Toasty Hilliard Flame

C

Chilli

Member
Hey folks, We ran too high a gear in a 30 minute road race and looks like we toasted the clutch. No smoke during the race but some blueing in the hub when we pulled it apart. Any chance we could save the shoe by sanding the running surface or is the material compromise where we should we just replace the shoes? Also curious on the in composition of the Hilliard shoes compared to the Stingers if anyone knows?

Thanks
 
I would not bother. The metal is already compromised and it’s only $30 to replace the shoes anyway. The springs are likely tempered as well and should be replaced.
 
Chilli said:
Hey folks, We ran too high a gear in a 30 minute road race and looks like we toasted the clutch. No smoke during the race but some blueing in the hub when we pulled it apart. Any chance we could save the shoe by sanding the running surface or is the material compromise where we should we just replace the shoes? Also curious on the in composition of the Hilliard shoes compared to the Stingers if anyone knows?

Thanks
Click to expand...
"Some" blueing is normal. You won't see me disagree with Gary very often, lol, but I'd say just sand it, clean it up, and run it. Unless you wore substantial material from the shoes. You've not gotten anywhere near the temp that the shoes were treated when they were made. Steel needs to be cherry red before losing it's temper from heat treat.
What have you got to lose?
Try it, and if you don't think the performance is there, replace the shoes and springs.


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Carlson Racing Engines
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I do not disagree with either Gary or Brian .
The one thing that would sway me is the cost of getting too and entering the race .
If parts were available at the track and or i had a spare clutch already .
Whether i wanted to mess with it at the track .
Time for new . Keep the old for a spare .
I have had them a warm orange color . ( Noram Clutch ) Its in the spare parts box .
 
Appreciate the info folks! We only do one race a month, and considering what entry fee's cost and limited track time, the cost of replacing the shoes and springs is not that big a deal. The shoes do look like they have alot of life left in them though. I'll refresh them and throw them in the parts box. We were able to pick up a Stinger our second day at the track last race. It launched hard at the start and performed well at first but then lap times started to drop. Hence my theory that we're running too small a sprocket on the rear and overheating the clutch.
We're just getting into karting and should probably be running CIK LO206 400. I have excellent mentors but none of them are heavy drivers. One of the folks suggested we run with the senior 375 folks because there would be more competition. That being said, I'm I correct in my thinking that with an extra 30 pounds, the clutch can't handle the gears the top guys are suggesting and I need to add a few extra teeth on the rear? Again this is a 2 mile road course with your throttle foot pegged 90% of the time running 21/55 gears. RPMs were showing at 5400 on the straight at first which we were told was good because this would probably send us close to the limiter in the draft. However as the race progressed, rev's would drop to 5000. I was thinking maybe running a 60 gear in the back for the next race and working my way lower.. Thoughts? I know this is a lot of info, Appreciate everyone's response!!
 
Stinger should not overheat in that situation .
stall speed or engagment rpm would affect that .
Chassis is likely getting tight .
 
If you have the engagement speed right you shouldnt be having clutch problems. Once its locked, its locked. Its the times (cautions and other slow speed times on the track) where slippage occurs. Ive run a Stinger at 390 pounds with no problems at all, unless theres a lot of cautions. I learned that, under cautions, you don't half throttle and slip the clutch. If you have to lag back a little then gas it and make it lock up under cautions, do it. Youll learn how to do it without disrupting the rest of the field while putting around. Watch your tach and set the clutch to engage using those parameters.
 
For road racing, once the clutch is engaged, forget about it.
Now, you may be up 1 or 2 teeth from your competitors at your weight. 30 pounds is probably closer to 1 tooth.
Especially in road racing, your clutch should never get hot -- leaving the grid is the only time it should be slipping. After that, it is locked up 1:1 (or very close.)
Make sure that you have the correct springs and weights in your clutch to engage it at peak torque and you should be good to go. The torque curve on these engines is very broad/flat so even if you missed the clutch set-up a bit, it still shouldn't be getting hot.
 
Thanks! As much info as I've read on the Hilliard's, I missed the recommendation to use two heavy weights on the shoes for the heavy's. I ordered a few more of those annoying little c-clips. LOL. Other than that, I'll freshen up the flame and the stinger and we'll see what happens.... New (used) kart and new driver. It can be tough figuring out if an issue is driver, set up or equipment. Probably all of the above..
 
Where are you road racing at? I can probably tell you what gearing you need to run. The 21/55 is a 2.6 ratio which is about right and a good place to start for road racing. If you go to the 60 rear gear more than likely you'll be on the limiter too much. You need be under the limiter when you are by yourself, but when your drafting you need to just hit the limiter for short time at the end of the longest straights. Everything depends on the draft and what gear you need to run. You need to go out and practice drafting with people in 206. If you gear the kart for the best times when your not with a drafting partner you'll be way over geared when some one is behind you pushing. The 30lbs extra weight isn't as big a deal as in sprint racing. You keep more momentum road racing. But plan on running 1 more tooth on the rear gear compared to the 375 guys.

