Could use some Professional help

[63SW]

I have a 406 sbc that carries 618hp dyno'd.

I have a oil pressure problem ... ITS GOING AWAY

Used to hold 60-80psi and now at cold start up it around 40 and with each pass , getting lower ....
At 180deg its at 15-20psi .



It does come up to 40psi when on the gas but this makes me very nervous.

OIL IS CLEAN and Full !

The car is a 72 camaro weighing in at around 3600Lbs.
the engine is a 406 , 6in rods internally balanced, has Worked iron eagle heads and Brodix intake with a 1050 Dom.
400Turbo / manual.
Ford 9" 4.30 gears.


Im not a engine Guru so need the best possible advise available.

Thanks

[myclone]

Since you said youre not an engine guru I would assume that a shop built this engine? If yes then by all means contact them before tearing into it yourself as Ive seen quite a few guys get an expensive lesson in "you took it apart so its gonna cost ya to fix it/put it back togeather".

However, if your situation dictates that diagnosing/fixing the issue will be up to you then the first place I would look is the filter. You said the oil was clean but it takes a sharp/experienced eye to spot bad stuff in the oil unless theres been a catastrophic failure of a rotating component(s) so cut a filter apart, remove the media, and look it over for material if you havent already.

If you dont find anything in the filter my guess is that one of the pressure bypasses in the oiling system has failed or there is debri stuck in the bypass causing it to dump off oil pressure. I dont have enough details on your specific application but its not unheard of for the bypass in the pump on a SBC to break the pressure spring which dumps the oil pressure. Yes, its rare but does happen as well as a piece of debri that could have been disloged from one of the block passages possibly fouling the bypass valve open or partially open.

Depending on your specific set up it may be the stock bypass where the filter screws on which can also fail in the manor I spoke about in the previous paragraph. Actually this one is the first one I would check if you have already inspected the oil filter since its located under the oil filter and is easily checked.

Lastly would be the oil galley plugs that are installed when the passages are drilled at the factory. Most builders "stake" these in place or replace them with threaded pipe plugs to keep the pressure from pushing them out but these get overlooked at times in a busy shop. A leaking or pushed out oil galley plug will kill oil pressure but unfortunately it requires the engine to be torn down to inspect them (see the warning in the first paragraph).

Other than any/all the above or a failed component like a lifter the only other thing is bearing clearance. Scuffed bearings will show up in the filter so cutting the filter apart will tell the story there. Also, if youve detonated the motor or the oiling system has gulped some air due to g loading/high RPM with too low oil level then which has scuffed any bearings that material will be found inside the filter.

HTH

[63SW]

Thats the kind of quality info i was looking for !!!

THANKS .

I cut the filter apart as directed ( at the engine shop) and had the owner look it over.
Everything looked good , No sign of failure!!!!

didnt notice any other issues . No noises in the engine so on.

Did a oil change with ZR1 20/50 racing and new Filter as directed by the engine shop to see if it changed anything ... IF NOT , then teardown would be the next step.

To my relief , it did change , and i am now back to 70lbs oil pressure with no drop.
Just like it should be and was befor...
Evidently , the oil had broken down and was possibly a little thin by fuel when i had a NOS fuel cylinoid that stuck open and washed out.

ALL IS WELL and THANKS for giving me some good advice and a place to start.

Jeff

[myclone]

Just like it should be and was befor...
Evidently , the oil had broken down and was possibly a little thin by fuel when i had a NOS fuel cylinoid that stuck open and washed out.

ALL IS WELL and THANKS for giving me some good advice and a place to start.

Jeff

Welp, I didnt know about the stuck solenoid but that, obviously, could have been your problem.

Glad everything worked out for the good with just an oil/filter change.

[gen3bu]

i lost an engine due to debris in the oil psi relief valve in the oil pump on a sbc. it sucked, i only had 1500 miles on it.

[63SW]

Thanks again Myclone .
i havent had the car out for a while due to a loose trany ( thanks to my girlfriend last time she ran the car and didnt shift) But i put a new trans in it a few days ago and noticed the oil pressure at that time.
I had forgotten about the excess fuel problem.

I know the more info , the easier to give advise but HEY , YOU HELP ME so im happy!

That really sucks Gen3bu , its costly thats for sure.

[Lowend]

Simple question
What are you using for a oilpan&pickup? did you tack the pickup to the pump?

I have seen some very goofy oil pressure readings when the pickup falls off the pump

[63SW]

Its a Milodon 7qt pan and yep , the pick-up is tacked.
Thanks for asking Lowend .
You still a regular on Mad Mikes ?
I pop in now and then but lurk around in here and Racingjunk mostly.
OH BTW , this is hugger1 from 2GCOG