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572 Oil Pressure

  
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572 Oil Pressure

 
Edward5 Edward5
I love my Chevy Chevette! | Posts: 4 | Joined: 04/13
Posted: 04/03/13
09:34 AM

The oil pressure in my 572R went to zero. I checked it with three gauges. When I start it the pressure goes to 20 psi very briefly and then zero. The engine sounds normal but I only run it for a short period. Does anyone know if this engine comes with a nylon bushing on the oil pump shaft? Any other ideas? This engine is in my race car and has been trouble free for three years.  

pepsi1 pepsi1
Big Block power for the win | Posts: 940 | Joined: 03/11
Posted: 04/03/13
12:53 PM

Do you know if your oil pump pick tube was tig welded, or brazed on. The pickup my have fallen off.

What you can do really quick is put an extra 1 or 2 quarts of oil in the pan. If the pressure comes up I'd say thats your problem.

That plastic piece for the pump shaft and oil pump is only there for assembly. When the engine is upside down the shaft won't fall out. Hope ots simple...

Bob  

waynep712222 waynep712222
V-6 Camaros rule! | Posts: 122 | Joined: 03/13
Posted: 04/03/13
08:12 PM

i agree with bob...

either the oil pump pickup has fallen off.. and when the oil gets sent up into the motor.. the oil level in the pan drops below the opening in the side of the pump.. so the pressure drops to zero..

i don't think that the plastic collar if it got used is broken as there would be NO oil pressure at all...

one additional thing that you will want to examine...

remove the engine oil filter...    carefully.. perhaps using an oil filter cutter .. cut it open and inspect the filter element.. there have been many engines destroyed by cold oil and high revs... where the oil pump pushes more oil than the bypass valve in the filter adaptor can flow.. this crushes the element..  can set pieces free into the oil galleys..

you have several options..

and they are..

as bob said. add 2 quarts above the full mark and start it.. you will know within seconds if your oil pressure is holding steady... if it drops shut it off...

if you pull the drain plug.... you can use some kind of device like a piece of NON COATED welding rod..  to fish around inside the pan to see if the oil pickup is still attached.. and that it's NOT TOO CLOSE to the bottom of the oil pan...

i have seen the bottom of the oil pan get crushed slightly by either IMPACTs with engine installation... floor jacks.. coming down off a wheel stand..  rough pavement or driveways and low ground clearance...

i have also seen the oil pressure drop.. because a beach towel got left under an intake manifold... that was on a 340 dodge.. that had roll pins to align the ends of the intake.. the after market manifold would not sit flat..   i pulled the studs for the car owner when i saw what was happening.. he was so excited that he forgot to remove the beach towel that was keeping the lifter valley free of dirt...  it wrapped around the crank and cam... when he went to drain the oil when the pressure went away.. there was beach towel end sticking out thru the drain hole..

i have seen vacuum sump crankcase venting systems..  pull up on the bottom of the oil pan.. pull the timing covers in until they are touching the timing chain..

a friend across the street has a honda that kept pulling the crank and cam seals in.. until i found him flanged versions and he glued them in with black super weatherstrip adhesive..  i pitty the poor sucker who it going to try to remove them if i can kinda quote mr T.

depending on the oil pump .. you could use one that has a flat drive that uses a plastic collar.. but the plastic collars are not designed for more than an stock volume oil pump.. the IS 55E with the steel collar fits a LOT of applications and an amazing number of parts stores keep them in stock even thou they don't know they do..  if this is a GMPP 572R.. its either going to have a hex drive oil pump or a steel collar... i don't know how they attach the pickup tube..

while you have the oil filter off.. but before you drain the engine oil... you might want to use your remote starter button directly on the starter... with the spark plugs out... so no compression will be pushing on the pistons... you might want to crank the engine from under the car while you watch with the oil filter off.. to see if you get a nice flow of oil...

if you have or can rent/borrow from the loan a tool section at many parts stores.. they have the chevy oil pump priming tool.. .  with a decent sized power drill you can run it for a minute.. before the drill overheats..  or spin it with a speed handle..  -----\__/-0    to see if the oil is really being pumped...

i don't have a diagram to look at the oil flow on that big block. there may be slight variations on what is normal..

there are also .. digital inspection cameras with tiny probe camera tips.. can slip into spark plug holes and thru the drain plug opening to see inside..  this one is almost 200 bucks from HF...

Image 19657


if the motor is under warrantee from GMPP... you will only be able to cut open the oil filter and do a camera inspection  .. don't remove the pan..  as that would be breaking the factory seal..  

chris206rice chris206rice
I love my Chevy Chevette! | Posts: 3 | Joined: 04/13
Posted: 04/03/13
09:18 PM

the pick up falling off is a very good possibility, but your all avoiding the very possible fact that he may have wiped a bearing. the bearing tolerances are what determine oil pressure. a cam bearing may have turned slightly blocking off an oiling hole. or the mains could just be worn out. you wont always hear a bad bearing. if you loose oil pressure and confirm that, drop the pan and see whats going on. you may do more damage constantly starting it to try this and that. my experience, no oil pressure = drop the pan and look. dont guess. do a visual and check tolerances. if you have had a trouble free race motor for 3 years, its long over due for maintenance and/or something breaking. most guys freshen up every season. also dont forget to check the spring in the oil pump that sets the pressure for the pump itself. they can fall out.  

