So why do my valve springs look like Christmas in July?

[kboldin]

Started the teardown process this past weekend and noticed the valve springs are different colors. Some are red and some green, six red and six green. The engine was from a donor bronco, supposedly a 1974. I know my 72' 200 has all red springs, just curious if anybody knows why there are half and half on the newer engine? I'm guessing either somebody rebuild the head already and went with stronger springs on the intakes (or exhausts) valves for some reason. Thanks!

 

[broncnaz]

Welcome
actually almost all the stock engines I've pulled apart are that way so Id say its how they were from the factory.

 

[73azbronco]

Might be a factory reman, different strength spring to meet seat pressure.

 

[kboldin]

I took a pretty close look last night, I'm not seeing anything funny, it all looks stock. The reds are exhuast and the greens are intake. When I get it all pulled apart I'll see if there are any differences and see what the spring ratings are. The head looks to be a large log 69-74 from the casting numbers. The block is a 69 from a falcon, again according to the casting numbers.

 

[Broncobowsher]

Remember the casting number refer to the change, not what it was originally installed in. So a change was made in '69 for the Falcon. But the same casting was used in all models. That probably was a factory built engine.

color coding of parts is an old assembly line trick to make sorting (and inspecting) parts faster and easier. Sometimes it is to fill a need (spring pocked got machined a little deep, use the longer spring to take up the space. A checker will measure the gap and show it needs a green spring to fit right. Lot easier in the fast paced mass production then having them look at the numbers and decide what goes where. Since they color codes follow the intake/exhaust valves so perfetly it could be the batch of valves was slightly off so all the the intakes were slightly shorter and needed the shorter spring to match. There are probably 100 different reasons for each of the color codes. They may have been testing a new supplier of springs on the customer and were using the color codes to see if they showed up in the warranty return pile.

 

[kboldin]

Check, check! I'll be sure to measure everything twice. I'm planning on replacing them, so I'll need to know "exactly" why there is a difference to begin with and what new parts I'll need. The picture is starting to become clearer and I appreciate the input. The color coded assembly line makes perfect since. I have plenty to start with and mull over!

 

[Rustytruck]

Does the exhaust valve have rotators in the retainers they would need a different spring.