1963 340 HP CV590 PCV Valve Whistling Dixie

[Frederick H.]

In preparation for judging in October, I installed a 590 PCV valve with new repro hose (nothing wrong with previous hose) today. It was purchased off eBay a couple months back and received in what appeared to be repro packaging. I have been using the later version 590C with no issues. After installing the 590, the idle jumped about 250RPM to 1,000. When I squirted Chemtool in the carb (needed some cleaning) and the RPM dropped, the 590 began whistling loudly at the RPM drop. I removed it and put the 590C back in and idle went back to normal with no whistling. Looks like $50 wasted unless the seller will take it back after 2 months. Just beware of repro PCV valves! I may try to do a vacuum test on it tomorrow but not expecting anything different. Other thoughts?

Thanks in Advance,
Fred

[Timothy B.]

Re: 1963 340 HP CV590 PCV Valve Whistling Dixie

Fred,

Other than finding out the true origin of the valve and cleaning it I would say it's just another cheap reproduction part. I think the original 590 valve can be taken apart and cleaned. The GM service replace CV590 works just fine though.

[Frederick H.]

Re: 1963 340 HP CV590 PCV Valve Whistling Dixie

Yep - it rattles and doesn't appear to be stuck but sure affects the RPM and whistles. I was able to find an original (almost NOS/used very little) AC CV590 on eBay - will give that a try. Still trying to get choke adjusted - stays open - lots of good info here and in the shop manual on that.

Thanks.

[Mark E.]

Re: 1963 340 HP CV590 PCV Valve Whistling Dixie

Interesting mix of issues: Whistling is a symptom of a valve stuck closed, while higher idle speed is a symptom of a valve stuck open.

[Frederick H.]

Re: 1963 340 HP CV590 PCV Valve Whistling Dixie

Yep - that's what is strange. I may try it again without squirting the chemtool cleaner and re-check RPM.

[Arland D.]

Re: 1963 340 HP CV590 PCV Valve Whistling Dixie

Fred,

Since it is a 340 hp, is it safe to assume the valve is installed at a 45 degree angle? Just checkin'

[Frederick H.]

Re: 1963 340 HP CV590 PCV Valve Whistling Dixie

Ah, I did not check that. At 45 degrees downward, it will put it very close to the manifold though. It's in the shop getting some things done this week - will check it out when I get it back.

Thanks for the reminder!

[Arland D.]

Re: 1963 340 HP CV590 PCV Valve Whistling Dixie

AIM shows it 45 degrees upward putting it close to the air cleaner. FWIW here's a couple of pictures of mine.

[Frederick H.]

Re: 1963 340 HP CV590 PCV Valve Whistling Dixie

Wow -that is one clean carb - thanks for the pics.