5.7 vortec

[stephen p luce]

So I put a 97 5.7 vortec in my 89 K1500 about 3 years ago and have been fine tuning it ever since.I'm running the TBI with the super chevy intake and all the smog equipment. So here's the problem I used the original steel horse shoe bracket for the alt, p/s, and a/c comp. ever since i put it together with the a/c on there is a horrible groaning/vibration with the a/c turned on.It blows 40* air but I'm afraid something is going to break. All the bolts are tight I don't see any cracks in the horseshoe brkt and I have all the support brkts in place. Do you think the aluminum brackets might cure this? where could I find a couple and what years do you think would work, up to 95? 97?. It's going to be a hot, hot summer this year and would love to be able to use it.

 

[sntrym]

Up to and including 95 should work fine if you can find them. You should be able to use a set from 4.3, 5.0, or 5.7. I'm not sure if the locations of the accessories changed, so you might need a new belt if the mount points are slightly different.

It almost sounds like the computer may not be compensating for the extra load when the A/C is on. Check your tune to make sure you are changing the parameters in the A/C on fields as well as the A/C off.

 

[Schurkey]

So I put a 97 5.7 vortec in my 89 K1500 about 3 years ago and have been fine tuning it ever since.I'm running the TBI with the super chevy intake and all the smog equipment. So here's the problem I used the original steel horse shoe bracket for the alt, p/s, and a/c comp. ever since i put it together with the a/c on there is a horrible groaning/vibration with the a/c turned on.It blows 40* air but I'm afraid something is going to break. All the bolts are tight I don't see any cracks in the horseshoe brkt and I have all the support brkts in place. Do you think the aluminum brackets might cure this? where could I find a couple and what years do you think would work, up to 95? 97?. It's going to be a hot, hot summer this year and would love to be able to use it.

1. PUNCTUATION, CAPITALIZATION, and PROPER SPACING. This stuff it taught by fourth grade.

2. What is a "super chevy intake"; and does it include the boss for the support bracket between the A/C compressor and intake manifold?

3. Does the automatic belt tensioner vibrate/shake when the engine runs?

 

[Erik the Awful]

1. PUNCTUATION, CAPITALIZATION, and PROPER SPACING. This stuff it taught by fourth grade.

What Schurkey means to say is that using punctuation, capitalization, and proper spacing makes it easier for us to read your post and help you. Personally, I don't think your post was bad in these regards.

 

[stephen p luce]

Sorry, I'm just a old poor country boy. The " super chevy intake" is designed so one can run the OE TBI on a vortec engine. There are 2 braces off the back of the horseshoe bracket where the belt tensioner bolts on and one off the back of the alt to the left side of the intake manifold. Yes the idle raises when the a/c is turned on and lowers when off. There is a little movement of the tensioner, which I think is normal. Thanks for the info on the brackets, will make it easier to locate a set close to home I hope. Sac, Ca area.

 

[stephen p luce]

From some of the posts I have read, I should be teaching grammar in school

 

[Schurkey]

The " super chevy intake" is designed so one can run the OE TBI on a vortec engine. There are 2 braces off the back of the horseshoe bracket where the belt tensioner bolts on and one off the back of the alt to the left side of the intake manifold.

My '88, and my friend's '89, have three braces. Alternator, to left side of manifold; tensioner to thermostat housing bolt, and the rear of the A/C compressor, to the right side of the intake manifold.

You vehicle is missing the brace from compressor to manifold. Not surprising that using the A/C causes resonance noises.

There is a little movement of the tensioner, which I think is normal.

Tensioners have dampers inside. When the damper wears out, the tensioner is junk. Sounds like yours is on it's way out. (Or the compressor is vibrating enough to cause tension issues.)

Install the compressor brace, see if the tensioner calms down.

 

[stephen p luce]

I check my braces and put one on the compressor if it is not there and report back.

 

[Supercharged111]

If it's groaning, doesn't the most likely cause seem to be the compressor on its way out? And for the vibration, as previously mentioned, could be the engine not compensating for the load of the compressor, because it's excessive? OP did you drain the freon when you did the engine? If so, how did you recharge?

 

[stephen p luce]

Well I checked and all 3 braces are there. I replaced the tensioner, not a lot of help. I just rebuilt the a/c system, new comp, drier, condenser, orifice tube. Evacuated with a vac pump came down to about 27in of vac and held overnight recharged with 32oz R134. Blows 40* air out the vents. used a scale to measure the freon. It did this before I replaced all the a/c components.