460 Ford Forum banner
1 - 11 of 11 Posts

·
Registered
Joined
·
2 Posts
Discussion Starter · #1 ·
Good morning ! Thanks for letting me join!

I have some odd oil pressure issues that has me scratching my head and quickly running out of ideas.... so seeing if anyone else has run into something similar.

The issue is intermittent and occurs at all oil temps and rpm's but seams to occur mostly after I will get on the gas and bring the rpm's up then return to normal whenever it feel like even after sitting over night. and the oil pressure change is quick not a slow fall or gain back to normal pressure. Also I am running rotella 15w-40 and wix racing oil filters.

first about the motor:
It started life and a ford racing technology 514 crate engine, I had the motor rebuilt by Pettis performance a very reputable machine shop and it is now a 528 cu in custom ross pistons 10.48:1/ford motorsport windage tray, crank scraper & screen with the ford motorsport 6 qt pan and pickup and a melling m84dhv oil pump /rebuilt cobra jet heads with tool steel retainers and locks/ cam in a custom hydraulic roller grind from comp cams 248/258 @ .050 .664/.672 lift 107 LSA, with comp magnum 8934 hydraulic lifters/ ford motorsport single plane intake/ 1050 gen III demon. It made 641 hp and 669 ftlb and I am not spinning it over 6000 RPM. (we figured out on the dyno that the motor likes an extra 1.5 qts of oil in the pan with no loss of hp and better maintaining oil pressure)

I will list this out in chronological order to the best of my memory...

Motor was dyno tuned at Westech performance October 2020 by Steve Brule who broke in and tuned the motor, no issues with oil pressure and changed the oil and cut open the filter with no bearing or suspect material in the filter. The motor would make 45-50 psi at hot idle(dyno idle was set to 1500-1800 rpm and water temp at 120) and 75-80 psi max hot.

I finished the truck october 2021 and started driving around on the road and the oil pressure 20-25 psi hot idle (900-1000 rpm idle and 170 water temp) but will climb to 45-50 psi around 1500-1800 rpm and same 75-80 psi max psi with rpm. and it was like this for the first 30 miles as i was driving it around easy

I had about 30 miles on the truck and getting things dialed in and was driving around that evening making a few stop and on my way home the oil pressure dropped to 10 psi at idle and 18 psi at 2000 rpm (no engine or lifter noise) and limped the truck home about a mile. parked the truck for the evening

Next morning I drained the oil ( no bearing material) and cut open the filter again no bearing material in the filter, replaced oil and filter. INSTALLED A MECHANICAL GUAGE Removed the distributor and spun the oil pump with a drill and had 80 psi cold oil (normal 80-85 psi when cold idle and 2k rpm) reinstalled distributer. drove the truck about 3 miles gently getting it up to temp with no problems, turned onto the main road and got on the gas a bit probably 3/4 throttle for 3-5 seconds and the oil pressure Quickly fell to the 20 ish psi again at 2k rpm and 10 psi at idle. was about a 1/4 mile from my house at this point so limped it home again when I pulled into my driveway the oil pressure shot back up to 45-50 psi. shut the truck down and started it again with normal oil pressure...... about an hour later I Decided to drive down to get my plates about 10 miles away again oil pressure was normal the whole trip until I pulled into the parking lot and the oil pressure dropped to 10 psi idle and 20ish at 2k rpm. it took me about 2 hours to get my plates and I came back out and started the truck with low oil pressure again was driving out of the parking lot and about 1/4 later the oil pressure shot back up to normal range again and was fine most of the way home until I got on the gas again and the oil pressure fell and I got it home and parked the truck.

At this point I am suspecting the oil relief valve on the pump was sticking open and decided to drop the pan and replace the pump.

Dropped the pan and replaced the pump with another melling m84dhv high volume pump and new gaskets. inspected the oil pickup and it looked fine so did the gaskets on the intake and output of the pump, double checked the pickup to pan clearance and it is right around .5 of an inch. Put everything back together and spun the oil pump with a drill again and for the first few seconds it only made about 20 psi (cold) of oil pressure I left off the trigger and hit it again and it jumped up to 80 psi. dropped the distributor in and took it for a drive gentle for a few miles to get it up to temp and got on the gas and oil pressure dropped to 10psi idle and 20 psi 2k rpm again. frustrated at this point I parked the truck for a few days.

Came back out 3 days later I installed the electric guage at the back of the cam and the mechanical gauge at the front of the motor right by the pump output and I fired the truck up and the pressure was still low shut it down and restarted it a few time and gave it a little rpm and the oil pressure jumped back up to 80 psi cold. (also never see more than a 7-8 psi split between the 2 gauges so the bearing clearances are good)

At this point I figured it had to be sucking air or foaming the oil, so I over filled the pan by about 4 qts for around 10 qts in the pan(i know this is high but was only a few miles but i wanted to make sure that the pick up and the oil pump were completely submerged in oil just incase it was sucking air somewhere) ran some parts back to napa and again oil pressure looked great even a few psi higher that what I had been seeing until just before I made my turn while coasting and the oil pressure fell to 10 psi again. Went inside was in there for about 30 min came back out and fired up the truck I had 10 psi again, I removed the line on the back of the pressure guage and started the truck drained the oil into a clear water bottle in the parking lot to see if it was foamed or had air in it and it did not (oil was clear). started the truck again gave it some rpm and it oil pressure came back up to normal started driving home again got on the gas and got the rpms up and did a pull (not full rpm or throttle) and the oil pressure fell again to 10 psi and 20 psi @ 2k rpm so i got the truck home and again parked it.

