19 replies to this topic

[nicky 65]

I'm just curious as which oilites racers like to use.

I have some cars set up with Slick 7 brass. And some Parma bronze.

i have noticed that if you forget to oil the Slick 7s during a race they tend to lock up... not good. I only had that happen once though.

[Ralph Thorne]

I prefer the JK adjustable bushings myself.

[Bill from NH]

Nick,

The Slick 7 bushings are beryllium-copper and the Parma ones are made from oilite, a bronze alloy impregnated with an oil lubricant.

The Slick 7s are machined to a closer tolerance and if kept oiled with a quality synthetic oil, will last longer. The oil on the Slick 7 bushings sits on the surface, it isn't absorbed by the bushing material. Oilite does absorb oil. That's why, unless kept well-oiled, the Slick 7s will lock up, like you once experienced.

Also, Slick 7 doesn't make a replacement for the square Parma ajusta-bushings.

[Guy Spaulding]

To add to Bill's explanation, Oilites are formed using powder metallurgy so that tiny pores are present in the metal. This process has its pros and cons. It does absorb oil, so you may only oil once per race, or less. Slick 7 and JK bushings are machined from solid materials. I oil mine every other heat.

[Hangtime]

How does the heat affect these?? I added a brace and with all fooling I did I know I had them pretty hot. It's a used axle and bushings, but I just couldn't seem to get it smooth. I tried to reseat the bushings (solder) I'm just wondering if the heat may have dried them out. I did oil plenty. I may just need new ones.

Any thoughts??

[Cheater]

Rick,

If you got the oilites hot, you might have boiled most of the oil out of them. Just get them hot again and dunk them in a small container of oil. As the oilites cool, the oil will be sucked back into the pores.

Some racers do this on purpose with new oilites. They clean their soldering iron tip of excess solder, then place the oilite on the tip for a few seconds until the oil boils out, then they drop the hot oilite into a small container of the oil they want the oilite to absorb. The thinking is that the quality of oil used to "charge" the oilite bushing may not be the best and replacing it with a good quality synthetic oil may have advantages.

Personally, bushings are so cheap I almost never reuse them.

Regarding the differences between sintered metal oilites and machined solid bushings like the Slick 7, my experience is that the oilites wear the axles much more than the Slick 7 bushings. As mentioned, the Slick 7 bushings are made to tighter tolerances than most oilites and, when properly aligned and if kept oiled with the proper oil, they last almost forever. I can't remember the last time I replaced a set of Slick 7 axle bushings due to wear.

[James Grandi]

I have used both types and can confirm from my own experience that the Slick 7s are very long lasting when properly oiled/maintained, have nice tolerances, and will lock up if not oiling enough or using the wrong oil. I have only had them seize up once in seven years of using them, and it was because I let a friend borrow the car and they didn't oil enough.

I also have cars with bushings, and they perform just fine but they do tend to wear the axles out over time, and do not have very tight tolerances. I've had brand new bushings with a brand new axle and could feel a slight amount of movement in them before they'd ever been used. But they do work well. I tend to oil them only once or twice in a race.

Bottom line, I can't say that I think one holds an outright performance advantage over another, but if bushing/axle wear is a concern, I would recommend Slick 7. But you have to use a good synthetic oil with them, preferably something thin.

[Guy Spaulding]

How does the heat affect these?? I added a brace and with all fooling I did I know I had them pretty hot. It's a used axle and bushings, but I just couldn't seem to get it smooth. I tried to reseat the bushings (solder) I'm just wondering if the heat may have dried them out. I did oil plenty. I may just need new ones.

 
You probably ended up with the bushings out of alignment with one another. (Just seating them flush to the chassis doesn't align them, because the chassis is not perfect. Best way to check:

Insert a fresh axle into one of the bushings.

Push it almost all the way to the other bushing.

Now, gently wobble the axle up and down, and forward and back, noting how much it wobbles in each direction. If it doesn't wobble the same in each direction, it's out of alignment.

Repeat by inserting the axle into the other bushing first, to test the alignment of that second bushing.

When you are done, the axle should fall out of the bushings under its own weight

[Bill from NH]

As cheater mentioned earlier, I'm someone who cooks the oil out of any oilite until the smoke stops, then replaces it with a clean oil while the bushing is still hot. My experience has been the oil impregnated in new oilites acts more like a cutting oil than a lubricant. I first got this idea years ago from John Ford.

We used to run some scale classes (ANE-AMCA?) that required all work on the cars, including oiling, be done under green. Everyone ran oilites in these classes because they didn't require any oil to be added between heats and the Slick 7s would have.

[Hangtime]

Yea, I think I boiled the oil out. Never heard of that, but I could tell something was not right. I'm gonna change them.

