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Slot-It Suspension Upgrade

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Hi Rosco,


I been taking a peek at your pics and mods. you look like you will be a great car sorter. very nice.



Shed People Mutual Admiration Society

2 times Australian National Champion

1991-Flexicar 1999- Group 12 Sedan

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Thanks John,

I have assembled the #40 car - and it is simply way and beyond what it was when I started... many thanks to those who posted up so much information to get this car to where it is.... it won't run until Sunday when we set a fair sized layout up during Bathurst... but the rear end is just so sweet now....


I'm treating two more motors OTB with the break-in run in water, isopropyl bath then Zippo squirt....

I'm not totally convinced yet that there is any great improvement... but, at least I will have done what I believe is given them their best shot.


I did a no-load minimum volt test on the one I fitted to the #40... and, believe it or not - there was zip in it... probably less than .005 of a volt... of course, different day, different atmosphere.. and a whole heap of other possibles to reveal this.... and this bench of mine is far from a laboratory standard environment....


Ok - just a bit more and I'm off early to bed tonight.... the second car #8 (yellow) is currently going back together without any need of slicing, dicing or sanding.... I still don't know why - but this one is a gem for rear suspension.... another one (exactly the same) landed here today from AR... and I can't pick the difference...


They have a current special on this model at present.... at $55 - it is probably the pick of the bunch for modding with the suspension upgrade.... let you know when I attack that one in the next few days.... it's motor is getting the "treatment" at present....


This #8 car is the second edition GT40 Mk1... it has the pinion on the can end.... which I believe I prefer..


I'm getting better at fitting motors to pods.... it seems a lot easier coming out if you try to push the open end of the pod sideways.. you'll see when the "jaws" start to open... just a tad more and it will pop out... then you need to work the other end.... it simply doesn't slip out... it must also be forced downwards and out against the pod hole.....


Yes, John - looking forward to running two of these cars on Sunday.... will post up a full report.. no tyre razor yet... but I have glued the rear tyres/hubs....


thanks for your encouragement..




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Looks like you're having a whale of a time with your GT40's Rosco. Probably my all time favourite car too. I also have the Alan Mann version and it goes real well although I haven't spent anywhere near the amount of time and effort you have. I figure tinkering with cars is almost more fun than racing them. It's certainly no less than half the fun. Just keep enjoying what you're doing there.


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Thanks Wobble - actually, that Alan Mann one is now on the bench.

It, as you well know - is the version one Slot-It GT40.... I believe the version 2 are more suited to the suspension upgrade - as in the above post (multiple posts).


The pinion is on the can end of version 1 models... Slot-It changed it over to the end bell side with version 2 and also included the 6 hole pod.

Both my version 1 and 2 pods in all models thus far have been twisted....


I put the CD18b (yellow #8) together last night after midnight.... it is now as sweet as the CA18c (#40 british racing green).


I'd point everyone towards this model - AR have it on special - so they won't last....... I still don't know why - but the suspension upgrade to this model did not require one jot of trimming to the body parts to accommodate travel.... it went together perfectly last night (this morning)... the only issue I had was getting the spherical front axle bushes to slide up and down (a bit of trimming) - the front axle is now set with wheels all square on the set-up plate.

As in the 18c - a gentle press down on the rear left - lifts the front right wheel by around 1mm... and a press down on the rear right - lifts the front left by the same...


The pod is true, the chassis is true - I've left about 1/4 turn loose on all mount screws - and the body just "sits" on the chassis.

I have around 2mm travel in the rear suspension - with the brass screws about 2 threads visible above the plastic upper suspension member.


I do now have the medium springs - and will also order the hard ones..... at present, all my suspension upgrades have been fitted with the "soft" springs.


Guess I've got some "running and testing" to do when the track gets set up on Sunday morning....


Now - question?........ those two holes in the side of the endbell motors.... there are two holes also in the pod.... they are obviously meant to be used....

Anyone fitted a 3mm M2 grub into these to secure the motor to the pod?... if so - any noted benefit?...


