Oil pressure issue.
#1
Fighting Global Cooling
Thread Starter
iTrader: (6)
Join Date: Mar 2009
Location: Minneapolis, Minnesota
Posts: 983
Likes: 0
Received 0 Likes
on
0 Posts
Oil pressure issue.
Does anyone have any ideas what would cause a motor to start fine and maintain normal oil pressure (30ish at idle, 60ish at 3k rpm) but as the motor warms up, the oil pressure dies off till theres nothing left. Im at a loss of what could cause this and if anyone has any idea, i would greatly appreciate it.
I should also mention that this is a 12a (freshly rebuilt) that developed a dowel pin oil leak between the rear plate and rear housing.
I should also mention that this is a 12a (freshly rebuilt) that developed a dowel pin oil leak between the rear plate and rear housing.
#4
80's car lover
Join Date: Jul 2008
Location: Lemont, IL
Posts: 145
Likes: 0
Received 0 Likes
on
0 Posts
debris getting sucked into the oil pickup screen until it blocks it off and looses pressure. I have seen this happen mainly on higher mileage engines or engines that werent properly cleaned out before assembly.
#5
I have a rotary addiction
iTrader: (18)
Could be the connection at the sender. Clean the prongs off and see if it helps. My FC would have erratic OP readings and I found out that there was oil all over the connector. I guess the last time I changed the oil the filter dribbled oil onto it and it got baked on and gummed it up.
You could buy an RB adapter plate and Autometer gauge and sender for roughly $130 or even cheaper used. It will be far more accurate then the simulated factory gauge.
You could buy an RB adapter plate and Autometer gauge and sender for roughly $130 or even cheaper used. It will be far more accurate then the simulated factory gauge.
#6
Fighting Global Cooling
Thread Starter
iTrader: (6)
Join Date: Mar 2009
Location: Minneapolis, Minnesota
Posts: 983
Likes: 0
Received 0 Likes
on
0 Posts
I use 20w50 oil in it. Could this have anything to do with the oil control rings? I put new rubber inserts in the outer rings but not the inner rings because i could not get them to seat properly with the new seals. Should the inner ring be loose in its slot? They actually fall out when i move the rotors around on my work bench.
Trending Topics
#8
Fighting Global Cooling
Thread Starter
iTrader: (6)
Join Date: Mar 2009
Location: Minneapolis, Minnesota
Posts: 983
Likes: 0
Received 0 Likes
on
0 Posts
Yeah its brand new oil with my rebuilt motor. First rebuild resulted in me putting in my apex seal springs upside down cause im an idiot, second resulted in this oil issue and a dowel pin oil leak thanks to a popped dowel pin o ring.
#9
1st-Class Engine Janitor
iTrader: (15)
Oil rings are supposed to fit snugly in their bores... whether or not your problem originates here, I don't know, but assembled properly they need to be carefully pressed into the groove (usually using the old ring to press them in) to avoid pinching the rubber. Once in, they shouldn't just fall out.
Least, that's how I remember them behaving each time I've built an engine.
Least, that's how I remember them behaving each time I've built an engine.
#10
Fighting Global Cooling
Thread Starter
iTrader: (6)
Join Date: Mar 2009
Location: Minneapolis, Minnesota
Posts: 983
Likes: 0
Received 0 Likes
on
0 Posts
Yeah thats kind of what i figured. Also, do you think that my problem could have been a blockage in the dowel pin line? I may have over hylomared the o ring and cause it to block around the outside of the dowel pin. I know the holes in the dowel pins were open however
#11
Moderator
iTrader: (3)
Join Date: Mar 2001
Location: https://www2.mazda.com/en/100th/
Posts: 30,844
Received 2,606 Likes
on
1,849 Posts
1st step would be to put a mechanical gauge on it.
#12
Fighting Global Cooling
Thread Starter
iTrader: (6)
Join Date: Mar 2009
Location: Minneapolis, Minnesota
Posts: 983
Likes: 0
Received 0 Likes
on
0 Posts
Ok I get the idea that the stock gauge isnt strictly accurate. Mine has always been correct-ish however. I know for a fact that the oil pressure dropped off as the gauge showed thanks to some burning on my housings that was luckily repairable
#14
Fighting Global Cooling
Thread Starter
iTrader: (6)
Join Date: Mar 2009
Location: Minneapolis, Minnesota
Posts: 983
Likes: 0
Received 0 Likes
on
0 Posts
Stupidly the low oil level appears to be the most plausible thing at this point. I filled it to the full line but i never bothered to check it after the car lost pressure, also because im an idiot. Is it plausible that it would drop below the pickup tube after the oil is sucked into everything in the rebuilt motor?
#17
1st-Class Engine Janitor
iTrader: (15)
Stupidly the low oil level appears to be the most plausible thing at this point. I filled it to the full line but i never bothered to check it after the car lost pressure, also because im an idiot. Is it plausible that it would drop below the pickup tube after the oil is sucked into everything in the rebuilt motor?
Easy enough to check it; just do a proper oil-level check now that everything's together. Warm the motor to normal temp, shut down, let sit for a few minutes, and check level. Should be on the checkered part of the dipstick.
