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-   -   oil pressure on startup (https://www.miataturbo.net/engine-performance-56/oil-pressure-startup-93618/)

AlwaysBroken 06-16-2017 11:10 AM

oil pressure on startup
 
How long is normal to wait for oil pressure to come up? Is 2-3 seconds OK? Car makes normal pressure at all other times.

Setup is
-built engine, slightly oversize crank/main clearances
-boundary eng oil pump from 949
-oil cooler/thermostat/etc
-autometer oil gauge on long extension line (so the sender isn't bouncing up and down directly attached to the T for the turbo oil line
-5w40 T6, clutch disconnect, etc

My feeling is that the 5w40 stuff drains out of the engine real easy and I'm just repressurizing everything each startup. I just don't want to lose my new engine over something stupid.

Update for resolution: (props to m2cupcar below, he was 100 percent right on everything)
Symptom:
  • Couple of seconds of no oil pressure on startup every time
Cause of problem:
  • Did not put an OEM style paper gasket between the oil pickup and the oil pump when assembling engine
  • Used right stuff instead of a gasket and it did not seal properly. Right Stuff is great RTV, but not for this.
  • As a result, car sucks air for a couple seconds before it sucks oil
Solution:
  • Remove front subframe, pry off oil pan, remove pickup tube
  • Clean RTV off gasket surfaces, install 6 dollar paper gasket
  • Clean off oil pan and redo the RTV on it
  • Annoying part- reinstall subframe
  • Reconnect everything, enjoy full oil pressure as soon as the engine turns over.

Bronson M 06-16-2017 12:11 PM

I use the same oil, but on a stock bottom end. I installed an electronic sending unit and logs show oil pressure starts to rise as the motor comes off the starter and over 50 psi by two seconds after startup.

The oil filter should have a check"valve" built in to prevent the entire oil system from draining. You'll see a black or orange flapper through the holes in the top of the filter.

At this point I would guess it's a guage issue, air in the line might add a delay. If you have good pressure once it starts I wouldn't freak too bad.

m2cupcar 06-16-2017 12:49 PM

I have a very similar oiling setup (stock pump) and see full cold oil pressure (after sitting for a week) in about a second after the engine starts running (counting one one thousand two one thousand three one thousand). Did the builder install a gasket between the pickup flange and pump? I originally did not and had severely lagging oil pressure on cold start. Installed the gasket and it was fixed.


AlwaysBroken 06-16-2017 04:31 PM

Ugh, I honestly don't remember what I put there. I really hope I don't have to pull the entire engine out again.

m2cupcar 06-16-2017 05:52 PM

Maybe you can get a usb endoscope in there to look? Through the turbo oil drain?

AlwaysBroken 06-16-2017 11:02 PM

Ordered a borescope, mentally preparing myself for the inevitable suffering involved in dropping the oil pan and putting everything back together afterwards.

I really hope it's just something stupid like the gasket and not a stuck relief valve or something.

extremely delayed edit- I just realized the relief valve is directly exposed without taking off the oil pan, so I could actually disassemble it without removing the pump.

AlwaysBroken 06-20-2017 10:26 PM

Bore scope says I put a dab of some Right Stuff on the mating surface. Pic below from the turbo drain port. Maybe I missed a spot and air is getting in?

If I drop the subframe I can inspect the relief valve while I'm in there.

Does anyone think I'm going overboard and making a big deal about nothing? The oil pressure is rock solid at all times other than the first couple of seconds after startup.


https://cimg5.ibsrv.net/gimg/www.mia...351a995712.jpg

psyber_0ptix 06-21-2017 07:38 AM

Looks like it's siliconed on?

shuiend 06-21-2017 07:46 AM

I would pull the motor to pull the oil pan, long before I would consider dropping the subframe and pulling the oil pan.

m2cupcar 06-21-2017 08:28 AM

Nice job on the borescope image! fwiw- I used rtv on mine and there was none on the actual mating surfaces when I took it apart. It was all stuck around outside edges of both pieces. I googled and it's regularly stated not to use RTV on the pickup/pump flange. But it's a question of what you're ok with. I was concerned about it enough to do the job, knowing it's not how it should be. BUT I also wanted to add another shim to my oil pump AND modify part of my oil pan- three things requiring pan removal.

