Supercharger Blow-By & Smoke out the oil cap

[BB1960]

Hi All,

It's been a while between posts, but since the last one I've put a powerjection 3, water to air intercooler and a vortech supercharger all under bonnet on my 60 impala.

One thing I've noticed is significantly more white smoke out of the oil fill cap on since putting the 4bbl manifold back on (I had a 3X2 before).

Suspecting the rings didn't bed properly after the rebuild (less than 1200 miles ago), I did a leak down test and the worst reading I got was 7%, the best was a little under 5%, which indicates a healthy ring to bore seal and no issues in the head......

This got me thinking (and typing). I know I'm getting vacuum at idle (the powerjection has a map sensor with on screen display), and there is a vacuum guage on the vacuum tank (see photo).

I've plumbed a custom oil/air separator (also pictured) with stainless steel wool filter medium inside from the back of the manifold where the road draft tube would be, then it goes to the base of the throttle body (I've got an adapter, 4gc to square bore, open plenum pcv plate and resin spacer) to lift it all 2 inches).

I'm pretty sure I've got my pcv system setup correctly, so I'm not sure why it's fuming soo much. This is even at idle......

The only difference in the manifolds is when I put the 4bbl one back on there was no baffle/oil shield and maybe the oil is burning on the bottom of the exhaust cross over???? But if this was the case, wouldn't it be sucked through the pcv rather than out of the breather?

The second issue I have, is oil pooling on the top of the manifold (only on the drivers side, see photo). I've replaced the valve cover gasket, so I dont think it's coming out the valve cover. It has also been pooling at the back of the manifold near the dizy...... Is it possible that it's dripping from the breather cap whilst driving and pooling???? Long shot?

Could not having the oil baffle on the underneath of the manifold be causing this issue??????

I'm about to install some header and make a new exhaust, but realy want to sort this out first......

Thoughts??????

 

[Fathead Racing]

My thought is that the supercharger is pressurizing the crank case either past the rings or intake gaskets. I would add valve cover breathers and see if that helps. I would had rather you install the baffle under the intake but that will not push blow by out the oil fill. Letting the crankcase breathe may cure your oil leaks also.

 

[Don Jacks]

I wonder if the oil leak is caused by oil is migrating up by way of the threads.I have seen this on small blocks where the holes are open as opposed to blind holes.As to the "blow-by"That little Pro-Charger dosent make boost until it's up into the rpm band,so why it's doing this at idle is a bit of a mystry.

 

[Fathead Racing]

Will a PCV system work at all with a supercharger?

 

[32witha409]

Will a PCV system work at all with a supercharger?

It will so long as you are not on boost like from idle to 29IN/HG. The system also needs to have a ventilation hose/tube large enough to releive the pressure in the crank case and vent it back into the intake up stream of the blower.

On a leak down note 7-5% I consider high for street especially on a newly broke in engine. What are you seeing for manifold vac at idle?

 

[BB1960]

It will so long as you are not on boost like from idle to 29IN/HG. The system also needs to have a ventilation hose/tube large enough to releive the pressure in the crank case and vent it back into the intake up stream of the blower.

On a leak down note 7-5% I consider high for street especially on a newly broke in engine. What are you seeing for manifold vac at idle?

Idle vacuum is at 15 inches (it has no vacuum advance so it could be higher). The leakdown was performed on a cold motor (to get to the plugs the supercharger has to be removed etc). I also didn't have the exact fitting for the plug thread so I used the one from my compression checker that is a rubber tipped push in type. I'm not overley fussed with the result, I'm not going to pull the engine unless I have to, and at 5% cold, I don't think it's necessary.......

I'm looking at installing a vac-u-pan system as I'm about to replace the entire exhuast system with dougs headers and a twin 2.5 system from the collector back.

I did run a vent to the fron of the blower (which is the back) and it helped, however, it was only 3/8 or -6 size which may not have been large enough........I removed that not long ago.......What size do you think would be necessary????

Looking at the vac-u-pan, the hose size is 5/8. The other thought I have had is I do not have a check valve in the pcv system (I thought the PCV would act as a check valve), which means some manifold pressure could be finding its was into the crankcase.......

 

[BB1960]

My thought is that the supercharger is pressurizing the crank case either past the rings or intake gaskets. I would add valve cover breathers and see if that helps. I would had rather you install the baffle under the intake but that will not push blow by out the oil fill. Letting the crankcase breathe may cure your oil leaks also.

I agree with this, I cant get the pressure out fast enough..... The vacupan system I'm considering at the moment will add breathers to the rockers (there isn't much spare space for these at the moment, I'm not sure where I'm going to put them). I am going to remove the intake manifold and install the baffle, I have one on another intake I have.

