Sunday, September 16, 2007

MSR September 15-16

I'm sitting in the paddock at MSR in Cresson, looking at the rising sun. It's Sunday. Yesterday, I re-learned the track. It's been forever since I came here, and I offered up a set of old brake pads to the gods of track memory.

MSR Cresson is a combination of an old 1.7 mile track that is well laid out and a newer section that looks like it was drawn on a napkin in a Ft. Worth bar. The whole is 3.1 miles.

There has been a good bit of development in the last year. There is now a gas station under construction at the entrance to the place, and there are more garage spaces taken up. The houses that are at the east end of the track are occupied and there are more going up.

Drainage is always a problem at Cresson. There are places on the track that are simply not usable when it rains. Even after the rain stops, there are seeps in the low spots that stay went for days. So it was this time, and there was one puddle at the turn in of the main lower course carousel that was kind of a dividing line: Inside of it was one line and outside was another.

I'd like to write more about the weekend, but it was really uneventful. No one crashed, there were a few mechanical issues. The best thing that happened was I ran with Mike for several sessions. Mike runs a mag red C5 and is much after my own heart. He has improved his car from the ground up, working on the suspension, and tires and seats, rather than the engine. He's smooth like glass in the turns and knows MSR real well. He was a good person for me to lap with, as when he made a mistake, I could pass him, and vice versa.

We also ran with Tom. I'm not using Tom's real name here. He's got two cars in his road course stable, and at least one more set up for straight line. He love Vettes. His wife drives as well, in the yellow group. His cars are characterized by immense horsepower. Generally, Tom runs over 500 at the wheels. His current corvette is a C5 body with an LS7 engine.

Unfortunately, he blew that car up. Something on the front of the engine went bad; I think it was either the balancer or the main pulley, but the car was gone for the weekend. He resorted to driving his wife's car, and thus was able to run with Mike and I. So for a couple of sessions, we were the three corvettes, blue, red and yellow, and everyone got out of our way. It was a blast.

Wednesday, September 12, 2007

Springs, part 2

So I helped the machine shop guy unload a multi-ton lathe and he bumped me to the front of the line for the head rebuild. I highly recommend Precision Machine in Round Rock for your engine rebuild needs. He's fast, knows modern engines and the heads looked like new when I got them back. The rebuild took three days, and cost a mere $270, parts included.

Strangely, the motor went back together far, far easier than it came apart. Even the surly power steering pump bracket went back without a fight. It was as if the engine wanted to run again.

Before I knew it, I was looking at an assembled motor, with only a broken exhaust flange bolt in damage. I refilled all fluids, reconnected the battery, and turned it over.

Running rough, but strong, I watched the oil pressure climb for those first critical seconds. It stayed normal, so I drove around the block. Still good. I took the engine up to operating temp, then took it back to the garage to cool off for 24 hours, to temper the springs.

I've been driving around on the rebuilt motor for a couple weeks now, and it seems as good as new. Going to the track this weekend, and we'll see for sure.

The experience of tearing down the engine and building it back up was a good one. I got some tools I needed, and learned a great deal about the machine I use every day. I also learned some good anger management. I've a pretty bad temper, and am prone to frustration. This project was a good way to learn to control that.

Oh, and I saved a load of money. The total cost of doing this myself was $750 or thereabouts, including all parts. I could have saved around $100 more had I used stock headbolts, but the ARP studs are just too good a deal to pass up, and are reusable.

Sunday, September 02, 2007

The Rite of Spring

Five weeks ago, I broke a valve spring. The #5 intake valve, to be exact. What I knew when it happened was that the engine started running horribly rough, and I felt the need to shut down as fast as I could.

Once I got it towed to a shop, we ran a compression check. #5 cylinder showed 0 pounds, and the others were erratic. I had the tow truck guys tow it to my home, as I wanted to think about what to do next.

That met resistance. The shop manager said,
"We have a saying, mechanics I mean. If we fix it, it'll be $80/hour. If you want to watch, it's $100 an hour. If you want to HELP it's $160."
He continued,
"If you tow it home, and tear into it, and get stuck, it'll take us longer to fix it than if we just kept it here and worked on it."

The gauntlet was thrown. I smiled at David the shop manager and said,
"That's fine. I'm just gonna take it home and pull the valve covers and see what I can find out."

He grudgingly let me take my poor sick car home.

Once I got it there, I opened it up, and found the broken spring. It had not shattered, but had just broken, and was still in place around the valve stem, so the valve had not dropped into the cylinder. However, since the LS6 engine is an interference engine, there had to have been valve/piston contact. The next question was how bad. Also, there was a bent pushrod and that meant likely a bad valve guide. So the heads had to come off. Hoo boy.

Pulling the heads on an engine is a bit like open heart surgery. On the C5 corvette, on can do it without pulling the engine, just. Some of the working spaces are very small, and there are many, many bolts to undo.

I do not have air tools. I have not torn down an engine since I was in high school, and that project ended in tears. I did have a set of manuals, and Google. I did have a burning need to see what the engine looked like inside, and how it worked. That surprised me a bit. It's an American V8, nothing too complex. And there was the fact that if I had taken it back to the shop, I'd have admitted defeat.

I started ordering parts. I needed head gaskets, exhaust and intake manifold gaskets, water pump gaskets, AIR tube gaskets, throttle body gaskets and gaskets for my gaskets. I needed tools. Some extensions for the socket set, a spark plug universal adapter, extra jack stands (I'd be using all four of mine for a while), some 10mm tools (all the bolts I'd be dealing with were either 15, 10 or 8mm) and a host of other little things. I also needed a machine shop.

I called my backup shop, not wanting to alert David and the primary that I was contracting something. I found a machine shop in Hutto that did good work and understood LS6 heads.

Now, I had to get the heads off, and get them to the shop.