Mustang II Swap Knowledge Base

Discussion in 'Technical' started by stockhatch, Nov 18, 2008.

  1. stockhatch

    stockhatch Re Member

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    So I have been reading and thinking... Terrifying concepts, I know. :cry:

    Anyhow, I was digging up several threads relating to the Mustang II front suspension swap, and it occured to me that lots of people are interested in the swap, and a few have performed the swap(or are in process). There are lots of threads floating around detailing parts of the process or addressing certain issues, but no one thread covers all of the details relating to the swap. Also, it is difficult to find all of the info in a search, because alot of the time the verbage is not consistant, ie MII M2 Mustang II, just II, Pinto etc.

    Can we maybe dedicate a thread to the parts, process, pros, cons, cost, and anything else relating the the swap? I know that I would love a centralized base for any and all MII info, and I think it would greatly benefit myself, and anyone else who is swapped or considering it.

    The people who have done the swap can link their threads(if they have one), and we could discuss anything and everything involved in the swap. We can cover issues people have run into and overcome, the source of their parts, stock or aftermarket, proven engine/trans combos, headers, sheetmetal mods, structural implications, cage if applicable, etc etc.

    I will do anything I can to help, though I am seeking knowledge, so I may be limited in the information department. Whatcha guys think? :cool:

    BTW, if there is already an "Official Maverick.to Mustang II Swap Thread", please direct me to it, and I will quietly(and sheepishly) go read ;)

    A couple links to start, hopefully the owners dont mind:

    Tech Article covering part sources and options. Includes pics of Mavmans setup

    Rod and Custom crossmember install

    Engine bay Sheetmetal mods

    Rod and Custom complete install

    Another Nice Rod and Custom install

    Header discussion

    After doing alot of reading, I have run across a couple websites reporting failures in aftermarket MII kits. Stefan, I hope it is okay to link to these sites directly. I think they educate and promote safe installs.

    Though it is very likely that these are isolated failures, I think that the points made in the second link are very valid, and that elimination of the strut rods should only be done if the kit is engineered to effectively withstand braking, and other loads. Research your kits carefully.

    Watch the video posted in the first post of the first link below. I'm not slamming the design of any products on here because I am not qualified to do so. This is for educational purposes only.


    MII FAILURE THREAD

    ANOTHER MII FAILURE THREAD

    ANOTHER FAILURE THREAD
     
    Last edited: Dec 25, 2008
  2. 71gold

    71gold Frank Cooper Supporting Member

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    ...:hmmm:...Good Luck...

    ...Frank...:Handshake
     
  3. stockhatch

    stockhatch Re Member

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    Well, thanks :D I found your experience very valuable, so I posted your thread up. Hope ya dont mind.

    Something I have heard mentioned a couple times, but not discussed at length is the effect on the structural integrity of the car. Apparently, some people run sans fender aprons, but with a cage. Others patch the tower holes with sheet metal. Does anyone run any kind of brace or monte carlo bar setup to aid in chassis stiffening? Is it necessary/worth it?
     
  4. Stefan

    Stefan Big Cheese Administrator

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    I made the tread a sticky.
     
  5. stockhatch

    stockhatch Re Member

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    Sweet, thanks. Hopefully some info stacks up in here that helps everyone, including myself :)
     
  6. johnson

    johnson Member

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    kudos for that one
     
  7. stockhatch

    stockhatch Re Member

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    I added some information related to failures in MII conversions. Please read and respond to these if you have anything to add or share.
     
  8. jayman

    jayman Member

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    "Something I have heard mentioned a couple times, but not discussed at length is the effect on the structural integrity of the car. Apparently, some people run sans fender aprons, but with a cage. Others patch the tower holes with sheet metal. Does anyone run any kind of brace or monte carlo bar setup to aid in chassis stiffening? Is it necessary/worth it?"

    Several good questions here. Most installations that I have seen install sheet metal patches over the holes and call it good. For a daily driver, this is considered to be adequate.

    If you drive over really rough roads, or are racing the car, either drag racing or any other type of hard usage, it is a good idea to install a brace from the frame rail in front of the suspension to the "A" pillars or a suitable point on the role cage. (If you are racing, you do have a cage, right?) If you are doing wheels up drag racing, the front frame rails will flex upon returning to earth. The higher the air gap, the more chance of damage.

    A monte carlo bar will be a good investment if you drive the car hard. In the original configuration, the shock tower braces help to triangulate stresses from the front suspension into the firewall and as a secondary function, reinforce the mounting points of the fenders. If you have removed the shock towers, then you have a relatively large flat area of sheet metal with no support to keep it from bending or moving. A monte carlo bar will keep the fender mounting points from moving around holding the fenders in place, assuring hood gaps stay even, etc.

    Do you have to do any of these things? No. Are they smart things to do? Yes, if you drive your car hard or race it.


    As for Mustang II suspension failures, there were a couple of primary causes of the one I have personally seen.

    1. Poor weld quality. This ranged from poor weld penetration, poor metal preparation, two hot of a weld causing metal fatigue around the welds, etc. If you are not an excellent welder, hire someone who is. It may save your life.

