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Thread: Excessive blow by, 1.5 quarts missing after ~10 pulls

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Posts: 1-10 of 11
2017-06-07 19:15:12
#1
Excessive blow by, 1.5 quarts missing after ~10 pulls
As the title states, my engine is producing LOTS of blow by and I need to do something about it. Before you say the rings are effed, it has JE pistons and the rings were gapped according to the specs JE sent with their pistons. The blow by is so much that I've just run a rubber hose from the T fitting on the valve cover straight to the ground, for now. I tried a cheap ebay catch can but it was too restrictive and caused the dipstick to pop out.

So what are my options here? I've read the 2 crankcase ventilation threads and they were semi-helpful, but I haven't actually tried anything yet. I was thinking my first step would be to remove the PCV check valve on the valve cover and plug the port on the intake. I was thinking maybe the check valve is leaking and actually pressurizing the crankcase? Another thought is that the oil loss is probably due to oil being blown out through the port on the block, which I have removed the factory catch can and run a hose directly to the T fitting, so that is certainly not helping.

I would love to see how you big turbo guys handled the insane amount of blow by these engines produce. Give me some ideas and suggestions.

Same motor/setup, but it is in a different car that I don't have photos of. Only difference is the breather has been removed and I ran a hose from the T to the ground.
Last edited by SR20? on 2017-06-10 at 01-41-36.
2017-06-07 20:46:29
#2
You mentioned JE pistols, did you do any head work? There's other places blow by can occur...turbo seals?
2017-06-07 21:04:02
#3
JE pistons, eagle rods, BC3 cams, BC springs & retainers, BC SS valves, port & polished the head, ARP head & main studs, VET head gasket, VE oil pump, ACL bearings

The engine doesn't smoke or burn oil. It just blows oil out of the T in the valve cover under boost. Currently running ~24 psi cause it maxes out the MAF at 30psi. I'm curious how turbo seals could cause blow by? Got me interested because I'm also having an issue with air in the coolant and considered that running coolant through the turbo may have something to do with it. When I pressure test the coolant system it will hold pressure with no leaks. But when I go get into boost a few times it blows all the oil out of the motor and the engine begins to "overheat". I say "overheat" because it is not actually overheating, there is just an air pocket by the coolant temp sensor and causes the gauge to show that it is overheating. It pushes all the coolant into the reservoir which overflows and then when I shut the motor off it will suck all the coolant back into the radiator within 30 min to an hr. I have to say Mishimoto has some poor quality control because the welds protrude into where the radiator cap should seal. I initially thought this was holding the cap open so I ground them down, bled the coolant again, got into boost, and again had air in the system.
Last edited by SR20? on 2017-06-07 at 21-22-57.
2017-06-08 02:11:30
#4
Sounds like there maybe a few issues, for the "blow by" it sounds like a pcv issue and your pressurizing the crank case..

The coolant issue sounds like your getting boost into your coolant, that could be a head gasket sealing issue..
2017-06-08 11:55:27
#5
Originally Posted by lynchfourtwenty
Sounds like there maybe a few issues, for the "blow by" it sounds like a pcv issue and your pressurizing the crank case..

The coolant issue sounds like your getting boost into your coolant, that could be a head gasket sealing issue..


As for the PCV issue, yes, that's exactly right. How do you have your PCV set up and why? I've seen people do so many different things with PCV and I need to come up with a good plan for my own.

The coolant issue seems like a minor hurdle. Like I said, coolant system pressure test doesn't leak down. I will have to try one of the chemical tests next to see if I am getting combustion gasses in the coolant system. If it turns out to be a head gasket, no big deal, head gaskets are cheap.
2017-06-08 13:34:38
#6
My pcv setup is stock
2017-06-08 15:39:43
#7
With that much, it's possible there's another issue going on.
Personally, mine was right up that alley and there ended up being a cracked sleeve. I would check compression/leakdown to start and verify all that is good.
Another possibility is a broken ring during install. I've seen this happen a couple times and it can be quite difficult to spot.
I only noticed the first one because of a light scratch on the cylinder wall.
2017-06-08 15:42:11
#8
Edit: didn't see that you stated it doesn't burn oil.
My question then would be what size line are you running to the catch can? and are the fittings installed in the valve cover beneath baffles? or are they direct access to the cams?
2017-06-08 19:54:16
#9
I had an issue w/air getting in the coolant system that ended up being lifting the head under boost...but I didn't have head studs that I see you have...were they retorqued per specs?

And the 'turbo seals' comment was because I failed at reading your post regarding excessive oil coming out the tee from the VC...sounds like there may be multiple issues but the PCV system routing is probably one of them.
Last edited by 1fastser on 2017-06-08 at 20-03-26.
2017-06-10 01:53:48
#10
Originally Posted by 1fastser
I had an issue w/air getting in the coolant system that ended up being lifting the head under boost...but I didn't have head studs that I see you have...were they retorqued per specs?

And the 'turbo seals' comment was because I failed at reading your post regarding excessive oil coming out the tee from the VC...sounds like there may be multiple issues but the PCV system routing is probably one of them.

I haven't retorqued the head studs, but the car pulls really hard in 4th and seems to run well just cruising around. How would I know if I'm lifting the head?

Originally Posted by L8YBUG
Edit: didn't see that you stated it doesn't burn oil.
My question then would be what size line are you running to the catch can? and are the fittings installed in the valve cover beneath baffles? or are they direct access to the cams?


If you look at the photo in the first post, the PCV is mostly stock, except I removed the factory catch can and I am venting the T to atmosphere. I plan to try a leakdown test and a compression test, but I have to get some free time to do it.
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