Cause for Low Oil Pressure?

[natallica]

Over the weekend I installed my new M28 head and new head gasket, while I was in there I cleaned everything and reinstalled all new gaskets from the HG, up, resurfaced all of the manifolds and properly set my cam timing and she's at 10 degrees BTDC and she started right up and idled relatively smooth (TPS still needs readjusted, I just ran out of time) I was amazed I got the timing procedure right the first time (thanks to SQC's and PQ's threads)

 

I noticed before everything went south (Belt snapped and she overheated, cracking the head too) that I had low oil pressure, upon initial start-ups it was about 3/4 on the factory gauge, and once warm, during idle, it's reads almost at the bottom of the gauge.

 

My 12A fried a while back and I found a sliver of the rear oil seal in the pan, with only a few tiny metal shavings from the previous cam/head situation.

 

My question is, what should I look into as far as isolating a low oil pressure scenario? Could it be a clogged pressure regulator (is that the one on the filter housing?) or could it be something internally wrong with the oil pump? I really wasn't looking forward to removing the timing cover at this point (took 3 days to tear down and re-install the head and everything is all back together) but I need to figure out why the gauge is reading low.... lifters still ticking too (after running for about 10 minutes) which leads me to believe that I'm not getting the pressure needed on the top end. New timing components were installed about 20k ago, but could this be attributed to the tensioner.

 

Specs, mostly stock, BSEK, JVEK.... 10W30 oil, STP filter (I was told to stay away from Fram and the DriveWorks filters looked generic and cheap so I didn't want to risk it )

 

I've searched the forums but wasn't successful at finding a solution for this particular issue.

 

Any help is appreciated! Thanks guys.

 

-N8

Edited May 6, 2013 by natallica

[Shelby]

your going to get 4 or 5 different ideas , on weight of oil to run but I hate to run 10-anything on a turbo engine

and that STP oil filter,, most of what they filter out is nuts and bolts,, quality of oil filter can effect the pressure your seeing on gauge,, and speaking of gauge,, temp install a real mechanical gauge and see what it says ,,back to the filter the better a filter is the more restriction it puts on the oil so the higher the running pressure can show up

 

also wasn't that M28 head the one that needed the oil passages enlarged before you could run hyd lifters

[Dad]

Mechanical gauge to verify hot pressure, the passage should be just fine, I would suspect bearings myself. Pumps don't just go bad, usually there is failures that put trash in the oil and the pump is the first thing that gets the debris, I have run STP filters on my white quest with no issues. I use that and wix filters.

 

Dad

[Caliber308]

Possible causes are in the 1987 Starion Factory Service Manual volume no.1. Section 9 Page12 Engine-Troubleshooting. The 1988 FSM can be downloaded from Starquestgarage.com. It is the same information.Maybe just a different page number.

 

Bill

Edited May 6, 2013 by Caliber308

[natallica]

your going to get 4 or 5 different ideas , on weight of oil to run but I hate to run 10-anything on a turbo engine

and that STP oil filter,, most of what they filter out is nuts and bolts,, quality of oil filter can effect the pressure your seeing on gauge,, and speaking of gauge,, temp install a real mechanical gauge and see what it says ,,back to the filter the better a filter is the more restriction it puts on the oil so the higher the running pressure can show up

 

also wasn't that M28 head the one that needed the oil passages enlarged before you could run hyd lifters

 

Thanks Shelby, I heard that running a thicker oil may assist with the low pressure issue, but I figured I'd stick with the recommended weight first to see if I had the same problem after the new head was installed.

Mechanical gauge to verify hot pressure, the passage should be just fine, I would suspect bearings myself. Pumps don't just go bad, usually there is failures that put trash in the oil and the pump is the first thing that gets the debris, I have run STP filters on my white quest with no issues. I use that and wix filters.

 

Dad

Thanks Randy, I was hoping the STP filters weren't the cause, good to know that YOU run them personally, so all should be good there. By bearing your referring to mains and/or rod bearings, is it possible to install new ones with the block and crank in the car (dropping the pan) or can this only be properly accomplished by pulling the motor...yet again?

