Saturday, January 16, 2016

Project update: time for a tune up and new NGK Iridium spark plugs!

Since the Sigma had been sitting in the garage "hibernating" through winter, I thought now that summer is here it would be a good time to give the car a check up and tune. Once again it started first try, despite being untouched for quite a few months. The engine didn't smoke at all besides a little bit of black smoke under full load and high revs. After tuning the engine and checking everything, I remembered one little thing I forgot to do after building the current high compression (12:1) setup: the spark plugs! I did fit new spark plugs, but they were still the recommended type for the stock (8.2:1 - much lower compression) engine. Basically the recommended plugs were a "5" temperature rating. It is advised that for each full point of compression you go higher than stock (under 12.5:1) you should also go down (or up depending on perspective) one point in the heat range of the spark plug.

Confused? Hopefully my example will shed some light on the matter. The standard plugs in the NGK brand were BP5ES for the stock 8.2:1 compression on the older Astron 2.6 engines (factory pre-unleaded Australian engines). On the NGK part numbers the part of the code that indicates the temperature type of the spark plug is the number between the letters (in this case, 5). The higher this number the colder the spark plug type it is and the lower the number, the hotter the spark plug type it is. So I went up to a code 9 spark plug (could've gone to 10 but these are too hard to find). I also decided to spend a bit extra and select the Iridium NGK plugs, which not only last longer but also (due to their shape and design) offer a much better combustion, which is much more important on a higher compression petrol engine. The correct colder plugs will also stop the plugs running so hot that they end up igniting the air-fuel mixture prematurely due to being too hot.

Friday, December 11, 2015

Project update: new heater tap!

So summer is here and it's time to start getting the old Sigma out of hibernation! Not many things need to be done, but there are a couple of things I need to devote some time to on the car. First of which is the heater system. The original heater control tap was rusted shut and one of the outlets broke off completely earlier in the year, so I completely bypassed the heater system to avoid any leaks.

As you can see in the photos above and below, the old heater tap was looking very overdue for a replacement. I've been so blessed to find a brand new heater tap at one of my local air conditioning and heating automotive specialists! And it was cheap too! A true bargain find. Next I have to remove the heater core, inspect it and clean, recondition or replace as needed.

Friday, October 16, 2015

Over 190,000 visitors!!!

This blog has officially had over 190,000 visitors!! That's great considering we've only been up and running since late September 2009 (about 6 years and 1 month). Thanks to all who visited, please keep coming back and also please leave some feedback, suggestions, etc.

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