Need some help - loosing oil pressure at high rpm's

[madmaxx]

Between block and frame rail with oil adapter removed is 4.125". Thread bushing which sticks out is .5". I and short .25" on 4" filter. Sure I could slide the motor over but enough is enough.

[Jerry Clayton]

At the end of the day----with the large main bearings of a 351w, especially on an aftermarket stroked crank, there is no way that you are going to feed the oil from a stock type oil pump thru all that plumbing and maintain pressure----------

Your system has violated just about every parameter of the oem type pump system that you are using even without going into all the pitfals of inadequate sizes and poor choice of hose ends(90*), plus attempting to do the filtering with a filter designed for a 1958 engine----

You are also overlooking many laws of physics pertaining to flow/pressure dynamics that are somewhat ignored in the motorsports hobby but never the less do still apply---besides the venture effect that I have mentioned several times, you are ignoring that you not only have a conglomeration of plumbing to the filter/cooler but that the after effects of the cooler (lowered temp) will effect oil viscosity and flow rates will decrease from that point on in the system--------

Ford made a right angle adapter for filters back in the 60s that would solve your space for a bigger filter (check cobra jet with oil cooler)--------

Those 3 inch mains are going to be impossible to feed with a stock type pump, and its going to be the rods that fail first from lack of oil----------


http://www.chevyhiperformance.com/te...nfo/index.html

[blown871]

I installed larger filter by... loosening.. (removing) remote oil filter bracket.. putting fillter on then tightening it all back down. A bit of a process.... but worth it for the extra filter.

[madmaxx]

I agree with everything you say, the ding dongs who assembled it viloated every parameter!!!!!!!! It is equiped with a high volume oil pump and I plan on going 12an lines....... The pressure drop is nauseating!!!!!!!

Originally Posted by Jerry Clayton

At the end of the day----with the large main bearings of a 351w, especially on an aftermarket stroked crank, there is no way that you are going to feed the oil from a stock type oil pump thru all that plumbing and maintain pressure----------

Your system has violated just about every parameter of the oem type pump system that you are using even without going into all the pitfals of inadequate sizes and poor choice of hose ends(90*), plus attempting to do the filtering with a filter designed for a 1958 engine----

You are also overlooking many laws of physics pertaining to flow/pressure dynamics that are somewhat ignored in the motorsports hobby but never the less do still apply---besides the venture effect that I have mentioned several times, you are ignoring that you not only have a conglomeration of plumbing to the filter/cooler but that the after effects of the cooler (lowered temp) will effect oil viscosity and flow rates will decrease from that point on in the system--------

Ford made a right angle adapter for filters back in the 60s that would solve your space for a bigger filter (check cobra jet with oil cooler)--------

Those 3 inch mains are going to be impossible to feed with a stock type pump, and its going to be the rods that fail first from lack of oil----------


Bearing Clearance Info - Tech Article - Chevy High Performance Magazine

[vector1]

On my JBL I use a remote with -12 lines, Mobil 1 filter. Fab'd a tray that lays between the rails that the filter sits on so it is just to the passenger side of the crank pulley, that way it doesn't drain back into the block or pan if it sits for a while. I see no less than 40 psi using 5w30 or 10w30, the FMS engine also came with a high volume pump.

[madmaxx]

I received my new smith oil temp gauge $140 plut $18.31 in shipping handling. I ****ed up bad guys. Before installing I stuck the bulb in a pan of boiling water. I live about 20 feet above sea level all my other thermometers indicated my water boils at 212F or 100C. This one violates the laws of physics, when my water boils it shows 90C. Should have been like every other dumb**** and just installed it.

Back to my $19.00 autozone model which works perfect.

My next ***** is Oltoff racing. How the **** it takes them 3 weeks to send motor mounts is beside me. I order stuff from Jegs and Summit and it shows up in 2 days!!!!!!!!!!!!! They never miss a beat and Jegs is free shipping and handeling.

[Keithc8]

If i understand you right you are losing about 5 lbs of oil pressure at 5000 rpms. Does it back up more with more rpms. what you see a lot of the time is pumping the oil pan down before the oil can return down there. Like mentioned earlier it not that uncommon to see this with a stock style oil pump with the lines, filter, oil cooler and all. we run a lot of engine with a bigger bearing at .003 clearance on the mains and it is not that big of a deal. If you are losing only 5 psi I am not sure I would worry about it very much if it does not go any lower.

Keith

[YerDugliness]

[quote=YerDugliness;1276557]Is Ford's FL1A a direct crossover to a Fram PH8A?

