Oil Filter Tech

I considered posting this in the LT1 tech forum, but I know I wouldnt get as many proven answers, and this is a very important question for my motor.

Many people including myself have ran into the mysterious falling oil pressure under acceleration at high rpm's. Some have found fixes in deeper pans and windage trays, and while that fixes alot of those peoples problems, it sometimes doesnt and is a very expensive trial and error. Some also say it is caused by loose mains, but in my case, that is very unlikely (as I have very good oil pressure all of the time except when this condition occurs, the motor only has 7k on it)

A fellow board member pointed me towards the oil filter, as he had found that to be the problem with his car that showed very similar problems. When the motor was first built I started out with a normal Wix filter, then after hearing about the larger truck version that held 1 quart, I went with the truck Wix filter. This did solve some of my troubles, but the problem is still there at times.

The fellow board member (altjar) told me about the Wix Racing oil filter, saying that was the filter that solved his issue. He then explained how none of the Wix filters that I had used had a bypass function, and how if the filter cannot keep up with the demands of the engine that there is no bypass there to keep the flow going.

The Wix Racing filter flows alot better, thus it can keep up with the demands, thus the oil pressure stays constant. But on their website it says the filter is for racing purpose only. Before I go out and put this filter on, I would like to know if this is the best option, and why the filter would be classified as race only. Does it not filter well enough to be used on a regularly driven engine, and if it doesnt, what is a filter that can solve both my problems?

Thanks,
James

AC Delco #1218 or #454 if you have clearance issues with longtubes. The 1218 is a one quart filter that replaced the old pf35 with the addition of a anti-drainback valve. It also does not have bypass mechanism. The filter better be good enough for daily driving because that is what the factory used on its big and small blocks for the last 30+ years. I use this filter all the time on engines that go through the traps at over 7 grand so I don't think there is a oiling restriction either.

AC Delco makes excellent filters, as do Wix and Purolator. I'm running a PF35L right now with no such high rpm pressure loss.
This site (http://minimopar.knizefamily.net/oilfilterstudy.html) seems somewhat relevant.

What is the part number on the wix racing filter? I'm having high RPM oiling problems as well.

51060R if you are using the truck 1 qt filter

Do local autozones, etc carry this or will I need to order it from somewhere?

I think a few people on the board have found removing their oil cooler and putting a standard adaper on and a larger oil filter has solved alot of their oil problems. For my new 383 stroker, i removed the oil cooler and put a standard adapter and am running a deep truck filter. Mite wanna try and get rid of the oil cooler and see if that improves ur pressure, mite be a restriction.

This filter we are talking about is already the large truck filter, no oil coolers on the car.

Im not sure who stocks the Wix filter other than Napa. My Napa carries it under their own name, Napa Racing filter, the part is just 1060R, however its made by wix (name on the box), same filter.

PF35L is the secret few know about--they are now out of stock as they were "replaced" by 1218s--which is a non-synthetic filter with a DB valve designed for vortec trucks.....35Ls are the best you can get if your a GMPP guy[like myself] not to say that others arent as good i just havent run 'em-----i heard donaldson was good, any opinions?
autozone and others have a backstock of PF35Ls--the older the better as they went to chinese a few years ago-same designation but no welds on surface and less media.
they handle HIGH press. and volume no problem and will save your motor from light debris...
anyone who says a 35L is the same as 1218--dimensions for sure;filtering and pressure ability, no.
you can challenge me to show pics of both cut open, but i cant post pics so you better be adamant because its a royal PITA for me.

Someone will have to explain to me why the oil filter has any effect on "lowering oil pressure while accelerating".

It doesn't make sense. The only thing I can think of is that the oil pickup is not fully submersed during acceleration. That condition would cause a loss of oil pressure. Another factor could be the aeration of oil at high rpm due to lack of a windage tray.

How does the oil filter have any effect in this situation? Enlighten me because it just doesn't compute.

Someone will have to explain to me why the oil filter has any effect on "lowering oil pressure while accelerating".

It doesn't make sense. The only thing I can think of is that the oil pickup is not fully submersed during acceleration. That condition would cause a loss of oil pressure. Another factor could be the aeration of oil at high rpm due to lack of a windage tray.

How does the oil filter have any effect in this situation? Enlighten me because it just doesn't compute.

The problem is that the filter I am running does not have a bypass valve to bypass the filter if it cant flow enough oil. So what I assume is happening is that the filter just does not flow enough oil to keep up with my demand, thus I am loosing a small amount of pressure as the rpms rise, and since there is no bypass valve, everything has to travel through the filter media.

I am going to try this Napa Racing filter as it seems to be a free flowing filter and can rule out this possiblity.

