ROE Crankcase Pressure at Idle

[TexasPettey]

I'm getting a good bit of crankcase pressure at idle on my ROE. I've got a full catchcan assembly on both valve covers. When I disconnect the hose from the valve cover, I can feel the airflow from the valve cover. Are others getting the same thing? If so, what's the cause. If not, looks like I'm in for some investigations.

 

[nfelmlee]

Similar issue here. The pressure blows my dipstick out of the tube and sprays oil everywhere. I'd love a fix for this.

-nick

 

[TexasPettey]

Similar issue here. The pressure blows my dipstick out of the tube and sprays oil everywhere. I'd love a fix for this.

-nick

WOW! That much pressure at idle. I thought I had it bad. I had enough that at WOT it would blow out the dipstick. One trick is to upgrade to a Gen3 dipstick. My ViperTech put in a Gen3. The difference is that the Gen3 uses a O-ring inside the tube. The Gen1 uses an external O-Ring. The internal O-Ring has better sealing.

 

[FE 065]

But why is all that pressure in the crankcase? Bad rings?

 

[TexasPettey]

I talked with the ROE folks. They said that there are only two sources of crankcase pressure:

1) leakage through rings
2) leakage through an intake valve seal

#1 is identified through a leakdown test.
#2 can be identified by looking for smoke in the exhaust, as there should be oil dripping down through the valve seal.

I haven't seen smoke, so I'm probably in for a leakdown test.

 

[dave6666]

I thought you were selling the SC to go back to NA?

 

[GTS Dean]

Similar issue here. The pressure blows my dipstick out of the tube and sprays oil everywhere. I'd love a fix for this.

-nick

Dilusi products use to sell a male threaded sleeve that brazed onto the dipstick tube, with an anodized aluminum threaded cap under the t-handle. My N/A motor used to blow the stick loose at the track before this mod. It is not just peculiar to forced induction cars.

Failing that option, you might try fatter o-rings on the t-handle.

 

[Viperless]

Pressure in the crankcase caused by windage and blowby past the piston rings is never a good thing. It's ******* seals, gaskets, and works against the piston rings sealing properly. When you install the Roe system, they have you eliminate the PCV and suggest installing some type of crankcase ventilation system that uses a catch can to trap oil. All this does is give the pressure a way to escape. It does nothing to promote negative pressure which is what we really need. A PCV will create enough suction at idle and part throttle to keep the crankcase evacuated but it does nothing at wide open throttle which is where you'll see the most benefit to performance by having suction in the crankcase.

Some race cars use a system that has check valves installed in or near each header collector with hoses running to each valve cover. The exhaust flow moving past the valve creates suction which pulls vapors and blowby out of the crankcase. The problem with this type of system is, if you're exhaust is too restrictive, it may not work at higher rpms so you'll see no benefit where you really need it. It will also **** oil out if you don't have adequate baffling in the valve covers. Oil in the exhaust creates blue smoke. I know several guys who run this system on the street and they say it works great. Only one way to find out.

The other alternative is some kind of electric or belt driven vacuum pump.

 

[Madduc]

To keep mine in I used safety wire and wired it to the clamp on the hose leading to the radiator.

 

[TexasPettey]

I thought you were selling the SC to go back to NA?

I was thinking of it, but haven't decided yet. I may end up keeping it, because it's hard to think about stepping back 100RWHP.

 

[FE 065]

To keep mine in I used safety wire and wired it to the clamp on the hose leading to the radiator.

That doesn't sound like a good long term solution for anyone having problems like this.

It's evident that there's a lot of blow by gas pressure in the crankcase, contaminating oil at a much faster rate than normal, and no active system to draw any of it out. Just a passive venting/catch can system I guess.

The pressure is costing horsepower, and more importantly shouldn't really be there in the first place.

Along with fixing the reason the blow by is finding its' way into the crankcase, I think a system to draw blow by out is needed.

 

[FE 065]

For the short term, how about fixing a hose over the top of the dipstick tube, running it up in between the intake and valve cover, and then back past the end of the intake with a filter at the end to at least let pressure vent?

Running the hose upwards from the dipstick tube to the gap between the intake and valve cover should present enough of a vertical climb that heavy oil can't follow it up and spread around the engine compartment.

