Engine: Of Valve Recession, Spring height, daily drivers, and other CASO matters.

[oilnsteel]

Hi all,

Subject is a 1957 3E7 that is a daily driver. It works hard, hauling steel, aluminum and finished products for my machine shop.

I'm not really a CASO, except with time.

I have it in the shop while the snowy nonsense we have here in the winter welfare wonderland (Michigan) is in its full nastiness, preferring to sacrifice a Ford to the salt gods, but spring is nigh, and I miss my Indiana road oiler.

One of the winter maintenance and repair projects was new valve stem seals.

I am installing the pretty blue stem seals sold by Fairborn Studebaker. Judging from the smoke trail left last fall, it needed them.

Now lets talk about seated valve spring pressure, or namely the lack of it. I am relatively sure that you should not be able to slide the exhaust valve springs around when the valves are closed. I suspect we are all in agreement about this.

The truck has valve rotators, but they're supposed to turn, not slide.

So, the expeditious fix being considered for now is shimming the valve springs. This being a stopgap measure to keep the old reciprocator going until a set of heads can be properly rebuilt, or perhaps a complete spare engine ( for I am no stranger to the fact that removing cylinder heads can expose other dark, ugly things.

So, the question I put forth is: How much do I shim the springs? I know that the assembled height is 2.031, but measured from where?, and to what surface? The valves have obviously eaten into the head, but I can compensate for this by adding shims to make up for the difference between the stock height and what it is now.

The surprising thing is, it runs pretty well.

Thanks,

Jim

ps, I'm well into the Dragon's Milk, which is a splendid local brew which makes me more eloquent but not more intelligent, so your patience is appreciated

[doofus]

Hi Jim, the spring is measured end to end when compressed to the installed height, 2.031. the figure 125 lbs plus or minus 5lbs (usually less). you can get .060 shims for a small block chev and use. read instructions with shims, they have a top and bottom. for a real boost find shims that fit under the valve retainer, and stay centered. there are inexpensive spring testers that work with a vise also. Luck Doofus

[Skybolt]

Hi Jim, the spring is measured end to end when compressed to the installed height, 2.031. the figure 125 lbs plus or minus 5lbs (usually less). you can get .060 shims for a small block chev and use. read instructions with shims, they have a top and bottom. for a real boost find shims that fit under the valve retainer, and stay centered. there are inexpensive spring testers that work with a vise also. Luck Doofus

What spring tester is that? Would like to get one.

Len

[DEEPNHOCK]

Here's a good video of Tom C using a Pro-Form hyd spring tester.

And a copy of a source to buy one..

http://www.streetsideauto.com/p/proform-mini-valve-spring-tester-66834/?utm_source=googlepepla&utm_medium=adword&gclid=Cj0KEQiAvJS3BRDd44fjndyii6MBEiQAN4EkPSRDqwmeHWbOWQfkswWAbK7q6hjAlGC6qhj_5jyhlNkaAiDp8P8HAQ

What spring tester is that? Would like to get one.

Len

[DEEPNHOCK]

Here's what Tom C found with some of his old springs....
Now he tests ALL of his springs...

[doofus]

Dont think checking spring with retainer in place will give accurate reading JMHO. Doofus

[PackardV8]

It's all about the RPM. If the engine isn't turned more than 4,000 RPMs, it will be OK with shimmed stock springs. If it's a performance build, go with R1 springs. If it's a real performance build, I go with R3 diameter 8mm stem Chevy LS valves and beehive springs. These require cutting the rocker stands and shortened or custom pushrods.

jack vines

[spokejr]

Here's a detail I am unclear on. Does the intalled dimension of the spring include the damper or is 2.031 the spring alone?

[TWChamp]

Here's a detail I am unclear on. Does the intalled dimension of the spring include the damper or is 2.031 the spring alone?

That should be just the spring end to end and not the damper, retainer, etc.

[DEEPNHOCK]

Pretty good video...

[Mike Van Veghten]

My tester is like the one above.
And yes, check all springs. You will have lighter and heavier springs as tested. Put the lighter springs on the exhaust side. But don't use any below 15lbs under the 125lb requirement, shim up to the 125lbs. as required. Tell the person you bought them from about the problem, they may or may not work with you on replacing the light springs.

Also as Jack stated, an around town, never reaching much over 4000rpm, you can get away with lighter springs (stock cam) without concern.

Mike

[spokejr]

I did have a local shop go through and all the springs were within about 2 lbs of one another, bracketing or matching the following spec;

60 lbs @ 2.031"
125 lbs @ 1.750"

Now when I measured the distance between the keeper and the damper, I got the following;

#1, intake 2.025"
exhaust 2.020"

#3, intake 2.060"
exhaust 2.025

#5, intake 2.025"
exhaust 2.025"

#7, intake 2.035"
exhaust 2.010

Please remember, the exhausts all go hardened valve seats and the intakes are R3. On the #3 intake, I had to go deeper to remove damage done due to rust damage done prior to the previous rebuild.

My method of measuring was thus. I turned a spacer 1.003" long with squared ends to fit into the damper and give me something to measure from with my dial caliper. I then assembled the respective valve into the head using a much smaller spring to place pressure on the keeper and leave me surface to measure to.

I am thinking of grinding #7 exhaust .015" deeper and adding .030" to #3 intake, the rest leave alone.

Thanks, Ken