Pumping oil out the PCV - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Engine Performance This section is for discussion on all engine building related questions.
Sponsored by:
Sponsored by:

Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old 07-30-2010, 09:37 AM   #1
Junior Member
Thread Starter
iTrader: (5)
 
Join Date: Aug 2008
Location: Northbrook IL
Posts: 105
Total Cats: 0
Default Pumping oil out the PCV

I was at 10psi when the vacuum/boost line that goes to the (begi)fmu came off and the engine went lean. the car runs but not on all cylinders and oil is being pumped out the pcv hole in the valve cover.

The rings are gone in one cylinder?
dima88 is offline   Reply With Quote
Old 07-30-2010, 09:47 AM   #2
Tour de Franzia
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

yes. If its puking oil then its probably over for the motor.
hustler is online now   Reply With Quote
Old 07-30-2010, 10:13 AM   #3
Junior Member
Thread Starter
iTrader: (5)
 
Join Date: Aug 2008
Location: Northbrook IL
Posts: 105
Total Cats: 0
Default

yeh thats what i thought...
Should i get another stock bottom end or reuse my old pauter rods from my other engine and get some new JE pistons because my old ones have a ton of detonation marks on top? going to make less then 250whp
dima88 is offline   Reply With Quote
Old 07-30-2010, 10:21 AM   #4
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,833
Total Cats: 1,786
Default

and sell the FMU and get real managment so it doesnt happen again. how does a vacuum line fall off?
Braineack is offline   Reply With Quote
Old 07-30-2010, 10:37 AM   #5
Elite Member
iTrader: (5)
 
m2cupcar's Avatar
 
Join Date: Jan 2005
Location: Atlanta
Posts: 7,236
Total Cats: 288
Default

stock bottom end + engine management ftw
m2cupcar is offline   Reply With Quote
Old 07-30-2010, 11:56 AM   #6
Junior Member
Thread Starter
iTrader: (5)
 
Join Date: Aug 2008
Location: Northbrook IL
Posts: 105
Total Cats: 0
Default

Its a vacuum/boost line to the FMU that came off and my fuel pressure went from 70psi to 43psi and i didn't notice. I got a parallel MS but never got around to installing it, i will probably go with a stock block again.
Thanks
dima88 is offline   Reply With Quote
Old 07-30-2010, 04:14 PM   #7
Junior Member
iTrader: (2)
 
Join Date: Apr 2008
Location: Gainesville, FL
Posts: 77
Total Cats: -2
Default

Quote:
Originally Posted by dima88 View Post
yeh thats what i thought...
Should i get another stock bottom end or reuse my old pauter rods from my other engine and get some new JE pistons because my old ones have a ton of detonation marks on top? going to make less then 250whp
Ton of detonation marks? How much detonation could you have sustained and still have a running motor?

My understanding was a mere few seconds of detonation was the very end of the motor itself...

Any pics of those rambo pistons? I feel like I've been getting a little det myself, just can't hear it :(

I'm also getting alot of blowby from my pcv... No oil coming out, but lots of air flow coming out of there at idle. Probably wouldn't hurt to do a compression check, but I maintain about 20 inches of vac at idle(900-1k rpms)
Turbobarber is offline   Reply With Quote
Old 08-01-2010, 10:30 AM   #8
Junior Member
Thread Starter
iTrader: (5)
 
Join Date: Aug 2008
Location: Northbrook IL
Posts: 105
Total Cats: 0
Default

Quote:
Originally Posted by Turbobarber View Post
Ton of detonation marks? How much detonation could you have sustained and still have a running motor?

My understanding was a mere few seconds of detonation was the very end of the motor itself...

Any pics of those rambo pistons? I feel like I've been getting a little det myself, just can't hear it :(

I'm also getting alot of blowby from my pcv... No oil coming out, but lots of air flow coming out of there at idle. Probably wouldn't hurt to do a compression check, but I maintain about 20 inches of vac at idle(900-1k rpms)
I still didn't take apart the engine that is pimping oil out the PCV hole, the pistons with the detonation(there are a bunch of small craters on top on one side of all the pistons) came out of my old built engine that also failed because the oil ring on #3 cylinder came off.

I was at 24/25 in at idle before this happened.
dima88 is offline   Reply With Quote
Old 08-01-2010, 01:14 PM   #9
Junior Member
iTrader: (2)
 
Join Date: Apr 2008
Location: Gainesville, FL
Posts: 77
Total Cats: -2
Default

well then... I probably could use a rebuild eh?

I believe before I went turbo I was around 22 inches.

That was about 3 years ago, so for all of my mishaps I guess I'm doing okay on a 73k motor..

I'd love to rebuild now, but just not possible.
Turbobarber is offline   Reply With Quote
Old 08-01-2010, 05:45 PM   #10
Newb
 
Join Date: Oct 2008
Location: Waterloo, ON
Posts: 14
Total Cats: 0
Default

Quote:
Originally Posted by Turbobarber
How much detonation could you have sustained and still have a running motor?
Quite a bit, I believe, depending on the severity of the detonation. If it leads to pre-ignition, or is severe and happens early in the combustion sequence, then that's when you vent your pistons, or remove your ring lands.

Quote:
Originally Posted by http://en.wikipedia.org/wiki/Engine_knocking

Detonation induced pre-ignition

... Eventually this [Detonation] can lead to the far more catastrophic Pre-Ignition as described above.

