Bypass Filter on 8.1L

[raventai]

I have been interested in oil lately and decided to try a bypass filter took a wile to choose one

 

Amsoil has several in 2 basic groups, standalone and dual remote the dual remote are the easiest to install but they restrict main oil flow to get differential pressure for the bypass filter , the standalone is a nice kit and has effective filtration but replacement filters are $26-32 and initial cost is $161

 

TP filters ( frantz , Motor Guard, and Gulf Coast ) witch have the cheapest filtering element (plain toilet paper) they are also effective but you are suppose to change the toilet paper ever 2,000 miles, wile the roll may only be .59 the quart of synthetic oil it is holding is $5, supposedly this every 2k refresh of the filter and 1qt of oil will allow you to go indefinably without oil changes at all (using oil analysis to catch if there is a problem) one of these would be my second choice

 

Baldwin has the cheapest for initial setup at around $40 for a simple filter head but its pleated paper element only filters down to about 10 micron (all of the others are around 1 micron nominal) witch is only a slight improvement over high quality main oil filters replacement filters are around $10

 

 

Oil Guard seamed the best for for me, it was $130 for just the filter case no lines or fittings, they sell complete kits that come with the lines for slightly more, replacement filters are $13 but I am looking into a possible source for the same filters for $5 these filters are suppose to be changed at every oil change

 

for this kind of bypass filter I needed a high pressure oil source and a low pressure area to return the bypassed oil to. The oil sending unit on this motor is buried deep behind the intake and almost impossible to get to, fortunately there is a 3/8 NTP plug on the side of the block along the center line of and just above the oil filter. It covers a drilled oil passage that taps oil off just after it passes through the main oil filter and oil cooler

 

 

 

I wanted to know what 1 was going to be working with (drive and thread) before I took it apart so I went to the dealer and got the # for the plug (not in stock) and ordered from GM parts direct, I received a 1/4NPT plug with a 1/4” female square drive. unfortunately I went to install and the plug on my truck has a square drive that is smaller than 3/8 and larger than ¼ and the thread is 3/8NPT I took an old POS 3/8 ratchet and slowly ground it down until it fit. seams to be around .320” witch lines up with 8mm and is also close to 5/16

 

so did the dealer parts person screw up or maybe GMPD or are there 2 different plugs on 8.1's?

 

Here I installed a 3/8”npt to 1/4”npt bushing in the block, 1/4”npt street el, 1/4”npt to 1/4”barb, hose and 2 clamps, I was worried about a catastrophic hose failure bleeding off all of my oil pressure, the filter has a .042” restriction in its outlet but if there was a failure before then it would immediately dump all my oil pressure so I made a second restrictor for right where the oil comes out of the block

 

 

I took a 3/16 monel rivet with a 426 head (large countersink) and drilled a #40 hole (.098”) down its length counter sunk each end slid it into the base of the barb, and using 2 punches and a hammer I slightly swelled the rivet to hold it in place and then re drilled the hole as it has closed slightly

 

 

now if there is a major failure there should still be oil pressure for a few minutes, some of the oil will be pumped overboard through the .1” restriction but not ehough to cause a loss of pressure, when the level gets 2qt low low oil level light will come on, the remaining oil should give me enough time to pull over to the sholder without engine damage

 

The second problem is where to mount the filter, there is a heat shield on the bottom of the cab just below the drivers feet just inboard of the frame, perhapses there is a cat here with other motors? This heat shield is installed with 3 bolts and is close to the oil filter and there are no obstructions in the area, looking at the air tunnel that every thing on my truck works its way around I think it will clear the front drive shaft for you guys with 4wd

 

the bracket it came with was not wide enough to catch the 2 front bolts so I bolted it to a piece of 2” alloy aluminum angle that was 11” long I then added a brace to the rear bolt to help out as these heat shield bolts are kinda thin and the filter had a lot of leverage on them the rear brace negates that leverage

 

view looking up at the drivers side floor, the head of the filter faces forward,

 

both inlet out outlet of the filter are 1/4npt I installed 2 street el's and 2 1/4”npt to 1/4” barbs hose with 2 clamps, there was also an 1/8”npt port marked aux, this is ported to the “dirty side” of the filter I decided to put a sampling port there got a valve that has a all metal seat there is a rubber seal around the handle shaft but it sees no pressure except when the valve is open I put a short piece of 3/16 vinyl hose on it and jamed a 3/16 bolt in the end of the hose as a dust cap, do not want dirt/grime to contaminate the sample

