vacuum line check valve
Thread Starter
Safety Car
Joined: Sep 2005
Posts: 4,222
Likes: 643
From: Orange County Ca
vacuum line check valve
Does anyone have a source for a good, original looking check valve?
I bought a couple in the past that look original, but either they didn't work right out of the box, or failed soon there after.
'69 bb
Or, are they all chinese crap???
I bought a couple in the past that look original, but either they didn't work right out of the box, or failed soon there after.
'69 bb
Or, are they all chinese crap???
Last edited by Sayfoo; Dec 20, 2022 at 11:05 PM.
Safety Car
Joined: Oct 2007
Posts: 4,206
Likes: 1,075
From: South Florida
Are you talking about a PCV Valve? PCV valves are check valves, but check valves are not PCV Valves.
In any case. I always use the same PCV valve for 25 years no matter what type of engine. 1998 Toyota Supra twin turbo PCV valve. If you are forced inducted they still need a pressure test because there is variability in manufacturing. It will check boost pressure up to 40psi roughly. I've successfully used this pcv valve in daily drivers for 25 years 500 to 1500hp.
Its not original looking. But its very small. What I like to do is, install the OEM original PCV valve in it's normal place, then, install the supra PCV valve in-line behind the engine in a hose somewhere. This way, you don't see it, but it works great, does its job out of sight out of mind. Original check be damned.
In any case. I always use the same PCV valve for 25 years no matter what type of engine. 1998 Toyota Supra twin turbo PCV valve. If you are forced inducted they still need a pressure test because there is variability in manufacturing. It will check boost pressure up to 40psi roughly. I've successfully used this pcv valve in daily drivers for 25 years 500 to 1500hp.
Its not original looking. But its very small. What I like to do is, install the OEM original PCV valve in it's normal place, then, install the supra PCV valve in-line behind the engine in a hose somewhere. This way, you don't see it, but it works great, does its job out of sight out of mind. Original check be damned.
Race Director
Joined: Nov 2006
Posts: 13,199
Likes: 7,798
From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
2024 C3 of the Year Finalist- Modified
2022 C3 of the Year Finalist - Modified
Cruise-In VIII Veteran
I too have tried a couple of these reproduction check valves. I even took one apart and compared it to a original. Not at all the same on the inside. I now run a repo one for the 2 way split. But a newer style one between it and the manifold and still it only holds vacuum for 10 minutes.
Safety Car
Joined: May 2001
Posts: 4,755
Likes: 1,644
From: Fairfax Virginia
I too have had issues with the reproduction check valves. The one on my C3 when I bought it in 1991 was white plastic and it lasted decades.
Hello Kingtal0n,
I have a 1968 C3 and there is an actual check valve with two hose fittings on one end and one at the other side. It is supposed to help hold vacuum in the vacuum reservoir after the engine has been run. The bad ones leak down very quickly and the good ones can hold vacuum for weeks. It is a totally different part than a PCV on these older beasts. The vacuum check valve is mounted on the drivers side between the brake booster and the rear of the engine block up near the top. The ones I have are either made out of aluminum and are natural colored or they come in Creamy white. With good vacuum in the reservoir you can open the headlights briskly weeks after the last running of the engine.
Hello Kingtal0n,
I have a 1968 C3 and there is an actual check valve with two hose fittings on one end and one at the other side. It is supposed to help hold vacuum in the vacuum reservoir after the engine has been run. The bad ones leak down very quickly and the good ones can hold vacuum for weeks. It is a totally different part than a PCV on these older beasts. The vacuum check valve is mounted on the drivers side between the brake booster and the rear of the engine block up near the top. The ones I have are either made out of aluminum and are natural colored or they come in Creamy white. With good vacuum in the reservoir you can open the headlights briskly weeks after the last running of the engine.
1967 Pedal Car Champion
Joined: Mar 2020
Posts: 9,074
Likes: 4,208
From: US-PNW
https://shop.docrebuild.com/1968-198...926296NOS.aspx
https://shop.docrebuild.com/1968-198...GM3926296.aspx
Thread Starter
Safety Car
Joined: Sep 2005
Posts: 4,222
Likes: 643
From: Orange County Ca
Have you tried Dr.Rebuild? He's pretty strict on keeping poorly performing reproductions out of his offerings. Here are links to an NOS valve and a repro:
https://shop.docrebuild.com/1968-198...926296NOS.aspx
https://shop.docrebuild.com/1968-198...GM3926296.aspx
https://shop.docrebuild.com/1968-198...926296NOS.aspx
https://shop.docrebuild.com/1968-198...GM3926296.aspx
Maybe, just temporarily for the covid?
Anyway, it's good to know he's still in business.
It appears that there is only 1 manufacturer of the valve and it doesn't make any difference where you buy it. Still probably hit or miss if it works.
Thanks all.
Safety Car
Joined: Oct 2007
Posts: 4,206
Likes: 1,075
From: South Florida
Hello Kingtal0n,
I have a 1968 C3 and there is an actual check valve with two hose fittings on one end and one at the other side. It is supposed to help hold vacuum in the vacuum reservoir after the engine has been run. The bad ones leak down very quickly and the good ones can hold vacuum for weeks. It is a totally different part than a PCV on these older beasts.
Race Director
Joined: Nov 2006
Posts: 13,199
Likes: 7,798
From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
2024 C3 of the Year Finalist- Modified
2022 C3 of the Year Finalist - Modified
Cruise-In VIII Veteran
NO, not the brake check valve. He is asking about the vacuum line check valve for the headlight/HVAC systems. At the rear of the intake manifold just drivers side of the distributor. There is a inline filter then a check valve that splits the vacuum into 2 lines as it comes out of the check valve.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Safety Car
Joined: Oct 2007
Posts: 4,206
Likes: 1,075
From: South Florida
I would still use a brake system check valve. They are reliable, and 100% sealed up when the vehicle is sitting. A check is a check, is a check. Worth a trial and error? Brake systems are no joke, they need to be absolutely flawless otherwise... yeah
1967 Pedal Car Champion
Joined: Mar 2020
Posts: 9,074
Likes: 4,208
From: US-PNW
I thought the Dr. had closed down?
Maybe, just temporarily for the covid?
Anyway, it's good to know he's still in business.
It appears that there is only 1 manufacturer of the valve and it doesn't make any difference where you buy it. Still probably hit or miss if it works.
Thanks all.
Maybe, just temporarily for the covid?
Anyway, it's good to know he's still in business.
It appears that there is only 1 manufacturer of the valve and it doesn't make any difference where you buy it. Still probably hit or miss if it works.
Thanks all.
Safety Car
Joined: May 2001
Posts: 4,755
Likes: 1,644
From: Fairfax Virginia
We should all do our very best to support people like Doc Rebuild as he is a great source of many quality parts that are becoming harder and harder to find. He sells good quality parts at reasonable prices and I have never had any issues with buying parts from him in the past 32 years.
Corvette Suppliers seem to be getting fewer and fewer as we age and the good ones are a really awesome help to us keeping our Corvettes on the roads. Doc has been with us since 1979 and helping all of us!
Here is the link to his homepage: http://docrebuild.com/dr-r-web/aaa-home.html
Corvette Suppliers seem to be getting fewer and fewer as we age and the good ones are a really awesome help to us keeping our Corvettes on the roads. Doc has been with us since 1979 and helping all of us!
Here is the link to his homepage: http://docrebuild.com/dr-r-web/aaa-home.html