Gramma's Car: the new project!

[njsteve]

Today I drove the gramma car to my buddy's gas station and we evacuated the A/C system and refilled it with R12. It now blows cold at 34 degrees! The coolant temp stays around 190 with the A/C on full blast.

I was thinking that the new heavy duty thermostatic clutch fan I bought last year must kick in around 190, hence the proclivity to run in that temp range at low speeds. Are the clutch fans adjustable to get them to kick in earlier?

[earntaz]

Just my opinion -- if you have replaced the fan clutch and the temp stays around 190 ... thats OK. TAZ

[njsteve]

I did a little research and it turns out that modern replacement fan clutches are set to engage at higher temps than the originals, so they can be used on a larger number of modern car application. You can adjust the thermostatic spring engagement temp lower if you move the outer spring starting point counterclockwise by a small amount. This thread deatils it: http://www.forums.maxperformanceinc....=776003&page=2

The first photo is the spring in the original factory location. The center valve only moves about 45 degrees to engage the internal valve and lock the clutch. I tested the spring with a head gun and a infrared thermometer and you could see the spring lengthen and turn the inner valve as it got hot around 190 or so.

Second photo shows the spring moved CCW to the left of the retaining location. When heated with the heat gun, it engaged at around 160-170 degrees. You can't just leave the spring like this as it will not disengage the valve if it is not retained in both directions of travel.

I fashioned a retaining clip out of a wiring retainer bracket so it encompassed the circular mount area as well as inside the circle through the original slot. I then used JB Weld to keep it in place.

The last photo shows another person's similar clip but on a rectangular mounting location on a different clutch.

Now, as I wait for the JB Weld to fully cure, I guess I'll give Gramma's car a well deserved wash, claybar and wax since I can't remember the last time I cleaned the outside of this car.

[Ryan1969Chevelle]

I love how you get to actual situation/issue/root cause:-)

Innocent until PROVEN guilty!!!

Ryan

[njsteve]

Guilty (allegedly, of course) ;-)

[njsteve]

Can't beat this for proof of the clutch fan spring modification:

Went for a 25 mile drive in the 83 degree heat with the A/C on max the entire time (38 degrees vent temp)

Photo 1 at cruising speed: 170 degrees

Photo 2 at a stoplight for a couple minutes: 175 degrees

Photo 3 beauty shot. :-)

[Ryan1969Chevelle]

Originally Posted by njsteve

Guilty (allegedly, of course) ;-)

Careful you are leading the witness with all kinds of alternative facts:-)

I love how you actually get to the root cause, very important but also very rare!!!

Ryan

[9999]

That car is absolutely beautiful, man I gotta get my projects going faster, hahaha.

[njsteve]

Brought her out to the first cruise night of the year on Saturday. Runs great and that A/C works chillingly nice. Here's a shot one of my friends took when I was wandering around.

[9999]

What paint did you use for the under hood area? Thanks a lot Steve.