TurboTim 06-21-2017 08:39 AM

If the car has been sitting a while (weeks), crank it over until it builds pressure then start it. If this is happening after refilling the gas tank or whatever, there's oil still on the bearings and load is minimal, hydrodynamic effect will keep everything ok.

If you're really worried about it, there's trick accusump setups or aux electric oil primer pumps out there.

AlwaysBroken 06-21-2017 08:54 AM


Originally Posted by shuiend (Post 1423187)
I would pull the motor to pull the oil pan, long before I would consider dropping the subframe and pulling the oil pan.

If I was doing another rebuild, I'd pull it again without hesitation. But after messing with the steering rack and all that nonsense down there I feel confident I can get it all back together more easily than hoisting it all out. This way instead of removing all my plumbing and wiring I just put a block under the tranny housing while I yank the pan. I think I can do it in one easy weekend vs several. Plus I have the Firestone 12 month alignment so I can get everything checked out when I'm done.

shuiend 06-21-2017 09:44 AM


Originally Posted by AlwaysBroken (Post 1423199)
If I was doing another rebuild, I'd pull it again without hesitation. But after messing with the steering rack and all that nonsense down there I feel confident I can get it all back together more easily than hoisting it all out. This way instead of removing all my plumbing and wiring I just put a block under the tranny housing while I yank the pan. I think I can do it in one easy weekend vs several. Plus I have the Firestone 12 month alignment so I can get everything checked out when I'm done.

The problem I have with dropping the subframe, is that you still have to use something to hold up the engine. I would use my engine hoist, which then has the silly legs under the engine bay which gets in the way of pulling subframe and all. You also need to drop the trans I think to get the oil pan off. I think the stupid rear main seal adapter will be in the way with the trans still on. So to me it really does not make sense not to pull the engine. I also have done several dozen engine pulls, so I can usually get the engine out of a miata within a few hours.

Also is your firestone alignment not lifetime? I signed up for the lifetime one about 2.5 years ago. One of my good friends works at the local firestone and he will hit all my alignment specs perfectly. Firestone at least has not started checking vins, so I bring in all my miata's and get them aligned without anyone noticing or caring. I also tip my alignment guy with some cash so that also makes him happy.

m2cupcar 06-21-2017 11:00 AM

This worked well for me:
http://fe3miata.com/site/wp-content/...rigging-2p.jpg

I happened to have the lumber laying around being a long time home owner. I think both have pros/cons. The lift made the difference for me- but I also did not want to have to break all my fluid connections right before a road trip.


Originally Posted by shuiend (Post 1423211)
Also is your firestone alignment not lifetime? I signed up for the lifetime one about 2.5 years ago. One of my good friends works at the local firestone and he will hit all my alignment specs perfectly. Firestone at least has not started checking vins, so I bring in all my miata's and get them aligned without anyone noticing or caring. I also tip my alignment guy with some cash so that also makes him happy.

That's a pro tip right there. :bigtu:

codrus 06-21-2017 11:20 AM


Originally Posted by shuiend (Post 1423211)
The problem I have with dropping the subframe, is that you still have to use something to hold up the engine. I would use my engine hoist, which then has the silly legs under the engine bay which gets in the way of pulling subframe and all. You also need to drop the trans I think to get the oil pan off. I think the stupid rear main seal adapter will be in the way with the trans still on. So to me it really does not make sense not to pull the engine. I also have done several dozen engine pulls, so I can usually get the engine out of a miata within a few hours.

Pulling the oil pan does not require removing the transmission. I think there are four bellhousing bolts that need to come out, but the rear main seal holder only bolts to the block, not the pan.

