Cranking Signal Valve

[Don H.]

What method do you use to test the cranking signal valve (F.I.)? I understand the operation, I was curious what test others use. Thanks, Don H.

[Jim L.]

Re: Cranking Signal Valve

A useful test involves disabling the CSV (while the engine idles) and seeing if the character of the idle changes.

To do this, temporarily replace the 1" section of rubber tubing that normally connects to the CSV with a 10" - 12" section of tubing. You'll need to let the replacement tubing form into a loop, of course.

Start the engine, as normal, and let it idle. Pinch the tubing completely shut. Did the idle change? If yes, the CSV is leaky. If no, it's usable.

Note, however, that this test won't catch a CSV that has failed closed. But in that case, getting the engine to start cold will be all but impossible. That, by itself, is a major hint of a CSV problem, though.

Jim

[Don H.]

Re: Cranking Signal Valve

Thanks Jim, that is simple & logical. Don H.

[Mike E.]

Re: Cranking Signal Valve

If it fails open, your eyes and nose will let you know very quickly!

[Jim L.]

Re: Cranking Signal Valve

If it fails open, your eyes and nose will let you know very quickly!

Oh, so very true! And there won't be any point in performing the test I described earlier!

[John D.]

Re: Cranking Signal Valve

I don't know if I can put this in writing good enough or not but I'll try.
Although there are sophiscated means of checking those critters here is a quicky I have been using for years.
Mity Vac hand held vacuum pump with a vac gauge (any brand will do) and rubber hose.
For this one time test force the hose on the threaded end of the valve.Then put a finger on the round tube of the valve and pump up to about 15 on the gauge. Then remove your finger from the tube and count how many seconds it takes for the CSV to leak down to zero. The leak down to zero should be a nice even sweep.
I like to see 6 or more seconds. More is hard to explain but lets say if it went beyond the teen range I would become suspicious that the valve was clogged up.
Say your CSV is clogged up and you think it's history. Since it's your car try this little tip. Zippo lighter fluid ("any brand will do")-pour it in the CSV in both holes. Then swish it around and gently blow it back out. You might bring the old valve back to life for a tad.
Jim Lockwoods tip is a good one that a pal told him about long ago. You can drive across the country with a blown CSV you know. Just do what Jim said. Longer piece of 1/4" ID rubber hose between the valve and the vacuum line. Clamp the hose off with vise grips or whatever and happy motoring. Works on 58 to early 64.
Rochester Products had a 75% failure rate on those valves you know. Please don't spend major bucks on the auction site for NOS valves as it give me heart failure. Do though keep your eyes old for an old core as they are great for rebuilding. You can tell the difference between a repro and an original quite easily.
Look at the round cover of the valve. It's the size of say a half dollar and is spun onto the body.
On the back side of the valve look for three distinctive crips evenly spaced. That's the real deal. John

[Tom P.]

Re: Cranking Signal Valve

In addition to what John said, you can send him your OLD valve in exchange for a rebuilt valve. The rebuilt valves are EXCELLENT! I've bought several for customers' FI units and they work great.
Of course, the ULTIMATE fix (and it is NOT NCRS correct) is to install an electric solenoid valve (made by SKINNER) either in place of the cranking signal valve, or, inline with the cranking signal valve and hide it behind the fuel meter.
An elec solenoid valve will 100% shut off the vacuum flow.

This picture is looking straight down at my FI unit and you can see the solenoid valve between the plenum and fuel meter. Almost no one will ever be looking straight down.


This is is looking straight from the front, which no one can do because the hood will be in the way.



Here is the solenoid valve with the fuel meter removed.

[Don H.]

Re: Cranking Signal Valve

This solved my idle problem in a 7017320 unit I just assembled (bought in pieces). Before all your good suggestions I put in a new CSV I bought last winter from Maxine Parsons (Gail's widow) and it idles GREAT! I have three bad ones that appear to be original from John D's crimp description (picture below). To be sure the other night (it was still about 90 degrees), I warmed it up and tried each of these pictured. None would idle but when I put the new one back in it purred like a kitten (with 100LL, right John!). Lesson learned! Thanks everyone, Don H.

[Willie R.]

Re: Cranking Signal Valve

have used a skinner valve on my 61 for about 20+ years no problems, read about it in the Restorer,member had it installed on a 59-60.

