Topic: 1966 factory air. Video, help diagnose problem. *Resolved*

[sed6]

After getting the air working on my 66 my compressor vibrates madly at certain rpm's. I read about belt slap and installed the additional fixed pulley. While that helped the belt slap and vibrations it didn't eliminate them. I'm spoiled by modern cars and wonder if the remaining vibrations are normal and I should leave well enough alone, or is there an additional problem causing the vibes that still needs fixing?

Here's a video I put on YouTube. Opinions and ideas are appreciated!

[67gtasanjose]

#1 ~Install a brace from the compressor to the intake manifold.
#2 ~ Check AC Pressure Readings. If high pressure out or range or needle is vibrating, you may have restriction within the dryer or restrictions in the expansion valve. Your readings will hold the answer to your question. Bearings could be bad but highly doubtful. Bad bearings could be picked up on with a stethoscope. Bad bearing would not affect your readings. For the most part, the only thing that can go wrong with a York is a seal leaking, a reed valve or a clutch failure. The Pistons, rings & rods are pretty much bullet-proof if they haven't been run without oil. On that note about OIL. The crankcase oil level check CANNOT should not be attempted with a refrigerant charge in the system without following service instructions carefully or injury may occur. A dipstick is used to measure the oil but it has to be checked or filled while the compressor is isolated from the rest of the system or when there is no charge in the system.

[sed6]

Thanks! The only brace I've seen is about $130 is that the one? My compressor only had about 1/8" of oil in and I topped it up to the recommended 3/4" before recharging. Think the low oil could have caused a problem? Without a charge and without the clutch engaging I wouldn't think so...

[sed6]

This brace?

https://www.johnsmustang.com/1965-1966-mustang-a-c-compressor-brace-anti-vibration

[sed6]

Here's my readings after replacing the receiver/dryer, a vaccumm to -27 inches and 28 oz of (edited) r-12. If there was any oil in left in my lines, which I doube since the system was open for 10 years, could it have overfilled the compressor and could too much oil cause vibes?

[sed6]

On that note about OIL. The crankcase oil CANNOT be checked with a refrigerant charge in the system. A dipstick is used to measure the oil but it has to be checked or filled while the system is not charged.

My turn to help you. It can be checked charged, in fact the compressor can be completely removed from a charged system with little freon loss. Here's how.

[rocket289k]

This brace?

https://www.johnsmustang.com/1965-1966-mustang-a-c-compressor-brace-anti-vibration

Yes that's the brace you need.  The anti-vibration bar secures the compressor to the intake manifold.  I didn't hear any knocking or other noises that a bad bearing would normally create.  In perfect working condition there is always a little bit of vibration in the foot board and pedals as the compressor cycles on (given the design of that AC compressor).  Not having the brace in place would definitely make any vibration worse and could be contributing to your belt slap too. 

PS - I noticed that you have an Monte Carlo bar installed.  I do not know if the AC brace and the Monte Carlo bar can be installed (without modification) at the same time.

Regards,

Ron

[67gtasanjose]

My turn to help you. It can be checked charged, in fact the compressor can be completely removed from a charged system with little freon loss. Here's how.

True. I did think of that too but didn't know it had been written down in the Service manuals. Thanks for adding the source. Mostly, I was concerned that if a person didn't understand or know that the oil service port/fitting was under pressure, they might be in for a surprise or injury. I amended my previous post

[67gtasanjose]

Here's my readings after replacing the receiver/dryer, a vaccumm to -27 inches and 28 oz of r-22. If there was any oil in left in my lines, which I doube since the system was open for 10 years, could it have overfilled the compressor and could too much oil cause vibes?

Doubtful you have too much oil by your description. I'm not sure how well the R-22 works in these vintage systems and what your readings ought to be when full. I can speak of R-12 configuration or conversion to R-134a from experience. Basing my understanding from experience, it looks like your readings are off on the low end. Problem being that if you add more freon (for example) you will raise the high side too. If the high side is too high, the belt will slap harder (compressor works harder).

If you are happy with the air temperature (cold enough) try just the brace. FWIW, it will never be as quiet as modern systems so if these modifications of the adding idler pulley and the missing brace help, it may be all you can do. This all assuming (since you didn't mention) the needles on your gauges are not bouncing erratically.

[sed6]

Thanks! I said r-22, oops, meant r-12. I am quite happy with the temp!

[sed6]

This all assuming (since you didn't mention) the needles on your gauges are not bouncing erratically.

Nope, no bounce. And when the compressor cuts out the gauges get pretty close to equal pretty quick.

[rodster]

Just curious, did you ever solve the issue?

[sed6]

Just curious, did you ever solve the issue?

Maybe, sort of? I don't have a baseline for how much compressor vibration is 'normal' for our stangs. The additional pulley helped, so did tightening down all the bolts, but it still vibrates quite a bit. I feel it now mostly in the pedals and the steering wheel, before I also felt it in the seat and the dash. It still sounds like crap, going down the road and I wonder if peeps are looking at my awesome car or looking for a paint shaker on wheels. Just not sure. I will probably get the aforementioned brace that attaches to the compressor and intake manifold and see how much that helps.

[rocket289k]

Maybe, sort of? I don't have a baseline for how much compressor vibration is 'normal' for our stangs. The additional pulley helped, so did tightening down all the bolts, but it still vibrates quite a bit. I feel it now mostly in the pedals and the steering wheel, before I also felt it in the seat and the dash. It still sounds like crap, going down the road and I wonder if peeps are looking at my awesome car or looking for a paint shaker on wheels. Just not sure. I will probably get the aforementioned brace that attaches to the compressor and intake manifold and see how much that helps.

You should find that the brace helps a lot.  It counteracts the natural "back and forth" due the stroke of the pistons will give the compressor.  When my compressor is running I do not see any vibration of the AC compressor and any RPM.  Also, in my case, I do not ever feel a vibration in the steering wheel when the AC is running.  I will hear a light rumble and slight vibration in the floorboard (very minor) if the engine is around 1600 RPM.  At cruising speed (e.g. engine around 2000 - 2200 rpm I don't feel anything at all). 

Ron

[rodster]

Maybe, sort of? I don't have a baseline for how much compressor vibration is 'normal' for our stangs. The additional pulley helped, so did tightening down all the bolts, but it still vibrates quite a bit. I feel it now mostly in the pedals and the steering wheel, before I also felt it in the seat and the dash. It still sounds like crap, going down the road and I wonder if peeps are looking at my awesome car or looking for a paint shaker on wheels. Just not sure. I will probably get the aforementioned brace that attaches to the compressor and intake manifold and see how much that helps.

Thanks for the update and good luck with the brace. Sounds like that may help a lot. Keep us posted on your progress.