Update on my hi-miler Z project

[VetteMed]

Hmm, guess I should go find my phone... didn't hear it ring

[GOLDCYLON]

Originally Posted by VetteMed

Hmm, guess I should go find my phone... didn't hear it ring

Thanks Andrew. will hit you up NLT Saturday. Thanks for the chat. D

[VetteMed]

So, my headliner project failed today. Apparently the adhesive was inadequate for holding up the relatively heavy material once the temps hit 90 degrees or so. I imagine it would have been fine for the usual foam/fabric material, but the vinyl was significantly heavier. A stronger adhesive might be what's needed, but I think I'll just go with standard headliner material at this time.

I'll update the prior posts about this issue so that nobody follows my previous suggestions

[4-cam]

I did my headliner last year. A fabric store here in Denver carry's the headliner material along with Special High temp Glue made specifically for headliners. I think Mid America also makes a kit to do this.

[VetteMed]

$15 for a yard of black headliner fabric from Jo-Ann, and I'm back in business!

The correct headliner material is much more "forgiving" than the vinyl was. The key here, is to cut the fabric about a half inch larger in all directions, to allow for proper coverage. The excess can be folded over and pushed under the frame using a plastic bondo spreader, as shown below:



Looks like OEM!

[VetteMed]

Lost a secondary cooling fan motor, which took out a fusible link as it drew too much current. See post here:

http://www.zr1.net/forum/showthread....633#post142633

[4-cam]

Nice job!
Jo-Ann is the place I got mine from also. Never thought I would be shopping at a fabric store on a Saturday but they have a great selection of upholstery material. My wife was wondering if it was a fraudulent charge on my credit card.

[VetteMed]

So, the performance of my A/C has been mediocre, since the temps are consistently at 90+ here in FL.

At best, I get 58-59 degree temps from my vents, given 85-90 degrees ambient temp, this is on recirc, and after at least a 20 minute drive. Even on longer drives, I haven't seen much lower than that.

Today in my driveway, I connected my gauges.

With a garden hose spraying the condenser, the low side will get down to the 28 psi range. Without the hose, the lowest was about 37. It's about 90-92 degrees ambient plus heat emanating from the engine compartment at idle.

I didn't focus too closely on the high side -- but without the hose it was 250+, with the hose I think it was around 175 or so.

A thermometer placed into the blower box, where the resistor module is located, yields 42 degrees as the lowest observed temperature.

Looks like there's a problem outside of the refrigerant plumbing, if there's 42 degree air coming off the evap but 58 degrees at the interior vents. Something not adding up here.

I did not want to add or remove any refrigerant, since it seems like 42 degrees from the evap is pretty good.

The door that blocks off the heater core appears to be functioning properly, looks sealed to my eyes at least.



Using the C68 display, parameter 34 shows that at 60 degrees selected, plus recirc, the requested temperature door position is 253 (full closed). However, parameter 31, which shows the temperature door travel range, shows 184, when in fact 200 is apparently full-closed, so it looks like for whatever reason the control head is reporting that the temperature blend door is actually NOT in the full-closed position. Hmm.

Also, another interesting thing, is that parameter 1, which is the temp setting (shows 60-90 range in the chart, just like the selectable temps), shows 64 when in fact I've got it set to 60.

Now I'm more confused than before.

Also, after I shut off the A/C via the control head, and the pressures equalize, the compressor clutch didn't fully disengage - the center of the pulley was still rotating at about one revolution every 3 seconds. I can't say I've ever noticed this before. I'm guessing it's just due to pressure equalization in the compressor, and not related to the problem.

I verified that the temp blend door is definitely going to full-closed when 60 degrees is selected. The door closes against its stop, then gives one more clunk as if to indicate that the actuator hit its internal stop.

Interesting observation:

I removed the blower motor, to verify that the recirc door is indeed closing completely - it appears to be. By removing the blower motor, I can see the aft edge of the evaporator core. Interestingly, there's about a 1cm gap between the end of the core, and the firewall. Seems like this would lead to air bypassing the core and making its way into the ductwork. My measured temp in the blower box was taken further forward, where air was going through the core rather than around it.

I sealed the gap between the evap core and the firewall, using a combination of foam strips and butyl rubber seam sealer. Also sealed a smaller (3mm) gap at the forward edge of the evap core where it meets the blower box housing. This IS an aftermarket evap core, and I didn't have the original to compare dimensions to, so it's likely that it's either smaller than it should be, OR the original had foam strips to make up the difference.

Anyway, I put it all back together, and with no other changes, this made an 8-9 degree difference. I saw a low of 49 degrees at the center vent, with all other vents blocked, 89 degrees ambient temp, sitting in driveway with hose on condenser and engine at 2000 rpm.

Test drive update: 43 degrees with ambient temp of 84! I'm thrilled!


Pics of evaporator gap:

As seen from blower motor housing:





As seen from blower resistor access panel:





In summary, if anyone else ever has to replace an evap core, take special care to note if there's a gap that will allow air to flow around the core rather than through it.

[cvette98pacecar]

250+ head pressure is excessively high.
Converting discharge pressure to SCT (Saturated condensing temperature) to ambient.
R12= 168.4df or equivalent ambient temperature of 138.4df.
R134=146.3df or equivalent ambient temperature of 116.3df.

I just recharged my Riviera as I had to replace a seal, after pulling a vaccum and putting in an exact charge my DA temperature was 56df at 95df ambient. Once the interior of the car got colder the discharge air temperature dropped.
Suction pressure 42.4, Head Pressure 191.6.

Tomorrow I will test both of the Z's and get some recordings, maybe that will help.

[Kevin]

Originally Posted by 4-cam

I did my headliner last year. A fabric store here in Denver carry's the headliner material along with Special High temp Glue made specifically for headliners. I think Mid America also makes a kit to do this.

i have two headliners that need done