 

the last thing to figure out is where to return the bypassed filtered oil to, you can buy hollow self taping bolts. you would punch a hole in the oil pan or valve cover and thread them in, on the 8.1l both are cast aluminum and I was not to keen on that method anyway

 

Amsoil sells a swivel for the oil cap with a nut on the back side for only $8 but I am not sure how well that swivel seals? Seams to me that if it gets worn out the vacuum in the motor would draw in air and the dust/grit that travels with it, I would like to hear from somebody that has one how it worked out? That amsoil swivel is 1/8npt but I could adapt

 

I wound up drilling and taping the oil fill cap for the return, I am not really happy with this setup wile the oil cap is off it drips oil all over the intake and since it has hose on it I cannot flip it over or move it elsewhere to prevent the drip also the cap is not solid but several layers of thin plastic not very forgiving of threaded fastners, I don not think it will last long, I have the gasket needed and may one day remove drill and tap the valve cover for the return line, in the mean time I am going to look for another way, I am still hoping to find a stock plug somewhere that I can tap into

 

 

 

 

here used 2 clamps a 1/4”barb to 1/4”npt, 1/4” elbow, and a 1/4” to 3/8” MS fillting witch is 7/16-20 strait thread, drilled a 3/8” hole in the cap and taped it, there is an o-ring between the fitting and cap to seal it

 

I also want to get better hose, the only 1/4” oil and temperature resistant hose I could find in Newnan was hydraulic hose, it was made for swage on fittings, I am using barbs and hose clams (witch are appropriate for the 70PSI it will see) but the 15,000 psi hydraulic hose has a metal wire layer that soaks up a lot of the hose clamps pressure and I am worried about it popping off I will be ordering some Parker 836-4 hose witch is ¼ id high temperature 300psi line, should be perfect, the filter could be installed with 10' of hose and still be well routed

[Shaners]

Good Info and nice pics to go along with it...

 

You might want to PM Mervz and see if he would like to put this in his "Tech" section.

 

Thanks...

[Black02Silverado]

Thanks for that post. A ton of great info and pictures to make it understandable and life like,

 

I'm still considering a bypass for my 5.3 just have to wait till the funds become available.

 

Again great post.

[raventai]

thanks for the compliments guys, glad you liked

 

ran into a bit of a problem, shortly after shutdown I get a burning rubber smell , I think the hose is getting overheated by the exhaust. not sure if it is all the time or gust on shutdown when there is little air and oil flow but much heat, temporary fix is going to be fiberglass insulation but I am going to switch that one over to a rigid metal line. Metal tubing will have a higher temp resistance and I should have more control over the routing getting it further from the exhaust

 

 

on my way back to the hydraulics's shop

[Black02Silverado]

thanks for the compliments guys, glad you liked

 

ran into a bit of a problem, shortly after shutdown I get a burning rubber smell , I think the hose is getting overheated by the exhaust. not sure if it is all the time or gust on shutdown when there is little air and oil flow but much heat, temporary fix is going to be fiberglass insulation but I am going to switch that one over to a rigid metal line. Metal tubing will have a higher temp resistance and I should have more control over the routing getting it further from the exhaust

 

 

on my way back to the hydraulics's shop

You might want to consider rerouting the line. If it is getting that hot and you add a metal line that transfers the heat to the oil inside that line it can cause the oil to coke up in the line and possibly over time restrict the flow and add carboned oil to the system. Just a thought. As we all know heat is not a good thing to oil and that sounds like it is getting some intense heat if you smell rubber hose on shut down. The fact that the oil is just sitting inside that line because it is shut down means it is just sitting there getting hotter and hotter.

 

Just wanted to mention that.

[ugeesta]

OK. Stupid question. What are the benifits of having a bypass oil filter?

[firecadet613]

More filtration.

 

The more filtration the better.

 

Joe

[Charlie in TX]

rav, good post. My dad had one of the tolet paper bypass filters in his '73 suburban 454. The motor burned a quart every 1000mls. He changed the filter then also. As I remember he used the cheapest oil on the shelf.

 

Well to make a long story short, at about the 150,000ml mark someone rebuilt the motor for him. Everything was in spec and clean. Just ringed it.

 

Good luck with your system.

[raventai]

transfers the heat to the oil inside that line it can cause the oil to coke up in the line and possibly over time restrict the flow and add carboned oil to the system.

