Crank evac inquiry
#1
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From: The coal ridden hills of Pennsylvania
Crank evac inquiry
Currently my engine burns a lot of oil, as I'm sure my rings are wearing and I'm thinking as I enter boost, my crank case also gets slightly boosted due to blow by.
Everybody who has followed Faeflora's build thread has seen his -12 braided line coming off his valve cover which goes to a check valve on his downpipe. The whole reason for this is to produce vacuum in the crankcase, thus helping the rings seal, etc.
Since I currently don't have time to pull my engine apart, and want to add that similar setup in the future anyway...would I hurt if I added a single -12 line with check valve setup now?
Would it improve the way my car runs and cause less oil consumption?
I just feel it's easier to pull my valve cover and weld a fitting onto it, drill my DP and weld a slash cut in there, than it is to pull my whole engine and rip it apart. The engine build will happen someday, I have a spare '99 head I am getting redone, but for right now, I just have to drive my car the way it is...winter '12-'13 build coming.
Everybody who has followed Faeflora's build thread has seen his -12 braided line coming off his valve cover which goes to a check valve on his downpipe. The whole reason for this is to produce vacuum in the crankcase, thus helping the rings seal, etc.
Since I currently don't have time to pull my engine apart, and want to add that similar setup in the future anyway...would I hurt if I added a single -12 line with check valve setup now?
Would it improve the way my car runs and cause less oil consumption?
I just feel it's easier to pull my valve cover and weld a fitting onto it, drill my DP and weld a slash cut in there, than it is to pull my whole engine and rip it apart. The engine build will happen someday, I have a spare '99 head I am getting redone, but for right now, I just have to drive my car the way it is...winter '12-'13 build coming.
#4
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Negative.
I only did a compression test like 2 years ago, and I can't remember what the numbers were, but they were consistent.
I can say this, my engine has 158,000 miles on it, and 40,000 of that was boosted. It smokes. Lets say I go down a big hill and it pulls a lot of vacuum. When I touch the gas pedal, it'll look like a James Bond smoke screen behind my car. Driving down the street? No smoke.
I only did a compression test like 2 years ago, and I can't remember what the numbers were, but they were consistent.
I can say this, my engine has 158,000 miles on it, and 40,000 of that was boosted. It smokes. Lets say I go down a big hill and it pulls a lot of vacuum. When I touch the gas pedal, it'll look like a James Bond smoke screen behind my car. Driving down the street? No smoke.
#5
Negative.
I only did a compression test like 2 years ago, and I can't remember what the numbers were, but they were consistent.
I can say this, my engine has 158,000 miles on it, and 40,000 of that was boosted. It smokes. Lets say I go down a big hill and it pulls a lot of vacuum. When I touch the gas pedal, it'll look like a James Bond smoke screen behind my car. Driving down the street? No smoke.
I only did a compression test like 2 years ago, and I can't remember what the numbers were, but they were consistent.
I can say this, my engine has 158,000 miles on it, and 40,000 of that was boosted. It smokes. Lets say I go down a big hill and it pulls a lot of vacuum. When I touch the gas pedal, it'll look like a James Bond smoke screen behind my car. Driving down the street? No smoke.
#7
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From: The coal ridden hills of Pennsylvania
So what you're saying is, my whole oil consumption issue could most likely be in my cylinder head? Meaning, if I get my spare head redone, I could throw that on and possibly not have any issues?
#9
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From: The coal ridden hills of Pennsylvania
I think I still am going to eliminate my PCV and breather, and run that system anyway. Looks like a leakdown is in order. If I can get away with just a head swap, I'll be stoked!
#12
See this thread regarding the connecting hole.
https://www.miataturbo.net/showthrea...ight=tiny+hole
I enlarged that as much as possible.
Note that the only problem with the slashcut in my experience is that sometimes, under some driving conditions, oil goes into the tailpipe. Lots of it. When that happens, unlike a VTA catch can setup, your exhaust will smoke A LOT.
If I did this over I would put a can in the line. Of course this will add about $120 with the can and fittings. The fittings are $35 apiece :| You can get a custom aluminum can from
http://www.petersonfluidsys.com/tank_spec.html
for like $45 and that includes bungs and petcock. I have one sitting in my garage. Just call em and tell em exactly what you want, and they will send you a technical drawing for your approval. Amazing source for... cans.
#15
+1 on compression test
also if you do the test and discover 1 or 2 cylinders are a little lower then the other 2, adding oil and testing again can help to point you in the right direction as to if the compression is leaking via the valve stem seals or rings -
if adding a little oil causes the compression to go up it's usually an indication that it's your rings
if adding a little oil results in no change it's more likely the valves
although it's a different car principals are still the same here's the fsm's detailed description on my old car -
it's probably more important to find the real source of your issue before you just guess at parts to install to fix the issue
also if you do the test and discover 1 or 2 cylinders are a little lower then the other 2, adding oil and testing again can help to point you in the right direction as to if the compression is leaking via the valve stem seals or rings -
if adding a little oil causes the compression to go up it's usually an indication that it's your rings
if adding a little oil results in no change it's more likely the valves
although it's a different car principals are still the same here's the fsm's detailed description on my old car -
it's probably more important to find the real source of your issue before you just guess at parts to install to fix the issue
#16
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From: The coal ridden hills of Pennsylvania
I have a compression tester, so this weekend I'll get new numbers. I also will do a leak down test and post all results. Like I said, if I could get away with doing a head swap, that would be so awesome.
#17
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From: The coal ridden hills of Pennsylvania
Thanks for the link Min..I guess I'll order just 1 slash cut and 1 replacement check valve. Since the valve is steel, I bet I could weld a -12 fitting on it so I don't have to be sloppy and use a hose clamp.
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