Quote:
Originally Posted by nUcLeArEnVoY
That's exactly the issue with your new fan clutch. The severe duty fan clutch is not meant for standard passenger car fans. In fact, in terms of spec-sheet standards, even the HD fan clutch is not meant for these cars, even though most get away with it just fine (including myself). The severe duty clutch is too strong for our factory fans and will pretty much remain engaged, putting a strain on the engine which in and of itself can cause it to work harder and build heat and also risks belt slippage.
These cars from the factory were equipped with standard duty clutches, not even HD's. I would start looking into your AC setup. Issues with the AC system will come out as an engine building up heat - a binding compressor clutch requires more engine power to turn, an overcharged or undercharged system can stress an AC system and thereby engine cooling, and outdated or incorrect components can overstress the AC system. Is your condenser upgraded for what I'm assuming is an R134a conversion? Is your evap core clogged up?
Lastly, your engine tune could be contributing. What's your initial timing, and are you running vacuum advance off manifold or port vacuum (or are you running vacuum advance at all?) Higher base timing plus vacuum advance allows engines to idle cooler.
Also never hurts to verify your temps with your gauge. It's normal for AC to increase the engine temp because of the strain on the engine as well as the fan having to exchange additional heat from the condenser, and 223 is getting pretty warm but a lot of new cars won't even turn on fans until 230 or so..
|
Thanks for the swift response - I appreciate it. And thanks for listing the specific things for me to check.
1) The AC system has recently been rebuilt due to a compressor front seal failure and converted to R134a in the process. New compressor, drier, expansion valve and readjusted POA valve. The only original parts left are the condenser. The evaporator is a recent piece. The system was completely flushed before the conversion and works flawlessly, so much so that my nephew nicknamed the car Frosty.
2) The tune I'm currently running on my Progression Ignition Bluetooth distributor is: 14 degrees Initial, 18 degrees mechanical, all in by 3000 rpms, 16 degrees vacuum adv giving 34 degrees @ 3K in WOT and 48 degrees total. The engine runs on premium (93oct in our area) fuel. No nocks or pings. Not bad for a 9.1:1 comp. engine.
3) The temps reported by the EFI controller w/ sensor located in the intake, next to the T-stat housing is confirmed by IR heat gun readings taken on the upper rad hose immediately above the t-stat housing. They agree within +/-2 degrees.
So, that 's my setup. If I understand what you're saying, it may be that even the HD clutch is not entirely appropriate for my situation? I actually am a proponent of the notion that Pontiac engineers actually knew what they were doing back in the day and was not aware that the heavy duty fan clutch I have might not be the equivalent to the OE standard piece. That's something to consider.
I should say that in all other respects the system functions flawlessly with the slightest of forward motion. Since the car idles at 650 rpm (in drive) and the heat buildup only got alarming with the AC on, that is what drew me to conclusion that it's an airflow (= fan or clutch) problem. If there is no fan blade available to work with the clutch I have, then I suppose I need a clutch that better works with my fan - perhaps a stock replacement clutch. I just not convinced that the electric fan route is necessary. Thoughts?