Does cam choice affect the ability to run air conditioning

[cratemodel014]

I was asked this the other day and and wasnt sure how to answer. I dont think it would but what do the experts say.

[427dart]

Guess it depends on how high you will rev the engine while the AC is on?

Back in the 60's the OEM's didn't offer AC on the max power engine options especially the solid lifter high RPM setups. The compressors and clutch I suppose were the weak areas back then.

Now though you have high power cars with AC too,like the Ford GT 350 Mustang with factory 8000 RPM redline! Of course they have a WOT kick out on the AC compressor.

[wyrmrider]

and a free wheeling overrunning clutch in the pulley
electric ac compressor?
or are you concerned with engine stall with the ac coming on?

[427dart]

I'm old school on having AC in my hot rod...don't want it. Nothing like having the windows down and hearing the HP roar. When it's in the 90's or high humidity,I don't take it out. If I can't breath I know the engine will struggle too!

[cratemodel014]

Thanks guys. Kinda what I was thinking. This is a customer of mine that wants me to build a olds 350 for him. He was worried about my cam selection causing problems with the ac. He was thinking low vacuum would affect the ac.

[PackardV8]

I was asked this the other day and and wasnt sure how to answer. I dont think it would but what do the experts say.

Short answer, yes.

Everything in an engine affects everything else to some degree. Back in the days before EFI and computer IAC, some AC equipped cars had an electric throttle kicker which opened the throttle to maintain idle when the AC compressor engaged. Longer duration, wide overlap cams are struggling to idle at the low RPM level most want on the street. Smaller cube engines, and today's hot rods a 350" is small, are relatively more affected by an increase in cam timing than are 455"-500".

BTW, why would he ask you to build a 350" Olds? Aren't 455"s same size and cost?

[ap72]

The idle speed will drop, sometimes significantly, with the AC on. There are many ways to deal with that but it does have an effect.

[cjperformance]

https://www.seanhylandmotorsport.com/12 ... ompressors

Electric aircon compressor pump. Of course the alternator and associated electrics must be up to task but these are great for freeing up space and having big cam friendly aircon.

[wyrmrider]

another effect with low vacuum is that his deflector doors may not work and you have to add a vacuum accumulator or pump- but if that's the case the brakes if power are more of a concern

[Steve K]

First hand experience...355 with Vortec heads, dual quad RPM intake, Thumper cam, headers, 2500 stall converter etc. This is in a 83 GM B body 4 door. The a/c works great in this car. The only minor issue is I have to throttle it a bit at idle to keep the rpm's up. It doesn't the idle solenoid any more so I have to compensate a bit. If I'm gong to play around with it I just shut the A/C off.

[Racer71]

May have to bump idle a touch in ac season. Most likely need at minimum a check valve on vacuum supply to the blend/mode doors if they’re vac actuated or a vac reservoir. I ran ac on my 396 Windsor and 408 with a carb both pretty nasty solid roller motors. Make sure radiator is up to task as the condenser adds a good bit of heat to the mix.

[c1500sbc]

Carb motor? If so they have an idle up solenoid that you can wire in to kick on when the compressor does. Bumps the idle up. On my 383 I usually push the a/c button on the dash if I plan to get on it a little.