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Old 05-02-2009, 08:30 PM   #1
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Default Huge F'up, need help!

So I am going through my Losi 8T 1.0 with the 427 on it making sure all is well. I was/am going to race tomorrow in my first race. Lately the engine has been giving me trouble starting, more specifically it seems I have a 1way bearing problem. If I hit the drill to start it (has the spin start on it) it will crank for 2 or three stokes, then spin without turning over the engine. I have been through this before with other engines, so I proceed to pull it all apart with the idea of roughing up the surface of the shaft the bearing rides on and cleaning the bearing itself.

Well, get that done and when I am putting it back together there is a little spring laying on the table. I decide it goes (here is where the drama starts) in the hole in the backing plate that the PS shaft goes in (the shaft the one way bearing rides on) thinking that it puts pressure on something when the shaft is in place. I thought that because I didnt see it when I took the spin start cover off in the beginning (we'll get back to that). So anyway, I slide the spring in, slide in the shaft, put the plastic disc inside the hex and put the cover back on. I get the engine set back in and set the spurgear/clutch bell mesh and tighten everything up. I threw a little afterrun oil in since I had run it a few minutes ago to tune it up.

So I get the drill back out and fire it up, or should I say, tried to fire it up. I turned over maybe 2 times and froze up. Now my first thought was that I put too much oil in it, and it was hydro locked, so I pulled out the glow plug and no dice. Then it hit me........that spring didnt go in that hole. I sharted.

I realized too late that the spring actually goes in between the plastic disc/spacer and the ps shaft, there is even a shallow hole that centers/holds the spring in place in the back of the shaft and a little bump on the disc that does the same. So I am skeeeerude. I pull it back apart and find the spring crammed in between the rod/crank and the side of the case, I backed up the crank a (needed a little force) and plucked out the spring. Luckily it is all in one piece, but unluckily, it is flat as a pancake. I dont see any major damage to the case other than a few minor scratches.

So how necessary is this spring? It is part of the PS shaft kit, and I am doubtful they stock it at the shop. It looks like it keeps the plastic spacer from touching the shaft once it is spinning when running, but what would happen if it wasnt there? Can I use any spring, like maybe one out of a pen cut to length?
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Old 05-02-2009, 11:39 PM   #2
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Quote:
Originally Posted by boatsnhoes View Post
So I am going through my Losi 8T 1.0 with the 427 on it making sure all is well. I was/am going to race tomorrow in my first race. Lately the engine has been giving me trouble starting, more specifically it seems I have a 1way bearing problem. If I hit the drill to start it (has the spin start on it) it will crank for 2 or three stokes, then spin without turning over the engine. I have been through this before with other engines, so I proceed to pull it all apart with the idea of roughing up the surface of the shaft the bearing rides on and cleaning the bearing itself.

Well, get that done and when I am putting it back together there is a little spring laying on the table. I decide it goes (here is where the drama starts) in the hole in the backing plate that the PS shaft goes in (the shaft the one way bearing rides on) thinking that it puts pressure on something when the shaft is in place. I thought that because I didnt see it when I took the spin start cover off in the beginning (we'll get back to that). So anyway, I slide the spring in, slide in the shaft, put the plastic disc inside the hex and put the cover back on. I get the engine set back in and set the spurgear/clutch bell mesh and tighten everything up. I threw a little afterrun oil in since I had run it a few minutes ago to tune it up.

So I get the drill back out and fire it up, or should I say, tried to fire it up. I turned over maybe 2 times and froze up. Now my first thought was that I put too much oil in it, and it was hydro locked, so I pulled out the glow plug and no dice. Then it hit me........that spring didnt go in that hole. I sharted.

I realized too late that the spring actually goes in between the plastic disc/spacer and the ps shaft, there is even a shallow hole that centers/holds the spring in place in the back of the shaft and a little bump on the disc that does the same. So I am skeeeerude. I pull it back apart and find the spring crammed in between the rod/crank and the side of the case, I backed up the crank a (needed a little force) and plucked out the spring. Luckily it is all in one piece, but unluckily, it is flat as a pancake. I dont see any major damage to the case other than a few minor scratches.

So how necessary is this spring? It is part of the PS shaft kit, and I am doubtful they stock it at the shop. It looks like it keeps the plastic spacer from touching the shaft once it is spinning when running, but what would happen if it wasnt there? Can I use any spring, like maybe one out of a pen cut to length?
On a system like that you need the spring, if pushes the little pin into the groove on the one way shaft and allows the crankshaft to turn over. I don't know what size the spring is off the top of my head, but here is the replacement, I wouldn't mess with a pen spring because if you cut it to the wrong length or if it is too strong or weak it could lead to problems, the shaft should help with the problem of it not turning over too.
http://www.losipartshouse.com/servle...n-Start/Detail
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Old 05-03-2009, 09:59 AM   #3
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Two words......Bump box.
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Old 05-03-2009, 10:05 AM   #4
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Originally Posted by Miniracer23 View Post
Two words......Bump box.
Agreed.

http://carolinasrc.com/Webstore/Scri...idproduct=4845
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Old 05-03-2009, 10:06 AM   #5
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yeah get a box, you will need one sooner or later.
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Old 05-03-2009, 03:49 PM   #6
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Originally Posted by Miniracer23 View Post
Two words......Bump box.
well said!
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Old 05-04-2009, 04:45 AM   #7
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So the shop didnt have the part, but after looking around on the hangars I found some sort of clutch shoe set with two of the identical springs in it. Worked like a charm. I got to race, but just as the first heat was ending, my damn throttle servo took a dump.......again. I was initially running the stock spektrum servo, but it went out, so I bought a JR 590 metal gear thinking it would be more durable. Must have gotten a bad one? Looks like its time to invest in some good servo's if I am going to start racing.

