I am running 8 psi on a forged 383 with AFR heads and a SuperRam Intake/Runners/Plenum. I am currently having an issue with the valve cover on the driver's side leaking in the rear outboard corner. It began leaking again (second time) last night after I got into boost several times. The strange thing is the gasket appears to be physically protruding out from under the cover as though it is being pushed from the inside out. The engine has approximately 5,000 miles on it and it was built from the start as a forced induction motor.
I have one way check valves in the PCV line and in the brake booster line. I have one additional hole in the driver's side valve cover with a breather on it as well as one like it on the passenger side. I don't want to think that I am getting so much blow-by that the crankcase would pressurize to such an extent that it would blow out a valve cover gasket even with two holes in the valve covers venting to atmosphere.
Has anyone else experienced this problem and what was the cause/solution? I have a BlowerWorks system that I have yet to install that will link both valve covers to the low pressure side of the blower to keep a constant negative pressure within the crankcase. This system may be the answer but I am interested in hearing some other ideas.
I would be very surprised if it is a blown piston. The engine performs well with no missing, loss of power or other irregularities. Also, it has been running rich since I put it all back together and I have been slowly leaning out the fueling tables and my data log shows the last tune to be still running a little rich. The engine has not overheated since the rebuild and stays a constant 190-200 degrees as I have a DeWitts radiator and the fan kicking on at 190.
I will keep your thought in mind while I hunt for the problem. Thanks for the reply.
I would be very surprised if it is a blown piston. The engine performs well with no missing, loss of power or other irregularities. Also, it has been running rich since I put it all back together and I have been slowly leaning out the fueling tables and my data log shows the last tune to be still running a little rich.
Melted pistons and blown rings...gimme a break. Blow-by is going to pressurize the crankcase, covers, etc. Yes, your going to blow out gaskets, dip stick tubes, and whatever else in order to relieve pressure. Things like you stated, primarily PCV's and lack of adequate block ventilation are the issue.
In the Honda world it's very common for us to add large ventilation systems to valve covers, as well as blocks. You have to give the pressure somewhere to go in order to save your gaskets.
Below is a picture of a setup I built. The -10an bungs were added to the valve cover and a baffled container was fabbed (behind the headlight) in order to capture the air, as well as de-aerate any oil vapor and allow it to settle in the can. From there you can either plumb the setup to return the oil, or you can have a petcock to release it at regular intervals.
It should be known that the fittings that were added in the pic above are behind baffles contained inside of the valve cover. Without it, the system would ingest too much oil.
With Honda's, we always eliminate the PCV system on boosted cars and go to an opened vent system. It's much easier on the motor, as well as your internal seals.
Hondas (specifically B18/20 combos) have much more "window area" than the SBC in the stroke/crankcase area. These cars are way different than a Honda. I have done my share of TC'ed swaps, and the Vettes are completely different.
I would highly suspect that 90Indy has a cylinder (or two) that is significantly down on compression from either a lifted ring land or washed rings. A simple compression test followed with a leakdown test would quickly answer these questions.
That's fine you have "TC'd" "swaps" in the past, but it doesn't make a basic principle any less relevant. Your use of the term "window area", which generally refers to valve lift and valve circumference, I assume is used here to refer to gas outflow areas of the blocks. Whether these blocks have more or less, doesn't sidestep the fact that blow by needs evacuated, and that the symptoms of blow by will cause the conditions like this person has explained.
That's not to say that there isn't a ring condition that has developed leading to excessive blow by and a developing issue. The fact is though, melted pistons and busted ring lands show other symptoms other than just what is explained here. If he's have no oil consumption, driveability issues, idling changes or anything of the like, then it seems pretty clear he's just having an issue with pressurizing the crankcase or valve cover areas, and that pressure needs relieved.
In reference to your B18/B20 combination comment, that'd be interesting to discuss because you say "specifically". The B18 and B20 castings are the same in terms of the block design, with only variations in deck height between the B16 and then the B18/B20 castings. Furthermore, a combo would be comprised of a head and block, and in the pictures case it's a B16a/B18b combo. So, while you may have "TC'd some swaps", it may seem that your specific knowledge could be lacking. It then leads me to question your entire statement of the differences between the two.
If you have some specific data in terms of square area, window area as you've defined it in this case, between the SBC's and Bseries Honda motors then I'd like to see it for the benefit of my own knowledge. Thank you.
Melted pistons and blown rings...gimme a break. Blow-by is going to pressurize the crankcase, covers, etc. Yes, your going to blow out gaskets, dip stick tubes, and whatever else in order to relieve pressure. Things like you stated, primarily PCV's and lack of adequate block ventilation are the issue.
In the Honda world it's very common for us to add large ventilation systems to valve covers, as well as blocks. You have to give the pressure somewhere to go in order to save your gaskets.
Below is a picture of a setup I built. The -10an bungs were added to the valve cover and a baffled container was fabbed (behind the headlight) in order to capture the air, as well as de-aerate any oil vapor and allow it to settle in the can. From there you can either plumb the setup to return the oil, or you can have a petcock to release it at regular intervals.
