Mods for 2003
Well I've had my first bang, and an expensive one it is proving to be. At the track on April 5, while in the pits and off-loading her from the trailer, she didn't seem to be running right, didn't want to idle, sounded a bit iffy, but I just thought it was cold and needed a good skid and 1/4 mile to be right. How wrong I was, didn't want to boost and blew a lot of oil out the breather resulting in a nice delay while the boys cleaned up the track (sorry fellas). Back at the pits she had a very bad rattle indicating one of our forged pistons had let go.
At home upon tear down, the problem seemed to be that no.4 piston was, how you say, a bit crook. Rebuild time.
Above is a shot of my new air_cooled piston design; and the shot on the right is the damage that was done to the combustion chamber in the head.
Our theory is that last november at the track on the last pass, she leaned out and popped and cracked the length of the track, and since then hasn't run quite as well as in the past. It also started blowing a bit of oil out the breather which it never really has done, especially on it's recent dyno runs. The positive part is that we made 550 rwhp with a crook engine, and the tear down has enabled me to make a few changes which we hope that now we have a decent tune as a baseline, will allow the car to run what it is capable of.
More soon...
July
With the engine stripped, everything was checked to see what was damaged and what we could use. Block, crank, rods and heads were crack tested, with no. 4 bore revealing a nice hair-line crack so she was sleeved and then overbored to .040. This of course meant a new set of pistons, while the crank only received a linish and the rods proved to be still in good nick. The heads were faced and the damaged combustion chamber was lightly machined to smooth as much as possible as we didn't want to weld-fill as Paul felt this would damage the integrity of the head.
We also thought it was time to step up to a set of main studs instead of the factory bolts, just for a greater piece of mind. The block received a total machine job :- bore, hone, deck, cam bearings, o-ring etc. with the main tunnel still showing the original specs.
Everything received an extensive wash due to the amount of metal that was found in the oil with pieces of piston ring being found in the links of the timing chain, and chunks of piston stuck inside the turbine housing of the LHS turbo. New bearings and a full chrome top ring set were also new additions with my good mate Gabe giving us a hand to assemble the complete engine.
I also had to fit a couple of valve springs that I forgot to give Paul when he re-assembled the heads, and my over-head valve spring compressor spat the dummy. I ducked up to see Aaron at Dyno Source to see if he had a tool I could borrow and he lent me this stud mount compressor. This is the greatest tool I have ever used, besides the hammer.
One of the other changes we made was in the convertor, with the small Dominator convertor not working very well with the combo as first thought, so a call to Phil Soderstom at TCE was made for a custom jobbie that would hopefully improve on my 1.7 60ft times.
Part of the mods required to put a SBC in a commodore is to use a remote oil filter setup and relocate the starter to the RHS of the engine bay. Over the last 4 years this has given me enough dramas to spark a nervous breakdown, so I decided with the extractor pipes no longer there, I would revert back to a proper starter/oil filter install. A new high torque/mini starter was squeezed between the pan and steering shaft with minimal modifications.
With all assembly done she was filled up with fluids and started first pop. With a slight adjustment to timing and fuel pressure she settled down to a nice idle as we headed off to the dyno for a session to bed the new rings and then see what she had.