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 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.

 

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/categorydi...?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/partde...=KeywordSearch

And the 8" long one.

http://store.summitracing.com/partde...=KeywordSearch