Has Anyone Used an Electric Pump to Suck out Blow-by and Decrease Oil Leaks? - Page 3 - PeachParts Mercedes-Benz Forum

Air&Road · #31 07-03-2012, 01:06 PM

You're basically describing a dry sump oil system. That would be quite a modification to a point that it would seem more practical and economical to simply put the engine back in proper mechanical condition.

Diesel911 · #32 07-03-2012, 03:29 PM

Quote:

Originally Posted by Army

I've been reading though the FSM trying to find out more about the return flow of oil from the IP.

Chapter 18-005 in both the turbo and non-turbo FSM versions don't help much. The only mention I can find about the return is in chapter 7-010 showing the "new" oil fed injection pumps...

...Oil goes in via the intermediate shaft and returns "to the crankcase" - how it gets there and the path it takes isn't clear in the FSM. I'm going to have to take my engine to bits again to see!

Even so for the crank case pressure to effect the diaphragm at the end of the IP the crank case pressure would have to be greater than the oil pump pressure...

...wouldn't that cause lots of other lubrication problems within the engine? Jets on the turbo OM617 version would have trouble spraying oil up and into the bottom of the cylinders for example.

Now I don't know by how much the oil pump pressure gets reduced by the time it reaches the IP (and crawls its way though the small path way through the intermediate shaft) - I guess that needs to be measured - but how?

After the Oil goes into the Fuel Injection Pump Housing it fills the Pump up to the level of the slot in front of the Pump and the excess Oil Drains out (instead of slots I have see pics where there is 2 holes that do the same thing).
So there is always a captive amount of Oil inside of the Fuel Injection Pump Housing once it has been filled.

Once the Oil Flows into the Pump Housing there is no Oil Pressure. The Oil just lays in the Sump like the Oil does in the Oil Pan.
The Fuel Injection Pump Camshaft is Under the Oil Level and the Bearings are almost completely immersed in Oil.
When the IP is moving plenty of Oil gets splashed around to lubricate the parts above the Oil Level.

Remember the Older Fuel Injection Pumps have no lubrication from the Engine Oil; you have to fill the IP with Oil and keep an eye on the Oil Level and for Fuel contamination.

I think everybodys questions but mine are getting answered in this thread!

See the green circle and arrow in the pic to view the drain slot from the pic I barrowed from another thread.

Markp · #33 07-03-2012, 05:17 PM

That must be some pretty severe blow by if you need to pull vacuum on the CC to bring to tolerable levels.

I had excessive CC psi for a long time, it got worse ever since i installed a 'cold' (use the term loosely)air intake. I vented CC to intake pipe thinking the vacuum would assist with venting. Not so, and as a result I chased oil leaks for a couple of years, did all the hard jobs with engine in car and the leaks kept coming. Finally i vented to atmosphere and the leaks all stopped. Why it took me two years and countless hours of seal/gasket changes to finally try this? no good answer, and in hind sight seems pretty dumb.

If you have not tried to run open to atmosphere do try this first. I used a catch can which dumped to oil drain pipe, CC was vented with 3/4 hose right out into Pass side coil spring. The spring is an oily mess now but who cares..

Gone are the days of an oily/dirty rear hatch, and big oil spots on inlaws driveway!

I am in the process of installing another engine now, i am confident this one is much healthier then the one i removed. I had bad blow by when i bought it 7 yrs/150k miles ago, now has like 350K on it. HG blew or head cracked which is why i finally swapped it.

Air&Road · #34 07-03-2012, 08:36 PM

This could end up going the direction of many R12 to R134a conversions, that is spending more money and time on the change than if the problem were just fixed via standard means to start with.

Stretch · #35 07-04-2012, 04:37 AM

Quote:

Originally Posted by Diesel911

...
Once the Oil Flows into the Pump Housing there is no Oil Pressure. The Oil just lays in the Sump like the Oil does in the Oil Pan.
The Fuel Injection Pump Camshaft is Under the Oil Level and the Bearings are almost completely immersed in Oil.
When the IP is moving plenty of Oil gets splashed around to lubricate the parts above the Oil Level.
...

I'm surprised to read that.

My experience (which is most definitely less than yours!) is that the oil shoots through the intermediate shaft with some impressive force. I found this out the hard way whilst arsing about (playing) with my engine with the IP off. I cranked by hand and then wondered where all the oil was coming from - there was shed loads of it all over the place and I'd only turned the crank about three times.

Stretch · #36 07-04-2012, 04:43 AM

Quote:

Originally Posted by Air&Road

This could end up going the direction of many R12 to R134a conversions, that is spending more money and time on the change than if the problem were just fixed via standard means to start with.

Larry I think you are right if the solution involves vacuum pumps and oil traps and oil seperators that don't need to be manually emptied(!) but "hacking a hole" somewhere and fitting a gauze filter and feeding an extra pipe to the rear of the engine so only the people behind you get the streaming eyes might be a cheaper fix.

Diesel911 · #37 07-04-2012, 02:08 PM

So I hooked up a Pressure Gauge by removing the Oil Fill Plug From the Fuel Injection Pump and replacing it with Fitting.

What I found is that while I could feel something blowing out of the Hose there was not enough pressure to move the Needle on the Gauge and it remained at Zero.

Revving the Engine also did not move the Needle.