If so, IIRC the Fram PH47 (or it might be the 48) is a shorter filter, but.../QUOTE]

I need to correct myself...the short version of the PH8A is the PH43, not the 47 (or 48).

The Bosch filter is still smaller...can take a measure if you need one.

Cheers!

Dugly 8)

[madmaxx]

Hey guys need to bring some closure on this one:

1) In the beginning oil pressure was 50 psig at 4K rpm and would drop to 42 psig at 6rpm. Engine lived like this for 5K miles.
2) I adjusted rv spring in existing Mellon 1083 hv oil pump. Oil pressure went to 57 psig at 4k rpm to 52 psig at 6K rpm. This was a huge score and proved the oil pump was bypassing the whole time!!
3) Replaced rod bearings - zero change, old ones were perfect as were new ones LOL!! main bearings were perfect but found Cleviet HX on the end indicating an extra .001" clearance on standard shaft. This lead me to believe engine was built with larger clearances. Who knows I do not trust plastigauge and had no way to determine. Builder either didn't have the bearing clearance informatio or refused to provide them to me. Their recommendation was 15W40 diesel engine oil, WTF!!!!
4) I bypassed oil cooler - zero change
5) Pressure drop across oil cooler plumbing was found to be 10 psig. Very interesting when I put oil cooler put back in circuit pressure drop did not increase across oil plumging and cooler circuit (standard Superformance set up)

As it stands know through exhaustive efforts I did some oil testing. Initially had Mobil 1 10W40. Went to Brad Penn 50WT. Oil pressure was 62 psig at 4K rpm and 58 psig at 6 Krpm (used to be 58 psig at 4 krpm and 52 psig at 6k rpms with previous oil). Got bored and tried Brad Penn 20W50 for cold start-up protection and oil pressure stayed at 62 psig at 4k rpm and 58 psig at 6 Krpm at 100C. I know the 50WT is a better lubricating oil blah blah blah but I wanted to minimize wear on start-up even though I am in Texas and the car rarely sees sub 60F temps since I start it in the garage.

In the end I honestly feel there is a venture effect somewhere on the block tap for the gauge or as noted earlier in the thread there is Teflon floating around in there as I dug a bunch out of the pressure gauge port. earler The engine internals are immaculate with zero wear, zero oil consumption, zero noises etc. I have run the living sheet out of this engine call it BFI testing (brute force and ignorance) if there was an engine issue it would have gotten worse.


I don't think anyone has an issue with 58 psig oil pressure at 6 k rpm and that is how the story will end. I seriously doubt the cause will ever be determined. Proof is in the pudding, engine has lived for over 5K miles with original owner and he only had oil pressure of 42 psig at 6 krpm!!! As Keith and others have said doesn't really sound like a problem!!

Got my motor mounts installed from Oltoff, they are a work of art!!! Polished my wheels over 8 hours, they glow like a mirror, next time I will contract that out as my finger nails are still growing back, LOL!!! I out did myself on those. Original owner never touched them in 5 years!!! It is nice to start and finish something.

Probably pull side pipes and headers off and get new ceramic coating. Once that is done the car will show as brand spanking new, just like I like them!!! I also picked up a Mota Lita wooden steering wheel. In my opinion it really dresses up the interior!!!!! If the car is ever tracked the leather steering wheel can be reinstalled.

Thanks to everyone who provide input!!!!!! I have learned more about oil, lubrication, bearing clearances, gauges, viscosity, oil pumps, oil filters, than I ever thought possible!!!!!! If for some reason I remember to ask God when I see him as to what caused this fluctuation I will post here as he is the only one IMHO that would know!!!

[madmaxx]

Problem solved!!!!!!!!!!!!

Executive summary - ordered new pump from Precision oil pump with high pressure spring and installed (recommendation from poster on this thread). New data as follows with brad penn 20W50 oil at 100C. 60 psig at 2krpm, 63psig at 3krpm, 65psig at 4K rpm, 67psig from 4Krpm to 6k rpm!!!!!!! no pressure drop. Appears the original POS Mellon fuking oil pump piece of sheet has an issue, probably sloppy clearances. In addition oil cooler, oil lines all plumbed and original OEM sizes!!!!! Oh by the way my gauge reads 3 psig low so add 3 psig to the above!!. Looks like I need lighter oil and back off the adjustment screw on the rv. The EPA has to love me with all the oil I spill, LOL!!! Reviewing my dyno sheet this engine had only 57 psig at 6Krpm on the stand where my last one had 68 psig. On the stand there is no oil cooler etc, that always seamed strange to me also leading me to believe the pump was weak or it had big bearing clearances.

