Hey guys I’m having a massive problem with my engine becoming pressurized and blowing oil through the valve covers gasket. I am also having a problem with low vacuum for the power brakes. We placed an electric vehicles vacuum brake pump to assist the system but I feel like I am only get 40% out of my brakes, with them being hard to push.

My questions are how should the PCV SYSTEM be plumbed. I hear some guys using exhaust vacuum, some putting an inlet before the turbo compressor. I need to know the best way to solve this problem.
Right now we have two hoses that are I believe are 5/8ths going from the middle of the valve covers to our scavenger tank that pumps it back through the system. One hose goes directly to the tank, the other hose for the other side goes to the port under the carburetor. This scavenger tank has filters on top which appear to become saturated with oil. This system has no vacuum as it’s open to atmosphere and is just a breathing port. Except the righ valve cover which is tied to the engine manifold. (This is what my dad wanted because this s hoe his old race car use to be)


Do I just need bigger hoses going to a tank? Is it okay I’m using the turbo scavenge tank? I know this adds extra pollutants in the oil but really is that bad.


How should the brake booster be plumbed? Currently have it plumbed to the manifold with a check valve. But really this only generates vacuum a few seconds after you let off the throttle which can lead to some terrifying stops. I also have a electric vacuum pump from an electric vehicle that is plumbed with a check valve in line. This has helped a bit wi5 the problem but far from fixing it.

Pictures, diagrams, threads, anything that could help.

Would investing in a vacuum pump solve all my problems??. What’s the bet bang for your buck vacuum pump. As I have more room for an electric pump than a mechanical one that might be the road I will go.



Big block 454 fairly stock everything, forged crank, high rise intake
Blow through XFI with ~10psi
Mostly track, Drive to car shows.



I’ve been searching around and couldn’t find a good answer for my application. Any help would be appreciates

 

Do you know whats causing the blowby?

 

The only reason for that much is I assume one of my check valves is leaking by that’s causing that much pressure. It’s seeping past the valve covers which are definitely not top of the line but I figured would hold better than this. Maybe the bolts walked themselves out and I will check this when I get home on Sunday. Other than that this appear to be what a normal big block pushes out of its valve covers. I just wanted to know the best way of doing this .From what I learned at the races this weekend with the 10,000horsepower motors is that they just have giant hoses going from the valve covers to the oil tank. Pretty simple. No real need for vacuum. As for the brakes not recovering full vacuum I was wondering if someone had a tried and true method of getting this to work. I think I’m onto something with my electric vacuum booster pump. Hmm definitely going to reroute it this weekend and try it a different way and see what happens.

 

If you have blowby and vac loss there is a good chance of damaged piston or bore

 

Any pics of your setup? Are there baffles in the valve covers preventing oil from being drawn into your breather? Unless you have a pcv valve, and a good check valve, I wouldn't hook anything to a vacuum/boost source other than brakes, gauges, fpr.... With a good check valve, and vacuum source your brake booster should have enough reserve for 2-3 brake applications, even in boost. Ever check to see what it makes for vacuum at idle?

 

You shouldn't have blowby issues on a stock motor with a PCV valve unless the motor is hurt. How much vacuum do you have at idle? Is the reading steady? Are you sure you do not have a vacuum leak (leaking/bad booster)?

 

Anytime ive had lots of crankcase pressure it was always a ring seal issue. Weather it was just worn, or a ring was broke.

 

I would disconnect the vac line from the oil/surge tank and plug it, then see what happens. A vacuum tank should help with the brakes. Put the engine and the electric pump on the inlet side, the booster on the outlet. Confirm the check valve to the engine id's good. I've seen many cases where the check valve was backwards and no vacuum making it to the booster or tank. Exhaust evac for the crankcase is best for short or open exhaust systems. I would run the evac to your oil/surge tank.

 

As Mnlx said: baffles in valve covers? If you're trying to ventilate crankcase from the middle of the valve cover, valvetrain is throwing oil up and since a 5/8" line is not very big and the air will flow at a high velocity which carries the oil mist to the breather/scavenger tank. If air flow is enough it will push it right out the breather. When ventilating through valve covers you want large lines pulling from a baffled valve cover.

The way you have it plumbed: Under boost you essentially have one 5/8" line to ventilate the crankcase and unless you have a check valve going to that right valve cover, you're also forcing boost into the crankcase making the situation worse. As a first step I would nix the line going to the intake manifold and add a second breather tank in its place. Another reason to do this is that the line going to the intake is contaminating your intake with oil mist and lowering the effective octane of your fuel. If it's lightly street driven and you change oil regularly you don't need PCV.

If oil mist is still an issue out of your breather tanks, you could try adding brillo pad for the oil mist to collect on before being forced out the filter.

Have dealt with this issue on numerous twin turbo small blocks. Adding ventilation to each valve cover (with baffles) to 2 breather tanks always fixed the issue.

If you must run PCV to the intake manifold, be sure the valve cover is baffled. Then you should first run it into a oil separator before it goes into the intake. Any PCV valves should have a check valve in line, or use a PCV valve with a built-in check valve (i.e. Grand National or TurboCoupe PCV valves came this way).

Technically this sounds correct. Have you verified your check valve works with the amount of boost you're using? The vacuum diaphram is in good condition? Check valve is facing the right way? How much vacuum do you have at idle?

Before going with a vacuum pump consider switching to manual brakes. With the correct pedal setup they work well, simpler and will always work under boost.

What type of ring package are you running? Conventional tension or low tension rings?

I think your issue can be solved using the suggestions above, but if you're running low tension rings then you might need to do some additional work like the vacuum pump you suggest. But if you're running standard tension there should be no reason for adding a vacuum pump for crankcase ventilation.

 

I put a hydro boost set up on my car and it might be the best thing that I have ever done. I use a Ford 9" with 1/2 ton drum brakes in the back and stock f body brakes in the front. It doesn't stop as well as my C5 Vette but its real close. I tried the Mopar ( Strange) master cylinder but ended up modifying my stock on in the end. It works so well I cant say enough good things about it. I have a remote reservoir mounted in the spot where the battery was and I am using a KRC power steering pump.

 

I did hydroboost in my f150 as well, I really like it.

 

#1: I'm pretty sure this problem could be fixed with a $3 check valve.
#2: Hydroboost has no place on a car that is mostly track and driven to car shows.

I have hydroboost on my personal car. The whole time I was converting it to hydroboost I was damning the hydraulic lines, pump, cooler, etc. Then the pedal feel is mediocre at best, it feels like you're stepping on a sponge. It's nothing to do with bleeding brakes or brake lines or anything like that: it's just how hydroboost feels. Car stops better than most everything I've driven, but the pedal feel sucks.

I've driven manual brake cars and properly setup you cannot beat the pedal feel. Show me a purpose built track car that uses hydroboost or vacuum assisted brakes.

That being said: in my mind the check valve is suspect. OP any update?

 

My hydroboost feels exactly like the one in my 2500 HD ...kick ass.