Vintage Air--Mechanical or Electric Fan

[kberger]

Is anyone out there with a Vintage Air kit running a stock mechanical fan? I ask because I just installed my kit and I have random screeches coming from the compressor. I'm thinking that maybe I don't have enough air moving across the condenser. Everything is brand new and the system is not overcharged. I'm just wondering if it's possible to run this system without converting to electric fans.

[chevyrestoguy]

I prefer a stock clutch fan with 7 blades for maximum cooling. Research has proven that a proper clutch fan with outflow an electric set-up. Some guys don't like the sound of a clutch fan, which makes more noise at lower speeds, especially with the heavy duty clutch units. Electric units are much quieter, and can be controlled thermostatically. Both methods will do the job, but if you're looking for max flow, I recommend the clutch fan. Just remember, a clutch fan won't work to it's full potential unless you run a shroud. Very important!

I like keeping it simple, and using stuff that is readily available at any parts store. You never know when you're going to break down, and after a couple of times with wazoo super-trick parts (and I have...), you realize that the stock stuff works pretty darn good.

[61K10]

I had V/Air in my 56 Nomad with a BB and a mech fan. I had to put two 10" fans in front of the condenser. to much heat at idle in the system ,and would do the same as you are saying. Air speed at idle is the main problem.

[kberger]

Thanks for the replies.

Chevyrestoguy: I am running the factory shroud. Did your 7 bladed fan just come from Autozone, O'reillys, etc?

61K10: So did you run BOTH the mechanical and the twin electric fans? Were the electric fans run from trinary switch?

Thanks again for your help!

[chevyrestoguy]

Originally Posted by kberger

Thanks for the replies.

Chevyrestoguy: I am running the factory shroud. Did your 7 bladed fan just come from Autozone, O'reillys, etc?

I got mine from a wrecking yard. I am using a complete serpentine set-up from an '89 half ton truck, and I grabbed the fan as well. The water pumps spin backwards on those, so I needed the fan with the reverse pitch blades.

[siggyfreud]

How much driving do you do at low speeds and in traffic? The problem with a mechanical fan is that it's tied to engine speed, so when you're sitting in traffic at idle you're not moving very much air. But at the same time you're still wanting to be comfortable, so the AC is cranked on taking the same power to turn.

I prefer Electric fans because they operate independently of the engine, can be controlled as needed, and won't hack off my hand when working on a running engine . Those with electric water pumps can also program their setups to continue cooling the engine after it's shutdown if needed (turbo timer, or just general cooling between laps/racing).

[kberger]

I probably only spend 10% of my time at highway speeds, so comfort at low speeds and idle are pretty important to me. Every time the compressor screeches, it grates on my last nerve, so I'm looking for a solution where that never occurs. I don't know if keeping the mechanical fan and just adding supplemental fan/fans for just the condenser is the best solution or going all electric would be best. I'm not particularly opposed to either method, I just want the most "optimum" solution. Thanks for everyone's help!

[brokenspoke]

your compressor should not be screeching......something is wroung

[kberger]

Brokenspoke: What kind of fan setup are you running with your VA system?

[brokenspoke]

Originally Posted by kberger

Brokenspoke: What kind of fan setup are you running with your VA system?

Mechanical fan with a clutch

[Mackie]

Could it be belt squeal... Or need compressor oil?

[kberger]

Definitely not belt squeal or oil. I'm 99% sure it's an airflow problem, I'm just not sure of the best way to solve it.

[luvbowties]

Originally Posted by kberger

Definitely not belt squeal or oil. I'm 99% sure it's an airflow problem, I'm just not sure of the best way to solve it.

Surely sounds like belt squeal! ...sounds as if you wanna try electric. Will cost nothing to leave the mechanical in place WHILE you add electric fan(s) out front. Then decide if you need more fan. Again, mechanical fan without a proper shroud is similar to using just 1 part of 2-part-epoxy glue(?) In my limited experience, mechanical 7-blade w/proper shroud outflows electric systems every time. Also, it limits possible go-wrong-points, around town AND out on the open roads.

After ensuring a proper shroud around mechanical fan, why not just add 1 pusher fan out front for the idling and slow-traffic in town, controlling initially with an under-dash switch? May be all you need--if so, convert under dash switch to thermost control.
Sam

[luvbowties]

Originally Posted by kberger

Is anyone out there with a Vintage Air kit running a stock mechanical fan? I ask because I just installed my kit and I have random screeches coming from the compressor. I'm thinking that maybe I don't have enough air moving across the condenser. Everything is brand new and the system is not overcharged. I'm just wondering if it's possible to run this system without converting to electric fans.

