Valve Springs? Ditch 'em? Test 'em?

[GrahamPaige29]

Hi guys.  I have my engine apart for my 1929 Graham Paige 612.  I'm currently replacing the valve guides, valves (expensive!!) and I'm wondering if the valve springs should be replaced as well.  They seem tight and visually good.  What do you think?  Take them somewhere to get them bench tested or pawn my wife's clothes to buy new ones along with the already costly list of parts?

[JFranklin]

The springs can be tested and determined if they need replacement. Don't replace good parts.

[PFitz]

Valve spring tensions should be within the manufactures tension range. Even new springs are often not and need to be shimmed to meet spec. Unless the springs have lost so much tension that they would bind if shimmed to spec then there's no need to replace them. Just shim them to the proper tension.

 

And don't assume that new springs will be within that manufactures tension range (they often are not), or you can have valve sealing problems.

 

Sealed Power still sells valve springs shims in sizes to fit many old engine applications.

 

Paul 

[HarryLime]

Where to find such specs for a 20s auto. They weren't even torquing bolts back then .

[JFranklin]

Spcifications are available you just need to find them. Most importantly the springs should all have about the same height and tension.

[Friartuck]

There was a picture several years ago using a bathroom scale on the bed of a drill press with the spring between the scale and drill chuck. The chuck was hand operated to the specified height and the pressure was read off the scale. Using the chuck's depth stops and the bed height adjuster, you can set this up to insert the spring, pull the handle down to the stop, and read the scale. As mentioned, the springs' compression should be nearly equal. What qualifies as equal, I'd say within 5-10 % or better of each other. Suggest having a small piece of plywood on the surface of the scale. What is the proper spring compression (for a given dimension) that is up to you to investigate. A typical value I've seen for a 1930's era spring was 20 pounds at 3.25 inches, and 40 pounds at 3.0 inches. I suppose you could use a hydraulic press to perform the same function, but it wouldn't have the benefit of the stops that a drill press offers. If you don't have either of these, you probably know someone who does.

 

Edited June 2, 2017 by Friartuck (see edit history)

[PFitz]

It doesn't have to be elaborate to check the low valve spring tensions of the 20's and 30's. And you don't need special equipment.

 

Some factory specs give just the tension of the opening pressure of an installed valve and spring.  That way any mechanic could test the springs right on the engine.  Often it was as low as 35 lbs in the 20's and 50 lbs  in the early 30's. 

 

As I said, some specs called for checking the tension with the valve and spring installed in the cylinder head, using a known weight, such as a steel cylinder. The cylinder was rested on top of the valve stem, or had a claw foot that straddled the stem and rocker arm tip and rested on the spring retainer. At that weight the valve should just start to open. You can do the same with a plastic container of water. Water has a known weight per volume and you can get surprisingly close to spec. Using that method to check and shimming the springs to spec, you can achieve less than 5% variation easily.

 

Also, sometimes you'll find evidence of the original springs having ben shimmed at the factory to achieve proper and uniform tensions. Often the shims are stuck down in the counter bore and hidden by burned-on crud in the head. Unless the head is boiled clean or glass beaded, the shims just look like the machined seat for the springs down in the cylinder head.

 

Shimming the valve springs to all the correct tensions is one of the ways that contributes to getting smooth, even running engine.

 

Paul

Edited June 2, 2017 by PFitz (see edit history)

[GrahamPaige29]

Thanks guys.  I'm going to inspect them again and try to find somebody who can test them.  I do recall seeing somewhere the specs.  I'll have do do some internet digging to find them again.  I guess no sense assuming brand new springs would be any more "accurate" than these ones.

[Rusty_OToole]

A quick test is to line them up on the work bench and lay a ruler across the top. If they line up like little soldiers, all exactly the same height they are probably good. If some or all are bent, lop sided, too short and uneven it is time for a new set.

[GrahamPaige29]

Thanks Rusty.

[Graham Man]

Graham-Paige built an extremely good quality engine.  Check the springs, there is a good chance they are fine. 

 

Hope to see you at the Graham Owners Club International Meet, June 19 Fort Wayne Indiana.  It is the 40th Annual meet!

 

 

 

[C Carl]

Here is a complete set of springs for sale. The catch is that you will be burdened with the entire complete engine , transmission , and the stand they are on. All , missing nothing , not locked up. Price is $300 USD. Now looka here : we have had this for sale here for 3 or 4 weeks without even a nibble. Maybe because it is near remote Tacoma , WA. I don't have any '20s Grahams , but I do have a couple '20s Cadillacs. Myself , I would drive half way across the country for this much '20s Cad machinery in this condition at this price. A carb , a distributor , a generator , a starter , a cyl head , a trans , a water pump , each alone could be aprox the price of everything here. I really don't understand why there has been no interest whatsoever . At this point , will not part out. Next stop for this will be even more remote. See the 45' Great Dane out my driveway by the high gate ? See it just past the Sno-Cat ? It will partially shelter the almost 90 year old eng and trans , where the mouses , rabbits , weasels , Bobcats , coyotes , wasps , and perhaps birds will find some shelter/hunting opportunities. If no interest , please give me some understanding why. Does everyone who might need this already have a couple sitting around in the way taking up space ? If it IS worthless , please let me know. In that case I will pull everything , and sell each at more or less what equivalent Cadillac junk is worth. The block and innards will be sent to our masters for their benefit , or sold before voyage for , say $300 , or so. I'm not much of a hoss trader , so I would be somewhat flexible on pricing. Oh , yes. Large animals hang out here , too. I have seen over 100 Elk grazing on my spread , with perhaps a couple dozen Mulies laced among them. I think the Elk find the Deer cute. They seem to have a respect for , and deference to the horses. Cows ? Couldn't care less. Mountain lions are a different matter. Lion does come right up to the house on rare occasion. The slickers over in the State Capitol are starting to realize there is a downside to Wolf propagation here. Apparently every county in the state will have Wolf in 6 or 7 years. And don't get me started about Brown Bear. Anyway , like I say , if you think Tacoma WA is remote and difficult to move machinery out of , take a look at a map of the State. Plant a flag in the middle , and wait for a Big Cat to howl. Again please let me know what I am missing here. Is it worth saving at all ?       Thank you ,  - Carl.         408-621-8261 , or P.M.  

 

Edited June 11, 2017 by C Carl
Add letter "s" to '20s" (see edit history)

[Rusty_OToole]

You just have to find the right party. To someone who owns a 1929 Graham of that model it would be like gold. To anyone who doesn't, not so much. I don't know how many of that model are still around but someone will need it eventually.

[JFranklin]

You might contact an automotive or history museum that might want a display engine and take a wright-off.