Compression 200 120 200 210
No blowby, no smoke, no oil in the coolant or vice versa. Weird.


Guess it's time to open it up. Again. I'm going to try and fix it without pulling the motor, wish me luck.

Damn man that scares me. Hope you get it fixed up soon. What do you think did it? It has to be pretty hard to blow a built motor. But then again you have high compression.

That's what puzzles me. The plug from that cylinder is beyond toasted. The plug looks like severe detonation took it out, but none of the other plugs look even remotely lean. I've never seen a plug lose the insulator - all the way up to the ceramic! There is not one piece left. The side electrode is definately melted off (the center electrode is perfect) but I don't know if that happened before or after the insulator came apart. EGT's were low on my 13.5 run, so I leaned it out a bit but not enough to do that to the plug. I'm thinking the plug came apart and created all kinds of hot spots in the cylinder which led to pre-ignition that either scored the cylinder or damaged the ring land. The car doesn't run that bad. A little hiccup every now and then at idle is the only noticeable symptom.

I was planning on taking the car to Indy for a lap around the roadcourse at the Brickyard in 2 weeks, so I'll probably wait until after that to tear it down.

You know what could have happened? The part of the insulator that melted off may have become lodged on the valve seat, giving you low compression. Even a small tiny particle stuck between the valve and the seat will cause the low compression. Do the oil in the cylinder trick to see if the compression raises any..if not, then suspect the valves..

Did the oil trick and it raised compression from 90 (cold) to 100 (cold). The 120 reading came after warming up the car.

Spark plugs die from detonation. Chances are detonation broke it, then it flew around and out. You might want to check your exhaust turbine..

I think you melted something. Depending on how bad it is, you might be able to see it from the bottom.

There may be an imperfection in the head on that cylinder, or wall, or piston that is leading to high EGTs. Consider moving your probe there in the future to check it..

Sorry to hear about it, Greg. That's not cool.

What? This can't be happening, again? Man, I hope it's nothing major this time.

Ouch, thats a kick in the pants, Greg. Knock on wood, thats about the only problem I havent faced since rebuilding. Keep us posted on the progrss, and take a bunch of pictures :-)

Only one plug looked like it was having detonation? You have aftermarket injectors right? Are you sure that the injector is not clogged or if it is even workin. Check there, your injector might not be giving that cylinder enough fuel, in turn fuckin shit up in there.

Dang that sux big time at least your numbers aren't like mine:
145 130 130 140

I was thinking about the injector being clogged, I'll send them out to be cleaned when I take it apart - which looks like it will be sooner rather than later. I replaced the thermostat, and the car seemed to be fine. I drove it to work this morning and it was fine until I got off the freeway, then the temps skyrocketed. Guess I won't be driving it to Indy unless I get it fixed. :(

Looks like you are now running into my problem. My car overheats when I pound on it...but not until I slow down below say 30mph. When I'm moving over 30mph, the air circulating around keeps the temps down, but as soon as I stop or something, temps blast through the roof! Then if I start driving again, the gauge will drop down to about 3/4, then back up when I stop.....I think my radiator is plugged up. Changed thermostat, upper and lower radiator hoses, and radiator cap and none changed a thing.....let me know what solves your problem. As of right now, I'm waiting for the Fluidyne to come off back order from RRE(16th), then I'll put that in and see if it fixes it.

Problem is, mine doesn't go back down until I park it.

You guys might wanna put a datalogger on yer car when its overheating to check yer ECT or put a thermometer in the coolent while the temps are up. I had the exact same problems as you and i replaced the thermostat, and the fan switch only to find out that my temps were perfectly normal all along. The gauge sending unit wasn't working right and caused the gauge to read high when it really was at 207 deg.

Both of my ECT's are giving the same reading. I'm hoping it's just a head gasket, but I'll be ordering a piston and a set of rings just in case. I have 9 days to get it running again.