• This topic has 4 replies, 3 voices, and was last updated 7 months ago by MiA.
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    • #18501
      Felix
      Moderator

      When the Scalextric Legends series became available, I recall people saying that they had a hard time taking them apart to remove the magnets, as needed for participation in proxy races on plastic track. Of the Lotus49 versions, the Lotus72 versions, the Eagle T1G Weslake, and the Tyrrell 002/003, it turns out that the Tyrrell is the most difficult to open and take apart. This is because of the ‘clamshell body’ as well as the way the rear suspension is built, both factors being different from the other models in the series.

      I needed to take apart my Tyrrell in order to see what was causing the irregular power loss, and repair it. I also wanted to convert to a regular guide keel. I later found that the left rear rim is wobbling slightly, and the gear mesh is rough from 8.5V all the way past 15V.   Since the other models in the series are easier to take apart, a description for the Tyrrell should cover those as well.  [ I will outline some of the differences as they arise in the discussion, and provide some suggestions. ]  Besides repair, it’s also useful to open these cars first if you are considering a scratch-built chassis.

      Two items to note:  Even within a particular model, the cementing of the connection joints may be different from one sample to another and therefore may separate at a different junction. Because of the nature of these bodies and the intricate suspensions, in order to take them apart certain cemented joints may have to be broken apart and the tabs may break in the process.

       

      A.  I would remove the rear wing and all tires, since they obstruct some of the joints you will be working on. The first main stage in opening these bodies starts with removing the 5 screws under the base plate. In the case of the Tyrell, this will loosen the seam between the top and bottom sections of the clamshell body. Now, slowly and carefully lift the front cowling, (top half, in front of the engine). This should eventually loosen and lift off.  That’s the easy stage, completed.

       

      As shown in the photo, you now have the driver, cockpit, guide keel, and front suspension open. This will allow replacement or repair of the guide keel, and you can re-assemble the car if no other work is needed. (I could now see that my red lead wire was frayed and must have finally broken; very fine wires, with little flex.)

       

      B.  If you decide to go further, the second main stage of separation starts with holding both front rims in one hand; twist the front assembly slightly. Try to identify the seam joints in the front suspension – see which joints are cemented and which are just dry contact. In the case of the Tyrrell, there is U-shaped tab joint on the bottom of the front suspension assembly. That joint is cemented and must be carefully loosened by twisting, prying, making a partial cut through it, wedging with a tiny chisel blade (one of the optional Exacto knife blades), or by any other careful means that comes to mind.  If it is strongly cemented together, you may have to do a partial cut then break the seam – it can be easily cemented back together at re-assembly. (In my sample, the cemented seam separated quite well using the above methods, and it stayed intact for re-assembly. The tops of the springs were in dry contact.)   Once those bottom joints are loosened, the whole front assembly, rims, axles, top half of the suspension, link-plate to the instrument cluster and steering wheel, can all be lifted up off the car. [ After a grueling race, you may need to carefully pry the driver’s hands off the steering wheel! ]

       

      As shown in the photo, unlike the other cars in the series, the Tyrrell has stub axles, so you would have to take things apart up to this stage if you were to change the plastic front rims to aluminum ones.

       

      [ Comparison with the other models:  Judging from the joint seams on the other cars, it appears that: In the case of the Lotus49, the whole front suspension assembly would lift off of the chassis plate, and remain intact with the body. In the case of the Eagle and the Lotus72, the whole front suspension assembly would stay intact with the chassis plate. (As mentioned, it’s possible that this may still vary from one sample to another, depending on which seams are more strongly cemented.) ]

       

      C.  The third and last stage in the work is a bit more tricky, but necessary if you want to repair or replace any parts related to the motor or rear axle assembly. There are two general ways to approach this stage.  Option-A involves breaking the seams at the bottom of the rear suspension uprights, and results in the top half of the engine-transmission housing, top half of the rear suspension assembly, and the full rear axle assembly, all lifting up off the rest, leaving the motor and bottom half of the suspension to remain with the chassis.  Option-B involves separating off the top half of the engine-transmission housing, lifting it upwards, and results in both the upper and lower suspension components, and the full rear axle assembly, remaining on the chassis along with the motor (basically as it would in a regular chassis).