Additional details. I called precision based on the recommendation on this thread. very knowlegdable, yet neither them nor Mellon would supply me a basic pump curve detailing flow vs rpm, how the fuk they stay in business. I told precision send me a new pump with high pressure spring. I had told him Mellon idiots had sent me a high pressure spring. He suggested to reuse mine and save $10.00 wtf. I said no way send new pump with high pressure spring installed and ship original spring loose. He did, what a miracle somebody doing what they are told. $180 later it arrives and I pull mine off. I decided to check his high pressure spring against Mellons. The first thing I notice is Mellons is 1/4" shorter!!!! I compare his spring length to his loose one in the box and my original I removed to install mellons high pressure spring and they are all the same length!!!!!!!!!!!! Fking Mellonidiots sent me a spring that I would have to bottom the rv adjustment just to get to what Precision spring is with the screw flush. I probably don't even need the high pressure spring. By the way cold at idle is 75 psig, LOL!! remember I have a 15 psig pressure drop across oil cooler. So the pump is discharging 90 psig at the pump outlet. RV Spring about 1/2 way in.

When I got the car it was 50 psig at 3Krpm dropping to 42 psig at 6k rpm. Kinda blows the theory about 10 psig per 1k rpm needed as this engine is perfect inside and I am confident it was that way for 5k miles!!!

I know a lot of profanity above but I deserve it on this one.

Randall Thomas from SCOF helped me tremendously on this one. He said leave no stone unturned and whatever you do to change it the culprit. It has burned in my head for months.

Got the sidepipes and headers back. Look great but we all know they dented one so now they get to fix it, when does it end????

[madmaxx]

Hey guys, reviewed my findings with some local engine builders who helped me in the past to reciprocate info and I called Precision to thank them. The consensus of the group was not to touch anything. They loved the 67 psig at 6K rpm. Precision said the 351W oil pump shaft is much heavier than the 302 and it is not a problem even when cold.

By the way my hot idle increased at 800 rpm from 27 psig to 41 psig!!!!! at 1100 rpm it is 55 psig.

I called Mellon and told them the story. Told them to send me a prepaid shipping lable and I will return the pump and springs so they can find the error in their ways. Told them I dont want money, credit or anything. Just learn from their findings so as to avoid somebody else having an issue. I told them it would be good in a 1975 Ford LTD but not a high performance street engine, LOL.

I hope Randall doesnt see my post on oil pressure above or he will loose it. More is not always better, I do learn but not very fast.

[Ace23]

Good lord this whole thread makes my brain bleed. I don't know if I want a cobra or a good dependable Miata! In all seriousness congratulations on bringing some type of closure to this where you can sleep at night. I know I would not have dug into this like you. I would have probably kept driving it an not known a problem existed until the motor went to the grave.

[madmaxx]

In the end I went with Brad Penn 15W40. Oil pressure hits 61 psig at 6k rpm. The oil pressure is a site of beauty. Max cold oil pressure 66 psig. I sent old pump to Mellon and their response was "its our fault we sent the wrong spring" I said what about the pumping inefficiency and they said it met spec, I said your spec is wrong. Never will I buy from Mellon again.......


I have a Miata with the power retractable roof, it is a mechanism of beauty. Love the car to death, cold AC, weather proof very loud on freeway at 80 mph regardless of top up or down. Big downside is zero power or torque!!! Great to run errands but not for just a drive vs cobra is great for a drive but not to run errands.

[sllib]

You know you can put a 5.0 Ford engine in a Miata...

[N2Cobras]

Originally Posted by Caprimaniac

As he said. Should be AN10 in oil system, someone told me....

Can you use the 90 deg filter adapter?

Also try removing the oil cooler to see if that helps, if larger lines do not so. You have a thermostat plumbed in?

Maybe oil pump "whipps" the oil like some water pumps do at high revs????

It doesn't seem like your pickup/ pan is a issue.
However; at higher speeds- more sucking- more vacum around the pickup and the pickup glue to the floor. There goes your lower pressure at higher revs.

After all your oil PSI looks OK even if it drops; doesn't seem too low.

Water pumps are a centrifugal pump, oil pumps are a positive displacement pump, totally different pumping concepts/how they react, sorta like a turbine vs. an internal combustion engine. PD pumps won't "whipps" the oil unless they suck in air with the oil. (I'm reading all the old SBF posting and this looks like something that needs to be corrected for future searching referencing, feel free to ignore this if you already knew pump engineering.)