bypass filter return line routing...WARNING!

[Weatherlite]

Nothing bad happened so that is good, but I figured I could post this and save some of you a little $$ and time.

I read in a post a whiole back where msparks was going to have a machine shop drill a hole through a drain plug and then tap one end of it so that he could route his bypass filter return line through it. This saved him from having to drill a hole anywhere else on his engine.

I thought this was a grand idea, esp since my valve covers are plastic and I have no desire to put metal shavings into my oil pan! I know...drop the pan first, right? WRONG!! I have to remove the engine to do it!!! Serious.

Anyway, I liked this idea so I went out and bought a replacement plug and brought it to a machinist I know. Guess what? The **** things are made out of the crappiest metal on Earth! It drill really easy because of this so that was good. What was bad is it wouldn't hold the threads. Every time he would back the tap out to break the metal free, the threads would come out as well! He quickly remedied this problem. However, he installed the fitting just fine but when he removed it so that I could put the lines together all of the threads came out!!!!

So, now I'm on the lookout for a bolt that is actually steel. One problem though...and maybe you guys can help. I can't find a 14mm x 1.5mm bolt ANYWHERE!!!!! The 14mm is easy. Finding it in 1.5 pitch is the tough part.

Anyway, just figured I'd want to warn anyone who was thinking of trying this.

Mikie

 

[ex_MGB]

Between Swagelok and Hoke you should be able to purchase what you need without any machining.

 

[dkcase]

The following is from McMaster-Carr Supply Co.
www.mcmaster.com
I entered cap screws metric in the search function, and followed the choices..

91180A778

Metric 8.8 Zinc-Pltd Steel Hex Head Cap Screw M14 X 30 mm Lg, 1.5 mm Special Pitch, Full Thread
$ 5.34 per Pack
This item is only sold in Packs of 10

 

[OneQuartLow]

1.5mm is the "default" coarse metric pitch. Should be very common. Stick to grade 8.8 or 10.9 hardware for better quality. Those are roughly equal to National grade 5 & 8 respectively.

David

 

[Weatherlite]

Actually, all I've been able to find are 1.25 and 2.00. I think I'll just order em through the link above though.....a replacement plug costs $3 for one and I can get 10 for $6!

Thanks for link!

Mikie

 

[Ron Jeremy]

weatherlite, Have you considered routing your return line to your oil fill cap? I know some people have simply drilled a hole in it and mounted a 90 degree orifice that swivels.

 

[RalphPWood]

Weatherlite,
I've been installing bypass filters for 40 years. I've never drilled a hole in an oil pan. I've never returned the oil into the drain plug. I don't know what filter you have but most filter companies have self tapping hollow bolts. You use a sharp punch to punch a hole in the pan. No metal in the pan. The self tapping hollow bolt is tightened in until the gasket and washer seats. So many drain plugs are in an area where something from the road can knock off a fitting. It is a good place to return the oil if it is in a protected area. Frantz had a sandwich adapter. I use PermaCool sandwich adapters with the Motor Guard submicronic bypass M-30 filter. The Motor Guard M-30 is very versatile.

Ralph

 

[Weatherlite]

I've thought about going the filler route but I have heard of some having problems with oil consumption when they did this because there was too much oil above the valvetrain and it was seeping past the valve guide seals.

As for drilling holes anywhere on the engine or even using the self tapping bolts I'd rather not alter the engine too much where I might have to replace a part if I ever sell it.

Ralph, as for the pan bolt option and road debris, the vehicle is a Ford Excursion so the pan is almost 3 feet off of the ground to begin with and there is also a skid plate just to the front of it that I plan on extending so it shouldn't be a problem.

Mikie

 

[Tommy]

The valve cover is my preferred location - have you considered a bulkhead fitting?

 

[Weatherlite]

Bulkhead fitting? Are these the type that have a retaining nut on the backside?

 

[RalphPWood]

Weatherlite,

You are right. If you return the oil too close to a intake valve or where the crankcase ventilation system can pull a mist into the intake it can be a big problem. On the 7.3 Powerstroke there is a 3/8" pipe plug just to the rear of the full flow filter in the bottom of the engine skirt just like a V8 Ford flat head. With the self tapping hollow bolt you leave it when you sell the truck and purchase a new one for the next truck. For gasoline engines I use the PermaCool sandwich adapter with the Motor Guard M-30.
You may know that most of the use of the Gulf Coast filters by the US Military started at the Maintenance Equipment Evaluation Program (MEEP) at Eglin AFB. They have tested a bunch of filters. I'm not allowed to talk about military filter ratings. I would love to post the filters and numbers for the members of the forum.

Ralph

 

[mangusta1969]

That was a great idea to separate the bypass filter forum from the full flow filters!

I am going to try to fit a bypass filter onto a car with very tight spaces (92 Corvette ZR1 with DOHC 350 motor). Although this is a very high performance motor, for some reason the designers chose to use a very small oil filter (Delco PF970C) that is typically used on small 4 cylinder motors. What were they thinking?

Anyway, can I use a sandwich adapter with both oil supply and oil return lines in it with a bypass filter setup? For space and line routing reasons, I was thinking of using the 3965 adapter from Flexalite. The ZR1 has a 20mm x 1.5 fitting for the oil filter.

Check this url for the flexalite sandwich adapter that I am planning to use:
http://www.flex-a-lite.com/auto/html/sandwich-adapters.html

Can a bypass filter such as the Frantz, Motorguard, or Amsoil BMK11 effectively return the bypassed oil into a relatively high pressure area (the return oil port on the sandwich adapter)? I know that Ralph Wood has suggested the use of sandwich adapters with bypass filters, but isn't the bypass oil flow greatly reduced with this approach?