    2. Using stock sheet metal cross member in a vehicle with much higher weight or in situations where the front suspension was being subjected to much higher loads than it was designed to support. i.e. A 53 Ford truck with a 460 using a modified Pinto front clip. The sheet metal cross member collapsed while towing a 10,000 lb trailer driving down a 6% grade. This could have been avoided by reinforcing the cross member, adding cross members to the stock Ford frame to keep the frame from twisting, etc.

    3. Rust in the floorboards of a 65 Mustang allowed the frame rails to break loose from the unibody. The rust was not really very obvious under the car when the new suspension was installed. However, once the shock towers and tower braces were removed, the floor was subjected to more stresses than before which caused the rust weakened floorboards to rip loose and the front clip of the Mustang to collapse. This could have been avoided by an honest assessment of the condition of the vehicle before the conversion.

    Hope this helps.
     
    Last edited: Dec 27, 2008
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  9. stockhatch

    stockhatch Re Member

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    Thanks Jay, for chiming in with that info. I think I will go ahead with some sort of bracing. most likely, I will design something similar to a strut tower brace. Triangulated and made from tubing, that will tie the aprons to the firewall for some added strength.

    I dont plan to race my car, it will be a driver. It also wont have the type of tires under it that support any kind of agressive cornering( bigs and skinnies). At this point, I'm debating on a cage. I think it would be nice to have if I did take it to the strip and something happened... Even so, the back seat would become pretty useless, and I think that detracts from what makes it a street car....IMHO.

    Anyhow, I sorta went off on a tangent Thanks again for sharing all the good info.
     
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  10. stockhatch

    stockhatch Re Member

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    Oh, I meant to ask about gusseting on the rear section of the lower a-arm mount tube. It seems like some of the crossmembers I have seen pics of have NO gusseting on this section, and some do. The strange thing is that crossmembers from the same companies can be found with and without this gusseting. I wonder if the gussets were added in a revision?

    I do know that if I run a setup that does away with the strut rod, it will have gusseting, and most likely and extra bracket like the one added to the car in that first failure link I posted.

    I'm no engineer, but I agree that it makes sense to have as much reinforcement in that area as possible. That lower a-arm tube gets hammered under braking especially, and it does not take a genious to see that.
     
  11. mav1970

    mav1970 Bob Hatcher

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    I'm putting a cage in mine and have designed it to be able to still use the back seat. I attached the rear kickers to the main hoop with electrical tape until I can get them welded in. I'm also doing the Mustang II deal and will completely remove the inner spring towers. I'm going to do front down tubes from the front of the frame rails and through the firewall to the front cage uprights. Then a Monte Carlo bar between them.
     
    Last edited: Apr 29, 2011
  12. stockhatch

    stockhatch Re Member

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    So are you not going to put a harness bar in? I guess NHRA certs are not your priority, and you are just after a little added chassis stiffening? Not that that is a problem, I am contemplating the same for my car. Or maybe even a removable harness bar that I can put in at the track. I know its not legal, but I am sure a removable harness bar is better than no harness bar, right?
     
  13. mav1970

    mav1970 Bob Hatcher

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    I already blew the NHRA certs by choosing tubing that might not be exactly what their spec book would want. There will be a harness bar but it will start out level right behind the driver's seat and then "S" shape it's way down towards sill plate level at the passenger side. That way the rear seat can still be used but only entered from the passenger side. I still may decide to pin a removable bar in there somewhere. I always wanted a car with a cage so this was going to get one regardless if it got the MII front suspension or not but now that I am getting rid of the inner spring towers, the cage will serve a more important function to re-stiffen the front frame rails. I've built many stock car cages and the design always worked well on circle tracks so this one should work OK on a street car. Additionally, the stock sheet metal front rails are getting replaced with 2 x 3 x .125 steel tubing. Then the MII cradle gets welded between them.
     
  14. stockhatch

    stockhatch Re Member

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    Sounds good. I like the idea of tying the cage to the frame rails up front especially. I agree that it would restore some of the structural integrity lost by losing the towers. Be sure to post some pics of that MII swap :) Hopefully mine will be posted up here very soon.
     
  15. mav1970

    mav1970 Bob Hatcher

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    If you look at the Heidt MII front frame sold for the 66-67 Chevy II/Nova's, you can see how the front down tubes come up and bolt to the firewall with plates (this is also a car that had inner spring towers that are removed with the MII kit). I saw 2 of these setups on Novas at shows this past year and that is all there is to it. I can't believe that they would just flat plate it to the thin sheet metal firewall plus one of the Novas had a 500+ big block in it. Mine will look similar to the Heidt kit but inside the firewall will also be identical plates with short tubes welded between the interior plates and the front cage uprights. Once bolted together it will be solid to the cage with the firewall sandwiched in between. I think this might be easier than trying to do multiple tubing bends to try to get the tubes from the front of the frame to the cage all in one piece.

    I can't start my MII conversion until my shell is off the roll overs and blocked up level on the floor. If I started sawing the towers apart, I'm sure I would fold the car up on the roll overs. I'll have pictures in the future for sure.
     

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