wtf did i do this thing after only 10 races? Any ideas? Cylinder 4 - exhaust valves unseated http://btdtracing.com/gallery/d/10706-2/head2.jpg Cylinder 1 - exhaust valve extended or bent: http://btdtracing.com/gallery/d/10703-2/head.jpg
Labor day weekend (a month ago, now) I raced. The car performed well, I didn't notice any power issues. I brought the car home and parked it. About two weeks ago I started and it sounded like shit, like it was running on two cylinders. I assumed the coil had GTSd. I didn't bother with it until this weekend when it wouldn't start at all. I started with the CAS then the Coil then the ignitor before I got it running again, but she still ran like shit. So I started a leak down. Cyl 1 - 30%, Cyl 4 - 100% (yes, on the compression stroke). Attached is a picture of the exhaust valve in cylinder 1. Cylinder 4 it looks like both valves are out about 1/16" or more. Cylinder 1 is at least 3/16" So the head is off my car, on its way to Gasoline alley. But my question is, *what did I do to cause this?* I've not missed a shift and I dont rev past the limiter. The motor is a Mazda crate which I bought in May of last year. It has maybe 10 races on it. I run Royal Purple XPR 10w30 (i think, off the top of my head) in the car and religiously change the filter every race and oil every 2. I noticed my header was cracked as well, i donno if this was the cause or the result of bad valves. The valve springs look fine and dandy, all operating well, the cams move smoothly. The valve, however, is very stiff and I couldn't move it with my bare (bear!) hand, nor did it move when i rotated the cam. There is a picture attached of cyl 4 here, the ex valves again are the ones in question, they don't seem to be seated properly. I have a feeling one of the cylinders has been screwed for a while To answer your other questions, the AFM is untuned and I thought I was using a pretty conservative timing. I ran 87 for practice and qual at the mile and then switched to 110 from a nearby pump for the race. I typically run whatever the track gas is but that wasn't available at the mile. BTW, this is a 90 spec miata with a 1.6L crate bought from mazda in May of 2008. It's got maybe 1000 miles on it, 400 of which were break in miles on the interstate :p -Blake SM#97 -- http://BTDTRacing.com - World Champion Miata Parts Sales. Now in HD! Our ebay store: http://stores.ebay.com/btdtracing-36 or Subscribe to our active listings page: http://esssl.ebay.com/GetListings/btdtracing36?fmt=g This is our decision, to live fast and die young. We've got the vision, now let's have some fun.
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