      I tried the first approach and found that, on my sample, the seams at the bottom of the rear suspension uprights were hard to get at, and were strongly cemented, and there didn’t seem to be any other advantage to that option. On the other hand, I found (at least in my sample) that option-B would allow me to separate the key components at dry-fit joints.  With either approach, the first two steps in the work of this stage are the same.

      The rear oil tank/exhaust support covers the back seam of the transmission housing, and must be removed. It can be pried loose with a tiny chisel or flat-head screw driver. (In my sample, it snapped off clean without breaking the tab or socket.)  You will now find that the horizontal seam all around in between the upper and lower half of the Cosworth engine and transmission housing, is loose. But don’t try to separate it yet.  There are left and right tie rods coming up from the bottom rear corners of the suspension, linking to stabilizing arms that cross the top of the transmission housing. I found that I could flex the top arms downward and slide and flex the tie rods backward, enough to separate the two. The rear suspension springs contact the lower assembly by dry-fit and will separate away attached to the top half.

      Now the top half of the engine-transmission housing, along with the attached driver, can be carefully separated and lifted up off of the bottom half. The reason I say carefully, is that the left coolant pipe winds its way from the front radiator, along the side of the body, over the exhaust headers, and up over the top of the transmission cover. Fortunately it’s a flexible pipe and is dry-fitted, so it can be slowly flexed away as you remove engine-transmission.

       

      This step completes the last stage of the separation work, and gives access to the motor and rear axle assembly, allowing changes in motor, pinion, axle, crown gear, bushings/bearings and rims.

       

      [ Comparison with the other models:  I’ve described how taking apart the other cars in this series affects their front suspensions. The Lotus49, Eagle, and Lotus72 models also have rear suspension constructions that are easier to take apart than the Tyrrell 002/003. The models other than the Tyrrell have rear uprights that have an inverted U-shaped opening with two pegs at the bottom that fit into holes in a plate in the bottom A-arm. This connection is either a dry-fit, or a minimal glue surface connection in the samples I’ve seen. There are two advantages stemming from this geometry; there is either little or no glue seam to break at the bottom, and the U-shaped opening allows the whole rear axle assembly to be lifted off of the rear suspension and a new one dropped in its place. Whereas, on the Tyrrell, even after fully separated, there is still a cylinder surrounding the axle at the outer end of the suspension, even if other parts were cut away. This means that, in order to change the crown gear or the bushings, you must pull the axle through those disc surrounds that are moulded extensions of the uprights. The only way to do so is to pull the rims off of the axle, and force the crown gear off the axle over what I would assume would be a knurled section. This, all the while the axle and crown gear are being housed in a structure of flimsy plastic. The way these cars are designed, I can only conclude that they are not intended to have parts repaired or upgraded!  (Finding aluminum rims correctly sized to match, is another matter!) ]

       

      I hope this description is of some use to anyone considering a replacement of internal parts, or design of a scratch-built chassis for these GP cars.        Felix.    

      • This topic was modified 7 months ago by Art.
      • This topic was modified 7 months ago by Felix.
    • #18519
      MiA
      Moderator

      I have a few boxes of these that will attest to just how little I like taking these things apart and how unsuccessful I have been at trying to get them back together. Thanks for posting this. Hopefully it will help?? :wacko:

    • #18522
      racer68
      Moderator

      I have so many broken cars, with so many broken pieces. Now Felix, I’m trying not to get upset, but are you telling me that they may have died in vain. Thanks for the step by step breakdown. It’s so much easier when you can follow someone’s example.

      Cheers

      Steve

    • #18525
      Felix
      Moderator

      Thank you, MIA and Racer68, for your kind encouragement.

      I’m still trying to adjust to the peculiarities of this scale. It’s good to know that others have had some of the same frustrations with these tiny cars!  I’m sure that a lot of fellows in the hobby have cars from this series in pieces. When I wrote that they are not designed to have parts replaced or upgraded, that was my attempt at a polite understatement; some of them seem to be designed to prevent any repair!   If you need any help with your adjustments to them, let me know; I have more details than I could fit into one post, so I left that for follow-up questions.

      Thanks again for your replies, and your other interesting contributions.        Felix.

    • #18526
      MiA
      Moderator

      The good thing about this is that you end up with  a body and motor that can then be used for a scratch build!! B-)

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