Bump box? Meh....I dont know. Just seems like more crap to have to lug around. What are the benefits of a bump box vs roto/spin start?
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Old 05-04-2009, 05:11 AM   #8
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Originally Posted by boatsnhoes View Post
So the shop didnt have the part... if I am going to start racing.

Bump box? Meh....I dont know. Just seems like more crap to have to lug around. What are the benefits of a bump box vs roto/spin start?
There are alot of advantages of a starter box. First and foremost, less weight in the vehicle, less complicated stuff to mess up (your situation with the spring), 12v battery battery in the box holds a charge for a long time (basically a 12v motorcycle battery). At the same time, like you said it's more stuff to lug to the track/they have some weight to them. It's like any piece of your R/C gear, if you take care of it, it will take care of you.
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Old 05-04-2009, 06:52 AM   #9
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to fix the servo thing put red o-rings the ones from the shocks
under the raido tray it will lift it up so the servo will not hit
the chassis and fry it
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Old 05-04-2009, 07:59 AM   #10
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For your throttle servo set-up please read this from losi on how to set-up your servo. It makes a difference.

http://www.losi.com/ProdInfo/Files/L...e_Addendum.pdf

and

http://www.losi.com/ProdInfo/Files/8...ndum_LoRes.pdf
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Old 05-04-2009, 08:10 AM   #11
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Quote:
Originally Posted by boatsnhoes View Post
So the shop didnt have the part, but after looking around on the hangars I found some sort of clutch shoe set with two of the identical springs in it. Worked like a charm. I got to race, but just as the first heat was ending, my damn throttle servo took a dump.......again. I was initially running the stock spektrum servo, but it went out, so I bought a JR 590 metal gear thinking it would be more durable. Must have gotten a bad one? Looks like its time to invest in some good servo's if I am going to start racing.

Bump box? Meh....I dont know. Just seems like more crap to have to lug around. What are the benefits of a bump box vs roto/spin start?
Everything about a starter box is an advantage. Is it really that big of a deal to carry a starter box to the track? You can get rid of all that spin start garbage hanging off the back of your engine. That stuff only robs power and creates the oppertunity for massive failure. Your engine will start easier and run better. Plus the fact that you will never again have to deal with a slipping one way, or weak starter wand.
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Old 05-04-2009, 08:14 AM   #12
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BUMP BOX - I was having major problems last year when I started racing - A bunch of pro Losi drivers told me to get the bump box - never been happier - switch to a 4 cell lipo in the box and it feels 20lbs lighter -

A bunch of stuff to carry around - get a box with a handle that you can carry with you from pits to the track, that way you have to carry two things..........
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Old 05-04-2009, 07:07 PM   #13
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Bump box is the way to go.

It will pay itself off after a few months of not buying one way bearings or pullstarts. It will save you blisters from pullstarts and charging the spin/roto start wand batteries and carrying spare batteries and wands around.

Plus it's a handy stand to throw your truck on and tune and work on it.
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Old 05-04-2009, 08:34 PM   #14
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Sounds good, guess I'll have to step up. As far as lugging stuff around, I have a really cool box I bought at home depot of all places. It's hard to explain but it is basically a big square box with the sides of it fold down and have clear tops on them. from there you open the, ahh crap, I will post some pics.

Anyway, that big box, my aluminum radio/field charger case, fuel, fuel bottle, cars (I usually bring at least 2, that way if one craps out I can run the other) ice chest, folding table, canopy (havent busted that out yet as it is just now getting hot) and chairs and I guess soon a damn bump box, hehe.

I wil now check out the servo links....
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Old 05-04-2009, 08:42 PM   #15
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Quote:
Originally Posted by cary View Post
to fix the servo thing put red o-rings the ones from the shocks
under the raido tray it will lift it up so the servo will not hit
the chassis and fry it
I have those set under the battery to keep the screw out of it as mentioned in teh addendum below, but my servos arent touching the chassis. Are you saying that with chassis flex they could touch and "'fry". How does that happen in a plastic case?

Quote:
Originally Posted by travis4380 View Post
For your throttle servo set-up please read this from losi on how to set-up your servo. It makes a difference.

http://www.losi.com/ProdInfo/Files/L...e_Addendum.pdf

and

http://www.losi.com/ProdInfo/Files/8...ndum_LoRes.pdf
Yea, I have read through both of those several times. I spent a couple of hours adjusting everything and think I have it pretty well adjusted. The one thing I am not sure of is the brake set up, is it possible to have too much servo pressure on the brakes causing the servo to overwork and fail?
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