 

 

 

unfortunately I am thinking the same

 

 

so today I made this to replace the high pressure hose

 

I got the components at a “ Parker store ”, (60 miles one way ) I used Compression Bite flareless fittings, they are strong and reliable but best of all no flare tool needed , just something to cut the tube with and a wrench.

 

10' of 1/4” tube, 4 complete “tube-to-1/4”-pipe” fittings (4-4 fbu-s) to screw into my existing “street el's” , and 4 extra ferrules (4 tu-S) in case I screwed up, the rest of the fitting parts are reusable, it was all under $20 it would have been cheaper and better to go tube to start out with, a little more work to install but I think it will be worth it, looks a lot safer and sturdier

 

If anybody is interested I will post a directions on assembling the flare-less fittings

 

sorry for the focus, camera decided it liked the background better than the fittings :o

 

 

the filter is installed to the body, the body moves in relation to the frame, the motor (where the other end of the line is) is mounter to the frame and is also allowed some movement I put in a long loop to allow to allow movement without much stress on the fittings and also so I could zip-tie it to an existing bracket for support,

 

 

 

sorry for the funny perspective, it is very hard to frame a good pic while on a creeper under a truck, view looking forward, big chunk of aluminum on the right is transmission's bell housing, red bracket and chrome cylinder on left is filter and its brackets, in the middle is left exhaust manifold and pipe with freshly added fiberglass wrap to reduce heat in the area (planned a wile ago to try to reduce transmission temps), in the pic the unprotected part of the line looks like it is close to the exhaust but it is actually over a foot away, the portion of oil line with the fiberglass wrap is close to the exhaust manifold, you can get a better Idea from the first pic in this thread, the metal line is loosely following a similar path as the hose did

 

I think my original fears of hydraulic on barb were BS, after removing the clamps on the line after just 24 hours I could not pull the line off the barb, It had taken the shape of the bard, with the clamps off I could still rotate the fitting in the hose so I just unscrewed the barbs and removed the hose and its 2 barbs as an assembly, I lost the barb with the restrictor that was in it, did not have enough time to come up with a new one, but I feel good about the metal line,

 

I have enough fittings and tube to run the low pressure side when I figure out a better place to pipe the low pressure return too

 

 

 

OK.  Stupid question.  What are the benifits of having a bypass oil filter?

 

 

a Bypass Filter is a very thick filter that can catch very small particles, usually catching the majority of the 1 micron particles on the first pass, but because of that thick filtering media they are very restrictive and can only filter a small amount of oil at a time, you send apox 10% of the pumps oil through the bypass filter and every few minutes all the oil in the engine will make its way through the filter, this keeps the oil free of abrasives that get past the air filter rings and into the oil to a minimum reducing wear

 

 

 

 

a standard oil filter usually does not catch very small particles, some are better than others. some claim down to 10 micron most only filter down to 15-25 microns,some people say to get the lowest micron filter you can find (like Mobil 1's branded champion labs filters) usually filters that get very small particles are also quite restrictive, some say with restrictive filter the filter bypass valve will be open more often especially with thick cold oil. When it opens unfiltered oil goes to you bearings lifters etc, Since we get no indication of when the filter bypass valve so it is hard to say how often it opens and how hwat we use for oil and filterers affects it operation (“filter bypass valve” not to be confused with “bypass filter”, “oil cooler bypass valve” or “pressure relief valve” all separate parts of the 8.1ls oil system)

 

some say running a low restriction filter (like the K&N branded champion labs filter) will give better wear #'s even though it does not catch ultra small particles is delivers more oil,

 

 

I want the best of both worlds, a high flow main oil filter to catch the big stuff first pass, but still deliver lots of oil, and then a bypass filter to eventually catch all the little stuff, together should be the best of both worlds

 

 

will it pay off? truckers the military, local governments and other vehicles that see a lot of miles are using them with good success, will it pay off in normal civilian use? Maybe if I can extend my drain interval (analysis governed) it may pay off in the short term but in the long term Probably not, most trucks hit a telephone pole/other cars or are sold, stolen long before the motor wears out, especially you notheners the bodies fall apart before the engine goes,

 

and If I am still driving it 300K from now will I be riding on borrowed time that the bypass filter bought me? Impossible to say, but it does add life to the engine and UOA's do show reductions in wear

 

and hey it is kinda fun to think about and work with