blue_74

Hi guys, I've been working off and on on my '84 coupe, and one thing I never was a fan of was the "pancake" style A/C compressor that came on early C4s. Has anyone successfully retrofitted an '88 & up style A/C compressor to an early C4? I need to replace some of the lines and the drier on my car, and now would be the time to do the update if it's possible. I had a '93 for several years, and the A/C compressor on it was like a dream compared to the one on the '84.

Any tips, ideas, etc. are appreciated! Thanks!

gerardvg

Hi

I have done this many years ago after going through a couple of the original compressors,
You will need the A/C bracket and the supports.
This is where it gets tricky, only the later years had the 3 supports.
without them the bracket will vibrate and eventually crack.

You will also have to drill and tap the head for one of the bolts and fit a washer if you are using the standard iron heads, aftermarket heads have that already there. put the later model a/c bracket on with the bolts just finger tight and get a center punch to mark the center of where the new thread needs to be then remove the a/c bracket. Carefuly drill only 1/2 an inch into the head, (put some tape on the drill) you do not want to go any further as you may hit the water jacket in the head then tap the hole. (you would then need thread sealer if you did hit the water jacket) See link number 2 the bracket with the extra hole on the top left that the early heads did not have.

you will need the 88-91 compressor bracket, supports and compressor with the refrigerant hoses and bracket. You can get the hoses custom made. (has been around 8 years ago i did it not sure if the hose to condenser needs a different fitting)

http://www.ebay.com/itm/88-91-Corvette-C4-A-C-Bracket-W-Belt-Tensioner-Assembly-PT-10105236-10055897-/121253892413?pt=Motors_Car_Truck_Parts_Accessories&hash=item1c3b4b913d&vxp=mtr
http://www.ebay.com/itm/91-Corvette-AIR-CONDITIONING-BRACKET-w-BELT-TENSIONER-C4-Vette-90-89-88-AC-/221406798761?pt=Motors_Car_Truck_Parts_Accessories&fits=Model%3ACorvette&hash=item338cdfa3a9&vxp=mtr
http://www.ebay.com/itm/88-91-CORVETTE-C4-AC-A-C-AIR-CONDITIONING-COMPRESSOR-DENSCO-W-CLUTCH-10135688-/190827297712?pt=Motors_Car_Truck_Parts_Accessories&hash=item2c6e317bb0&vxp=mtr
http://www.ebay.com/itm/89-CORVETTE-C4-A-C-AC-AIR-CONDITIONING-COMPRESSOR-HOSE-/190918668174?pt=Motors_Car_Truck_Parts_Accessories&hash=item2c73a3af8e&vxp=mtr
See pic's below, 1 the bracket diagram, 2, 3 and 4 the pics where they bolt to.5 pic of it on the car with the bracket to the no. 4 cylinder exhaust manifold.

Cliff Harris

I've been wanting to do this for years. The old compressor slings oil on the hood and I figure if oil is coming out then freon is also. From what I've seen the newer Nippondenso compressors are always clean, so they seem much better.

I thought getting all the appropriate brackets and miscellaneous pieces would do it, but that seemed like a BIG task.

I was thinking of asking SunCr (our Forum AC expert) about the possibility of doing something like this but I sorta never got around to it...

blue_74

Thanks, that was exactly the information I was looking for. My original compressor isn't leaking (other than slowly leaking freon out over a summer season), but it's noticeably more jarring than the later style compressor. When you're idling at a light and the compressor kicks in, you'll definitely know it.

WVZR-1

Perhaps just correcting the "air-gap" would give you better or ease the engagement.

blue_74

Sorry, I don't follow? Air-gap?

WVZR-1

The coil and clutch plate requires an "air-gap" for the engagement of the clutch. Without looking I believe .020 -.025 is the suggested. It's more frequently discussed as an engagement or non-engagement adjustment but I would think it could effect the harshness. Voltage at the coil could likely have a similar effect maybe.

Cliff Harris

I have been looking at this recently. My evaporator has a very slow leak so I was thinking of upgrading the system and switching to R-134a.

The '94 through '96 systems have larger evaporators and condensers because they use R-134a, which is less efficient than R-12. If you need to replace one of these components then it would be good to go with the larger version even if you're sticking with R-12.

Cliff Harris

I bought a bunch of parts from a 1990 and the evaporator and condenser from a 1994. I bought everything so I could get an idea of what could be reused and what could not. It turns out that the receiver/drier is mounted in a different place on the later cars so the hoses won't work for me. The condenser is definitely thicker than the R-12 version. I wanted to jump right on this but then I thought it's the middle of August and September is coming, the two hottest months of the year, so I don't want my AC system apart right now. Postponing this project for a while...

WVZR-1

If I were considering the change to the 'Denso I'd consider buying the most appropriate "block" to attach to the compressor and have my hoses constructed locally. There's many options:

http://www.starkmfg.com/EngineeringR...ion.aspx?id=14

Cliff Harris

I came across a thread where the guy was converting a cast iron head Corvette to the Denso compressor. He had quite a few pictures showing how he drilled the needed hole in the head. Somehow I neglected to bookmark the thread and now I can't find it. It would have been a nice addition to the information here.