'87 Shelby CSX
#321 of 750
davidr at shelbycsx.com
Engine Buildup Progress
08-20-02 -- My condolences to the family and friends of Thomas "Gus" Mahon, who died last night as a result of injuries sustained in a traffic accident. While I had never met Gus in person, I exchanged several e-mails with him in the last two or three years. In fact, I sent him a message just days ago. Gus was an inspiration to many in the Shelby Dodge community, and he will be missed. I will always think of him in connection with the manual boost controller we call the "G-valve" or "Gus-valve."
That was the 4th and last run of the night. Boost was 24 psi and fuel pressure was 55 static minus 1 turn of the regulator, because I'd been running rich. This is with a FWDP +40/3-bar calibration. I'd been trying all night to get over 20 psi, but even without my leaking BOV installed, I was having problems. I had to stretch the spring in the G-valve to finally get it going. I was beaten by a 13.3-second Firebird on that last run, but I'm especially happy with it, because it was on my super-hard Firestone Firehawk SH30's (460 treadwear rating!). My previous best was at SDAC-12 with BFG Comp T/A's I borrowed from SuperDave. Tonight was just the way I drive it every day, except I took the spare and jack out. And my son's car seat. I wish I had left it in there; it would have been funny. :-)
The first three runs were terrible. The first one at 17 psi I bogged off the line and ran 15.75 @ 95.69, but still beat the 17-second Probe I was up against.
The second run, also at 17 psi, I blew the shift to 3rd and ran 15.959 @ 92.40, but beat the 19-second F250 pickup they put me up against.
The third run was at 19 psi, and there were no problems except being slow. I ran 15.221 @ 97.00 to beat a 16-second Civic hatchback.
It was a typical Texas night, about 90 degrees. I was definitely the fastest FWD car there. LOTS of Camaros, Firebirds, and Mustangs; it was high school night. :-)
MAJOR UPDATE 07-23-02 -- Back in November I noted that there was a nasty-sounding rattle from the #1 cylinder end of the engine, and that a loose water pump pulley was the cause. There ended up being multiple Bad Noises. I also found that the two halves of the timing belt idler pulley had started to separate, and it was making a lot of noise, so I replaced it.
In February 2002, even though it was still making a lot of noise, I went to Texas Motorplex for a test-n-tune day. It was the first time at the track for the car and for me. I was only able to get in 3 runs, and I discovered how hard it is to launch one of these cars! My best ET was 15.241 seconds and best speed was 95.42 m.p.h. Short times were 2.7's and one 2.4. Lots of wheel spin and some hop.
At the beginning of June 2002, I pulled the oil pan and discovered that the wrist pin bushings were beat and broken, especially #1. They had been newly installed in the September 2001 rebuild! There must have been some kind of lubrication problem, because the bushings, and even the wrist pins themselves, were really chewed up. So, I did another short block rebuild, replacing the wrist pins and bushings, honing the piston skirt clearances out to 0.005" instead of 0.0035", and replacing the rings and bottom end seals for good measure. I had the machinist add oiling holes to the small ends of the rods, as well.
The only advantage I see to rebuilding your engine every six months is that it looks nice and shiny. :-) I just managed to get it all back together in time for SDAC-12 in Memphis. It was my first SDAC, and it was a lot of fun, except for the day I had to take my wife to the emergency room. She was having really severe abdominal pain, and it turned out to be a fairly large kidney stone. Fortunately, the problem "passed" the next morning, and we were able to enjoy the rest of the trip.
On race day at SDAC I was able to make 14 runs. The first 3 runs were above 16 seconds! I pulled into the pits, retarded the cam timing 2 degrees, and set the ignition timing to 14 degrees BTDC. The next run was a 14.8. The rest of the runs for the the day were 15.0's and high 14's, but the best ET, speed, and short time were on one run of 14.572 @ 98.58 2.36 60' .693 RT.
I wanted to run 22 p.s.i., but couldn't seem to get above 20. I was running about 10% xylene/90% 93 octane to prevent knock (and didn't have any trouble with it). It wasn't until I was done for the day that I looked under the hood and saw the unmodified 1G Talon BOV, well-known to leak at about 20 p.s.i. Duh! I don't have the BOV or D-valve installed right now, but once I modify the BOV, I'll probably put them back in.
I think the car's currently running better than it ever has, which is nice for a change. I'm looking forward to another shot at the track. At 98 m.p.h. 13's should be well within reach, once I learn to launch it properly. That's the goal, and if I can get there I'll be satisfied. This is still my daily driver, after all.
I've moved all of the old progress reports to a buildup archive page.
(Click to enlarge--these are big pictures, about 300K-400K each.)