The Stovebolt Site Forums The Shop Area Engine Shop Crankcase ventilation and oil change milage

This is sort of a mixed up question.
The casting number on my truck's motor is 2324002 corresponding to a 248, although the motor number is A228.

Assuming it is a 248, did all 248's for 1/2 ton came with roaddraft crankcase ventilation? On Maintenance manual it says so.

Can a road draft crankcase ventilation system can be changed to a positive type, provided I can find a valve cover with the plug, the manifold and the PCV valve?

Which factor determines the milage the oil should be changed, having a PCV to road draft or not having an oil filter to having one? I have a road draft tube and no oil filter, but don't want to change oil every 1000 miles. Ive seen configurations with the two (bypass and full flow) filters. What do you recommend?

Thanks

You can add a PCV system with the valve drawing from the valve cover or the draft tube area. You need a place to draw the air from and a place for it to enter. On my 216, there is an oil filler cap on the valve cover so I made that my intake. I have a new cap with a filter there. I am using the draft tube as a place to mount my PCV valve.

The oil change interval is 3000 miles for normal driving, as mentioned in the original manual. There is no stated change with or without PCV or filter.

In my case, can I use the draft tube to draw the air and connect to the intake manifold with a PCV valve in some of the plugs it has?

I must have read on some thread that the oil should be changed every 1000 miles if no filter present, I don't have the maintenance manual. So with or without filter, change should be at 3000 miles. Dumb question, what would be the benefit of having the filters (either by pass or full flow) on the engine?

I thought the 228 had the oil filler cap on the draft tube. If the tube has a solid top and the filler is on the valve cover, the change is easy. I popped the cap off the top of the tube and installed a pipe inside to block the holes that feed the lower vent to the outside. I drilled the cap for a PCV grommet and put it back on. The PCV hose from the valve was attached to the intake manifold vacumm. I will use a filler cap with an air intake filter built in.

The bypass oil filter was a an accessory that was added by the dealer or someone else. Some people (such as me) feel that they are useful and some don't.

Do you have some pics to show? My draft tube is missing, only the hole left on the filler pipe.

If you can't get a tube then I would mount a piece of pipe in there and bring it up maybe four or five inches. I haven't taken a photo yet but I will.

You have another easy option. You can mount an inlet filter on the block where the tube goes and attach the PCV hose to the valve cover. I have such a filter which I bought and I am not going to use.

to make it a clean looking and functional job you need to find a big gmc 350-450 series truck. they came from the factory with the pvc valve, pipe and breather/oil filler pipe. you will also need an intake manifold that is tapped for either 3/8" or 1/2" npt. plus the little vacuum manifold that screws into the intake. plug the connection for the two speed rear and hook up you wiper line to the 1/4" connection. if you still have a 1/4" tap left on the manifold you can top that off with a vacuum gage which will come in handy at some time. plus you'll need the valve cover with the hole in it for the S pipe. if you find a bigger truck just take everything off of it and swap it over to your engine. my ashton which is a 350 came that way and it originally had a 248. the valve train will stay much cleaner when the air entering the engine is filtered. the breather is an oil bath type which can also be modified to accomodate a dry element. luckily for me i found a 46-350 that has the same script on the cover that i was able to convert my 40's 270. i used it on the 228 that was in it until i upgraded to the 270. find everything you need is the hard part unless you know where a big truck is lurking in the weeds.

Thanks for the pics 51. I've seen a 1 ton lying here, I'll go check the engine to see if it comes this way. If not, Truckernix: planing on selling the filter?

I would send it to you for the shipping. If you are interested I can Email you a photo with measurements. The only problem is that it is finished in chrome but maybe that wouldn't matter.