While it is not uncommon for an automobile engine to continue on for thousands of miles with mild detonation, preignition can destroy an engine in just a few strokes of the piston.
Craig N is offline   Reply With Quote
Old 08-01-2010, 05:47 PM   #11
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,833
Total Cats: 1,786
Default

boring...
Braineack is offline   Reply With Quote
Old 08-01-2010, 05:50 PM   #12
Newb
 
Join Date: Oct 2008
Location: Waterloo, ON
Posts: 14
Total Cats: 0
Default

Like 'boring' a hole in the piston? (sorry, bad joke...)

Well, he asked; I answered.
Craig N is offline   Reply With Quote
Old 08-01-2010, 05:54 PM   #13
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,833
Total Cats: 1,786
Default

no, just boring lack of knowledge.

pre-ignition is just when the spark plugs get too hot and cause an explosion event before the desired time.

detonation doesn't lead to it, it however, can lead to detonation.
Braineack is offline   Reply With Quote
Old 08-01-2010, 06:23 PM   #14
Newb
 
Join Date: Oct 2008
Location: Waterloo, ON
Posts: 14
Total Cats: 0
Default

This seems to be a well mis-understood area, so I'll post what I understand to be true.

Quote:
Originally Posted by Braineack
pre-ignition is just when the spark plugs get too hot and cause an explosion event before the desired time.
This statement is true, although it doesn't have to be the spark plug that lights off the mixture too early.

Overheated exhaust valves or sharp edges in the combustion chamber (unradiused valve reliefs, etc) can cause pre-ignition once they become hot spots.

Quote:
Originally Posted by Braineack
detonation doesn't lead to it, it however, can lead to detonation.
You're right, pre-ignition can lead to a detonation like event. However, there is an important difference.

In a standard detonation event, the two (or more) colliding pressure wave fronts are created by the spark plug firing, and the pressure rise due to the expanding wave front autoigniting the remainder of the mixture, respectively. However, this mode of detonation will always occur after the spark plug fires.

In a pre-ignition event, the flame front can be lit off by a hot spot before the spark plug has fired. This can lead to the cylinder achieving max pressure before the piston has reached TDC. Another piston will be on its power stroke, and (along with the engine's rotational inertia) will force the piston from the pre-ignition cylinder up against the high pressure, usually resulting in catastrophic damage. There will probably be a colliding wave front (detonation) in this situation due to the massive pressure rise, but if the pre-ignition occurs too soon before the spark is planned, it's all over anyway.

Detonation can lead to pre-ignition, in that repeated occurrences will break down the boundary layer of gas around the spark plug, and other edges, and can then allow these spots to heat up to a pre-ignition temperature.


This is the way I understand it. Feel free to disagree, but please post your reasoning if you'd like to discuss this more. I'm always eager to learn.
Craig N is offline   Reply With Quote
Old 08-01-2010, 06:40 PM   #15
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,833
Total Cats: 1,786
Default

boring.
Braineack is offline   Reply With Quote
Old 08-01-2010, 06:53 PM   #16
Boost Pope
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Chicago (Over two miles from Wrigley Field. Fuck the Cubs. Fuck them in their smarmy goat-hole.)
Posts: 26,317
Total Cats: 1,914
Default

I like this Craig guy. Argumentative, sadistically ---- about the very esoteric, uses complicated words and phrases to describe simple phenomenon... Reminds me of me.
Joe Perez is online now   Reply With Quote
Old 08-02-2010, 12:22 AM   #17
Newb
 
Join Date: Oct 2008
Location: Waterloo, ON
Posts: 14
Total Cats: 0
Default

Quote:
Originally Posted by Braineack
boring.
Ha! I actually did laugh out loud when I read that. I can't argue with such a succinct rebuttal!

I slept in this morning... makes me a bit wordy My apologies.
Craig N is offline   Reply With Quote
Old 08-02-2010, 10:56 AM   #18
I'm Miserable!
iTrader: (11)
 
Join Date: Apr 2008
Location: Texas, 'Murica
Posts: 2,505
Total Cats: 7
Default

I used methane injection by farting into my intake. It caused detonation, then pre ignition so bad that my engine spun backwards and opened a worm hole. I am from august 21, 2010.
chicksdigmiatas is offline   Reply With Quote
Old 08-02-2010, 12:47 PM   #19
Newb
 
Join Date: Oct 2008
Location: Waterloo, ON
Posts: 14
Total Cats: 0
Default

Hardly worth the effort for 19 days worth of travel. Maybe you should make some bovine friends to up the ante?
Craig N is offline   Reply With Quote
Old 08-21-2010, 10:28 PM   #20
Junior Member
Thread Starter
iTrader: (5)
 
Join Date: Aug 2008
Location: Northbrook IL
Posts: 105
Total Cats: 0
Default

Found the problem
Attached Images
File Type: bmp piston [320x200].bmp (208.6 KB, 101 views)
dima88 is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
OTS Bilstein to motorsports ASN conversion stoves Suspension, Brakes, Drivetrain 5 04-21-2016 04:00 PM
Moroso Air Oil Separator Catch Can Aroundcorner Miata parts for sale/trade 2 10-01-2015 04:20 PM
Walbro 255lph Fuel Pump $50 lsc224 Miata parts for sale/trade 2 10-01-2015 10:17 AM
Bad head gasket or ? shooterschmidty Engine Performance 8 09-30-2015 11:28 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 09:11 PM.