This link goes to an "oil filter study" that actually appears to have some technical merit.

http://www.oilfilterstudy.com/

The PF35L was replaced with the UPF1218, but that too has been discontinued. I've been trying the Moroso filters (which are probably someone else's in a Moroso wrapper :) ), and have good results.

http://moroso.com/catalog/categorydisplay.asp?catcode=20002

Fred-
How much are the Moroso filters?

I think they are about $12 for the 5-1/4" "long" filter. Check the price at Summit of JEG's. Might have goen up since I bought a few of them about 2 years ago.

Prices as of summits web site.

http://store.summitracing.com/partdetail.asp?autofilter=1&Ntt=moroso+oil+filter&N=0&part=MOR%2D22460&autoview=sku&Ntk=KeywordSearch

And the 8" long one.

http://store.summitracing.com/partdetail.asp?autofilter=1&Ntt=moroso+oil+filter&N=0&part=MOR%2D22461&autoview=sku&Ntk=KeywordSearch

Eh thats about the same price as the Wix, plus I have to pay shipping. I was hoping for something a little cheaper. Thanks for the links

autozone and others have a backstock of PF35Ls--the older the better as they went to chinese a few years ago-same designation but no welds on surface and less media. So the Chinese ones have no welds? What welds are we talking about?

PF35L = synthetic filter media
PF35 = regular filter media

You know, I really hate it that the oil filter manufacturers are constantly crapifying their products and switching things around. Every time I need a filter I have to spend a week researching what's good and what's not that particular month. :mad:

This is a copy of the warning that has been floating around on the 'net for at least 8 or 9 years:
AC Delco PF35L Filter Warning

This is a note from Jeff, a Bay Area Listmember:

Just a warning to the newbies and a reminder to the oldies, the PF35L's you're seeing/buying may be the "bogus" variety that Delco is foisting off on an unsuspecting public. I did some fact-finding last year after Chris Chow noticed that the PF35L's I forwarded to him (from Dal at Lambert Buick) didn't match the one he already had. The new filters were much lighter and generally less sturdy appearing, and didn't have the readily visible spot welds on the top.

Delco swears that the filtering ability of the "new" PF35Ls is just as good as the originals, but I don't think they're being entirely honest with us.

This all happened because Delco switched to an "offshore" plant for the filters. They are taking the product from this new source that comes the closest to the PF35L specs and labeling it as a PF35L. Caveat emptor.

Jeff

That's from another decent link on oil filter comparisons:

http://www.shoclub.com/lubrication-oil/lubrication-oilpart5.htm

Where are you still getting PF35L's that you can look at the welds? I thought they stopped making them and replaced them with the UPF1218 at least 5 years ago. And then discontinued the UPF1218.

This filter we are talking about is already the large truck filter, no oil coolers on the car.

Im not sure who stocks the Wix filter other than Napa. My Napa carries it under their own name, Napa Racing filter, the part is just 1060R, however its made by wix (name on the box), same filter.

Carquest filters are "Wix" filters.... Part # 85060 .... Not sure if they can get the racing type, Part # 85060R, but I will check into it...:)

The problem is that the filter I am running does not have a bypass valve to bypass the filter if it cant flow enough oil. So what I assume.....Chevy hasn't ever had the bypass in the filter. It is in the filter adapter housing. As far as loosing pressure is concerned, the bypass valve, which in reality, is a pressure differential valve, opens at a pressure differential of ~ 8#. This bypass is put in place to allow oil to bypass a restrictive/plugged/dirty filter. With the pressure available to the engine at high RPM, the lose of say 10# by rerouting from a restrictive filter, thru the bypass, is not enuf to cause engine problems. Ironically, the major issue, as exploited by filter mfrs., with a resrictive filter, that causes the bypass to function, is not of pressure, but a lose of more complete filtering of the oil.

Chevy hasn't ever had the bypass in the filter. It is in the filter adapter housing. As far as loosing pressure is concerned, the bypass valve, which in reality, is a pressure differential valve, opens at a pressure differential of ~ 8#. This bypass is put in place to allow oil to bypass a restrictive/plugged/dirty filter. With the pressure available to the engine at high RPM, the lose of say 10# by rerouting from a restrictive filter, thru the bypass, is not enuf to cause engine problems. Ironically, the major issue, as exploited by filter mfrs., with a resrictive filter, that causes the bypass to function, is not of pressure, but a lose of more complete filtering of the oil.

Thanks for that information, I havent ever researched oil filters this much, so alot of this is new to me. I havent gotten time to change the filter, but I did just do a couple of WOT runs and what you said makes me think the filter is a very good possiblity. The motor will continue to make more pressure until around 4000+ rpms, then it drops from 60+ to 50 then it will rise back up to 65+ psi. I think what is happening is that the filter is staying up with demands until 4000+ at which time the filter is becoming a restriction, thus the bypass on the filter adaptor is relieving the pressure difference and thats when the pressure returns to normal.

Anyone agree/disagree with this hypothesis?