It's also possible that you've got a leak in your oil pickup tube that's sucking air as RPM increases and oil gets warmer. This is most likely around the connection point of the pickup; gasket didn't seat, got left off, or attachment screws weren't torqued properly and got loose, fell out, or cracked off.
#19
Moderator
iTrader: (3)
Join Date: Mar 2001
Location: https://www2.mazda.com/en/100th/
Posts: 30,844
Received 2,606 Likes
on
1,849 Posts
since its apart NOW is the time to get the book out, and take some extra time and measure/spec everything out, it does make a difference....
couple little teeny things, put a little dab of silicon on the oil pump to engine flange.
couple little teeny things, put a little dab of silicon on the oil pump to engine flange.
#20
Fighting Global Cooling
Thread Starter
iTrader: (6)
Join Date: Mar 2009
Location: Minneapolis, Minnesota
Posts: 983
Likes: 0
Received 0 Likes
on
0 Posts
Everything is to spec as far as i can tell from the three times i pulled the engine out so far this summer =(. Im going to double check the oil pump again though just to be safe
#21
Old Fart Young at Heart
iTrader: (6)
If the oil pump is even close to failing specs, replace it with an SE pump. Same goes for the oil pump chain. Then look into bumping up the pressure by modding the rear oil pressure regulator. You are the first member I've heard of that had a rear dowel pin o-ring failure. Aren't you special, lol. Good luck on the re-assembly.
As a side note, check all the main bearings for any new wear along with the e-shaft. If the o-ring is still in place and shows no sign of damage, you may wish to have the rear iron magnafluxed and the rear housing dyed to check for cracks. Lastly, make sure the o-ring between the front iron and front cover is in place and that the thermostat in the FMOC is opening at temp and installed correctly, it you have an FMOC.
As a side note, check all the main bearings for any new wear along with the e-shaft. If the o-ring is still in place and shows no sign of damage, you may wish to have the rear iron magnafluxed and the rear housing dyed to check for cracks. Lastly, make sure the o-ring between the front iron and front cover is in place and that the thermostat in the FMOC is opening at temp and installed correctly, it you have an FMOC.
#22
Round and Round
iTrader: (10)
I use 20w50 oil in it. Could this have anything to do with the oil control rings? I put new rubber inserts in the outer rings but not the inner rings because i could not get them to seat properly with the new seals. Should the inner ring be loose in its slot? They actually fall out when i move the rotors around on my work bench.
#23
Fighting Global Cooling
Thread Starter
iTrader: (6)
Join Date: Mar 2009
Location: Minneapolis, Minnesota
Posts: 983
Likes: 0
Received 0 Likes
on
0 Posts
Well my gasket kit, viton oil ring inserts, and video came from atkins today. I think I alone am keeping them in business this summer =P. Time to get things right.
The dowel pin leak was caused by a broken seal. Somehow my brand new dowel pin o-ring snapped and obviously leaked. Sucked too cause i took special care to hylomar them to prevent it from leaking lol.
I still cant figure this thing out. After the first rebuild, the oil pressure was regular. After the second, where i got the apex seals to seat properly, it dies off as the engine runs, what gives?! I blame the oil control rings not seating properly. Sound true?
The dowel pin leak was caused by a broken seal. Somehow my brand new dowel pin o-ring snapped and obviously leaked. Sucked too cause i took special care to hylomar them to prevent it from leaking lol.
I still cant figure this thing out. After the first rebuild, the oil pressure was regular. After the second, where i got the apex seals to seat properly, it dies off as the engine runs, what gives?! I blame the oil control rings not seating properly. Sound true?
#24
Fighting Global Cooling
Thread Starter
iTrader: (6)
Join Date: Mar 2009
Location: Minneapolis, Minnesota
Posts: 983
Likes: 0
Received 0 Likes
on
0 Posts
So its doing the same thing after my third time rebuilding the motor. All seals were good, replaced all the gaskets and the oil ring viton inserts.
Starts fine cold, shows oil pressure, then after a couple minutes, it dies off. What the hell. I need help. Now. I go back to school in 3 weeks and I havent driven the car since may so I'd like to get it going again...
Starts fine cold, shows oil pressure, then after a couple minutes, it dies off. What the hell. I need help. Now. I go back to school in 3 weeks and I havent driven the car since may so I'd like to get it going again...
#25
Moderator
iTrader: (3)
Join Date: Mar 2001
Location: https://www2.mazda.com/en/100th/
Posts: 30,844
Received 2,606 Likes
on
1,849 Posts
So its doing the same thing after my third time rebuilding the motor. All seals were good, replaced all the gaskets and the oil ring viton inserts.
Starts fine cold, shows oil pressure, then after a couple minutes, it dies off. What the hell. I need help. Now. I go back to school in 3 weeks and I havent driven the car since may so I'd like to get it going again...
Starts fine cold, shows oil pressure, then after a couple minutes, it dies off. What the hell. I need help. Now. I go back to school in 3 weeks and I havent driven the car since may so I'd like to get it going again...