an original truck that rides like an original truck then the
> solid axle is the obvious choice. Once rebuilt they will provide more
> than adequate service. If you're going to upgrade to a modern V-8 and
> still want to keep the original axle then common sense dictates at least
> a brake upgrade, dual master cylinder, and if the owner is so inclined
> power steering. Many would consider these modifications to be perhaps
> the best compromise between the old and the new, however others may want
> a bit more comfort. If this is the case there are several options.
>
> If you're going to use your truck as a daily driver or as a cruiser an
> IFS system presents several advantages. Remember there is a very good
> reason why modern 2WD pickups use an IFS. It's because this system rides
> and handles much better than a straight axle. If you want your truck to
> ride like a modern pickup then an IFS should be on your list of things
> to do, especially if you're upgrading the drive train. Now days custom
> kits specifically manufactured for these trucks are available from
> literally dozens of sources with a wide choice of brake systems and of
> course power steering. Some are better than others, and the old adage
> that you generally get what you pay for still applies, but none the less
> there are a myriad of choices available.
>
> The most popular of all these options seems to be the venerable Mustang
> II IFS. It has been suggested in a previous post that this suspension
> was designed for a light weight car and isn't really suited for a
> truck. Although designed for a car the Mustang unit is more than
> capable of handling the weight and stress of almost any street rod
> including trucks. When evaluating a suspension for suitability you have
> to look at what the system was originally designed to do and what loads
> it was designed to carry. Without going into a dissertation on the
> details of the design, let me just say this... the Mustang suspension is
> very strong. It was designed to carry the weight of a modern V8 mounted
> directly over the centerline of the suspension. This gives the Mustang
> suspension much more strength than you would think. As an example, the
> first time I used a Mustang II suspension system I was absolutely
> convinced that I needed the heavy duty V8 with air springs to handle the
> weight of the 454 I was going to install. As it turned out I couldn't
> have been more wrong. All that was required were light weight (4 cyl.
> Pinto) springs just as the manufacturer of the kit had suggested. Why?
> Because in most street rods as well as in our trucks the motor is
> mounted behind the centerline of the suspension. Every inch the center
> of the mass of the motor is behind the center of the suspension shifts a
> surprising amount of weight to the rear of the vehicle. Therefore the
> Mustang suspension winds up only seeing a fraction of the stress and
> weight it was designed to handle. Here's another example. I keep a
> spare set of the V8 springs (the ones mentioned earlier) around the shop
> to use in projects while they are under construction. In my '53 3100
> with a 354 hemi and TH-350 transmission in place, even my 250 lbs
> jumping up and down on the front of the frame barely forces the
> suspension to move. Additionally the springs are so strong that the
> lower "A" arms are at an extreme angle. Because the center of the mass
> of the motor is significantly behind the centerline of the suspension
> there just isn't enough weight to compress these springs more than an
> inch or two. For this truck (750 lbs of Hemi with air conditioning) a
> simple set of 6 cylinder without air Mustang springs will be more than
> adequate. So much for the strength of the Mustang II suspension.
>
> There are of course other IFS options if you don't like the Mustang
> setup. The Jag as mentioned in an earlier post is definitely a viable
> one. It's just not as easy to install and repair and you can't go into
> your local parts house and pickup new bushings or ball joints for the
> Jag suspension like you can for the Mustang unit. This is one of the
> drawbacks of using something different. On the other hand the Jag
> suspension definitely has more sex appeal than most any other conversion
> I can think of. Yet another option is the Pacer front suspension. But
> this unit has the same problems as the Jag when it comes to parts. You
> just can't get parts easily and I think everyone would agree that the
> Pacer system certainly lacks any kind of sex appeal. There are other
> options such as torsion bar suspension etc., but these require
> fabrication skills which are beyond most backyard mechanics abilities
> and I'm not going to go there.
>
> The next option is the sub frame. This isn't my cup of tea but for some
> people this is the only way to go. The sub frame has the advantages of
> a modern suspension system, good brakes, and all the mountings necessary
> for a V8 all packaged into a single unit. The drawbacks are that
> extreme care must be used in mounting a sub frame both for overall
> safety and proper suspension geometry. Also one must exercise good
> judgment in choosing a sub frame in order to end up with something that
> fits well and looks good. Nothing will lower the value of an old truck
> more than an amateurish sub frame installation. If you must go this
> route, pick carefully and have the welding done by a certified welder.
> Do not pick a sub frame that requires narrowing. The amount of problems
> you'll create by narrowing a sub frame are directly proportionate to
> every millimeter it's narrowed. You just don't want to go there. Keep
> in mind also that a using a sub frame will require significant
> fabrication when it comes time to remount the front sheet metal. Very
> often people seem to forget this little but significant fact.
>
> Perhaps the most drastic option is the complete frame swap. For me this
> would be a last resort. There are just too many options available to
> make an original frame ride and handle well to just throw one away.
> But, when you have a truck that has significant frame damage, either
> from rust, and accident, or just a previous owner's hacking with a
> torch, sometimes this becomes the only option. Again careful selection
> is the key. Just buying a donor car (or truck) because it's available
> and cheap won't do. Take all the measurements you can and pick a frame
> that closely matches your dimensions. Its not terribly difficult to
> make minor adjustments when mounting the cab either forward or back to
> adjust for an inch or two of wheel base difference but you want to keep
> these compromises to a minimum. The last thing you want is a wheel base
> that's too long or a track that's too wide, unless of course you're
> looking for that East LA tires outside the fenders look. In that case
> as the Pontiac add says, "Wider is better". Also just like the sub
> frame option, mounting the front sheet metal (and bed in this case) may
> require significant fabrication and alignment.
>
> Before choosing a suspension system, you the owner must decide what you
> want your truck to be when it grows up. Do you want an original truck
> that rides like an original truck or a cruiser that rides like a new car
> or something somewhere in between? You ultimately have to make that
> choice and you have to live with it. If you build your truck to satisfy
> everyone else, you are the one that is going to be the least satisfied
> with it.
>
> OK, I'll get down off my soapbox now.
>
> Bill
> '53 3100 Hemi
> 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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