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Post by rkcarguy on Aug 27, 2012 20:26:07 GMT -8
Hey guys...we've been having a few clones turn up at the SIMA races, and have not had very good luck with them. 2 loose sidecovers that resulted in one seizure and one broken rod, and last weekend my 2nd kart(the loaner kart) broke a rod out of the blue with a spectacular blowout from the top of the case despite being full of fresh oil. It had about 90 minutes on it since I built it, only about 30 minutes on the oil, and was only running around 325*. It was doing great down the straight and started slowing near the tower and then popped when I looked back to see where my brother in law was.
My standard prep includes solid side cover dowels, loctite everything, and I even brake clean the female threaded holes in the rod and then toothpic some loctite into them so the bolts don't come loose. Because we run with some seattle kart club and canadian ASN GX200's, we opt to run their 18# springs here and shoot for around 6300 rpm because we can't run the lower gears to keep up with them otherwise. The local clone regulars are planning to meet at the next race and discuss where we want to go with this class and how we can make the motors more reliable. I'm considering asking for the billet rod to be a legal optional item, and maintain the rest of the rule set as it stands.
Most of us are either running royal purple or mobil 1 full synth.
Any feedback or other idea's?
Anything we are doing wrong?
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Post by Ricky Worley on Aug 27, 2012 21:26:24 GMT -8
You should be running a racing oil with high zinc content. Something like amsoil dominator 5w20 or redline racing 5w20. Also would recommend switching from bolts to studs w/ nuts on side cover or check them often. The other option would be drill them all and safety wire them all together so they cannot back out. Also, how often are you changing oil?
Sent from my PG06100 using proboards
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Post by mikezamora on Aug 30, 2012 5:21:56 GMT -8
Royal Purple and Mobil 1 are not intended for use in an engine with a splash oiling system, they will work fine in your lawn mower but you're also not running your lawn mower as hard as it will run. I would recommend running an oil made for 4-cycle kart engines. In my son's clone we run Red-E 20w, Redline 20w will also work very well..
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Post by rkcarguy on Aug 31, 2012 18:43:10 GMT -8
I change my oil every day, so it might get an hour of time on it.
In my messing around with different oils(in different motors), I had the best luck with 5w-30 maxima motorcycle oil. It came out the cleanest after a race day than anything else but there was some performance loss compared to 5w-20.
I'm aware of the side cover stud kits, that sounds like the way to go.
Would it be acceptable to add some zinc additive to the mobil-1?
I got a gallon jug of the stuff.
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Post by rkcarguy on Jan 29, 2013 16:56:46 GMT -8
Was just going to update this post. I presented the remains of a broken stock rod, a new stock rod, and the HEAVIER arc bilet rod to our class racers in a spiel to allow the billet rod as an racers option and it met no objection. On a gram scale it's about 10% heavier than the oem rod. The oem rods are made from vacuum cast aluminum and are very pourous and gummy, not a good bearing material for a 6000rpm rod bearing.
Our clone class as SIMA is slowly growing and we are working on weight adjustments to deal with all the different motors we are seeing. GX200's under Seattle Kart Club and ASN rules, and Clones under IKF int'l stock. The goal is to get weights adjusted so that someone can show up running one of the above sets of rules, and compete without changing anything besides weight. As the group grows and diversifies we'll do some splits then by motor/weight and go from there.
One important thing I have found is we do not have anymore valve problems since everyone went to 18# Honda springs. The rpm capability of the springs seems to surpass the range of the stock cams so the can starts to choke before the valves float and chew up stems or potentially break and drop into the motor.
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Post by rsection8 on Jan 30, 2013 4:30:15 GMT -8
Sounds complicated. Run a briggs world fornula After all that your spending almost as much
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Post by rkcarguy on Jan 30, 2013 12:21:52 GMT -8
Not really. Clone was $150, Honda 18# springs $5/pair, extra lash cap and exh valve retainer(used both sides) $5, $100 billet f/w, $60 for the rod, and another $100 in air filter/adapter top plate and fuel pump....all stuff you can reuse on the next engine. And besides no one is running a WF, it was the 1st engine I was ready to buy before I checked what was being raced at our track.
If I was paying some builder to put it together, sure. But I'm DIY so it's a couple evenings in the garage.
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