Tuesday, May 17, 2011

The Engine, and Damage

My luck ran short after a few months of owning the car when the engine developed a slight knock at high RPM's. In March 2005, the engine was torn down and reassembled. The picture above was damage caused from excessive harmonics as a result of detonation. Adjusting timing, running the car on 100 octane and replacing a damaged plug did not do the trick. The engine at the time also started leaking oil from the rear main seal and at the front of the oil pan. The slight knock, was a symptom of detonation that would occur when spinning the engine over 5000 RPM. I sent out a sample of the oil for analysis, and the results came back conclusive for contamination. The oil filter had a large amount of fine metal fragments and my drain pan magnet was cluttered with fragments. The hole in the picture you see above was from harmonics causing the windage tray to bounce, catching the corner of a connecting rod bolt and shearing the windage tray off the studs.

After the tear down, damage was found on #1 cylinder connecting rod bearing, and slight scoring on the journal that was polished out. The timing chain had over an inch of play, which more than likely caused havoc on timing. Valve seats had significant damage which most likely caused hot spots to develop, and led to detonation.

After a quick trip to the machine shop, the block and rotating assembly was hot tanked, magnafluxed, honed and checked over. The cylinder heads (Trickflow Trackheats) were cleaned up and had new valve seats installed. Instead of going back with a timing chain and windage tray, I picked up a timing gear set for less than I'd pay for a double roller (previous owner didn't want a noise model). I also picked up a Canton girdle which the windage tray attaches to rather than studs.

Everything was buttoned back up. The headers are just a cheap Hedman 289/302 model that had some ceramic paint thrown on it to cover up the rust to make for a nice picture. I planned on ditching the Holley 750 4160 for a 700 4150.

At the same time the engine was being rebuilt, I had the transmission and torque convertor rebuilt as well. It's a C4 auto with a full manual valve body (no trans brake). The torque converter is a 3000 RPM TCI unit. Everything ended up being bolted in place back into the car as a temporary means of storage. With the plans I have for the car now, I've decided not to go with the 302 and C4. Instead, these will be stored and kept for a future project (the wife wants a 65' coupe).

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