I'm almost on the point of doing this to the Alan Mann version 1 CA18A whilst I put it back together...... it's the one which had the turning motor body in the pod - which I used some hot glue to hold...... I believe those grubs will be a much better proposition - and easily removable/replaceable.....




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Ok - another huge day on this suspension upgrade... today, I hit the GT40 Mk 1 CA18A again.

But first - a pic from yesterday with the #40 GT40.... the second series Slot-It - this one needed work, and quite a bit of it...

I had cut back so deeply to get the suspension clearing all the underside components - that I'd actually broken all contact with the manifold and the cowl.

I made up a styrene sheet card and c/a'd the manifold onto it, painted it black - then c/a'd the assembly to the cowl..... something tells me I've posted this somewhere above... but three very late nights and just about to finish another one... I'm just a bit fuzzy with what I've posted and what I wanted to add to this thread...


Here's a pic of the #40 car....




You can see where I've ground down the entire underside of the cowl... and made up the styrene manifold base.... you might also just see in this pic where I've had to break the rear frame and move it backwards... to clear the crown-wheel... which was striking it....



Ok, today - the #24 car... Slot-It version 1.... CA18A - the Alan Mann model.


I have the chassis now straight - and the pod will come out of the water tomorrow - so I should have the model back together tomorrow sometime.


Today, I spent almost all of it scraping, sanding, c/a & baking soda on the cowl/manifold area...as I had done with the #40 series 2 car....

I was a bit more careful today - and didn't end up breaking through - but it took an awful lot longer.


With the depth of material now known - I was confident enough to cut very deeply with my shavings on the cowl... then finished off with a sanding block and some wet'n'dry.... to get the flat base...


I then pushed the cowl down as far as I could into the body and re-glued it... added some baking soda - and ended up with a very pleasing ducting - if I don't say so myself.... (arms now fully extended over shoulders and loud patting noise heard from behind).


I made up a laminated manifold base this time - as the difficulty in fitting the previous one was exhausting... this time, the lower section sat slightly proud of the now flattened down cowl... and the upper section fitted nicely...... I painted some "engine black" around the opening - then the manifold and new styrene card upper....


Then glued it all in place and started sanding back again to make it look acceptable....


In all this huff and puff - I broke off the two exhausts - and also one of the mounts for the cabin interior... I wasn't too fussed about the interior - as it now gave me access to remove debris from the front window - and also a lot more room to work on the cowl and manifold base.....


Again, I broke the rear frame - and moved it back... away from the crownwheel.. c/a'd it in place then sprinkled some baking soda over it to make a good bond to the body...


By now - it's nearly 23:00 and I was thinking of calling it a day... but I really want these three models up and running for Sunday's marathon.... so I kept going.


I drilled through the two exhaust stack with an 0.8 mm drill and also through the frame.... as it turned out - there is a wonderful groove in the frame - and my drill made it exactly into this groove.... by good fortune more than any skill.... I repeated the same for the other side...


I cut two leads off a 1W resistor to a length of 14 mm and glued them into the exhausts.... when they set - I trial fitted them for angle and bent the lead accordingly so that both came out at the same angle and in line....


Once I had that - I simply added a drop of c/a to the now exposed lead then slipped them quickly into place... I believe I have retained the original angle of these pipes....


So, apologies for not adding pix in order with this diatribe... but I'll add them now... if I had more time - I'd edit this and make it flow a bit better....


So - pix... oh, if you scroll up to the previous attempt at this #24 car - I believe you'll observe just a little bit more QC has gone into my efforts this time....


The model will go back together tomorrow.. oops, forgot - I had a lot of trouble with the front bearings (spherical) going into the uprights with this model - I had to align them and open up the channels to get a sliding fit .......


PIx...... - then I'm going to bed...





Cowl flattened and ducting filled.... all sanded ready for intake manifold base.





Intake manifold on laminated .020" styrene card base.




Base and manifold mounted into cowl and sanded.




Completed top view (pic quality shocking)..




Exhaust pipes re-mounted on 0.8 mm resistor wire and through radiator/exhaust frame..