I'd first call VA and get advice from them.
Sam

[kberger]

Thanks Sam, it's definitely not belt squeal, you can tell it's an internal compressor sound like there is high head pressure. I AM running the factory shroud with all of the seals installed around the radiator. I'm wondering whether converting the straight mechanical fan to a clutch/fan combo would make a significant difference along with the electric pusher out front.

[luvbowties]

Originally Posted by kberger

Thanks Sam, it's definitely not belt squeal, you can tell it's an internal compressor sound like there is high head pressure. I AM running the factory shroud with all of the seals installed around the radiator. I'm wondering whether converting the straight mechanical fan to a clutch/fan combo would make a significant difference along with the electric pusher out front.

If you are running a "solid-mount" 7-blade fan, changing to a clutch-mount will NOT help at all. The s/m never free-wheels/slips, whereas the clutch/m free-wheels/slips/slows down at times. The fan IS spinning correctly to draw air IN, isn't it? Dunno & cannot picture it, just thinking of reverse-flow water pumps.

With the sound coming from inside the compressor, definitely contact Vintage Air. Agree with 'sixysixss' here.
Sam

[kberger]

I'm actually running a 5-blade solid-mount fan. This might not be right, but I was told that the advantage of a clutch driven fan was that at high speeds, the fan slows down because the air rushing through the radiator can actually flow better without the fan turning as fast(because of turbulence). At idle, I was told that it would turn at normal speed.

[luvbowties]

Originally Posted by kberger

I'm actually running a 5-blade solid-mount fan. This might not be right, but I was told that the advantage of a clutch driven fan was that at high speeds, the fan slows down because the air rushing through the radiator can actually flow better without the fan turning as fast(because of turbulence). At idle, I was told that it would turn at normal speed.

Seems I recall reading that a fan is not even needed after getting to approx. 50mph or faster. Anyone chime in with references/tests?
Sam.

[sixysixss]

I recently installed VA in my 66 GMC and am running the mechanical clutch fan and shroud with no problem. Mine screeches every so often, when cold, due to the belts loosening and stretching. Tightening the belt on the compressor solves the screeching problem for me.

If yours is not the belt, and it's coming from the compressor, it sounds like there is a problem with the compressor itself.

[argonaut]

I believe most ac compressors or positive displacement type units. Operating in a closed systen I dont see how they would intermittently squeal unless there was a seal issue or metal to metal contacy. I would have guessed that when the system is loaded and the clutch clicks from off to on you get a little chirp. But then again, I've not actually heard it happen.

[61K10]

back to mine it was belt squeal and i was running a after-market serpentine system. to much pressure and the belt would slip on the compressor pulley. I had a b-cool cross flow and finally put a b-cool duel elect. fan and shroud, probably your best bet?

[argonaut]

The key is to run a thermal clutch. These have a bi-metallic coil on front that changes the engagement of the clutch. When hot the coil turns and the clutch provides a ratio closer to 1:1. It is important to know what clutch youve installed. Severe duty types typically have more heat sensing surface area and also provide a hot ratio of 1:1 where as many stock or heavy duty are only make to spin at 60-70% of the shaft speed. I find a good clutch, good 7 blade fan and the correct water pump pulley diameter can provide plenty of cooling. But again, this is just my experience on my pickups, one small block and one big block.

[forestb]

If you decide to switch to a electric fan you will need to contact Vintage Air. One of the parts that comes with the kit (I can't remember which one) is specific for electric fan or mechanical fan.

[sixysixss]

I'm still not sure how changing the fan, or changing from mechanical to electric fan, is going to solve your problem if it is not belt related. I recommend you call VA and explain what is going on and see if they can help.

[kberger]

Originally Posted by sixysixss

I'm still not sure how changing the fan, or changing from mechanical to electric fan, is going to solve your problem if it is not belt related. I recommend you call VA and explain what is going on and see if they can help.

I'm hoping it will solve my problem by keeping the condenser cooler, reducing the head pressure of the compressor. If the clutch, fan and electric condenser fan I ordered don't fix it, I plan on calling VA.