Project Miata Update

It’s going to be 80°F today where I live. Unfortunately, the Miata project is still hibernating in a cold, unheated, non-insulated garage in upstate NY. So instead I am acquiring more parts, tools and knowledge so that we can work on it when warmer spring weather permits.

I wasn’t really happy with the compromises we had to make with the air filter position in order to clear the hard AC lines, hood, coolant reroute hose and other underhood components. The packaging is all very tight in that area. So I’ve decided to take the road less traveled. It is a costly, complicated and challenging road but it should get me to where I want to go. I’ve ordered a new air filter base plate and I will make a custom coolant reroute hard pipe and custom AC lines to replace the OEM hard lines so that I can get the clearance I need to position my air filter in a better location. This will also help immensely if/when I upgrade to a cold air box further down the road. Most people don’t have this clearance problem as they either don’t have the coolant reroute or they delete AC at the same time they install ITBs (because racecar) but keeping AC was a project requirement.

ITG JC50 Backing Plate Blank
^^^ get the aluminum 18JC50 blank plate. It’s much easier to drill than the powdercoated steel plate.

The AC system was professionally evacuated prior to pulling the old 1.6 motor out and left with a partial vacuum inside. It was converted to R-134a a few years back with a new compressor, drier, adapter fittings, etc. so the system is in good shape and I intend to keep it that way. To make the custom AC lines using Aeroquip EZ-Clip system fittings and hoses, I must first undo the fittings on the existing AC hard lines and measure them. Because the AC system is sealed, anytime you open the system you risk introducing contaminants such as moisture and non-condensible items. As such, you should limit the amount of time the system is spent open to the atmosphere and then after the repairs are made you should draw a deep vacuum on the entire system to remove the contaminants prior to refilling with the correct type and amount of refrigerant and oil.


AeroQuip E-Z Clip system


Accordingly, I purchased a used JB Industries Platinum DV-200N vacuum pump and a new CPS Products MA1234 Pro-Set Manifold A/C Gauge Set with Hoses. With these two tools you can perform most routine auto AC system diagnostics and repairs.


JB Industries Platinum DV-200N vacuum pump

I went a bit overboard on the vacuum pump but I figure better to have more tool than you need rather than less. It’s no lightweight at 31lbs. It’s made in the USA, supposed to last a lifetime, has the best reputation on the market, repair parts are widely available and I saved more than 1/2 compared to buying new. It’s designed for professional HVAC techs to pull a deep vacuum on auto and residential/commercial AC systems and is rated for continuous use. I also plan on using it for vacuum bagging some future composite projects or maybe vacuum resin infusion process. I ordered a few replacement parts to refurbish it: feet, handle w/ safety cap so it doesn’t leak oil during transport, o-rings and 2 quarts of compressor oil (special type of mineral oil that gets changed after every use). I found instructions online that talk about flushing the pump to get all the old oil and contaminants out. I ordered 2 quarts of the special JB vacuum pump oil. Hopefully it will be enough.


CPS Products MA1234 manifold front


Initially I was planning to purchase a micron gauge to measure how well the vacuum is working (better than guessing), some hoses and fittings to connect the vacuum gauge to the pump and/ AC system. Well I decided to get the AC manifold gauges instead of the micron gauge. The AC manifold gauges will simplify hooking up the vacuum pump to the car’s AC system and it has a composite gauge on the low pressure side that reads vacuum, although not to the same level of detail or accuracy as the micron gauge. From my research, very few auto AC techs use the micron gauge. Heck, few residential/commercial/refrigeration techs use it either. It’s an advanced tool for advanced users and costs $150+. Maybe another day….

Here are some pictures of coolant hard pipes I’ve seen on the web. Feel free to post other trick setups you’ve seen. Thoughts on aluminum pipe vs. stainless, clamps should I try this new Gates Power Grip heat shrink clamp?












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