Oil Return Fitting Location - Too Low?
#1
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Oil Return Fitting Location - Too Low?
I picked up a used engine as a replacement in my '95. Luckily it already has a fitting for the oil return in the pan. Unluckily it looks a bit low on the pan:
FM says to tap the pan 2" below the upper lip, then adds "no lower!" in parenthesis afterwards. BEGI however suggests 2.3", which appears to be in line with where this hole has been drilled.
Any guidance?
FM says to tap the pan 2" below the upper lip, then adds "no lower!" in parenthesis afterwards. BEGI however suggests 2.3", which appears to be in line with where this hole has been drilled.
Any guidance?
#2
Cpt. Slow
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You're fine. Look how low the dip stick goes, it's in the lower part of the pan, below that fitting. And it'll be even lower when the engine is on and there's oil coming out of the drain. It appears to be at 2" anyways. I'm assuming that 2" location from FM is the center of the hole. It looks like it lines right up.
#6
It looks a little low compared to mine (drilled/tapped on the car, pictures 4-7 on this thread): https://www.miataturbo.net/build-thr...70/#post969041
But I agree with everyone so far, it should be fine.
At the location I drilled mine the oil pan was 100% full to the top of the dipstick, and no oil leaked out with the front of the car raised up slightly. With the motor running there's probably 1/3 to 1/2 of the oil running throughout the engine anyways, so the amount in the pan is almost certainly lower than that bung.
But I agree with everyone so far, it should be fine.
At the location I drilled mine the oil pan was 100% full to the top of the dipstick, and no oil leaked out with the front of the car raised up slightly. With the motor running there's probably 1/3 to 1/2 of the oil running throughout the engine anyways, so the amount in the pan is almost certainly lower than that bung.
#9
Why all oil return fittings are located to the front of the engine? Mine has been there in couple of builds as well. To miss the downpipe?
The reason I am wondering is making sure the sump where oil gets picked up has most oil in all times. Spec miatas have oiling issues with high G:s and in that light one might bring the oil return from turbo in the sump area if the car will see track use.
On the other hand the oil from turbo is hot and may be aerated as well, is the front return location thought to allow the oil to cool and settle a bit before returning to pick-up sump.
Any thoughts theory where ideal location should be?
The reason I am wondering is making sure the sump where oil gets picked up has most oil in all times. Spec miatas have oiling issues with high G:s and in that light one might bring the oil return from turbo in the sump area if the car will see track use.
On the other hand the oil from turbo is hot and may be aerated as well, is the front return location thought to allow the oil to cool and settle a bit before returning to pick-up sump.
Any thoughts theory where ideal location should be?
#11
Boost Pope
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Because most of us drill the hole while the engine is still in the car. That's pretty much the only spot that's easily accessible. Fortunately, apart from having the pickup tube right behind it, it's a perfectly serviceable location.
#12
It you've got the engine out of the car, put it where I did:
Makes for a straighter drop for the oil, requires less hose, and it's not competing for space with the AC, power steering pump & hoses, compressor outlet piping, coolant hose, etc.
If the engine is still in the car, the front location works fine.
The stuff about oil level in the sump is unnecessary -- the turbo doesn't have that much oil flow through it anyway (remember the feed line is usually -4 and often has a pressure restrictor in it).
--Ian
Makes for a straighter drop for the oil, requires less hose, and it's not competing for space with the AC, power steering pump & hoses, compressor outlet piping, coolant hose, etc.
If the engine is still in the car, the front location works fine.
The stuff about oil level in the sump is unnecessary -- the turbo doesn't have that much oil flow through it anyway (remember the feed line is usually -4 and often has a pressure restrictor in it).
--Ian
#13
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It's got less to do with flow and more to do with pressure. If you plug up a drain line by submersing the end in the oil, the CHRA ends up pressurized and the seals will leak. That's why it's important to keep the oil drain fitting at least partially above the oil level in the pan.
#14
It's got less to do with flow and more to do with pressure. If you plug up a drain line by submersing the end in the oil, the CHRA ends up pressurized and the seals will leak. That's why it's important to keep the oil drain fitting at least partially above the oil level in the pan.
I agree re: submerging the end of the drain in oil.
--Ian
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