Was thinking hard what changed between the dyno and now and figured the only difference with the motor was the remote oil filter kit so I decided to remove it and put the filter directly on the block

last night I drained the over filled oil, removed the remote oil filter kit (hamburgers billet unit not cheap stuff) and changed the oil and oil filter again and installed it directly on the block. started it up and it had low pressure for about 30 seconds again then the pressure climbed back up to 80 psi cold. took the truck out again for a few miles to get it up to temp get on the gas and again fell to 10 psi idle 20 psi at 2k rpm. get the truck home and park it again let it sit for 2 hrs while I open a bottle of whisky to quell my rage lol. go back out to the garage to get a few videos of it the motor has cooled down but is still warm. The engine started about 10 times with the same low oil pressure condition and I was varying the rpm till about 2 k rpm and the oil pressure came back up to 50 psi at idle, I shut it down and started it again and it was back at 50 psi again.... went inside and continued on the bottle of whisky lol. and that is where I am currently at. :poop:

So I am feeling fairly confident I do not have an oil pick up problem (with air or the pickup being too close to the pan), The pump is fine because I have had 2 of the same pumps with the exact same issue, The bearing of the motor are in good shape(for now), and that it is not the remote oil filter causing the issue.

if you made it this far reading all that your a saint ....

For the love of god someone does anyone have any idea going on with my oil pressure
 

·
Registered
Joined
·
446 Posts
Cam bearings dumping oil PSI. Many moons ago I pulled my 429CJ and replaced the cam with a solid Crower one. When I pulled the Ford one the cam bearings, with 50k on them, wear shot. Put new ones in and picked up 10 PSI at hot idle.
Cam bearings would be my guess.
 

·
Registered
Joined
·
2 Posts
Discussion Starter · #3 ·
Cam bearings dumping oil PSI. Many moons ago I pulled my 429CJ and replaced the cam with a solid Crower one. When I pulled the Ford one the cam bearings, with 50k on them, wear shot. Put new ones in and picked up 10 PSI at hot
Cam bearings dumping oil PSI. Many moons ago I pulled my 429CJ and replaced the cam with a solid Crower one. When I pulled the Ford one the cam bearings, with 50k on them, wear shot. Put new ones in and picked up 10 PSI at hot idle.
Cam bearings would be my guess.
Well figured it out last night… lifter body failed by cracking in half and must of been opening up the galley weird it was so intermittent
 

·
Premium Member
Joined
·
9,536 Posts
Well figured it out last night… lifter body failed by cracking in half and must of been opening up the galley weird it was so intermittent

That is really good information.

Thanxx for sharing.
 

·
Registered
Joined
·
446 Posts
Well figured it out last night… lifter body failed by cracking in half and must of been opening up the galley weird it was so intermittent
Sometimes you just never know what you might find. I once broke a pushrod and it popped the lifter out. That was fun getting it back without pulling the intake. Built myself this for using a hyd or mech cam. Figured if they can make them for Generic Motors and SBM I can to.
 

Attachments

·
Registered
Joined
·
317 Posts
Sometimes you just never know what you might find. I once broke a pushrod and it popped the lifter out. That was fun getting it back without pulling the intake. Built myself this for using a hyd or mech cam. Figured if they can make them for Generic Motors and SBM I can to.

How is it attached to block?
 

·
Registered
1990 Ford Mustang LX 351M powered!! Project Cherry Bomb!!
Joined
·
313 Posts
@dacofa My friend, you may have something there that you could slap a patent on!! Hell, I'd buy one off of you when I get to that point in my build!!
 

·
Registered
Joined
·
446 Posts
@dacofa My friend, you may have something there that you could slap a patent on!! Hell, I'd buy one off of you when I get to that point in my build!!
I might have another on the shelf. It only works with solid/hyd cams. All I've ever used. Give me a few days. I also made them for a 302 and 351W I built up. I actually sent, to Milidon, a copy and pictures of the first one I made back in 1994 for a 460 I built for my Zephyr. I guess being a non-Chevy they didn't care. So I used theirs for an idea to do it. Wife and I are getting ready to go hunt Buckasorise
Musical instrument String instrument accessory Guitar accessory Human body String instrument
 

Attachments

·
Registered
Joined
·
80 Posts
What a pain in the ***. I would have probably swapped the pump again, thinking I had two in a row with the same defect in the pressure relief valve. Kudos for figuring it out.
 
1 - 11 of 11 Posts
Top