On the "Model Motoring" thread and elsewhere, I've read references to chassis problems with the Model Motoring Tjet replicas. Can I get some details?

I picked up a new-in-box MM car at an out of the way hobby shop, that had been sitting in the case for a long time according to the owner, so it probably is an early one. Before I run it, is there anything I should do to the chassis?

-- D

Check the gearplate of the chassis. The early MM's came with NOS Aurora chassis. But play it safe........The MM T+ chassis say "Model Motoring Co" on the gearplate. If it is a T+ chassis, check the ohmage of the arm. Ther first MM chassis came with those horrible 50-ohm arms that quickly smoked up. If you don't have a multimeter to check the ohms, just run the car at slot speed. If it get hot quickly, you have a bad arm. Just replace the arm with an Aurora arm and it's good to go.

Just what I needed. Thanks DLW.

When checking an armature with a meter, is the 50 ohms the reading from one commutator plate to the next or the total of all three readings?

The sorry thing was MM had brought back some great memories with their new bodies and use of the Tjet chassis. Then their excursion into chassis manufacturing didn't fare as well. I know the first six of their chassis I picked up way back, had something left to be desired. I replaced them all with original TJets. Too bad, Harrison had a great thing going. If you get a chance to get some MM bodies you won't be disappointed. JMHO! Thanks MM! :thumbsup: :thumbsup: rr

When checking an armature with a meter, is the 50 ohms the reading from one commutator plate to the next or the total of all three readings?

The 50 Ohm reading would be from one tab to the other. Each reading (tabs 1-2, 1-3 and 2-3) will be either 50 Ohms, if it's one of the bad armatures, or something in the range of 15-16 if it's a good one.

Although I collected all the MM cars and have them in a display case, I only have a few duplicates that I run; one of which has the T+ chassis. That chassis runs just fine; I'm guessing it's not one of the 50 ohm chassis.

Joe

The problem I ran into was that the arm was not attached firmly to the rod that attached to the gear. The motor sounded like it was running but the car barely moved.

I bought 4 on eBay from the "selling off my cheating husband's slot car collection" if any of you recall that. They all were fitted with alu. wheels and slicones, but the gearplate clamp would not hold the car together. Loose enough that the brushes would come out of the holes and the gears at the rear axel would "demesh". I'll have to have another look at them and try an aurora gearplate clamp and check the arms.

Twolff, tey rebending the ends of your 'bad' gearclamp.

Thanks for all the help, guys.

It appears that my MM blue GTO is one of those with the NOS Aurora chassis. Patent no. on the gearplate, mold mark A in the usual place by the rear axle. All reassuringly familiar.

-- D

Twolff, tey rebending the ends of your 'bad' gearclamp.

Pulled 'em out of the parts bin for a closer look. The gearplate clamps aren't bent funny at the ends. They just don't fit the chassis. The gear plates are MM. The slots for the gearplate clamp are higher than on an Aurora chassis. The clamps fit Aurora T-Jets very nicely. It's posibble that the gearplate clamps were replace with Aurora peices by the previous owner??

Took a min. to check the arms. Three are 15.1 or 15.2 across all three segments. One has a 41.5 segment and two at 21.1. I made sure to mark that one.