[John D.]

Re: Cranking Signal Valve

Frank Sciabica held a fuel injection seminar at the NCRS Regional sponsored by the Western NY chapter in the early 90's. Frank was chairman of the chapter (I think?)) then and a retired employee of RP.
He was a pal but didn't hesitate to embarass me in front of say 500 people.
"DeGregory back there is still installing cranking signal valves on his restoration as he doesn't know any better"
Hard to forget something like that folks. My friend went on to say that since his employer had a 75% failure rate on manufacturing the valves he wouldn't dream of using them. Frank used a valve from an hydramatic tranny or something like that. Was not something you would want to show up with at a show but for a driver it would be OK.
Tom Parsons is quite an inventor and I like his setup although don't look for it on my 63, the LWC.(little white car) ..Chairman of Pittsburgh chapter. Whew!!!

[Michael H.]

Re: Cranking Signal Valve

[quote=John DeGregory (2855);566438 Frank used a valve from an hydramatic tranny or something like that. Whew!!![/quote]

Decades ago, I set up several FI units with a vacuum valve from early 70's passenger cars to replace the cranking signal valve. (may have been used on Corvette too) I don't remember what it was exactly but I think it was the electric/vacuum switch mounted on the intake manifold for vacuum advance??

I'm sure our C3 guys will probably know what the switch/solenoid is.

Much easier to find than the old Skinner valves.

[Tom P.]

Re: Cranking Signal Valve

Decades ago, I set up several FI units with a vacuum valve from early 70's passenger cars to replace the cranking signal valve. (may have been used on Corvette too) I don't remember what it was exactly but I think it was the electric/vacuum switch mounted on the intake manifold for vacuum advance??

I'm sure our C3 guys will probably know what the switch/solenoid is.

Much easier to find than the old Skinner valves.

From your description, it sounds like you're referring to the TCS (Transmission Controlled Solenoid) that was mounted on the right side of the manifold, just below the carb. The TCS controlled vacuum to the dist vac canister. It was one of the components of the emission control system on many cars beginning in the mid 70s.

The purpose of the Cranking Signal Valve on 58-63 FI units is to provide added vacuum flow to the main diaphragm during engine startup to enrichen the fuel flow to the nozzles-----------especially during cold starts.

The TCS solenoid had an electrical connection and was energized by being grounded from a switch on the tranny. Those of you with late model Muncies (661 cases) probably remember seeing, and wondering about, the single wire switch on the side cover at the 4th gear position. When the tranny was shifted into 4th gear, the shifter shaft (which had an internal flat on the shaft) rotated and engaged the switch which provided a closed circuit to the TCS solenoid. In turn, this opened a vacuum path to the vac adv can on the distributor.
Sooooooooooo, where the hell am I going with all this? Simple, a TCS could easily be rigged (but with questionable aesthetics) to replace the cranking signal valve on 58-63 FI units.
BUT, a neat installation of a Skinner valve, either replacing or hidden inline, makes a very good substitute for the cranking signal valve.
NCRS correct???? Of course not. More reliable and functional? Oh hell yes!!!!!!!!!!!!!

Skinner valves are still readily available, but the Skinner company is now owned by Parker and the valves now come in Parker boxes. The old Skinner valve, seen in my pictures above, is no longer available, BUT, THERE IS NOW A FUNCTIONALLY EQUIVALENT VALVE AVAILABLE FROM SKINNER (Parker). I just ordered 2 today. About $40ea.

[Paul Y.]

Re: Cranking Signal Valve

I took mine apart and resealed the diaphragm about twenty five years ago and it is still ticking away. I checked it after reading the loop test and it is good to go. I always carry a spare forceps though in case I ever need to clamp it. I probably have 75000 miles on it. Must have used good sealer. Hard to remember back that far. Brian Futo taught me how to rebuild it.

[Don H.]

Re: Cranking Signal Valve

What switch do you hook the valve up to (on a 320 unit)? Don H.

[Tom P.]

Re: Cranking Signal Valve

What switch do you hook the valve up to (on a 320 unit)? Don H.

If you install a Skinner valve, one wire goes to a ground connection (anywhere you choose) and the other wire goes down to the small terminal on the starter which is hot ONLY when the key is in the start position. Once the key is released from the start position, the Skinner valve needs to be closed.