 

[RTTTTed]

The easiest way to check the rings is a simple compression test. Not the best test as it may not show slight problems, but it works and only takes a short while.

I've got a 10# Roe and have no dipstick problems. However I do have an electric vacuum pump (adds a few hp) and a catch can.

If you vent your breathers to the headers it does have a tendency to often cause some blue smoke, but it sure wouldn't pass any smog tests if you do that. The best checkvalve to use is the old ('73?) vette (ouch) PCV. Use the one that has a few inches of 3/4" metal pipe to weld into the header collectors on an angle.

Ted

 

[Knight Viper]

I've got a 10# Roe and have no dipstick problems. However I do have an electric vacuum pump (adds a few hp) and a catch can.
Ted

I did a search and a post on vacuum pumps for our motors with no luck or positive feed back. I know they work in a race car application, nice to see someone who has luck with them. Thanks, KV

 

[Madduc]

That doesn't sound like a good long term solution for anyone having problems like this.

It's evident that there's a lot of blow by gas pressure in the crankcase, contaminating oil at a much faster rate than normal, and no active system to draw any of it out. Just a passive venting/catch can system I guess.

The pressure is costing horsepower, and more importantly shouldn't really be there in the first place.

Along with fixing the reason the blow by is finding its' way into the crankcase, I think a system to draw blow by out is needed.

My dipstick does not seat firmly in the tube, plus add oil into the mix and it doesn't take much effort at all to pull it out. Once I forgot to wire it down. Under normal to spirited passing no problem. Then had some empty highway to play and after a short period at full throttle the dipstick came out. I don't feel that I have excessive crank pressure at all. But I will look into a vacuum pump if it gains me more hp. 8# at 645hp now.

 

[FE 065]

I was running an electric vacuum pump on my FE for a while..

It'd hold 8 in vacuum on my car.

Summit sells them.

 

[Schulmann]

I have rarely seen so much bull****.
What **** did you smoke guys !?
First time I hear that you check the health of the engin by verifying the blowby

All engines (no exception) have blowby. It is not a problem but a feature.

A race engine (with forged pistons) will have a lot of blowby when shifting or at idle (when pressure is reduced on the pistons).

My engine is in top shape and has only 6-10% leakdown. It is nothing. At idle it smokes through the ventings like a diesel truck. Once my wife thought the Viper was under fire. It is all normal. All together I have 3 huge ventings on the engin.

I don't have a vacuum pump and the way the old Gen2 engines are designed it is a waste of money. The pump will quickly be fooled by the oil from the engine.

What is not normal is having the oil stick popping out. It indicates a very poor venting.
You better fix it by additional venting before your head gasket pops out.

On the 2008 engine one of the main challenges was the redesign of the head cover to improve the PCV system and reduce oil suction. SRT group has done very extensive testing on this PCV issue and the result is very positive.

That's being said don't worry for the pressure at idle. It is all normal and you have to evacuate somewhere that smoke. On a supercharged system you better vent it into the nature.

Those who still don't know, poor venting is No 1 engine killer on GEN2 Vipers ...

Make a search on this forum on "catch can" "smoke under breaking" and so on.

 

[FE 065]

I have rarely seen so much bull****.
What **** did you smoke guys !?
First time I hear that you check the health of the engin by verifying the blowby

All engines (no exception) have blowby. It is not a problem but a feature.

A race engine (with forged pistons) will have a lot of blowby when shifting or at idle (when pressure is reduced on the pistons).

My engine is in top shape and has only 6-10% leakdown. It is nothing. At idle it smokes through the ventings like a diesel truck. Once my wife thought the Viper was under fire. It is all normal. All together I have 3 huge ventings on the engin.

I don't have a vacuum pump and the way the old Gen2 engines are designed it is a waste of money. The pump will quickly be fooled by the oil from the engine.

What is not normal is having the oil stick popping out. It indicates a very poor venting.
You better fix it by additional venting before your head gasket pops out.

On the 2008 engine one of the main challenges was the redesign of the head cover to improve the PCV system and reduce oil suction. SRT group has done very extensive testing on this PCV issue and the result is very positive.

