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Early 1952 M38A1, fording valve has been removed and there are some couplers. The PCV valve male end (threads) point to the crankcase and not the manifold. No arrow on the PCV valve. Based on other photos, isn't this backwards?

If so, what are the negative effects?

I have photos, but don't know how to attach yet.

This is what it should look like and which way it goes. If your's does not look like this PCV valve you will need to learn to post your photos.

How to post photos from your M jeeps album:

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You may also remove the valve and blow through it (low pressure), air will flow one way but not the other, you can then put your own arrow on it. This does not answer whether this is an appropriate valve merely the direction of flow.

Here is a photo of PCV valve. Please confirm it is backwards.

I have a a rich condition, heavy exhaust smoke, carbon in cylinders and some oil/fuel fouling on plugs. Could an inoperative PCV valve lead to any of these conditions?

It looks correct in the photo, if it is a factory supplied or replacement valve.

Easiest way to tell is remove the valve and take it apart. You can see the split right next to the short end.

It is supposed to be installed so that the ball closes the valve preventing flow back to the crankcase. So the short end will have just a seat for the spring.
Next goes the spring, then the ball, then the ball seat machined in the long end.

You have it apart, may as well give if a good cleaning. And might scratch an arrow in the body for later.

Take care,

I took it apart. It was installed backwards (per the parts manual diagram). The spring and cone should be pointing to the manifold to control crankcase ventilation based on manifold vacuum.

What negative impact would a PCV valve (ventilation valve) have on the engine when installed backwards like this one?

It can pressurize the oil sump (Pan) causing loss of oil, usually thru the fuel pump diaphrams.

I have a a rich condition, heavy exhaust smoke, carbon in cylinders and some oil/fuel fouling on plugs. Could an inoperative PCV valve lead to any of these conditions?

Could but you really need a complete set of tests for engine operating conditions to compare all test results and determine the true culprit/culprits.
IE compression check, leak down check, vacuum check, fuel pressure check, timing check.

Here's a direct comparison of your PCV valve to the Manuals:

Thank you Wes. PCV valve direction has been corrected. Working thru the other tests to diagnose engine condition.