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Bump - only one of these six GT40's to finish off - the unassembled one... have to put the body together and paint it.... chassis is finished.


My Tyre Razor has just arrived... wow, what a bit of gear... will be in the back room this afternoon hopefully truing up some tyres.

Jon also donated me some excess spare silicone tyres (thanks Jon)... I'm waiting for the MJK's to arrive, along with some more bits'n'pieces and the Slot-It pinion puller/installer.... but will try to true up a couple of rear silicones and see what comes of it...


I initially fitted washers to the brass screws of the suspension unit - and am now progressively removing them.

I found that on a couple of occasions whilst setting it up - that the washer would "lock" down the screw into the pod recess... so, they are now coming out.

I also found that the unit works far better with a little bit of Parma grease on the shaft of the screws.... makes sense, really....


I further found that the front pod screws are pivotal (pun intended) in setting the chassis/suspension up... they really have to be loosened unformally - or one front corner will lift before the other when applying central downward force to the chassis/body mount.....


Once I set these, I'll probably put a very small dab of nail polish onto the underside of the screw thread/pod - just in case it decides to turn of its own accord in running.... I will also put a small dab on the side of the screw head and also another one on the pod to give indication that it has turned - a check mark, if you like.


So folk - maybe next weekend I'll set the track up.... didn't get a chance whilst Bathurst was on....... there was a lot going on around here during the day... the models will have my full attention this weekend - and I'll write up a report on what I've found... including the motor break-ins with the water/isoprol/Zippo treatments...

as detailed in the "motor tips" thread....




Edited by rosco01

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Ok folk - little bit more to this long winded and educational process..... there's a bit more that many might find useful.


I read about straightening chassis by using the hot water/ long cool down process - and found it to work perfectly,

I further applied this to the motor pods - as mine were all skewed with the front upper corner mount riding high.... I found this when I fitted them back into the chassis and it drew on the chassis - distorting it.


I have now done this to all six of my GT40's.... the I put the last one together last night... but - when it came to setting up the suspension - the rear right of the chassis hung low.... by around 1.5 - 2 mm.


I stripped the chassis completely - believing that something had reverted to being twisted... but, on the flat steel plate which I used to flatten them - both chassis and pod were both perfectly true.....


The only thing I changed was fitting motor screws through the two pod holes..

I fitted the screws back into the pod and checked again - no change....


I measured as accurately as I could - the distances from the pod mount holes in the chassis to the steel plate - they were equal left to right, but front to rear was maybe less than 0.5mm different.... which would not make any difference to this lateral imbalance under spring suspension...


I measured the same distances in the pod mount legs to the steel plate - and again - perfect.


I put the pod into the chassis on the steel plate - and bingo! - there it was... the right rear pod mount/chassis revealed a gap of this 1.5 - 2mm - with the remaining three mounts all seated.


I could not for the life of me understand why.... I took to all moulding marks with a fine file and wet/dry using a rubbing block.... no better.


I fitted the two front screws which resulted in this gap being held captive and began to look for what was holding the pod up.

It took a long, long time - but I found the culprit.


Now, word of warning for all those who want to straighten their chassis using the boiling water treatment and magnets..... be particularly careful where you place the magnets.... especially as suggested on the inside of the thinner parts.... they will pull down under the force of the magnet and mould themselves to the steel plate.


This is where my issue emanated from... and I had not noted it..... because - when I tested both the chassis and pod for true - they did not reveal anything.

But, with the pod "in" the chassis on the steel plate - it was not seating.. and I didn't pick up on it.


I filed, scraped and cajoled the high parts away - until the pod sat neatly in the chassis - and all four mounts were flush on the pads.......


Re-assembled the model - and tuned the suspension....... it is now as well set up as the other five..... why this one decided to pull those thin inner side walls down is beyond me.... maybe I poured the boiling water directly onto them before the level of water had covered them.... I simply don't know.....


When I purchase my next model - and subject it to this treatment - I believe I will fit the pod into the chassis - and then apply the magnets....