When I first installed my turbo I drilled the oil drain hole in the pan in the wrong spot, so I had to take it off and fix it. I did it with the motor still in the car, supporting the motor with an engine hoist and the subframe with a floor jack. The two most annoying parts to it were cleaning all the RTV off the block before reinstalling (hard to get access) and lining up the steering column with the splines in the rack while jacking the subframe back up.

--Ian

AlwaysBroken 06-21-2017 11:26 AM

I was wondering about that, but isn't it just the 4 easy to reach bolts on the bottom of the tranny? I was planning to secure the engine by holding up the PPF from the bottom and using the engine hoist bits on the head to hold it to the shock tower brace and a 2x4.

IIRC from a few months ago, the rear main seal has a little bolted on half-moon thing around it on the bottom, which gets a funky shaped rubber thing between it and the oil pan. And the oil pan basically just gets a heaping amount of Right Stuff. Instead of putting right stuff on the block and lowering the oil pan over it, I could just put the Right Stuff on the pan and raise it to the block. But I don't see why it wouldn't work.

IIRC, also the oil pump bolts on to the front of the engine, basically wrapped around the crank and sealed to the front of the engine with Right Stuff in a long bead. The oil pan seals up against the bottom of this in the front. So I should be able to remove the pan without messing with the harmonic damper.

My main worry with puling the engine is that it involves way more disassembly than I feel is necessary, which means way more opportunities for me to fuck up the reassembly. Like forgetting a 3 dollar gasket in the middle of the process.

AlwaysBroken 06-21-2017 11:29 AM

I think I have the option to upgrade to lifetime on the alignment, and I will probably do that.

m2cupcar 06-21-2017 12:19 PM

I put the RTV on the pan and raised it up to the block. Tip: use several spare bolts you can cut the heads off to thread in as guides to align the pan when raising it to the block.

andytwo 06-21-2017 05:31 PM

Your cold oil pressure delay you describe sounds normal to me.

Similar build to yours and with the "o" ring fitted and a mechanical oil pressure gauge fed from the sandwich plate, mine takes a couple of secs to hit 80psi on 10:50 oil and is "normal" the rest of the time. Been like this for about 6 years no issues to report. After all it a mechanical pump releying on increasing rpms to hit the required pressure so a delay is to be expected plus the further away the sender is the longer it will take to register a reading.

Intresting woodwork though!

AlwaysBroken 06-21-2017 05:51 PM

For oil pressure, I am at the stock location (sort of) I removed the stock oil sender (which is garbage on the 97) and replaced that empty hole with a steel braided line that goes to an Autometer electric sender (which goes to my gauge pod)

My oil circuit looks like:
oil pan > pickup > BE pump > adapter attached to stock oil filter location > 10AN line to 3/4 16 filter housing (IIRC) > oil filter from a mustang (5" L x3" diameter) > thermostat > oil cooler w/fan > return to adapter on stock oil filter location > rest of engine

I run the oil filter I run because I did my oil cooler/filter relocation about a million years ago when there weren't any miata specific applications. I also did it on the cheap. I ended up rigging together an oil cooler setup from a bunch of stuff designed for a ford v8. On the upside, the filters are readily available (something like 5000+ ford applications and like 5x the size of the miata filter).

aidandj 06-21-2017 06:04 PM

hmmm. if the oil drainback valve is pre filter then the drainback valve wouldn't do anything for it.

AlwaysBroken 06-21-2017 06:42 PM

Huh? What do you mean? I thought the drainback valve was inside the filter? The stock filter inlet line goes directly to the inlet of my filter. After the filter it goes on to the thermostat/cooler/engine.

Engine filter orifice]----->[oil filter]---->[thermostat]------->[oil cooler]
Engine filter orifice]<---------------------[thermostat]<-------[oil cooler]

tetraruby 06-22-2017 12:44 AM

From my experience with oil filters, not all have equally well functioning internal check valves. Might want to take a shot at a different brand oil filter. A lot easier to try before dropping the frame. I've never noticed with my Miata, but have with some other vehicles / motors I've owned in the past that were sensitive to the how well the check valve / anti drain back valve worked. Maybe the amount of extra path you've added to the circuit is just enough to be noticeable? Might want to remove the oil cooler while you're at changing the filter out and see how things change?

