ConcoursMustang Forums

1st Generation 1964 1/2 - 1973 - Questions & general discussions that apply to a specific year => 1966 Mustang => Topic started by: sed6 on August 12, 2017, 09:43:04 AM

Title: 1966 factory air. Video, help diagnose problem. *Resolved*
Post by: sed6 on August 12, 2017, 09:43:04 AM
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!

https://youtu.be/glB8UEietDk

Title: Re: 1966 factory air. Video, help diagnose problem.
Post by: 67gtasanjose on August 12, 2017, 11:22:13 AM
#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.
Title: Re: 1966 factory air. Video, help diagnose problem.
Post by: sed6 on August 12, 2017, 05:30:08 PM
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...
Title: Re: 1966 factory air. Video, help diagnose problem.
Post by: sed6 on August 12, 2017, 05:53:39 PM
This brace?

https://www.johnsmustang.com/1965-1966-mustang-a-c-compressor-brace-anti-vibration
Title: Re: 1966 factory air. Video, help diagnose problem.
Post by: sed6 on August 12, 2017, 06:00:48 PM
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?

Title: Re: 1966 factory air. Video, help diagnose problem.
Post by: sed6 on August 12, 2017, 06:08:50 PM
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.


Title: Re: 1966 factory air. Video, help diagnose problem.
Post by: rocket289k on August 12, 2017, 06:31:12 PM
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
Title: Re: 1966 factory air. Video, help diagnose problem.
Post by: 67gtasanjose on August 12, 2017, 06:51:49 PM
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 ;)
Title: Re: 1966 factory air. Video, help diagnose problem.
Post by: 67gtasanjose on August 12, 2017, 07:02:30 PM
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.
Title: Re: 1966 factory air. Video, help diagnose problem.
Post by: sed6 on August 12, 2017, 08:36:36 PM
Thanks! I said r-22, oops, meant r-12. I am quite happy with the temp!

Title: Re: 1966 factory air. Video, help diagnose problem.
Post by: sed6 on August 12, 2017, 08:55:34 PM
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.
Title: Re: 1966 factory air. Video, help diagnose problem.
Post by: rodster on August 18, 2017, 11:34:10 PM
Just curious, did you ever solve the issue?
Title: Re: 1966 factory air. Video, help diagnose problem.
Post by: sed6 on August 19, 2017, 02:35:25 PM
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.
Title: Re: 1966 factory air. Video, help diagnose problem.
Post by: rocket289k on August 19, 2017, 04:16:53 PM
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
Title: Re: 1966 factory air. Video, help diagnose problem.
Post by: rodster on August 20, 2017, 12:04:03 AM
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.
Title: Re: 1966 factory air. Video, help diagnose problem.
Post by: sed6 on August 20, 2017, 12:45:21 AM
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

I'm guessing you have the brace? Could you post a few pics of it installed and the two attachments points? I'd like to see how it mounts and maybe determine of it'll clear my monte carlo bar. Thanks!
Title: Re: 1966 factory air. Video, help diagnose problem.
Post by: rodster on August 20, 2017, 02:53:54 PM
Not 100% sure if this is 'correct' but gives you an idea of the connection points on my 65.

Title: Re: 1966 factory air. Video, help diagnose problem.
Post by: rocket289k on August 20, 2017, 03:48:37 PM
I'm guessing you have the brace? Could you post a few pics of it installed and the two attachments points? I'd like to see how it mounts and maybe determine of it'll clear my monte carlo bar. Thanks!

I had mentioned in post #6 that I noticed that you have an Monte Carlo bar installed.  I do not know if the AC anti-vibration brace and the Monte Carlo bar can be installed at the same time (without modification).  The picture that Rodster provided illustrate the attachment points (compressor connected to intake manifold).


Ron
Title: Re: 1966 factory air. Video, help diagnose problem.
Post by: ChrisV289 on August 20, 2017, 06:14:32 PM
That bar is installed wrong.
Title: Re: 1966 factory air. Video, help diagnose problem.
Post by: 69cobrajetrugae2 on August 20, 2017, 07:21:18 PM
All sound advise you have received from fellow members but I might add a few points of interest.

There is fake R-12 out there so be careful if you buy some online.

There is nothing wrong with using R134 if you know what you are doing.

Condenser fins might look clean but they are not clean unless you use sodium hydroxide to get them shiny but again, you must have experience with this stuff because it will eat metal alive if used improperly. A condenser that looks clean but has grey oxidation on the fins loses about 30% capacity which can cause liquid slugging.  Liquid slugging is the kiss of death to a compressor.  The inside coil must be clean as well.  In a properly maintained AC system, half the refrigerant should be in the condenser and half in the inside coil.  If a coil is dirty then the system is thrown out of balance.  Since the returning refrigerant cools the compressor it's important that everything is checked especially the inside blower and the expansion valve or fixed orifice.  Vent temperature by itself means nothing if the blower is on low or does not move enough air because the squirrel cage fan is dirty.

If you know the temperatures of the pipes you know the pressure since R-12 like all/most refrigerants are predictable.  Using a pressure temperature chart will tell you if the system has R-12 in it or something else. I would need to consult a factory service manual insofar as the oil level and everything else.  Some oil mist circulates to lubricate the compressor moving parts but I'm not sure.

I know that a fan shroud and a thermostatic fan would be a good idea with AC on a early mustang.
Title: Re: 1966 factory air. Video, help diagnose problem.
Post by: sed6 on August 20, 2017, 07:47:36 PM
So I fixed it! I replaced the old Delco AC belt with a correct one from Marti. Vibrations gone! Who knew something so simple and obviously overlooked would do the trick! Thanks everyone for the input!
Title: Re: 1966 factory air. Video, help diagnose problem.
Post by: rodster on August 20, 2017, 10:34:50 PM
So I fixed it! I replaced the old Delco AC belt with a correct one from Marti. Vibrations gone! Who knew something so simple and obviously overlooked would do the trick! Thanks everyone for the input!


Congrats!  Funny, first thing I noticed in your video was the cogged belt and wondered about that right away.  I'm thinking the new belt from Marti isn't cogged?

 
That bar is installed wrong.

In what way?  To my old eyes looks like the bars in the pictures are installed the same way.

I'm not sure the bar I have is correct, my car was missing it so I just picked one up after doing some research on what was correct.  I might even have an old post on here.
Title: Re: 1966 factory air. Video, help diagnose problem.
Post by: ChrisV289 on August 20, 2017, 11:54:11 PM

Congrats!  Funny, first thing I noticed in your video was the cogged belt and wondered about that right away.  I'm thinking the new belt from Marti isn't cogged?

 
In what way?  To my old eyes looks like the bars in the pictures are installed the same way.

I'm not sure the bar I have is correct, my car was missing it so I just picked one up after doing some research on what was correct.  I might even have an old post on here.

You know what it is, your valve cover and the position of the oil cap is throwing me off...
Title: Re: 1966 factory air. Video, help diagnose problem.
Post by: sed6 on August 23, 2017, 05:40:09 PM

Congrats!  Funny, first thing I noticed in your video was the cogged belt and wondered about that right away.  I'm thinking the new belt from Marti isn't cogged?

Correct. Replaced all three belts, PS, AC, and Alt, all from Marti and none are cogged.