RSS Feed

Monthly Archives: August 2010

That’s a wrap

My internship concluded two weeks ago in a flurry of engine disassembly and excited documentation. Then a road-trip to Virginia happened to get some folks from College Part I (also known as my stint as an undergrad) married off. Huzzah to KT & DJ Chazzy Chuck, and Mischief & Paddy, and Samwise & Ian!!!

As a result I’ve sort of had a car heavy past few weeks just not enough time to blog.

However, my internship completely rocked my summer for so many reasons:
-hands-on experience
-really great mechanic team
-Bobcat driving lessons
-but also my engine project

One of the mechanics at the garage had purchased a truck on Craigslist that gave him nothing but trouble from the word go. He started having radiator trouble about a month before the engine started giving him fits. When he replaced the spark plugs he found that two of the six were rusted in place (That’s red flag number one). The oil circulated poorly throughout the engine and it leaked antifreeze out the tailpipe (That’s red flag number two).

Shortly before my last day, he scrapped the engine and let me have a go at taking it apart and seeing what went wrong with it.

Capstone internship project

This beauty had a variety of troubles. Formerly a V6 out of a 1997 Dodge Dakota, this is the laundry list of an engine gone bad.

Uncovered engine problems
-cracked cylinder head as evidenced by the hairline crack between all of the intake and exhaust valves
-blown headgasket
-worn rod bearing inserts
-burned valves
-clogged oil pickup screen … which would have contributed to the poor oil circulation

It would have been great if I had the time and finances to put it all back together but the exercise gave me a critical insight into all the things that can go wrong. When I took engine disassembly and repair last fall we discussed the sort of things that can lead to poor engine performance. Things like a cracked cylinder head or burned valves.

But I had no context for what it looked like and very little idea of how big a crack it would have to be to cause a problem. In this case, we saw that a thin crack no longer than the distance between your pinky fingernail and its first joint can be enough to cause some serious damage. Same for the rod bearing inserts. Okay. So they’re worn. What does that even look like?

Turns out it look like this:

The inserts are parts that are intended to be replaced anyway if you were doing a major engine overhaul but you really shouldn’t be able to see the copper. The construction of the rod bearings is kind of like a flaky pastry. There’s a whole bunch of layers and that make it all up but the copper part is like the crisp golden bottom. You don’t see it, it just provides a base for everything else.

I’ll put more pictures up on flickr because I’m just this weird menagerie of news hound meets grease monkey meets shutter bug. Right now though, more road-trip recovery in the form of Pirate-Ninja laundry needs to happen.