Thursday, July 07, 2005

New heads for the Commodore

Well, I've decided that it's down to pick and pay less (The local wreckers) to get a couple of second hand heads for the old V6 Buick motor. I'm sure that cylinder number 3 has a sticky valve, and I don't want to replace the whole engine as I was considering, as I'm going to build a whole new one with some decent performance parts when I get some money. For the time being, I'm going to get some heads that are in reasonable condition and just replace them. They are about $100 each. I'm going to do both to prevent uneven carbon buildup in the ports causing it to run un-evenly. The old heads will then become the basis for my new motor. I'm sure there is not much wrong with it, as at revs, it does fire on 6 cylinders, it's only at idle that it misses. I'm just a bit worried about it "dropping" that valve in the meantime though, but if it happens it happens I guess. I'm not going to have funds for the head replacement until next weekend. Money is a little tight at the moment.
It's actually amazing how smooth and powerful this V6 is even when running on 5.5 cylinders. I heard of a guy with a Chev 454 tow truck motor that he put in a statesman. It was perminantly running on 7 cylinders and he didn't even notice.
All my non-car savy friends recon this car has been bad to me, but for $750 bucks, and the only dodgy parts were the engine and electricals. The electrics just needed a freshen up, and the engine should be fine with these repairs, but even if I have to replace the engine, I'm still on top. I'm interested in building the 3800 Buick motor because it seems better than the 5 litre V8, and if I can achieve similar power from it, I will have a great weight advantage. I like the way the car handles at the moment, and I would like to keep the balance the same. I'm looking at doing a rebuild from a second hand motor, which will include:
Stronger valve springs,
ported heads (Match port exhaust to extractors),
possible valve train upgrade (Roller rockers)
Aftermarket cam

To feed all this, I will modify the induction system by fitting the V8 throttle body which is slightly larger, and I will also be removing the bellmouth in the air intake that Holden fitted to this model to smooth out the idle. This bellmouth is a restriction that sits just after the throttle body. Eventually I will be upgrading to a twin throttle body set-up which will again settle the idle and deliver a more uniform mixture distrobution across the cylinders.

Then, of course, the obligitory ECU re-write. I plan to use an HSV memcal that is available on the internet. It's pretty cool, you can download the memcal contents, and write it to the memcal using an EPROM writer.

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