Anyone “upgraded” from the tensioner style AC compressor to the stretchy belt?

[Geotrash]

you can buy the belts different size stretchy belts to. so I don't think you'd need to change the compressor?



I fought thru the belts on my c6. proper annoying. Google around and holy crap, it's a ls thing. there's a 100 page thread on a gto board. once it starts it doesn't stop on its own. the older sports cars had a upper idler pulley which seemed to help. there was a company that made add on one years ago but I emailed them and wouldn't make any.

after a good 6 months of trying things, including a Lazer belt alignment tool made by gates, I didn't get it. I got a go pro video of it. a kinda non car guy friend of mine saw the video, commented the belt wasn't centers on the crank pulley. I'm like sure it is, what are you looking at?

long story short, I got to looking and he was right. damn compressor wasn't aligned right. there's no adjustments, it just bolts to the block and over 100k miles of hard use never a issue. but once it did it, it kept doing it. I could toss it on demand. 2 new oem tensioners, different belts, nothing. in the end a old school starter shim put under both rear bolts, belt centered up on the crank pulley and never threw it again.

I got nothing.. my only theory is core shift in the block.

View attachment 428663

I honestly didn't see it at first, it was towards the front of the pulley in this Pic. once shimmer up it ran even on both sides and never have had a issue since. beat the crap out of it trying.

here's it rolling off.

Interesting theory about core shift...I assume you mean while the block was being cast, yes? 0.100 isn't uncommon, which is probably about the thickness of the washers you used. The question it doesn't answer though is why it doesn't manifest for 100K+. I noticed in my case that it correlated with colder temperatures and harsher compressor engagements. But it would only happen while driving and having to got WOT to merge, pass, prevent an ****** from cutting me off, etc. Perhaps as @91RS suggests it's a shift in the bracket, but mine hadn't moved, I'm sure. Could it be slight warpage of the block? AFAIK, this happening on aluminum blocks in these examples.

 

[mikez71]

it would only happen while driving and having to got WOT to merge, pass, prevent an ****** from cutting me off, etc.

Might be worth turning compressor off at high rpms! It can free up power and its a belt saver.. Of course its better you got the belt squared away first..

 

[91RS]

Might be worth turning compressor off at high rpms! It can free up power and its a belt saver.. Of course its better you got the belt squared away first..

The factory tune does disable the AC compressor on WOT but my tuner has mine set to disable at 80% throttle. So, it doesn’t seem to matter.

 

[j91z28d1]

Interesting theory about core shift...I assume you mean while the block was being cast, yes? 0.100 isn't uncommon, which is probably about the thickness of the washers you used. The question it doesn't answer though is why it doesn't manifest for 100K+. I noticed in my case that it correlated with colder temperatures and harsher compressor engagements. But it would only happen while driving and having to got WOT to merge, pass, prevent an ****** from cutting me off, etc. Perhaps as @91RS suggests it's a shift in the bracket, but mine hadn't moved, I'm sure. Could it be slight warpage of the block? AFAIK, this happening on aluminum blocks in these examples.

what I mainly saw when researching was aluminum blocks but the cars like corvette, gto/holdens and camaros are also more likely to be driven hard. I got to where I could make it run it off quickly on a test drive by stabbing the gas in 2nd gear, run up to redline and let off the throttle without clutching it. about 3k stab it again. once or twice and it would run off like clock work.


the first time mine happened was the end of a track day, first one for me in this car, and I don't know if the car had ever been before. so it may have been a bit but harder on it than usual. it didn't over heat till after the belt was tossed, but it did get way over temp by the time I got it slowed down, off the track. even thou if you've been on any fast trips thru the tail of the dragon chasing bikes, the track isn't much harder on it then that on off throttle nightmare haha. and it never had any issues with that.


Yes, the shim I used is probably about 0.060-0.080. I honestly don't remember, I had some old starter shims laying in my tool box and grabbed one of the thicker ones, slid it in. fired up the engine, saw the belt ran in the middle and took it for a test drive. Haven't had to mess with it since.


there's definitely no play or adjustments in the bracket, I had unbolted and tried a few times and I don't believe it's in the compressor housing, because it's still perfect. any misalignment in that and it would be leaking from a seal pretty quickly.

 

[j91z28d1]

Might be worth turning compressor off at high rpms! It can free up power and its a belt saver.. Of course its better you got the belt squared away first..

it doesn't seem to matter with ac off or on.

 

[j91z28d1]

I actually had thought about asking around to see if anyone I know has a GoPro I could borrow to see what’s going on. I do see in your video it looks like the belt is pushed toward the front of the balancer. The AC compressor bolts to a bracket in the trucks, it could be possible there’s just enough movement in the bracket to the block and in the compressor to the bracket that it could be misaligned, or maybe the bracket could bend a little with age. I don’t think the C6 has a bracket though, but it’s been a while since I’ve done a compressor on a C6. I was thinking about trying those gates green HD belts but that may not doing anything.

I still was planning to replace my AC compressor at some point anyway before I get stuck with a crappy aftermarket one, but if replacing it won’t fix this issue, then I’m not sure it needs to be on the immediately if not sooner list. And then I don’t know if I should get the 07-09 compressor or the 10-14 compressor. I’ve known they were different for a while but always assumed it had stronger bearings to deal with the stretchy belt but, something else has to be different if the accumulator is different. Both OEM accumulators are discontinued. I found a seller on eBay with 10 of the early accumulators but haven’t looked for the later one yet.

you know, you're right the compressor does bolt straight to the block on mine. I didn't realize the trucks had a extra bracket (my yukon doesn't have a belt driven ac) I just remembered loosening it up and trying to move it around thinking it might have some slop in the mounting holes, but nope. it's centered very well by the factory bolts.

the c6 is so tight you can't even get the bolts all the way out before they hit the frame rail. I'd have had to discharge the system and pull the hose mounting block off and I didn't want to crack the seal if I didn't have to.

 

[j91z28d1]

In a similar vein, I used old-school suspension shims to align the brackets/pulleys on an aftermarket serpentine system the previous owner had installed on the 401 in my '79 AMC Spirit. You can get sets on Amazon for under $15 and there will likely be more than enough 1/64", 1/32", etc. to take care of any/all brackets on an engine.

those would work well and cheap.

might be worth a try?

 

[91RS]

I was looking at mine today and it almost does look like the belt is pushed up on the balancer but my 13 basically looks the same. While I was looking around, I did notice my compressor hose is leaking so I must be a little low on refrigerant, which might be putting more stress on the compressor. Either way, that does need to be addressed immediately.

 

[91RS]

I also looked at the accumulators and the difference is the early ones have a low side cut-off switch the later ones don’t have. The differences in the compressors is likely more than just different bearings to deal with the stretchy belt (or that’s not different at all). There is probably no way to find out if the bearings are different. Either way, I’m not sure it matters. I’ll just stick with the compressor my year calls for but now I’ve got to decide if I want to go ahead and do it now or try replacing only the leaky hose first and see if it still does it with a full charge.

 

[j91z28d1]

you might research the compressor style itself. they might have went from something that cycles with a low side switch to something like a v7 variable displacement. I find they do cool better at idle speeds but few different switches and wiring to change them. not sure if the auto hvac would care. if you don't have cooling issues and sanden makes a comppressor for your application, I'd just buy that.