 

[BB1960]

OK, I've installed the baffle back on the manifold (and given it a fresh coat of chevy orange), used the manifold vacuum port for the power brakes ( and replaced the 2 one inch spacers with a 2 inch spacer. One interesting note was how much burned oil there was on the bottom of the manifold...... This I think is one source of the smoke.....

I picked up the vac-u-pan kit today, I dont like the breathers they include in it (ie the mopar style baffled breather), I'm thinking of installing a baffle inside the rocker covers and mounting a port to the rear of the covers to go down to the exhaust, this should help relieve some of the pressure inside the rockers and hopefully enough to create some vacuum at cruise.....

The other option is to use baffled PCV grommets in the back of the manifold with no internal baffle.........I have some, but dont really like the restriction they pose.........

Has oneone made baffles for inside a 348-409 cover?????

I can now use the vacuum port at the base of the throttle body for the PCV system, which I still think needs a check valve........ I would've thought the PCV would've been enough........

 

[models916]

Is the heat riser valve opening correctly? If it's stuck closed or partially closed it will overheat the bottom of the intake.

 

[Fathead Racing]

I think you should block off the heat riser anyway!

 

[BB1960]

If you mean the one in the exhaust, the valve/butterfly and shaft has been removed and the shaft holes plugged.

If you mean the exhaust cross-over, it hasn't been blocked....... I'v e heard if you block this you need a cross-over pipe or x-pipe in the exhaust and I stuggle to see where that is going to fit under the car......

 

[Ishiftem]

Nah, you don't need an x or H pipe. Unless you plan to drive when its really cold, I would block it off.

 

[Fathead Racing]

I think you should block off the heat riser anyway!

Yeah, I meant to say manifold heat crossover. If you go with 3" exhaust pipes that exit in front of the rear axle you can get away with no crossover and still get a nice sound. Small 2.5" full exhaust may sound a little "rappy" without an X or crossover. Running with a supercharger and performance upgrades and leaving the intake manifold heat crossover open is like taking two steps forward and one step back.

 

[Skip FIx]

FWIW I was just at the Texas Mile watching one of the local Texas Pontiac Super Stock racers go 179 mph in his 64 Tempest "street car" that has a Vortech on a 72 455 HO motor. He uses header evacs and no PCV. Not a drop of oil. It was first outing with the boost so alot of bugs. Did a mild burnout then let off fast and torre some teeth off the blower belt as the wastegate wasn't big enough for that whee the throttle blades slam shut. Alternator belt spun and had to realign it's bracket. Still ran 165 mph missing teeth though! Drove the car home an hour after the last race.

One of the other Pontiac guys that came down from Detroit is a boost engineer for Ford(Eco boost motors) and says I need to boost my W motor.

 

[BB1960]

Yeah, I meant to say manifold heat crossover. If you go with 3" exhaust pipes that exit in front of the rear axle you can get away with no crossover and still get a nice sound. Small 2.5" full exhaust may sound a little "rappy" without an X or crossover. Running with a supercharger and performance upgrades and leaving the intake manifold heat crossover open is like taking two steps forward and one step back.

I've got 2.5 inch outlet Doug's Tri-Y's with the ceramic coating. The exhaust currently exists in front of the rear tyes (ie out the sides), I'll see how is sounds after the header install, a ballance pipe isn't a massive issue to make. As for the cross-over cut outs, I've seen the one's for sale, to save freight and time, I'll just make some.....

Thanks for your help everyone.... Esspecialy Fathead, you've helped me in the past....Cheers, Simon

FWIW I was just at the Texas Mile watching one of the local Texas Pontiac Super Stock racers go 179 mph in his 64 Tempest "street car" that has a Vortech on a 72 455 HO motor. He uses header evacs and no PCV. Not a drop of oil. It was first outing with the boost so alot of bugs. Did a mild burnout then let off fast and torre some teeth off the blower belt as the wastegate wasn't big enough for that whee the throttle blades slam shut. Alternator belt spun and had to realign it's bracket. Still ran 165 mph missing teeth though! Drove the car home an hour after the last race.

One of the other Pontiac guys that came down from Detroit is a boost engineer for Ford(Eco boost motors) and says I need to boost my W motor.

I'd like to say that 179mph would be nice, but it's not that kind of supercharger setup. It's mainly for a little more go, not a race car. If I can make 450-500hp at 10psi I'll be happy. I think I'll need a cam upgrade to get there with some dyno time and programmable ingition (ie MSD 6AL2) I think it's achieveable.

 

[Skip FIx]

Just saying also a simple header evac system worked fine for him.