At idle speed I removed the Rubber Elbow from the top of the Valve Cover and covered and started counting 1000 one; 1000 two and so on until the Engine Shut Down.
It took 10 seconds for the Engine to shut down at an approximate pressure of 3.1 psig.

I did no other tests.

So, I have un-measurable Bow-by pressure that does not increase with Engine speed.

I also do not have excessive Oil Leaks from the Crankshaft Seals (I wish I could say the same for the Transmission).

If I was having the excessive Oil leaks they only need to get rid of a max of 3.2 psig of pressure. Because if I had more pressure than my Engine would shut down.

I am surprised by the results.

Stretch · #38 07-04-2012, 02:17 PM

So what do you conclude?

3 PSI crank case pressure is enough to stop the crank from turning?

Diesel911 · #39 07-04-2012, 03:10 PM

Quote:

Originally Posted by Army

So what do you conclude?

3 PSI crank case pressure is enough to stop the crank from turning?

Was not trying to prove anything; just some observations.

One of the members was asking for some real evidence; thats all I could come up with on short notice.

In My Case 3+ psig is enough to make the Shutoff Valve shut the Engine off.

I will try the test sometime later if I can find my better quality Gauge.

Stretch · #40 07-05-2012, 03:43 AM

OK interesting - I'm sorry to be a stuck in the mud but I'm still not convinced about the shut off valve!

(Don't worry I'll probably get used to the idea in a bit...)

But working on the assumption that it is the shut off valve (as I can't think what else it could be) how about putting a vent next to it then?

Wouldn't that be the place to put in a vent?

Is the fill plug high enough not to have oil squirting out of it?

See through tubing attached to fill plug hole, held up high, vented to atmosphere - and then repeat test?

kerry · #41 07-05-2012, 09:14 AM

Good test.

funola · #42 07-05-2012, 09:43 AM

Quote:

Originally Posted by Diesel911

So I hooked up a Pressure Gauge by removing the Oil Fill Plug From the Fuel Injection Pump and replacing it with Fitting.

What I found is that while I could feel something blowing out of the Hose there was not enough pressure to move the Needle on the Gauge and it remained at Zero.

Revving the Engine also did not move the Needle.

At idle speed I removed the Rubber Elbow from the top of the Valve Cover and covered and started counting 1000 one; 1000 two and so on until the Engine Shut Down.
It took 10 seconds for the Engine to shut down at an approximate pressure of 3.1 psig.

I did no other tests.

So, I have un-measurable Bow-by pressure that does not increase with Engine speed.

I also do not have excessive Oil Leaks from the Crankshaft Seals (I wish I could say the same for the Transmission).

If I was having the excessive Oil leaks they only need to get rid of a max of 3.2 psig of pressure. Because if I had more pressure than my Engine would shut down.

I am surprised by the results.

What mechanism in the IP is making it shut down with crankccase pressure? Can you post a pic of the part?

I tried that same test last year on my 83 300DT and it never shut down no matter how long I blocked the crankcase vent. I remember reading this test only works on certain IPs.

Diesel911 · #43 07-05-2012, 10:19 AM

Quote:

Originally Posted by funola

What mechanism in the IP is making it shut down with crankccase pressure? Can you post a pic of the part?

I tried that same test last year on my 83 300DT and it never shut down no matter how long I blocked the crankcase vent. I remember reading this test only works on certain IPs.

The circled item is where I measured the pressure.
The Arrow points to what the Shutoff Valve that the internal pressure pushes into the shutoff position if it s high enough.

Diesel911 · #44 07-05-2012, 10:36 AM

Quote:

Originally Posted by Army

OK interesting - I'm sorry to be a stuck in the mud but I'm still not convinced about the shut off valve!

(Don't worry I'll probably get used to the idea in a bit...)

But working on the assumption that it is the shut off valve (as I can't think what else it could be) how about putting a vent next to it then?

Wouldn't that be the place to put in a vent?

Is the fill plug high enough not to have oil squirting out of it?

See through tubing attached to fill plug hole, held up high, vented to atmosphere - and then repeat test?

It was one of our Members who suggested that the Crankcase Pressure could cause the shutoff to shut the Engine Down.

I think I will let someone else to the rest of the experimenting.

I think if someone blocks off the port or clamps the Hose where the Vacuum Hose goes into the Vacuum Shutoff Valve you it will keep the Crankcase Pressure from causing it to Shutoff.

For myself If I was looking for a larger Vent Hole I would find a way to use the Oil Fill Cap Hole in the Valve Cover. It is big and you would only need one tube.

To get the benefit of that you would also need to find a place to use a largter ID Hose. That means a none stock Breather/Canister.

In my case that would mean I would need to find a place for a larger Fitting on my modded intake and Cookie Can breather. So far it has been adequate so I don't see the need to change it right now.
Also I don't have any excessive Oil leaks at my Crank Seals.

Stretch · #45 07-05-2012, 01:21 PM

Quote:

Originally Posted by funola

...

I tried that same test last year on my 83 300DT and it never shut down no matter how long I blocked the crankcase vent. I remember reading this test only works on certain IPs.

Whoa nice googly (cricket term) from funola!

For the turbo OM617 the pump halves of the "IP" were all the same however the governor halves changed see chapter 07-001 (in the turbo part of the manual) for the numbers. In 1982 there was a change which might explain funola's 1983 behaving differently...

...which governor do you have Diesel911?