Thanks,
James

If you wanted to test your hypothesis, you could put in a bypass valve plug and see how the oil pressure behaves. I'd use the Perma-Cool one because you can easily remove it.

How is your pickup attached to your oil pump? I had a problem where the oil pressure would drop to 30-40psi if I went over 3000rpm. I found that if I removed the retainer bolt, the pickup tube would easily slide in and out of the pump! I replaced the pump and pickup. The new Milodon pickup has a thick-wall machined end welded onto the tube, and the machined part is what presses into the pump. It has to be pressed HARD to get it in (the shadetree method of using a hammer and an open-end wrench to pound it in failed miserably). Even though it's not welded, I can't imagine it will ever come out or suck air.

I thought that solved the problem, but perhaps it allowed me to uncover another problem. Now if I go over 3200rpm either maintaining speed or accelerating, the pressure drops from a rock-solid 60psi to 40psi. Oddly, if I let off the gas and decelerate, the pressure comes back up to 60psi even if I'm over 3200rpm. I'm currently thinking it's an oil-control issue, as I have no windage tray or crank scraper.

I think a few people on the board have found removing their oil cooler and putting a standard adaper on and a larger oil filter has solved alot of their oil problems. For my new 383 stroker, i removed the oil cooler and put a standard adapter and am running a deep truck filter. Mite wanna try and get rid of the oil cooler and see if that improves ur pressure, mite be a restriction.
I'm going to delete the stock oil cooler when my new engine goes back in, where can I purchase this adaptor? Thanks.

As far as oil filters go I use the Baldwin B6 which IMOP is one of the best out there, I also have plugged the bypass on my filter housing and see no problems with oil pressure and I run a stock pan with windage tray and a HV oil pump and the stock oil cooler. I think more oil pressure problems are caused by not having the oil pick the right distance from the bottom of the pan i.e. (to close to the bottom ) and no windage tray, also t he stock oil pressure sensor is mounted on the top back of the block which is quite a ways away from the oil pump, I would guess people are seeing up to 10psi less oil pressure than you really have than if the sensor was mounted down by the oil filter so I would take that into consideration when looking at oil pressure.Just my .02

To those that have taken off their oil coolers. Did you also take off the boss that bolts on to the block that the oil filter threads onto? When I did my oilpan gasket it came with a few paper filters that were the correct diameter and had correct hole (bolt) spacing to mount between this piece and the block. I'm thinking this could be the cause of my oil pressure issues.

I still havent gotten around to it, but I can tell you the pickup is definitly still on the pump. I had my machine shop weld it and check the clearences.

I will let you guys know.

As far as oil filters go I use the Baldwin B6 which IMOP is one of the best out there....After Baldwin engineers flatly REFUSED to offer upon request, simple pressure differential specs on their filters, specs AC freely submits on their website, I have written off Baldwin. It is not like this info is top secret/classified. I like the idea of knowing a little more about the filter I use, than just whether or not, it can screw on. Sure they may filter, but at a price.

This is a copy of the warning that has been floating around on the 'net for at least 8 or 9 years:


That's from another decent link on oil filter comparisons:

http://www.shoclub.com/lubrication-oil/lubrication-oilpart5.htm

Where are you still getting PF35L's that you can look at the welds? I thought they stopped making them and replaced them with the UPF1218 at least 5 years ago. And then discontinued the UPF1218.
thats cool that stuff i thought was local benchracing knowledge is on the net, we were comparing the two [old and new 35Ls]side by side long ago, and noticed the spot welds on the top were weaker and it weighed less than the old one, and the old crusty dude i got my stockpile from said its because they were chinese.
i have been going into every autozone i drive by and they still have some in inventory as noone asks for them anymore and the computer doesnt give that part # when the desk jockey punches any type of engine in there. downside is you have to do it in person as their computers show they have none if you call.
im trying to find a couple cases in bulk from supplier somewhere but its hard--im down to my last one on the car and my GMPP guy wont give me anymore of his.
oh and if you live in socal 35Ls suck and you dont want to run one.



also i just chunked my last used 35L today so if ya wanna see one cut open next to a 1218 youre gonna have to wait a few thousand miles, as im not cutting open a new one.

I'll be picking up that filter from Napa tomorrow and will report my results back in a couple of days.

I'm going to delete the stock oil cooler when my new engine goes back in, where can I purchase this adaptor? Thanks.

Ya don't need an adaptor. Use the existing screw on plate and get the correct bolts from GM for an early SBC or I have been using allen bolts with no washers and a little blue locktite.

Ya don't need an adaptor. Use the existing screw on plate and get the correct bolts from GM for an early SBC or I have been using allen bolts with no washers and a little blue locktite.

Or just cut the guide pins in the existing bolts down.

Forgot to post back up on this. Swapped to this filter and oil pressure jumped across the board. Exactly where it should be in all spots.