Benefit of aftermarket valve cover?

pysical

Sergeant
Jun 16, 2017
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2009 335xi E90
I currently have the head ports plugged and run a BMS and Mishimoto catch can. I have a valve cover on my car now that sat outside of a guys house on a motor for about a year. Turns out it has a crack on the usual spot and the cap doesn't seal very well. Between the two its causing a lot of oil residue to appear. I was reading around and people mention the stock valve cover pcv system even when externalized isn't big enough for 30+ psi? I don't know if that is true or not.

My options are going with a FCP Euro 400$ valve cover to fix the crack and oil leak and use my current cans/setup. Or I go with an aftermarket setup. Two options are M18 and VTT. I have read that some people have cracked the corners of the M18 from tightening them and I have heard of people having bad oil seeping on the VTT cast valve cover. So it is either the 400$ fcp or the 1300$ billet. I also like how clean the billet and catch can setup is.

So is there a benefit of going to the aftermarket other than looks?

Thanks
 

SlowE93

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Jul 2, 2017
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I currently have the head ports plugged and run a BMS and Mishimoto catch can. I have a valve cover on my car now that sat outside of a guys house on a motor for about a year. Turns out it has a crack on the usual spot and the cap doesn't seal very well. Between the two its causing a lot of oil residue to appear. I was reading around and people mention the stock valve cover pcv system even when externalized isn't big enough for 30+ psi? I don't know if that is true or not.

My options are going with a FCP Euro 400$ valve cover to fix the crack and oil leak and use my current cans/setup. Or I go with an aftermarket setup. Two options are M18 and VTT. I have read that some people have cracked the corners of the M18 from tightening them and I have heard of people having bad oil seeping on the VTT cast valve cover. So it is either the 400$ fcp or the 1300$ billet. I also like how clean the billet and catch can setup is.

So is there a benefit of going to the aftermarket other than looks?

Thanks
I would save the money and go OEM
 

pysical

Sergeant
Jun 16, 2017
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I was in the same situation early this year. I went with the oem from FCP. I rather deal with a cracked cover years down the road than a chance of a constant leaky cover.
Yeah I wouldn't think everyone of them is going to leak. I'm sure most of the ones leak is because of the person who installed it.
 

SLOWESTN54

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Feb 9, 2021
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Yeah I wouldn't think everyone of them is going to leak. I'm sure most of the ones leak is because of the person who installed it.
They don't mean leak as in from the gasket. It's more seepage through cracks in the valve cover.
 

Torgus

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Nov 6, 2016
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If the cast cracks it is a bad casting no? My m18 better not leak when I install it! I also agree most install issues are probably user related. Use an accurate tq wrench, tighten the factory suggested pattern, then double check a few days later after some heat cycles in. Should be good to go.

The length of the VC means it is a large piece of billet that have to start out with.

IF I was going to get a billet VC I would go with this one:
 
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pysical

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Jun 16, 2017
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2009 335xi E90
If the cast cracks it is a bad casting no? My m18 better not leak when I install it! I also agree most install issues are probably user related. Use an accurate tq wrench, tighten the factory suggested pattern, then double check a few days later after some heat cycles in. Should be good to go.

The length of the VC means it is a large piece of billet that have to start out with.

If I remember right, the M18 comes with its own "torque screwdriver" or something like that. Thought that was pretty cool.

The main reason of going with a aftermarket was I thought I would get some sort of benefit. I have read from multiple places that the stock valve cover can't handle 30+psi even if it is external. Something about the ports on the inside or something I don't know. So if that helps the engine breath then I would pull the trigger on something. If not and it doesn't make any difference then I would go with a stock valve cover so I can have the engine cover on.

Just looking at whatever places I can to help the motor.
 

fmorelli

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Aug 11, 2017
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I don't get how the valve cover and turbo PSI come in to play - can someone explain that?
 

pysical

Sergeant
Jun 16, 2017
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I could have misread and it might be that the bigger PSI numbers just require you to go external.

Here is a good picture of a stock vc clogged https://www.spoolstreet.com/attachments/1559172002080-png.27530/

not sure how often that occurs or what issues it would cause but its something. I doubt it is something that happens quickly so it probably isn't a issue. I will probably just go with the stock valve cover. Just didn't know if the aftermarket had any benefit.
 

fmorelli

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How much of that is a function of a poorly metered vacuum system possibly causing excess oil vapors/mist? Just curious. I believe the intent of the factory baffling system is that it is generally meant to reduce that oil mist ended up in the PCV recirc system. I'm not sure why it would work differently for various PSI unless the engine vacuum system is not properly configured.

Others will argue for an aftermarket valve cover, which I understand. But I think it is worthwhile to nail down facts as to why. Hopefully others will chime in.
 
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Reformatt

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Oct 28, 2019
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I have the VTT billet valve cover it is quite expensive but I justified the purchase as not having to buy another valve cover.

After a yearish my only slight gripe would be the fasteners and bolt holes… in my opinion if the bolt holes would allow for the factory hardware the install would be a bit more fool proof cause my installation skills are obviously lacking lol.
 

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RuskiRacer

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Jul 17, 2019
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Thats the issue with basically all metal valve covers they don't seem to squish the gasket and sandwich it bit seem to have more of a pinching effect that eventually causes valve cover gasket weepage. As @fmorelli pointed out the aftermarket valve covers have basically no internal baffling which does lead to more oil vapor in the crankcase and in the catch cans
 
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pysical

Sergeant
Jun 16, 2017
430
104
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2009 335xi E90
I have the VTT billet valve cover it is quite expensive but I justified the purchase as not having to buy another valve cover.

After a yearish my only slight gripe would be the fasteners and bolt holes… in my opinion if the bolt holes would allow for the factory hardware the install would be a bit more fool proof cause my installation skills are obviously lacking lol.
Is that oil in your picture that you are showing?

EDIT: Nevermind I zoomed in and can see. Looks like gasket is pushed out.
 
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Reformatt

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Oct 28, 2019
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Thats the issue with basically all metal valve covers they don't seem to squish the gasket and sandwich it bit seem to have more of a pinching effect that eventually causes valve cover gasket weepage. As @fmorelli pointed out the aftermarket valve covers have basically no internal baffling which does lead to more oil vapor in the crankcase and in the catch cans
I have debated taking the valve cover to a local machine shop an have it match drilled/honed with stock valve cover so I could use the stock mounting hardware. An while it’s there redo the outlets to accept something like the attached. To add alittle but of internal baffling.
 

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Reformatt

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Oct 28, 2019
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Is that oil in your picture that you are showing?
Yeah that is some oil originally there was no oil leaks…but if you read the install guide it does mention after a heat cycle you should re torque the fasteners “total pain in the azzz” with relocated inlets. But again it did drive for a few thousand miles before this leak came about…inspecting the seal it looks like it was tightened down too much…that’s why I would like to install the factory hardware they have a actual built in hard stop to prevent over compression of the seal…