I would prefer to return the filtered oil to a no pressure area in the oil sump, but this car has a high dollar cast aluminum sump and I don't want to molest it. The other alternative would be to use a hollow bolt in lieu of the standard 5/8 inch dia. oil drain plug. The filtered oil would return to the pan through that hollow bolt. That option is a little scary due to the lowness of the car, but the plug is at the back of the oil sump and not on its bottom.

Any recommendations from those that have BTDT would be most appreciated.

 

[Mike_dup1]

quote:

---

I read in a post a while back where msparks was going to have a machine shop drill a hole through a drain plug and then tap one end of it so that he could route his bypass filter return line through it. This saved him from having to drill a hole anywhere else on his engine.

---

Not a good idea. You would be returning the oil to the lowest point in the system and there would some back pressure from oil in the pan. You want to oil to flow unrestricted so find a place as high in the pan as possible.

Many of the newer engines have cast aluminum oil pans (new GM V8's) and finding a good place to return the oil is a big challenge and the oil filler cap may be the only logical location.

 

[mangusta1969]

Mike,

Thanks for the reply.
While I agree with you that it would be better to return the bypassed oil to a "no-pressure" area above the sump's oil level, the back pressure from 3 inches of oil would have to be pretty minimal (something less than 1 psi would be my guess).

Since the bypassed oil is still under more pressure even after passing through the pressure reducer/flow restrictor orifice, the oil would flow into the sump at this point as fluid will move from a high to a low pressure area. Don't forget that the bottom of the sump is a much lower pressure area than the return oil port of a two port sandwich adapter that some people have been using.

Does anyone have pressure measurement numbers on the output side for any of the bypass filters? If not, I will take some measurements when I do my installation. I have not yet decided on the type of bypass filter, but space constraints in this car are very tight so that may do my selection for me.

The oil filler cover return is out, as I don't want to introduce any more oil into the top of the ZR1's engine, as these motors already have trouble with too much oil in that area at high rpms (above 6000 rpm).

Since the Oilguard guys are located about 15 miles from me, I think I will take a run up there next week and see what their engineers have to say on the subject of sandwich adapters and oil return line routing for bypass filters.

 

[Ken2]

It takes about a 2-1/2 foot vertical column of oil to equal 1 psi. In any case, the additional 3" drop of oil in the hose down to the pan would exactly equal entering the oil pan 3" under the oil surface.

A 33' tall column of water exerts one atmosphere of pressure...14.7 psi. Oil is what?...approximately 9/10ths the specific gravity of water? If so, one atmosphere (14.7 psi) is 33' ÷ .9 = 36.7' of oil.


Ken

 

[mangusta1969]

According to the figures provided by Ken2, the 3 inch sump depth would equate to .10 psi, as compared to returning the filtered oil at or above the surface of the oil in the sump. This is hardly a significant factor to consider for an oil return line that is under some pressure from the bypass filter... Thanks for the information.

Now, can anyone provide some measured input and output oil line pressures for any types of bypass filters installed on internal combustion engines?

 

[Mike_dup1]

Anytime you return oil to the lowest point in the system, there is always the possibility of something impeding the flow. Since the drain it the lowest point, something could possibly seek this spot and imped return flow. Chances are that is could happen, slim but its always possible.

Besides, all GM oil pan drain plugs are magnetic and if you use a modified plug, you no longer have this feature.

I still think its a bad idea.

 

[Mike_dup1]

I installed a Amsoil By-pass on a small block 80's GM truck with 350 V8 for a customer back some 10 yrs or more ago. I removed the valve cover, noted where the return hole in the head was, then ran the return line so the oil would flow right back down to the pan and not linger in the head. Worked great for many years.

 

[mangusta1969]

Mike,

Thanks for the idea of internally routing an oil line within the head to quickly return the filtered oil to the pan. Unfortunately there really is no "valve cover" on the ZR1 motor. It is just a cam cover for the dual overhead cams and there is no economical or aesthetic way to route the oil from the top of the engine back into the sump.

I guess the dipstick tube could be used as a return. Has anyone tried that?

I don't see the concerns about returning pressurized oil at the bottom of the sump through the oil drain plug: A. oil in the sump should stay pretty **** clean, and B. the pressurized oil from the bypass filter should clear any small debris that tries to enter the hollow drain plug when the engine is not operating. This is by no means a gravity feed setup.

My only real concern with this type of drain plug return is the possibility of snagging the oil return line on some road debris, thereby draining the sump through the hollow drain plug and also causing the filtered oil to be returned to the pavement surface via the broken return line.

For this engine, I think the cleanest/simplest return method would be through a return oil line in the sandwich adapter. Since the bypass filter is fed first by the adapter, if I understand things correctly, this requires a spring-loaded bypass valve within the sandwich adapter to be open all the time in order to feed oil into the full flow oil filter.

I am not thrilled about the fact that, with this design, spring loaded valve pressure in the sandwich adapter has to be overcome before oil is sent to the full flow filter and to all of the engine's bearing surfaces. This was definitely not part of the engine's original design and will certainly reduce oil pressure and flow to some degree over an open oil passage. It also puts the engine at risk if the adapter's spring loaded bypass valve gets stuck in the closed or partially closed position.

What I don't understand is how the bypass filter (with it's small pressure restriction orifice) can return filtered oil at a lower pressure into the high oil pressure area that is just ahead of the spring-loaded bypass valve. Can anyone explain this or point me to some diagrams that show the overall oil flows with a full flow filter/sandwich adapter/bypass filter setup?

 

[Mike_dup1]

Have you looked at the Amsoil BMK-13 bypass setup?

With those you don't have to route the lines, it comes from the filter boss and back to it.

I have one of those on one of my trucks, a 1992 Chevy 4X4 I use for snowplowing.