Oil fumes from te exhaust after WOT between 3000 and 2000rpm
#1
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Join Date: Mar 2011
Location: Eindhoven, The netherlands
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Oil fumes from te exhaust after WOT between 3000 and 2000rpm
Not sure wich topic i should post this.
When i drive around there is not much a problem, atleast nothing i can smell or see. WOT and lifting the paddle nothing. But WOT to high RPM and when i let the RPM lower to 3000rpm there are alot of blue smoke coming off the exhaust.. Till about 2000rpm and then its over. WOT to high RPM and brake to low rpm there is nothing. When it starts to smoke and i press the paddle to accelerate its over.
Its only between 3000 and 2000rpm. At first there was smoke at idle and starting the car when its hot. But that seems to be over now.
Blowby is normal and oil consumption is almost nothing for the last 150km or so.
Ive done about 7k km on my newly build block. BP 1.8 NA block with BP4W head. It still got good power and everything.
Parts used are
-Wiseco forged pistons
-Forged rods
-BE engineering oil pump
-ARP bolts
-ACL Bearings
-Brand new TD04L core
Compression is 158/160/160/160
And since the problem begun, I welded some tubes on the valve cover to connect 2 AN-12 hoses on either side.
Is it still my crankcase pressure to high and i should drive more to evaporate the oil?
Sorry for the bad english
When i drive around there is not much a problem, atleast nothing i can smell or see. WOT and lifting the paddle nothing. But WOT to high RPM and when i let the RPM lower to 3000rpm there are alot of blue smoke coming off the exhaust.. Till about 2000rpm and then its over. WOT to high RPM and brake to low rpm there is nothing. When it starts to smoke and i press the paddle to accelerate its over.
Its only between 3000 and 2000rpm. At first there was smoke at idle and starting the car when its hot. But that seems to be over now.
Blowby is normal and oil consumption is almost nothing for the last 150km or so.
Ive done about 7k km on my newly build block. BP 1.8 NA block with BP4W head. It still got good power and everything.
Parts used are
-Wiseco forged pistons
-Forged rods
-BE engineering oil pump
-ARP bolts
-ACL Bearings
-Brand new TD04L core
Compression is 158/160/160/160
And since the problem begun, I welded some tubes on the valve cover to connect 2 AN-12 hoses on either side.
Is it still my crankcase pressure to high and i should drive more to evaporate the oil?
Sorry for the bad english
#2
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Join Date: Mar 2011
Location: Eindhoven, The netherlands
Posts: 197
Total Cats: 19
Oh and im so annoyed by this problem that i dont have fun anymore in this car and thinking about selling the car after 6 years and all the hard work if i dont find the problem within a few weeks.
#3
Its blow by, happened when engine braking on my old built motor (non miata) too. Whats your full PCV set up currently? I see you said you welded up two tubes, but what are you using as a vacuum source, or are you VTA?
Also, how many miles on the motor (is it broken in?), and what weight oil are you using? Conventional or synthetic?
Also, how many miles on the motor (is it broken in?), and what weight oil are you using? Conventional or synthetic?
#4
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Join Date: Mar 2011
Location: Eindhoven, The netherlands
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I have 2 AN-12 VTA. Ive done around 7k Kilometers. It makes good power. Im using Castrol 10w60 Fully synthetic
Compression is near perfect. When i unscrew the filler cap when the engine is running the oil cap just wobbles a little on top and not blowing off
Compression is near perfect. When i unscrew the filler cap when the engine is running the oil cap just wobbles a little on top and not blowing off
#5
Ok, mine was VTA when i was smoking as well. I would look to move back to having vacuum on the CC, the vacuum really allows the piston rings to seat properly and helps with that blow by.
There are ways to relatively easily have both VTA when WOT and a sealed system when DD if you chose, but for now see about getting some vacuum on that crankcase.
There are ways to relatively easily have both VTA when WOT and a sealed system when DD if you chose, but for now see about getting some vacuum on that crankcase.
#7
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Join Date: Mar 2011
Location: Eindhoven, The netherlands
Posts: 197
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Everything was rebuild including the BP4W head. How can i measure blowby?
I drove the first few kilometers easy, not high and not low RPM. And slowly more throttle. After 2000km i changed to oil.
I drove the first few kilometers easy, not high and not low RPM. And slowly more throttle. After 2000km i changed to oil.
#8
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Join Date: Mar 2011
Location: Eindhoven, The netherlands
Posts: 197
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Did a leakdown test and all cilinders where about 4-5%
Placed a new PCV valve between the inlet manifold and the valvecover and still alot of smoke, also my parents told me that between shifts at WOT there was also oil smoke from the exhaust. Those i didnt know.. but i recon these are always there but i hadnt noticed these.
Most of the smoke i see and smell are between 3000rpm and 2000rpm after WOT. And only when i let off the throttle and let it slow down by itself.. if ie slow down with the normal brakes i can not see smoke.
Placed a new PCV valve between the inlet manifold and the valvecover and still alot of smoke, also my parents told me that between shifts at WOT there was also oil smoke from the exhaust. Those i didnt know.. but i recon these are always there but i hadnt noticed these.
Most of the smoke i see and smell are between 3000rpm and 2000rpm after WOT. And only when i let off the throttle and let it slow down by itself.. if ie slow down with the normal brakes i can not see smoke.
#11
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Join Date: Mar 2011
Location: Eindhoven, The netherlands
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My turbospecialist still thinks its not the turbo itself, but he was thinking about the valve stem seals.
And maybe there were 2 problems, crankcase ventilation and the valve stem seals. And lets say the crankcase ventilation is solved by know.. the valve stem seals will still keep it smoking.
The car is now at a MX-5 specialist and they will look for any problems and i think i will let them replace the valve stem seals.
And maybe there were 2 problems, crankcase ventilation and the valve stem seals. And lets say the crankcase ventilation is solved by know.. the valve stem seals will still keep it smoking.
The car is now at a MX-5 specialist and they will look for any problems and i think i will let them replace the valve stem seals.
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