Guy, I had checked the alignment and also had the axle in when I reseated them. I know now that I boiled the oil out. This is a Champ Turbo and those suckers are a tight fit. LOL.

Love this forum. You guys are awesome! Thanks!

[Guy Spaulding]

I know what you mean, feeling certain of your alignment by having the axle in when reseating them.

Try my test. You'll discover that having the axle in is not as effective as you might think.

[Cheater]

Rick,

If the bushings are fitting tightly into the uprights, pull them out and enlarge the holes a wee bit so the bushings aren't a tight fit. That tight fit compromises your ability to get the bushings aligned well. You might want to review what I wrote about installing axle bushings in the T-Flex tome again...

Guy just gave you a very important tip about aligning bushings using an axle. For years, we all thought that was they way to do it, but we forgot that there's always a running clearance of a thou or two. If you really want to get bushings aligned properly, find an axle or pin that fits tightly in the bushings with as little clearance as possible. I use machinist gage pins to align bushings and can assure you doing it that way makes a very noticeable difference.

[Hangtime]

I'll definitely check into this completely. I understand what you both are saying regarding axle tolerance and bushing fit. I have a carpenters background so I'm kind of a bonehead about machine stuff. LOL!

I'll pickup some new blanks and bushings. No doubt this is critical.

Greg, I had actually browsed your T-Flex Tome thread. I want to sit down and give it a good read. Thanks!

[greggw]

I am having some issues with this topic also, reading this post has given me some tips about proper alignment.

 

While running top speed I am getting a vibration or a harmonic that resonates through the chassis. I checked the bushings for wear and found the bushing nearest the motor was ever so slightly worn egg shaped. That makes sense seeings how that is where the bulk of the stress is being generated.

 

I will be getting some adjustable bushings as replacements to get a better alignment and to adjust for chassis squareness.

 

Good stuff, guys!

[Matt Sheldon]

IMO the Koford 3/32" oilites are the nicest there are as far as quality. They also have a nice thrust ring machined in.

 

The JK adjustable are not bad either and are great when you need to setup rear axle height in a class that does not allow and chassis modifications. These can also be used to alter wheelbase and put a kick in the rear end if running ovals.

[James Grandi]

I would double-check the axle for wear in the area it was in contact with the bushing. On a few occasions I've found both the axle and bushing needed to be replaced.

[havlicek]

I have used both types and can confirm from my own experience that the Slick 7s are very long lasting when properly oiled/maintained, have nice tolerances, and will lock up if not oiling enough or using the wrong oil. I have only had them seize up once in seven years of using them, and it was because I let a friend borrow the car and they didn't oil enough. 

I also have cars with bushings

 
Just for clarity, both types are "bushings"... whether solid material or sintered metal, at least in slot car terms and to differentiate them from "ball bearings"... although when a tube-shaped metal piece is used to run an axle in... it can be called a "bearing".   

 

Anywho, when slotters say "bearings", they mostly likely mean "ball bearings" as opposed to "bushings".   
 
Some of the Chinese motors use a sintered metal "bushing" that's magnetic and (I suppose?) that means there's some steel in the mix, even though they're "yellow" colored. I would think that those can be tough on armature shafts, especially if they're not kept well oiled, but I've never seen that material used for axle bushings.
 
-john

[Ralph Thorne]

All of the JK adjustable bushings I've bought recently have been way undersized and are a PITA to ream and get right, therefore I've switched back over Slick 7 bushings.

 

Speaking of bushings, I've heard a few people complain recently their Hawk 7s are wearing out the can bush abnormally fast, as in on the power supply before even getting raced. I have not had this problem.

 

Has any one else seen that happen?

[PCH Parts Express]

The Kelly 3/32" axle bushings should be worth a try if you like adjustable bushings.

[A. J. Hoyt]

Ralph,

 

I have had pinion end bushings wear out in a Hawk 7 and a Hawk 6 in a surprising way - it left a "Figure 8" shape where the shaft would run in "either" position. One was in a stamped steel car and one was in an inline car - both have a thrust component pushing the shaft away from the gear. One was so bad that the car just stopped on a turn and spun the motor with the pinion gear not even meshing the crown gear. There was no evidence that this was progressive (car slowing down or odd spur gear wear).

 

If anything, I over-oil my cars.I was told (and immediately believed) that I was using the "wrong oil" and they offered to sell me the "right oil" and that has worked.

 

Also, keep in mind that tighter bushings soldered into the chassis uprights tend to get mis-aligned and bind pretty significantly in a crash, undoing all of the careful alignment work you did. Always consider this and feel the gear mesh looking for axle bind as soon as you can after a crash - the motor might still "power through" to the end of the race but might burn itself up in the process.

 

Keep it in the slot (and keep that bushing alignment),

 

AJ