VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc 216 oil filter like you'e never seen

OK ladies and germs this story goes back a long time to just after I got my 38 running. I wanted to put an oil filter on but didn't like the fact that the bypass filters didn't filter most of the oil every trip through the engine. Since the oil distributor valve circuit is just off of the oil pump I reasoned that if I could intercept the oil before it goes through the distributor valve and run it through a filter I could filter much more of the oil, making the filter more effective. I had a friend machine the device you see below. For lack of a better term I'll call it a bypass block. As shown in the pictures it went between the distributor valve and the engine. The oil would enter the bypass block and be directed out of the hole at 3 o'clock to the filter. The oil returning from the filter would enter the block through the hole at 12 o'clock. The oil would then enter the distributor valve and be sent on it's merry way as normal. With this setup in place the engine would show extremely high oil pressure when running, even hot. Not knowing a lot about the internal workings of the engine I was concerned I was starving something for oil, causing the high pressure, so I removed the bypass block and to this day it's on a shelf in the garage. I've always wondered if I was running the risk of damaging something by using it or not. My main concern was, was the extra oil pressure causing the squirters to miss the dippers. I don't think so but I'm not sure. The high oil pressure wouldn't damage the mains would it? The limited time I ran it on the engine the valve train was being oiled as I had oil coming out of the rocker holes. Opinions and questions are welcome.

Hi Tiny

The oiling system in your 38’ 216 isn’t really very complicated, but it seems to me a lot of people don’t really understand it well just the same.
In fact, it’s finer points are often misunderstood.
An important point though, is that the system is divided into a higher pressure side and a lower pressure side by the metering valve.
And the metering valve’s sole purpose is to provide oil pressure to the main and camshaft bearings.

If you were seeing very high oil pressure with the adapter plate installed, the only part of the system that would be running that higher pressure would be the main oil gallery, and the passages it feeds.
The tubes that are located AFTER the metering valve, and run to the nozzles pointing at the dippers on the rods, run at very low pressure, and are essentially free flowing.
At low revs the oil runs out of the ends of the nozzles down into the troughs in the oil pan and the dippers on the rod scoop through it to pick up the oil.
At higher revs the stream straightens out and hits the dipper directly.
Higher pressure cannot make the stream “miss” the dipper as it is aimed straight at it.

So…
You don’t say how high your pressure was, but the only way your adapter could raise the pressure would be by causing a RESTRICTION in the flow to the low pressure (rods and rocker arms) side of the system.
Would the higher pressure to the main and camshaft bearings damage them?
It would have to be really high to do that. More likely it was good for them as higher pressure equals higher flow through the bearings, equals cooler running bearings.

But…
The pressure in the low pressure side of the system would be unaffected.
The FLOW however would be slightly less for 2 reasons.
First, any time you increase the pressure a pump is asked to deliver, the flow will be at least slightly reduced.
Second, the increased pressure in the main oil gallery to the mains and camshaft bearings will increase the flow through those bearings, and leave less left over to go to the rods and rocker arms.

Your idea should work.
You just need to be sure you have wide open free flow of oil from the main oil gallery to the right side of the metering valve, and free flow back to the oil tubes in the oil pan from the other side of the metering valve.

I doubt I'll ever reinstall it but I've been curious all these years whether my reasoning was sound. The only restriction I'm aware of was to the distributor valve which allows oil to the valves only after the rest of the engine has sufficient pressure and it sure had that (pressure)! The pressure pegged the gauge cold and barely came off of pegged at hot idle. Since I used a full flow filter I was surprised at how high the pressure got and that was my main concern, what's causing it to get that high. I know the low pressure side of the distributor valve was getting oil since the rockers had oil coming out of the top holes. The only oil line exiting the distributor valve is the line going to the rockers.

You are right
Oil coming out of the rocker arms confirms that there was oil on the low side of the metering valve, and therefore to the rods as well.
Unless... the restriction was in your adapter in the return from the metering valve to the supply to the rods (the larger hole furthest forward), in which case the very high pressure would exist all the way through the metering valve to that restriction, and the rocker arms would then be supplied with the high pressure oil.
But going by your pictures, that is unlikely to be the case.

I would be interested to see more pictures from enough angles so I can visualize exactly how your passages are routed through the adapter!

I'm currently recovering from ankle surgery to repair a dumbass attack from 45 years ago. It's two months tomorrow and will be at least another month before I'm mobile enough to tinker around the garage. When I get mobile again I grab it and post a few more detailed photos. I didn't realize the squirters were also fed from the low pressure side. Now I know.

The full flow filter is possibly causing the restriction.

Most filters have an anti drain back valve. It's just a one way valve, basically a flap, usually crude plastic with a metal spring holding the flap shut. Since the filter is designed for a modern engine, the operating oil pressure is way higher than your 1938 engine so this flap takes a fairly good amount of pressure to push the flap open and also to keep the flap held open. I recall reading specs years ago of 15psi to just crack the flap open but who knows which brand/model filter this was. Even when open, it is only open partially and under spring pressure so will be constantly be pushing back against the oil flow causing a rise in pressure.

You can find some filters without the anti drainback valve as well as spin on hydraulic filters. In this case the only restriction would be the filter media.

Tiny I noticed in another post you replied to that you are running 15/40 oil., That alone will increase your oil pressure considerably. I ran that in my 51 216 as it had lots of miles and many leaky gaskets. With a hot engine at idle it would run 12 lbs pressure and anything over 30 MPH 20-25 lbs., After changing some gaskets I went back to 10/30 and it changed to 7 lbs and 15.
The lighter oil will mist up and lubricate better in a dipper engine in my opinion.

On a factory engine with a full flowfilter the oil by-passes the filter when cold as the filter is a restriction. Even with hot oil it is a restriction thus the higer gauge pressure.
A by-pass filter does more filtering than you think andis adquate unless you drive through a dust storm.

I think some very good points have been made here.
I would not have expected a 20 psi difference (from 7 or 8 psi to nearly pegged at idle) across a full flow filter with hot oil and 216 oil flow rates (about a gallon/minute at idle).
But I'm probably wrong.
Especially in view of the 15W-40 oil as per Steve above.

I agree with Steve on the use of lighter oils and have always used them.
And so I am always thinking along those lines and not accounting for the fact that not everyone uses lighter oils.

After I did the head, tightened the rods, and cleaned out the pan on my 46', I filled with 0W-16 just to do a quick flush and drain.
I was surprised to find I had 7-1/2 psi at hot idle and 14 psi at 50 mph with the 0W-16, so I refilled with the same and have been refilling with it ever since.
Doesn't seem to use oil, and hardly leaks any either.
The viscosity at 210 degrees is still higher/heavier than a straight 10W, and nearly up to an SAE 20, which was the recommended oil at the time.
So it's not quite as crazy as it sounds!

Oh, and I agree with Gene regarding bypass filters.
They are a lot better than you might think!

This all might turn out to be a moot discussion. I managed to hobble out to the garage this morning to look for the block to take more detailed pictures. In the 17 years since I removed it, it seems to have grown legs and hid itself. It's going to take some time to figure out where it's hiding.

The Garage Gremlins strike again!

In this case I think the Gremlin is tall, old and fat. I can remember seeing it from time to time over the years but I'll be danged if I can remember where. It was probably "in the way" in the past & got moved to "where I can find it if I need it".

I would be very wary of routing rubber oil hoses so close to the hottest part of the exhaust, otherwise looks like a good idea well carried out.
Tony