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Motor issues.


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Last event a month ago we were having some bad misfire issues, and replaced the ign coil on saturday night. Sunday morning the car was running well and went very quick. put the car on the trailer and parked it.


I didn't do any motor related work in between then and this last weekend at Autobahn. First session saturday morning the car immediately had a misfire at wot above 4k rpm. I did about 2 laps and came in. We replaced a questionable plug wire, double checked any grounds, or loose connections went back out and it was much the same. That was it for saturday, since I had to leave early.


Sunday morning we replaced the tfi ignition module, and

went out to find the car way down on power but not specifically misfiring. I came in and we checked, and set timing to 12 degrees. Headed out to grid for the next session, and the car popped the 150 amp fuse that is on the main battery cable. When I would crank it I was starting to notice that there was kind of a "flat spot" when I would try to start it. It would crank but about once per rev it would kind of bog down, and I believe that was what popped the fuse. We got the car back, and coincedentally were going to replace that old fuse holder anyway so we already had a nicer new one waiting.


We replaced the fuse holder with a 200 amp and fired it up. I noticed the same flat spot with the starter but the car fired. Went out again only to have the same problems. That was the last session before I said screw it. I parked the car after about 3 laps and It was extremely hot, and was dumping water into the expansion tank. I could not get it to fire to get it on the trailer. The battery is showing 12.0 volts as it sits, but if you hit the starter it just clicks once. I looked at the traqmate data for a reference, and the hp/distance value was always right at 250hp at blackhawk and at ACC it was just under 200hp.


Where should I start?

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That sux man. I don't know, have you checked the valve train? Sounds like you covered the ignition and electrical pretty good. Good luck and hope it's not to serious.

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Did a compression test tonight. Warmed up the car and heres what I got.


145 125

140 130

100 130

140 120


front of car



I squirted some oil in the low cyl and got maybe up to 105. So bad valve maybe? Is this bad enough to worry about or should I keep looking outside the motor?

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Think I would check the pushrods and rockers to be sure nothing is bent or loose up top of that cyl. Check the valve springs too, if one broke the valve may have caught a piston and bent. If you have the adapter to hook a airhose to the cyl you could listen for a leak if it's a valve.

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Thanks for the help. The headgaskets are brand new, with maybe 6 hours on them, so I guess I could have messed something up putting them in. However I bought these heads off of craigslist, so they are the variable I am looking hardest at.

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