AlwaysBroken 06-26-2017 01:09 AM

I did it this weekend. Supported the engine/trans with a crane, dropped the subframe, dropped the oil pan, installed a pickup gasket and then put it all back together again with AWR motor mounts.

Lessons learned:
  1. Subframe is much easier to drop than to reinstall afterwards. Holy shit. The subframe itself is probably pretty light but with brakes/suspension and steering attached it's heavy and unwieldy. With the legs of the crane under the car, it's cramped.
  2. Engine hoist plus one jack are all the tools you need to maneuver the subframe. Finding the right technique was a huge pain in the ass tho.
  3. Procedure I discovered for for subframe:
    1. Using the jack and some elbow grease, Install rearmost subframe bolts loosely because that's the easiest part to get to
    2. Jack up the center front of the subframe until you can align the motor mount studs
    3. Thread on the nuts to the motor mounts. Don't tighten all the way, just thread them on all the way
    4. Remove the bolts at the back of the subframe so it can move freely around the motor
    5. Release the subframe jack
    6. Jack up the subframe again slowly, align the front subframe studs with the holes in the subframe
    7. Jack it up all the way
    8. Put on the nuts to the front subframe bolts on both sides
    9. Put on the other bolts, tighten down the motor mounts, reinstall all the brake lines and suspension bits.
When I finish putting everything else back together I'll update about whether this fixes the startup pressure thing.

AlwaysBroken 06-30-2017 10:15 PM

PROTIP: the dipstick tube has a little tab on it with a threaded bit.... it has the strength of a cheap wire hanger and will bend if you look at it funny.

I just spend two fucking hours days trying to figure out what I had done to my oil pan to make the dipstick tube not seat right.... and there was nothing wrong with it. The tab that attaches it to the motor up top was bent a 1/4 of an inch. I bent it back and everything went together perfectly. FUUUUUUUUUUUUUUUU.

Also, I broke off the plastic tip of my dipstick again. Why the fuck isn't there an aftermarket metal version of the dipstick?

Bronson M 06-30-2017 10:25 PM


Originally Posted by AlwaysBroken (Post 1425164)

Also, I broke off the plastic tip of my dipstick again. Why the fuck isn't there an aftermarket metal version of the dipstick?

There it's actually, I've seen a few metal replacement handles behind pedaled on Facebook sale pages

albumleaf 07-01-2017 12:42 PM

Dipstick aside, any difference?

AlwaysBroken 07-01-2017 03:25 PM


Originally Posted by albumleaf (Post 1425231)
Dipstick aside, any difference?

Yes, m2cupcar was entirely correct. I left off the gasket, the seal wasn't perfect, it sucked air for the first 2 seconds whenever I started up.

So far, the first time I started after doing the gasket, it took like 2 seconds to pressurize everything (my filter is downhill from the thermostat/filter). I shut down, waited and started again... 50 psi oil pressure within half a second.

So in conclusion, that gasket is important, don't leave it out when you assemble your car. All glory and all cats to m2cupcar.


Originally Posted by m2cupcar (Post 1422197)
I have a very similar oiling setup (stock pump) and see full cold oil pressure (after sitting for a week) in about a second after the engine starts running (counting one one thousand two one thousand three one thousand). Did the builder install a gasket between the pickup flange and pump? I originally did not and had severely lagging oil pressure on cold start. Installed the gasket and it was fixed.


AlwaysBroken 07-03-2017 09:52 PM

Driven the car a few more times after letting it sit for over a day and on the initial startup, it still takes a couple of seconds to build full pressure (but it's like 1-2 seconds after sitting instead of 2-3 seconds every time). Subsequent startups under an hour apart seem to get instant pressure.

So I think the gasket is important but it looks like the extra post-filter volume of my oil cooler/thermo/lines is overwhelming the ability of the drainback valve in the filter over time. Or the oil pressure is escaping some other way. I'm going to continue switching filters at each oil change and see if I find one that gives the results I desire.


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