It should be known that the fittings that were added in the pic above are behind baffles contained inside of the valve cover. Without it, the system would ingest too much oil.
With Honda's, we always eliminate the PCV system on boosted cars and go to an opened vent system. It's much easier on the motor, as well as your internal seals.
Very nice looking setup. I am hoping you are right and I have taken steps to connect both valve covers to the low pressure side of the blower. I should know whether or not this will rectify the problem this weekend.
Well, crankcase ventilation is always going to help a blow by condition, the question is the blow by the sign of some wheels in motion that leads to a bigger issue. I read your post above I'd missed earlier, referring to the rich condition, and the progressive leaning you've done.
Rich conditions can certainly damage motors just like a lean one, so be cautious. Increased blow by can be a sign of wear, so it's something you should monitor closely.
I'm definitely curious about this blowerworks setup though. It sounds as if it's venting the crankcase like a pcv style setup, which is kind of surprising considering the last thing you want is the presence of oil in the combustion chamber with a boosted motor. I assume it's working for folks though, as it seems popular..just seems interesting is all I'm saying. I'm still learning how you Corvette guys are forging through the forced induction barriers and still seeing what's available on the market for these cars.
That's fine you have "TC'd" "swaps" in the past, but it doesn't make a basic principle any less relevant. Your use of the term "window area", which generally refers to valve lift and valve circumference, I assume is used here to refer to gas outflow areas of the blocks. Whether these blocks have more or less, doesn't sidestep the fact that blow by needs evacuated, and that the symptoms of blow by will cause the conditions like this person has explained.
That's not to say that there isn't a ring condition that has developed leading to excessive blow by and a developing issue. The fact is though, melted pistons and busted ring lands show other symptoms other than just what is explained here. If he's have no oil consumption, driveability issues, idling changes or anything of the like, then it seems pretty clear he's just having an issue with pressurizing the crankcase or valve cover areas, and that pressure needs relieved.
In reference to your B18/B20 combination comment, that'd be interesting to discuss because you say "specifically". The B18 and B20 castings are the same in terms of the block design, with only variations in deck height between the B16 and then the B18/B20 castings. Furthermore, a combo would be comprised of a head and block, and in the pictures case it's a B16a/B18b combo. So, while you may have "TC'd some swaps", it may seem that your specific knowledge could be lacking. It then leads me to question your entire statement of the differences between the two.
If you have some specific data in terms of square area, window area as you've defined it in this case, between the SBC's and Bseries Honda motors then I'd like to see it for the benefit of my own knowledge. Thank you.
Uhhhmmm, yeah, please dismiss all of my info, technical knowledge, and experience as I probably know nothing of which I speak...
Let us all gather around the CF campfire and hear "relevant" stories about TC'ed Hondas.
Uhhhmmm, yeah, please dismiss all of my info, technical knowledge, and experience as I probably know nothing of which I speak...
Let us all gather around the CF campfire and hear "relevant" stories about TC'ed Hondas.
No one dismissed anything, I just asked for further and more specific info. Your trying to make it seem as if applying a turbocharger to a motor is two different worlds because mine happened to be Honda's. So on the same token your sarcastic last sentence attempts to dismiss my decade of turbocharging, engine building, tuning EMS and racing both as a hobby and through the frequency that comes along with owning a business because it's predominantly a brand you feel is inferior.
If that's the case, I could talk further about RB25's and 4G63's. They use iron block castings and have much poorer gas outflow areas. The 4G63 crowd often struggles with block ventilation and have very frequent problems with blow by leading to blown dipsticks and blown oil filters, along with various gaskets. Aggressive ventilation is also the cure for many of those issues, while the motors continue on for some time.
Like I stated above, I'm not saying a ring wear issue isn't contributing to the problem, I just feel that jumping to the conclusion that his ringlands are destroyed or his pistons are melted is premature. He should use the Blowerworks kit because it's proven to aid these types of issues then troubleshoot further from there if he continues to have problems. My experience has led to me to always start simple, then move forward, not the opposite.
"Starting simple" would mean buying nothing. A static compression test and leakdown test is what is needed, not buying parts.
I dismissed nothing; but I will say that after spending many years working through import applications and upgrades (never felt that Honda was inferior; however, you are on CF), and many years working through each of the later generations of Vettes, the practical application is considerably different between a Vette and a Honda. Experience is an excellent teacher...
I would ask that everyone focus on the OP questions and do not dismiss others "experienced" assessment of what may be the problem with the OP engine. This forum is for everyone to learn from other's similar experience in similar situation. There is a lot of "experience" that floats through the CF boards, but many times goes untapped due to comments like some of those made above.
And as an aside, I am technically degreed through Masters, and I have owned multiple very successful businesses, but do not really feel it necessary to bring that into the picture in an attempt to influence others.
... So, while you may have "TC'd some swaps", it may seem that your specific knowledge could be lacking. It then leads me to question your entire statement ...
Ummm, yes you did. Be careful what you write and the potential interpretation.
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Possible Crankcase Pressurization?