waynep712222 waynep712222
V-6 Camaros rule! | Posts: 122 | Joined: 03/13
Posted: 04/04/13
05:38 PM

i looked thru the parts lists for the various 572 motors.. and could not see which oil pump and screen they used...


here is the BBC oiling diagram..

oil comes up from the pump into the rear main cap... makes a hard turn left and goes out to the filter housing area... from the filter either thru the bypass valve or the filter.. and into the main passage going back into the block...   the big blocks are slightly different than small blocks.. big blocks the passage goes upward toward the oil galley between the rear main and rear cam bearing...  but it seems that the first 4 mains and cam bearings are oiled by a side passage (visible in the rear view..just above the right side of the oil filter in the passage with the arrows pointing right.) ..  that is taken off the side of the passage heading upward toward the rear cam bore... (visible in the lower left image.. side view)

i still think that you should do a cranking test with the oil filter off.. verify the flow.. without the filter.. preferred with the spark plugs out..

eliminate the oil pump as an issue.. that motor may have the oil pressure relief valve pressed lightly into the block under the oil filter..  

i just don't have a 572 block laying around to pull some of the oil galley plugs out and stick some wooden dowels into for a photo ...

BBC Oiling Zps83f2d446

BBC Sideoilgalley Zps1ea35d93  

waynep712222 waynep712222
V-6 Camaros rule! | Posts: 122 | Joined: 03/13
Posted: 04/04/13
06:44 PM

does this look like the oil filter area of your block????

Bbc Geniv Oilbypassvalves Zps6a63a959

there are 2 oil pressure bypass valves... can you see them...    before going any farther..

stop by your local chevy or GM dealer.. and pick them up.  replace them..

i will look around and see if i can find a part number .. but it might require a call to GMPP...  

waynep712222 waynep712222
V-6 Camaros rule! | Posts: 122 | Joined: 03/13
Posted: 04/04/13
06:50 PM

man.. those oil bypass valves above look like they are STAKED in..  what do you guys think???
25013759Lg
Product #: 25013759
Price: $2.98
Parts #25013759
For high-performance and Bowtie Big-Blocks with 4-bolt main bearing caps. Must be installed in the rear hole behind the oil filter adapter bolt to route oil trough the cooler.

are both the oil pressure relief valves the same ?? i will research more..


plus... where are you measuring oil pressure at??
FYI..
"Chevy Big Block Oil Pump and Pick Up, 572 Engine"
19131250Lg

Parts #19131250
"For use with all 572-cubic-inch engines. Use with oil pan P/N 10240721, oil pan gasket P/N 10106407 and windage tray P/N 88962187."


3865886Lg
Parts #3865886
Heavy-duty all metal. Intermediate shaft fits all Big-Block engines  

waynep712222 waynep712222
V-6 Camaros rule! | Posts: 122 | Joined: 03/13
Posted: 04/06/13
11:44 PM

I had to go to work and won't be back in my shop for a couple of days. To answer your question about where the oil pressure gauge is connected, it is a 1/4" pipe thread hole on the driver's side in the front near the damper. Edward5

Read more: http://forums.superchevy.com/70/9405271/tech-talk/oil-flow-diagram/#ixzz2PkrzbYNM

a few things..

there is a oil galley plug out the front of the block... just in front of the oil pressure switch if its in the front as you describe...

remove the oil filter... remove the oil pressure relief valves... remove the oil sending unit...

use some compressed air to blow into the block where the sending unit was installed..  this should blow any debris backwards out of the galley...

you might want to take the plug out the side of the blond above the oil filter  if you can get past the header tubes.  if it does not blow out with just the filter off..  this also gives you a straight shot at the rear main passage.. not something you really want to push stuff into

this is the reason to own an oil filter cutter...

Filtercloggedmains  

pepsi1 pepsi1
Big Block power for the win | Posts: 940 | Joined: 03/11
Posted: 04/10/13
06:47 AM

Edward5
Sorry I've been very busy also. I don't know if you have found the problem.

1.If you can pull the oil pan. Pull the front main first, and #1 #2 rods. You will know if you have a problem for sure.

2.Or remove a valve cover.

3.Let the engine run and watch to see if the oil gets to the rocker arms in a short period of time.(If you don't have any engine noise). Let the engine run...

4.Sometime you can look inside a breather in the valve cover while the engine is running.

5.Or let the engine run and if you hear any noise it will be in the valve train first.

6.Whatever the reason you'll want to pull the engine and go threw it by now anyway. Just for a rebuild anyway.

7.Thats what I would do

8.I say this only because the damage is done anyway. Beit a bearing or nothing.
In my 45 years it will haunt you so you will want to pull it apart. I've seen the thrust bearing wear and cause low oil pressure. Especially if you have a manual trans, with a lot of pressure plate (Pressure).
 Try this: If you have a manual trans. Have the engine running, have a helper push the clutch in a few times as you watch the damper. If the thrust bearing is worn you will see the damper move with the movement of the clutch pedal, being pushed in. "Hope this all makes sense"....

Bob