Possible causes are in the 1987 Starion Factory Service Manual volume no.1. Section 9 Page12 Engine-Troubleshooting. The 1988 FSM can be downloaded from Starquestgarage.com. It is the same information.Maybe just a different page number.

 

Bill

 

...and here several years of being a member on the forums, I never thought to download those and narrowing my possibilities down to 40 or so causes.

Just kidding Bill, I know that's your first "go-to" for most issues for VM queries, but I'm looking for some practical advice based on my recent upgrades and problems. I refer to them quite often, but I was hoping with all of the info I provided there would be some more insight into a fix besides a trouble shooting chart and alot of tail chasing... no offense Sir, I appreciate your help.

 

-N8

Edited May 6, 2013 by natallica

[polarisman14]

I was able to replace all of the main and rod bearings besides the upper thrust bearing (center main cap). If you are careful and use an old bearing curved slightly and some finesse you can pop the old one out and "spin" it around the crank to get it out.

 

With the BSEK you should definitely have higher oil pressure than you have, mine is 3/4 on startup and 1/2 or more at idle when warm.

[Dad]

Mechanical gauge.. should be first thing to check with.

[ucw458]

How old is your oil? Contaminated oil will read low on the dash gauge.

[natallica]

Mechanical gauge.. should be first thing to check with.

Is there a detailed write-up on how to install and what thread adapters I need for this procedure. PQ's stuff has a lot of missing pics and such

How old is your oil? Contaminated oil will read low on the dash gauge.

It was a week old when the belt snapped and I just filled it up last night and started it...same issue as before.

[Caliber308]

I never thought to download those and narrowing my possibilities down to 40 or so causes.

 

-N8

 

There are only SEVEN possible reasons listed in the Engine-Troubleshooting section of the FSM for a oil pressure drop (Some have been listed here via responses) One, or more of them could be, or might be the reason for your problem.

 

If you do not wish to look them up, here they are:

 

Oil Pressure Drop:

 

Engine Oil level too low.

Oil Pressure switch faulty.

Oil filter clogged.

Oil pump gears or body worn.

Thin or diluted engine oil (Like in running too rich. i.e. Raw fuel entering the crankcase, then being re-cirulated (via the oil pump) into the entire oiling system.

Oil relief valve stuck opened.

Excessive bearing clearance.Because of crap (metal pieces) being distributed throughout the Oiling system.

 

40 or more possibilities?

 

Pull your Oil Dip stick. Does it smell like fuel? Oil level higher than normal?

 

Drain your oil. Does it have a lot of metal pieces in it?

 

Bill

Edited May 6, 2013 by Caliber308

[BuGG]

I might be wrong but I think the hole in the side of the block is 1/8 BSP which is straight thread. A 1/8 NPT adapter will only get 3 threads on. You can tap it out to 1/8-27 NPT or what size fitting you need. I dont think runninig a adapter is recommended for long term use. The plug is 5mm allen.

 

http://i1052.photobucket.com/albums/s450/buggsuperstar66/Pic2_zpsb4e30e0b.jpg

 

http://i1052.photobucket.com/albums/s450/buggsuperstar66/Pic1_zps27841e32.jpg

 

http://i1052.photobucket.com/albums/s450/buggsuperstar66/Pic3_zpsc17094ea.jpg

Edited May 6, 2013 by BuGG

[natallica]

Oil Pressure Drop:

 

Engine Oil level too low.

Brand spankin new oil change with new filter

Oil Pressure switch faulty.

Doubtful, lifters constantly tick, and the sender does read higher pressure upon initial startup

Oil filter clogged.

New

Oil pump gears or body worn.

Possibility

Thin or diluted engine oil (Like in running too rich. i.e. Raw fuel entering the crankcase, then being re-cirulated (via the oil pump) into the entire oiling system.

New 10W/30

Oil relief valve stuck opened.

Possibility

Excessive bearing clearance.Because of crap (metal pieces) being distributed throughout the Oiling system.

Possibility

 

40 or more possibilities?

 

Pull your Oil Dip stick. Does it smell like fuel? Oil level higher than normal?

Nope

 

Drain your oil. Does it have a lot of metal pieces in it?

