Flattening RM McLaren chassis

[slothead]

I have a stock RM Can-Am McLaren (#4 - Bruce Mclaren) with PG tires that's been a solid performer on my track. But, now I notice the right front tire doesn't touch the track surface, making the chassis out of balance. This is with the body off, but might explain why the car seems more unstable on the track now and has rolled over a few times recently.

As is I can flex the chassis and get it to sit flat on all 4 tires, but within a few minutes it reverts back to the right front being about 1/8" off the track. I'd like to get all 4 tires to be planted firmly on the track so the car is stable, but I don't want to disassemble the chassis. I'm asking for feedback on slowly heating the whole chassis so it gets more flexible while holding the tires down, then letting it cool slowly. How? What about using rubber bands to hold the tires down on a setup block and heat the chassis with a hair dryer?

Anyone have thoughts about this or other ideas?

Slothead

[docdoom]

sorry but if you want it to stay flat your going to have to strip it down to the bare chassis and do the following
http://www.slot.it/Download/FAQ_PDF_en/ ... sis.en.pdf

[cj74]

The straightening method provided may work. Before you go that far, check the car with the motor in and then take the motor out. I had the same issue recently and discovered the motor was slightly too large for the pocket. After some focused filing and sanding the motor for snuggly (I reinforced with shoe goo equivalent) and all for wheels were planted.

Sent from my SM-G965U using Tapatalk

[slothead]

Yeah, Docdoom, I must have started this thread because I knew someone would respond as you did and tell me not to be so lazy and take the time to do it right. I'm going to stop on the way home to get some magnets in the craft department at Walmart and do what the instructions say tonight. Then I'll let it cool overnight and reassemble the running gear tomorrow and see what it looks like and do some time trials.

If and when Bruce Mclaren claims another victory later this year in my retro Can-Am series, I'll be sure to let him know you helped make it possible. This will be part of my Endless Summer Racing Series - 'where everything good, that ever was, still is'.

Slothead

[slothead]

I still need to do this - the craft magnets at Walmart were definitely not up to the task. But, I found out Home Depot has Nd magnets so I'll be getting some there this afternoon. Now I just have to make sure I have a flat metal surface to stick the chassis to.

Slothead

[busterfla]

And old 7 1/2 inch saw blade will do the trick

[chappyman66]

Yup, I used an old circular saw blade and the magnets that I pulled out of my slot.it and Fly cars. :lol:

[slothead]

I didn't see the posts about using a circular saw blade before going to Home Depot so I got a 12" square piece of 28 gauge galvanized sheet steel along with 3 packs of Nd magnets. The magnets really stick to the metal sheet which fit perfectly in the big pan my wife uses for cooking turkeys.

I got the chassis 'nailed' down flat in the front and on the sides, but didn't think I could get a magnet into the structure at the back so I used a bag of pebbles. A day later after the treatment, the chassis appeared to be flat except the very back part where the body mount screws go. The tail end of the chassis was up in the air a bit - so I did the whole process again using another magnet to have the whole chassis pinned down.

My biggest problem reassembling the chassis was getting the motor wires reattached to the guide. I'd pulled on them till they broke at the guide rather than cut the wires halfway to the motor. When I got it back together all 4 tires where on the setup block and the chassis ran well by itself. When I put the body back on and loosely tightened the screws, the right front tire lifted off the track again. So I took the Dremel to the inside edges of the body and bottom of the interior. As best I can see, it could be the wires being pinched under the interior that's causing the chassis to twist so now I'm only using the front 2 body mount screws and letting the rear of the body float at a higher level than usual. While it's not the ideal stance, the chassis is flat on the track and I've requalified the car about half a second per lap faster than before. It's now less than a tenth of a second behind my fastest Can-Am car, a Slot.it Ferrari 312 PB. (Note: both cars are stock except for PG tires.)

Slothead

[Pappy]

I used the above method to straighten all my 1/32nd chassis. But on my Racer/Sideways chassis I think it might have made the plastic brittle. I had four Racer/Sideways Daytona Prototype chassis ready for the Michigan 24 race a couple weeks ago. Saturday morning the one I wanted to run had a motor that I wasn't sure how much time was on it so I decided to put a new motor in it only to find the chassis was broken. So I took out another DP chassis and it was broken, so was the third one. The only one that was not broken was the new one I had just put together before I got to Michigan but I was not about to chance it breaking in the race. So we ran a Slot It Porsche GT1 that ran great and no problems in the race.

My only guess as to why this happened is that maybe on some plastics pouring hot water on them makes the plastic brittle.

[slothead]

Bruce - thanks for sharing that, it occurred to me I might be pushing my luck doing it twice in 3 days. So far I haven't noticed any problems.

As noted in my update, the chassis was flat afterwards till I mounted the body. It's possible the body is warped, and is less flexible than the chassis so it warps the chassis. Anyone try doing the flattening treatment with chassis and body as a unit? Would the paint and decals survive? Could this be done at a lower temperature?

Slothead