F.I. spill valve

[Don H.]

I am not a fuel injection expert but have kept mine running for over 30 years. I am helping a friend that bought a 320 unit partially dissassembled. The spill valve is very odd looking and not what I have seen in the past (on the left in the photo), is this what is called a "good guy" valve? The "thumb tack" type (on the right) is all I have seen in my limited experience. Is good guy the correct name and can you tell me anything about it? Thanks, Don H.

[Charles M.]

Re: F.I. spill valve

Donald, the valve on the left is one of two variations of the earlier "good guy"valve although I have heard the thumbtack valve is better.

[Jim L.]

Re: F.I. spill valve

The spill valve on the left of your photo was used in '58 through some time in '59. It is NOT the "good guy" spill valve. A photo of a "good guy" spill valve is attached; the style of the spill plunger is radically different as is the way in which the sleeve is drilled.

The early spill valve, like you found in that 7320 unit, can, if a burr or surface imperfection is present, bind up causing a momentary loss of fuel control. Preventing this requires the plunger and the sleeve to be clean and highly polished.

Jim

[Tom P.]

Re: F.I. spill valve

I would highly recommend to anyone who has, or is interested in, FI, download BOTH of these pictures to a file and save them for future reference purposes.
These are 3 of the 4 different styles of spill valves that were used in 57-65 FI units.

Now, someone needs to post a picture of a 57 valve. I don't have one to take a picture of. Also, the 57 style valve IS NOT interchangeable with the other 3. The other 3 are interchangeable.
At one time the "Good guy" style was promoted as the better valve, but it seems that lately most people feel the "Thumb tack" style is the best. I have the Good guy style in the unit on the 56 and have had ZERO problems with it for 25+yrs.

[Ian G.]

Re: F.I. spill valve

So I guess the thumbtack style valve was used 60+?

[Tom P.]

Re: F.I. spill valve

So I guess the thumbtack style valve was used 60+?

Introduced in 62.

[John D.]

Re: F.I. spill valve

Here is what old JD preaches at the shows and over the phone about spill valves for our old 58 to 65 FI's. (except the '59 '7300 unit).

I ONLY use the thumbtack style spill valve on '58 to 65's. I refuse to use the Good guy spill valve as it results in comebacks. I don't want to belittle the man who named it "Good Guy" as he just passed away. But i call it the Bad Guy. One little speck of dirt or sand and the piston sticks. Old timers say the Good Guy will give a better idle. Well I am old now and I will tell you the Good Guy is a POC.

Referring to the nice photo. As Jim Lockwood mentioned the spill valve on the left is from a 58-59 unit. If it's your car and you like to play around go ahead and use that spill valve. But I consider it primitive and worthless and pitch them.
If you want to bring a '58 to 62 to life use the thumb tack spill valve. Good repros readily available. I don't like the term idiot proof but that best descibes the thumb tack style valve.
Refer to the ST12 manual. Corvette Servicing Guide for a nice pic of a good guy and thumbtack valve.
Recap: In my restoration hobby I only use the thumbtack style valve. No complaints. But make sure it's not worn out. If the nail wobbles around the part is history. JD

[Don H.]

Re: F.I. spill valve

Thanks all for your replies! Don H.

[Tom P.]

Re: F.I. spill valve

And here is the 57 style spill valve (with cover).

[John D.]

Re: F.I. spill valve

Don, If you have a really good "Good Guy" spill valve and it's your car go ahead and use it. Yes I know I am contradicting myself in a way but the key word is your car.
Now if you are restoring for other people then by all means use the thumbtack style spill valve to avoid complaints/combacks. John

[Tom P.]

Re: F.I. spill valve

John DeGregory has been my FI mentor for-----------------------well, let's not say how long, he may not appreciate me tellin how long it's been, but I don't think Lincoln had delivered his Gettysburg Address yet.
If John says the Thumb Tack is the best, then so be it. Although, the modified/hybrid FI unit in the 56 has a Good Guy that's been there for 25+yrs with no problems. The next time I go through it (in 10-20yrs), I'll probably install a Thumb Tack.