Oil pressure drop under load and right hand turn 351C - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars
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post #1 of 26 (permalink) Old 10-25-04, 08:56 PM Thread Starter
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Oil pressure drop under load and right hand turn 351C

Guys, I hope some brainstoriming on this one will help...

1. 2 wiped lobes on previous hyd cam, both lifters in bad condition, bores OK.
2. ran in new cam/lifters with over 50psi - no problems.
3. changed oil and oil filter with filtermag - 20W50
4. re-adjusted valve lash per cam spec Comp Cams 270S.
5. Idiot proof mechanical oil pressure gauge - Autometer.

Oil pressures stationary and during test drive

-80psi cold idle
-35psi-40psi hot idle

I noticed, the pressure drops to 0 !! when turning right, regardless off engine speed!!, and then when you straighten up pressure returns to normal 40 - 80psi depending on engine speed. This does not happen when turning left ??

Also straight acceleration causes the pressure to drop to 0 for a few seconds and then jumps back up to normal regardless of engine speed ??

I had to drop the sump during the cam swap ... DO NOT ASK WHY! and noticed the pickup screen was bent, probably due to clearance issues with the sump/crossmember. I did not replace it as oil pressure was fine before the cam swap.

I have refrained from driving it until I fix this problem...

Any ideas?

Thanks

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post #2 of 26 (permalink) Old 10-25-04, 08:58 PM
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Re: Oil pressure drop under load and right hand turn 351C

low oil or your doing high rpm with a stock sump. The pickups on the left side of the sump.

[edit]If the oil pressures too high you'll also activate the relief valve. So pressure will drop but not to "0".

Brenden

XB Fairmont (street car) 11.07@123.02mph.
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post #3 of 26 (permalink) Old 10-25-04, 09:02 PM Thread Starter
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confused Re: Oil pressure drop under load and right hand turn 351C

Brenx,

5lt of oil with new filter and stock sump, i think should be OK??

still drops on right hand turns only regardless of low/high rpm...

Its got me spooked
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post #4 of 26 (permalink) Old 10-25-04, 09:08 PM
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Re: Oil pressure drop under load and right hand turn 351C

Should be fine. You stated it drops under straight line accel. You may also find that your oil pumps toast. So unfortunately you may need to remove the sump again. If it dropped when your doing a steady rpm and at ie 60->100kph? I'd be looking @ a pump replacement. It's too easy to loose an engine due to a oil pump failure.

I find it's easier and faster to remove the engine. More room = less mistakes.

Brenden

XB Fairmont (street car) 11.07@123.02mph.
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post #5 of 26 (permalink) Old 10-25-04, 09:26 PM Thread Starter
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Re: Oil pressure drop under load and right hand turn 351C

I've never replaced a pump/pickup/driveshaft...

Apart from raising engine to drop sump, is there anything else i need to know.

Tonez.
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post #6 of 26 (permalink) Old 10-25-04, 09:40 PM
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Re: Oil pressure drop under load and right hand turn 351C

Not really. Just make sure the guage isn't fautly and the oil line isn't kinked either before you remove the sump. Wouldn't be the first time an autometer gauge was faulty.

Brenden

XB Fairmont (street car) 11.07@123.02mph.
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post #7 of 26 (permalink) Old 10-25-04, 09:56 PM Thread Starter
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Re: Oil pressure drop under load and right hand turn 351C

I'll also try another gauge I have tonight...

thanks
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post #8 of 26 (permalink) Old 10-25-04, 10:31 PM
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Re: Oil pressure drop under load and right hand turn 351C

Standard sumps are borderline with a high volume/pressure oil pump. Mine used to do this only when it was low on oil.

Only sure remedy is to fit an aftermarket bigger capacity sump and get the pick-up straightened out.

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post #9 of 26 (permalink) Old 10-25-04, 11:41 PM
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Re: Oil pressure drop under load and right hand turn 351C

I had the same problem on my car.

Checked the gauges, tried different oil filters and oils and even drove around with a mechanical gauge sticking out of the shaker hole in the bonnet so that I could see the PSI reading.

It ended up being a stuffed Oil pump.

I replaced the pump with the engine still in the car............on a hoist.
It was easy enough to do. Engine mounts were undone and a screw pole was placed under the transmission housing and the whole assembly was lifted slightly to ensure clearance for the sump to slide out.

I replaced the old Hi Volume pump with a new Standard Volume unit and a Hi Energy anti cavitation pick up. This new pick up is smaller so the Hi Energy Sump I have slid on a lot easier.

I haven't had any issues since.........................but bloody hell did it take a while to diagnose the problem..........
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post #10 of 26 (permalink) Old 10-26-04, 12:42 AM
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Re: Oil pressure drop under load and right hand turn 351C

ESP, i am about to try and remove the sump with the motor in the XD. I am hoping i have a brand new "dud" oilpump. I have a 7 litre High Energy sump and was wondering how hard it is to remove while motor is still in. I was just going to live the with low oilpressure, but when hot and doing a bit over 100kmh, 2 different mechanical gauges start flickering from 50 to 40 and back to 50 and with a bit more pedal, it gets even more erratic. (I hope its the pump).

10.70 @ 125.00 on the black fun top
408 Cube Cleveland.
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