For those of you who like reading my long-winded technical experiences: About 8 months ago I had a noisy a/c compressor. It "clunked" when the clutch engaged and it rattled as it pumped. I took the system apart to find aluminum shavings spread through the system with water. I get the expansion orifice out and find that the previous owner tried but failed. When I got it out, it was banana-shaped. Because they couldn't get that connection out of the way, they didn't replace the accumulator either. I cut it open to find it was saturated with water. I flush the system, install a rebuilt compressor, pull a vacuum.... pull a vacuum... put some freon in it anyway, find a leak at the evaporator, pull the damn thing out... .leave it out for 8 months. I found out that the PO in his unsuccessful attempt to remove the orifice managed to put deep gouges in the pipe with what looked like channel-lock teeth. A nice flow of R-12 was coming through one of them. I have a local a/c shop solder on new pipes. I didn't get a warm fuzzy feeling from the results, so I buy another evaporator from PJ Grady $480. I thought this would be better than new. Turned out it was copper. This guarantees the system will be 8ºF less efficient. This is Florida. So I install the repaired evaporator. Now the fun got really interesting. The damn expansion orifice wouldn't fit. The new pipe soldered on was too small. Was I going to take it back to the a/c shop? Hell no. I just put it in the dash for the last time. So I get my best set of drill bits out and make it larger. It took three bits before I got something big enough for the orifice. The last diameter I used was size "K". Prefer metric sizes? Hate fractions? You'll love letter sizes. Anyway, I mopped out the shavings with oil-soaked Q-tips, pulled a vacuum and charged her up. It works great now. I really have to listen for the compressor to cycle where before there were so many metal chips gumming it up that the clutch made a loud oil-can sound with each cycle. I used an upgraded expansion orifice (variable orifice valve) in place of the antique fixed orifice valve. It works about the same when cruising but makes much more efficient use of the pump at lower speeds. Instead of dumping the flow through an orifice too big for the low pressure, the VOV restricts accordingly chilling every last drop of freon and allowing the compressor to cycle much less often. The DeLoreans original design was adequate. The upgrade is highly recommended if converting to R-134a. Being used in a R-134a system should make it even better. More testing will tell. I've only had it for 2 days now. :-) While I had everything apart, I cleaned up the insides. All the foam seals turned to goo just like a headliner backing. What wasn't covered with goo was rusted. I sanded it all, painted with rust-sealing primer, painted with black high gloss, replaced old foam with auto/marine grade gasket from local hardware (closed cell), remove inadequate factory insulation (earlier cars weren't even insulated), replaced with www.b-quiet.com L-comp so it is now sound-proofed as well as insulated. No more drips in the passenger foot well. Modified the defrost duct so that it shuts off when front vents are on. This took adding a vacuum actuator that operates a custom-made throttle plate pivoting in the duct. All made from brass plate, rod & tube (hobby store). Now no more fogging the outside of the windshield at night. I undid some idiocy the factory built into the system. They put a stainless steel mesh screen on the evaporator. In theory this seems good. The purpose of a screen is to keep stuff out of the evaporator. So then why did they put the screen on the other side where it holds stuff IN the evaporator? I cut a circle of this screen to fit the air input to the box and install. I was slightly worried that the screen would be too restrictive, but I notice no reduction in air flow. This screen will keep leaves out of the system. I want the evaporator to last forever. On a later thought maybe they put the screen to build up air pressure passing through the evaporator, but I've never heard of this before. (I'm still kinda green on a/c. No really!) There is a piece of plastic riveted in restricting the airway anyway that looks adequate. So I think the guys just put the screen on the wrong side. There are photos of it in the first (and at present only) issue of Gullwing magazine. Well, I could go on for a few more thousand words, but you got the gist of it. And as you can tell, I've been smoking some really good pot. Walt To unsubscribe from this group, send an email to: DMCForum-unsubscribe@xxxxxxxxxxxxxxx Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
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