That's being said don't worry for the pressure at idle. It is all normal and you have to evacuate somewhere that smoke. On a supercharged system you better vent it into the nature.

Those who still don't know, poor venting is No 1 engine killer on GEN2 Vipers ...

Make a search on this forum on "catch can" "smoke under breaking" and so on.

I think you're smoking home grown myself.

Whatever else, the dipstick shouldn't be popping out at idle on any car. None of my 5 Vipers ever has-and 3 of them had forged pistons.

Please don't compare race engine and their loose tolerances - that are routinely rebuilt, to production engines.

My vacuum pump wasn't being fooled by anything fwiw.

I don't have a dog in this fight. I'm not spewing pressure out of engine orifices. But none the less I'm going to add pan evacs or a vacuum pump again to pick up the HP lying beneath.

 

[Schulmann]

FE065 you are funny and what you discribe is absolutely right.

Your engines were likely built "tight" and you had a very effective venting on your Vipers. Blowby is highest at shift and idle. No Viper engines are the same, but all have blowby. If the venting is poorly setup deep stick can and will popup at any rpm.

I have done a LOT of tests with those blowbys for a simple reason : increase the longevity of my engine. Blowby is a very vicious killer on the GEN2 Vipers. My Gen2 engine has now 30000mi .....

I never put money into a Vacuum pump. Having 600hp or 603hp doen't make much difference for me. I rather put my money into two good WBO. But your are right you can gain a couple of hp with the Vacuum pump.

What I want to say to all these guys is that the blowby is normal. You can vent it to free air with or without vacuum pump. But please don't recirculate it into the engine on GEN2 High Performance Vipers. I have seen a lot of guys running with the stock PCV. They all, with no exception, blowup their engine because of the oil sucked out the engine ....

 

[TexasPettey]

Your engines were likely built "tight" and you had a very effective venting on your Vipers. Blowby is highest at shift and idle. No Viper engines are the same, but all have blowby. If the venting is poorly setup deep stick can and will popup at any rpm.

I'll bite. Why is blowby highest at idle? I would think that with less air/fuel in the combustion chamber, there would be less pressure on the rings and subsequently less blowby.

 

[agentf1]

I have a Roe CrankCase Breather on my Viper. I figure it is probably not needed or overkill on a stock engine but it won't hurt either. I guess better safe than sorry. Anybody else use one of these?

Roe Racing Crankcase Breather Assembly - All Vipers - Supercharger - Roe Racing

 

[Nadine UK GTS]

Yes, that Roe crank case breather is good, as you do need to open up the amount the valve covers can breathe with the SC install, and I always blank off the front OE vents, don't plumb them going back into the intake on the GenII's you don't want oil/crank case vapours going back into your motor. Presence of oil lowers the octane of the mixture and will cause hotter running. I drilled the valve covers and fitted 90-degree angle 3/4" breather lines each side to a vented catch tank. (Just be cautious if you drill the covers, they are magnesium.)

Anyone remember the debate on here some years back, running the "crankvent valves" that the Harley motors use?

 

[treesnake]

I have the exact same problem. The solution should be arriving from Arrow racing next week, a new forged piston engine. The new engine's pistons have lowered ring lands to deal with additional S/C (TT's next year) boost.

The blower blew out my rings ("01-GTS) after eight hundred miles. First I hooked up a catch can. The pressure blew right through it and all over everything. Then I hooked up an electric vac pump out of an LS1 camaro. That worked great until the blower's boost kicked in. It would fill the vac pump reservoir and would actually have a negative "blocking" effect. The whole time making a mess out of the engine compartment and the rear of the car. Now I have removed the vac pump and have run a one inch rad. hose off of the valve covers, underneath and to the back of the car and point straight down at the ground. Most of the oil "mist" blasts to the ground. The rest I wipe off the back of the car after each time out. It really ***** wiping the oil "mist" off the car but I love to drive my car and that's what I need to do until the new engine is installed. I installed baffles in the valve covers which helped in the beginning. I also use "Restore" and "Ryslone" oil additives for the short term. They actually do work.

If you have a cast piston engine, and you want to run a S/C or TT, it is just a matter of time until you will be changing the pistons, at least.