As far as your clutch goes, just sand the shoes and drum and call it good. In road racing your not using your clutch, but for a short time on the start. If your running the hilliard at 400lbs I'd go with all black springs or maybe 2 black and 2 white with some weights.

If you lost 400rpms over the coarse of the race I bet it started happening around lap 4. More than likely your kart is getting tight when the tire temps or track temps come up. Or you just lost a drafting partner.

What tires where you running? When I road race the 206 I normally run a harder compound tire or a used set of my sprint tires that I'm about to toss out.
 
With the gear ratio on road race the clutch sees a LOT of heat from taking off on the start. I’ve seen plenty of Hilliard springs that will just fall off because they’ve been overheated.
 
Scrad, We're running at Summit Point. Both the main course and Shenandoah and we're using Hoosier R70's. Track was hot with air temps in the low 90's. I'm pretty sure most are going a little softer on the compound. The fastest CIK/LO206 Heavy racers are about 2 seconds slower than the seniors on both tracks. We're way off that pace. On day two, we put a fresh stinger clutch on and the kart launched nicely from a standing start at the beginning of a short morning practice session. That was our fastest lap of the day. On the race that afternoon, we had much clutch slippage at the start. You are correct that our biggest speed drop off was between lap's 2 and 4.
 
Ok, I was there that weekend, but racing in the animal classes. It was hot as hell. I had a similar issue as you where I was really fast on Friday and the morning practices when it was cooler, but kept loosing time though out the day when it was getting hotter. My kart gets tight when the temps get hot. I was running 3rd the first 3 laps, but then just kept loosing speed. I haven't had enough time with my chassis to figure out what it needs when the temps get over 80-85. The kart just gets bound up off the corner and looses straight away speed.

I've never run 206 at summit, but I'll ask some people I know that have and get the correct gear. But I think your in the ball park for gearing right now. I personally run a hard compound tire when the track is hot. I'd run those R70's. You can also play with tire pressure. More pressure gives a little better roll speed down the straight and will be a little better on the standing start. But it will get the tires hotter faster, which you might not want. Sometimes it gets too hot and the tires get greasy and might loosen the kart up, which might help.

I always take the clutch apart before the race and clean it up and sand the drum. You glaze the clutch during practice and should clean it.

Just remember a lot of those guys road racing the 206 have been doing it a long time. Don't expect to just jump in with a sprint setup and experience and be fast right away.
 
Appreciate the info Scrad. Will definitely freshen up the clutch before each race. We heard folks bump up the pressure on Summit main but was also concerned about the heat. I believe it was pushing 95 on Saturday an we ran at around 4pm. Still had a blast.
 
Intersting how a few are saying just a little bit of clutch use at the start. This couldnt be farther from the truth!!

There was one intelligent post about sanding it and slapping it back on. If those are ceramic shoes, you cant overheat them. Sand the drum put new springs and run it. Make sure the stall speed is right...its what pulls you out of the slower corners.
 
I've never in my life seen a clutch in road racing not get hot period bar none. Been running enduros for a long time from birco, horsemen, bystrum, heartman,and smc wet or dry they all will get hot. I would not touch one after a 45 minute race for no money. Heck the wet axle clutches get plenty hot. I don't care what the best of the best say no clutch in enduro racing stays completely locked up if they did they would be ice cold. I've never seen it later Chuck.
 
If a clutch is getting hot, it's wasting power by transferring that energy into heat rather than torque to the rear axle. The hotter the clutch gets, the more power you are wasting.
All clutches slip some and never completely achieve 1:1. If your clutch is slipping excessively at full lock up, then add weight to the shoes and go with stiffer springs while maintaing engagement at, or very near, peak torque.
Road racing is particularly hard on clutches because of the tall gear ratios and length of race. Granted, for those reasons alone, road racers will be harder on their clutches than sprint and oval racers. Add to that, the OP said that he ran too high of gear and the clutch got hot.
An LO206 is so under-powered to begin with, you can't afford to be wasting any power. Keep the clutch cool(er) and you'll see better lap times as a result.
 
Mr. Carlson, I respectfully have to disagree with your post #9. In a perfect world that might be correct not for the enduro world. I have close friends some of which are national Champions that have tested many prototype clutches for the current manufacturers and they all get hot. Just saying I also know people that can almost flat foot some of the bigger tracks and heat is always an issue. It's just the nature of the beast .respectively Chuck.
 
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