koker replacement nylon cam question

Came home last night to find a small hopper fire in my koker. Stove and direct vent were both recently cleaned so I don't think that was the problem hopper was full too. I am thinking I was trying to run it to low and was down to 3 pins on the timer since it was 60 degrees it was only idling for a long period even though i was showing .2 on draft gauge.
I plan on having dealer come to check it out and replace melted cam he said they use original nylon cam I was wondering the pros and cons if there are any to replace with the aluminum cam. Just thought I would ask for those of you that have replaced the cam and Can I get a replacement aluminum direct from keystoker?

thanks for any input

vulcan On: Fri Oct 12, 2012 10:22 pm
from my understanding Closing the shuttter for the combustion fan will increase the draft. Mine was set at 1/2 open from the factory but i am closing it little by little to increase my draft it is now up to .15 but I would like to see .02

Do you still have the combustion motor choked down? If so, your vent motor may be making up for what it needs by pulling the air thru the coal and causing the fire to work it's way back into the hopper.
Just a possibility...

thanks for the reply Coalen that post was back in early october when it was pretty warm and I had closed it down but I had opened it back up to just about 1/2 way or the factory setting prior to this happening as it got colder out and everything was fine. Then we had that warm spell when i had the problem, I am still thinking it was me trying to cut back on coal use in the warmer weather.
My real question is about the cam and if its nylon so that it will melt and prevent something else from happening.I have seen a few posts here about replacing them with aluminum cams and i am just wondering about my options.

I've read about an aluminum cam and I suspect it's homemade. I don't think it would be difficult to do. I know LiftedAWDAstro bought a used Koker that had one.
For what it's worth, (and I fully understand you can/will do whatever you think is best) I think installing an aluminum cam because the nylon one melted is equivalent to putting a penny in a fuse socket. It'll keep the system working through what would normally be a disabling failure only to allow a more severe failure to take place. Solve the issue that caused the original cam to melt and stay with nylon.
Good luck!

Keystoker has been in business since 1946. I really think if they thought the nylon was a weak link they would of changed it. That area of the stove should never get hot enough to melt nylon. The nylon is somewhat self lubricating and should insure smooth, and quiet operation.

I know I am off topic here also but.....that draft thing still concerns me.....you sure that your grates are all cemented down correctly and there are no leaks?

I really think that is the only way the fire would creep back into the hopper with a correct draft.

I have a koker myself and can't see how bringing any settings down low can cause a hopper fire if your draft is ok.

I would not dismiss this as what you are saying so easily. Just my thoughts.

As far as the nylon or aluminum I looked into that a while back myself and everytime I take mine apart for cleaning the nylon always looks nice and smooth...I purchased another gear motor instead with the nylon from keystoker as a backup...it was cheaper.

Thanks for the replies I didn't realize the aluminum cam I have seen mentioned was a home made item. I am sure there is a reason for the nylon and for it to melt to prevent further problems. The dealer didn't make it out so I spent yesterday removing the cam and cleaning all parts, the worst part was by far getting the melted nylon cam and melted screws cleaned up. Went to dealer and got the new nylon cam and screws.
Jrn my grates should have been fine and looked like they were the unit is new so it only had about 2 months of burn time on. Since I had it apart I removed the grates and cleaned under them and re-cemented them in last night, hopefully sealing correctly. I replaced all parts last night and allowed cement to sit overnight. I have fired up this am and watching it now to see how it goes, so far so good.
I am new to this coal burning and obviously still have alot to learn, I have a tendency to tinker more than I should although I didn't make any right before the hopper fire I think it was a combination of things including draft, trying to cut back on coal usage, and 2 60 degree days causing extended idling. I have the combustion shutter and direct vent back to the factory settings and plan on leaving it there! My draft is measured with a magnehelic and has always been on the low side but the gauge was something that was previously used and I am not 100 percent sure it is accurate. I am concerned that my feed screw adjustment may have changed from the unit running with the melted cam and it is currently running hotter than normal but I am watching and not making any changes until I am 100 percent sure.
Hopefully I have learned to leave well enogh alone and have learned a little more about how the koker operates.

once again thanks for the replies and info.

Mine did in fact come with an aluminum cam. The machine shop I bought the stove used from didn't maintain it and had a hopper fire. They made the aluminum cam and it is a little smaller diameter than the nylon one as I run the feed screw in all the way for max fire. I think they use the nylon for a couple reasons. The biggest is that it will remain quiet. My aluminum cam get noisy unless I oil it occasionally. We can hear it squeak. Another reason is that there generally won't be enough heat to melt it. The side of the carpet also has nylon machine screws. Check them as they may have melted. Mine now has brass wear plates.

How much for the aluminium cam at dealer?

Fyi I called the dealer and they say there's no such thing as an aluminium cam. The nylon cam is a safety feature as it shuts stoker off when it melts... somehow. The nylon cam is around $12.