Had a few (4-5 about 16th of inch in diameter) sparkly flat shiny pieces after dropping the pan (first time I've pulled the pan since the rebuild), but not enough to show excessive wear...unless it doesn't take much at all to cause the loss of pressure. May be looking into this though among the other possibilities.

 

Bill

 

Thanks Bill, I appreciate it.....any thoughts on what you think it could possibly be?

[AUSSIEOLDIE]

Mechanical gauge.. should be first thing to check with.

^^^ x 2 the electronic gauge is slow to respond .If the mechanical gauge checks out ok and the motor has been serviced correctly with quality oils & filters then it will almost certainly need a new sender.

Remember pressure is the oils resistance to flow and IMHO as a general rule 10/40 is fine as the lower number is to make/help the oil flow thru the motor easier/faster when cold start .The lower number has no bearing on how the high number performs at operating temps To put it in simple terms a 10/40 pours/behaves like a straight 10 grade oil when cold and like a straight 40 weight when hot .

[Shelby]

I found one that you will not find in the fsm's ,,a stuck pressure reg valve,, it was stuck wide open

due to trash and grit in the bore , took some doing to get it out and in the end I went with another oil pump ,, I have seen this happen to the chain tentioner also but stuck in not out

[Starfighterpilot]

Having 3/4 on your oil pressure guage running 10W30 oil is good oil pressure at stone cold engine idle RPM's. However as the your engine warms up, it's oil pressure drops, indicates to me, that the oil cooler or one of it's lines is clogged up causing insufficient flow to or through the oil cooler. Remember that the higher the oil temperature the less viscious (resistance to flow ie. reduced pressure) it becomes.

 

I would suggest that perhaps you pull the oil cooler and its lines, and the oil filter adapter housing and clean 'em.

 

It could also be that the oil bypass valve in the oil filter adapter assembly, which routes oil to the oil cooler depending on engine oil temperature, is heading to Starquest heaven and is stuck in the retracted position or not extending sufficiently to route adequate oil flow to the oil cooler - remember that oil will flow through the path of least resistance. That bypass valve is controlled by engine oil temperature - same way as the engine coolant thermostat which maintains engine coolant temperature. See the FSM picture of the oil system on page 9-4.

 

PQ did a write up about the engine oil bypass valve in i-x.net, which is buried in one of the Engine Topics, altho I think that the picture of it is missing. But he did note at what temperature the bypass valve fully extends and retracts which is still in the write up. You can pull it and test it the same way with warming up water in a pot on the stove, as you would to test the engine coolant thermostat.

 

For What It's Worth.

 

KEN

[natallica]

Thanks so much guys...digging back in to tear her down tomorrow!

 

-N8

[natallica]

Update, Pressure problem fixed:

I tapped the block as per instructed and installed an adapter and a brand new Sunpro (manual gauge) that I had laying in a bin of parts.

Upon initial start-up I had about 85lbs of pressure and once she warmed up I was averaging approx. 11-13lbs.

 

So, according to the FSM it's pretty darned good (curb idle speed approx 11.5 psi) Changed the oil and upped the weight a tad, While I was in there I re-torqued the head bolts to spec, and I had to drill out and helicoil one of the holes for the front cam bearing cap.

 

I still have a slight tick in one of the lifers though, somewhere near the rear of the head, I replaced the back 4 with newer ones, but that didn't seem to make it go completely away. Should I invest in a complete new set of lifters from Dad, or is there something else I need to look into?

 

Thanks for the info fellas, hoping to get her back on the road really soon.

 

-N8

[Shelby]

did you leave the mechanical gauge in the block,, and how much did the fresh oil change the readings

[Dad]

Pull your rocker shafts and thouroly clean them, watch your presssure I think 11psi at idle is bare min. ( mine is 25-30 lbs idle) 85 @ 65mph

 

Dad

[importwarrior]

well as far as lifter tick. might want to read this.

i had to modify mine on my car. seemed to fix my

lifter noise.

 

http://b2600turbo.com/Marnel%20Cap.htm

 

lots of great info on here.

 

http://b2600turbo.com/

Edited May 13, 2013 by importwarrior