I am hoping this will keep all parts straight as they need to be - and also straighten both chassis and pod in the process....




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Bump..... ok - time for some reports.

Finally, I managed to set the track up and do some running.


Somewhere back in this thread, I made mention to having two of these cars running - the green one without suspension and the first of my two yellow ones with it.


All six now have suspension and chassis straightened.

Further to this, I have glued and true'd the rear tyres and true'd the front plastic wheels and tyres.


These models now just run so sweetly - nothing else I have comes anywhere near close to speed, cornering or smoothness.


It is simply amazing how quickly one forgets how much better these are in their trimmed state than the Carrera Cobra's and Cheetah's I have - I don't know how many times I completely de-slotted with those... but they are fun for "drifting".


Ok - the GT40's...

I have meddled a little bit with tweaking spring tensions and suspension travels...I don't believe there's really a lot which changes much on Sport track... it might need some adjustment for other types and layouts... but, from what I have been able to determine - for Sport track with all variants of curves... setting the adjustment to give about 2 mm of travel and winding the tension down so that each front wheel "just" lifts when the opposing rear corner is pushed down - has resulted in a very "drive-able" and enjoyable state.


Being the novice that I am, I can honestly state that on the 25 or 30 so metre Scaley Sport track length that I put together for this session - with a 180 deg R4 curve, two R1 chicane curves each at the end of two 7 "D" straight, a 90 deg R3 curve and finally a reverse 270 deg series of R2 curves to bring it back to the 10 "D" straight leading back to the R4's .....


My best time came in at 6.84 seconds.... mostly, I was up at around the high 6's and low 7's - but one exceptional lap where the model was right on the edge all the way around saw the lap timer reveal a best lap at 6.84........


I have absolutely no idea how this equates to what others can run with similar cars - but I can very much state that it was quite demanding to keep the model on the track at those paces.... and, I should point out - I do not run magnets.....


My original green car (Ch 18 c) now runs faster - it just corners an awful lot better with precious stepping out - but it will begin to do so before letting go... which I believe is what we are trying to achieve.


The red car (Ch 18 a) is a little different - it's the only one with the first series Slot-It motor pod... with the pinion on the end-bell side.

I can't explain why this should run differently.. but it does, and it's noticeable.

It will not corner as well nor does it seem to run as smoothly at full tilt down the straights..... but, compared to the Carrera or Scaley cars - it's a tenfold improvement.


My gold painted white kit (Ch 18 z) with replaced motor (29k), pinion (10 tth ergal), spur (36 tth ergal) and version 2 motor pod - is by far the fastest, best handling and smoothest of all my cars.


I will type up a follow-up report on that thread shortly.


With the second yellow car (Ch 18b) , I changed the motor to a 25 k with an 11 tth ergal pinion and 35 tth ergal spur - it is marginally faster than the other three - but not quite up to that of the white kit model with all the goodies.


But - the first yellow car and the green car (which are basically identical) both run and perform congruously.... there really isn't much in it between them - save for perhaps the green one having the edge due to having done quite a bit more work and is probably bedded in better....


So, I suppose this almost brings to an end this thread on the suspension upgrade... yes, I believe if i were to do it again - it would only be the yellow (Ch 18b) which I would take on - there was absolutely minimal (exhaust frame excepted) need to shave or file anything away in both those two models I upgraded to... but the others all needed quite an effort to cajole out clearance for the motor and wiring to prevent fouling against the intake manifold shelf.


All of them, however - needed the rear frame (exhaust and radiators/coolers) to be cut and re-positioned away from the spur gear.... it cuts deeply into the corner of the frame .... by the time I got to the last one, I didn't even fit it... I simply made up a replacement corner section with an angled piece which cleared the spur completely...


And - I had to sand off the outer corners of the tyres of all of them... to get clearance when the suspension was depressed.

If you do not do this - the tyres will grab under power.

It is only the outer 2 mm of the tyre which needs this... I further believe that this might also allow the model to corner better... and reward you with a bit of drift indication if you are nearing the edge of stability....


thanks for your time, folk...




Edited by rosco01

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