Does this old hot rod trick work or is it just a myth?
Does this old hot rod trick work or is it just a myth? I've heard it's possible to squeeze more horsepower out of a motor if you fill the lifter valley. (With something like Hardblok.) Supposedly how this is set up is by cutting tubes that are closely matched with the diameters of both the lifter bores and the oil drainback holes, setting them in their appropriate locations and then casting them into place with the Hardblok. You're supposed to make the tubes just long enough that there is still enough clearance under the intake manifold for the oil to come out the top, and then you fill the valley with Hardblok just enough that there is still a quarter of an inch or so's worth of tube still sticking up above the surface of the fill. Then you drill passages through the Hardblok at both the front and rear drain holes in the valley, and those become your primary drainback holes.
The premise behind this is that it's supposed to keep oil from draining back down through the oil holes next to the lifter bores and splashing onto the spinning crank. Oil dripping onto the crank causes additional turbulence in the crank case which robs power. Also, because there's less room in other parts of the engine for the oil to go, more of it will stay in the pan which decreases the chance of the oil pan being pumped dry. (Which I'm not sure is that much of a concern, but what the hey.)
I'm just reiterating how this was explained to me. I'm skeptical about how much truth there is to it so that's why I'm here.
Has anybody heard about this trick or had any experience with it? What kind've power increase did you see, if any? Is there some kind've catch if you do it? (Like, having to convert to a dry sump system, etc.?)
The premise behind this is that it's supposed to keep oil from draining back down through the oil holes next to the lifter bores and splashing onto the spinning crank. Oil dripping onto the crank causes additional turbulence in the crank case which robs power. Also, because there's less room in other parts of the engine for the oil to go, more of it will stay in the pan which decreases the chance of the oil pan being pumped dry. (Which I'm not sure is that much of a concern, but what the hey.)
I'm just reiterating how this was explained to me. I'm skeptical about how much truth there is to it so that's why I'm here.
Has anybody heard about this trick or had any experience with it? What kind've power increase did you see, if any? Is there some kind've catch if you do it? (Like, having to convert to a dry sump system, etc.?)
A windage tray works the same way- keeping oil from the sump away from the spinning crank. I used them on Ford's for years, and the claim was about 8-10 rwhp on a stout FE series, or 385 series motor. I do know of oiling mods on 351C motors that require blocking drain holes in the heads to keep oil down at the crank, but that was due to high rpm oil starvation at the crank, and losing a journal or main.
Launching!
Joined: Nov 2003
Posts: 210
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Sounds like a stock eliminator mod to me. They run tight side clearancees on the rods and three quarts of oil in the sump to keep the windage down in the crank case. They have to kill the engine or bring it to an idle imeditely after a run to keep it from running out of oil. These mods are for class racing where they are looking for every last hp.
Not common in the Stock engines I have seen. Chevy's do not need it, just screw in bleed tubes. Pontaics may benefit because of the openess of the lifter area. Some may also do it to sure this area up and have support all the way around the lifter bore.
Tighter side clearances loose HP. Control the oil.
No need to shut them down at the end of a run.
It's 3.5 qts of oil when we are on kill.
Rich
Tighter side clearances loose HP. Control the oil.
No need to shut them down at the end of a run.
It's 3.5 qts of oil when we are on kill.
Rich
Originally Posted by STOCK1090
Not common in the Stock engines I have seen. Chevy's do not need it, just screw in bleed tubes. Pontaics may benefit because of the openess of the lifter area. Some may also do it to sure this area up and have support all the way around the lifter bore.
Tighter side clearances loose HP. Control the oil.
No need to shut them down at the end of a run.
It's 3.5 qts of oil when we are on kill.
Rich
Tighter side clearances loose HP. Control the oil.
No need to shut them down at the end of a run.
It's 3.5 qts of oil when we are on kill.
Rich
"SBC lifter valley vent tubes are designed to be installed in the eight lifter valley drain back holes. These 2" tall vent tubes reduce crankcase pressure by allowing air to freely pass through but not allowing oil to drain directly onto spinning crankshaft absorbing horsepower and increasing temperature.
The oil is redirected to the sump through the timing cover and rear block holes. #22-220 SBC lifter valley vent tubes sold in a pack of 8 per set.
Recommended or related parts.
#65-061 Lifter Valley Baffle."
Launching!
Joined: May 2005
Posts: 210
Likes: 0
Originally Posted by thesoundandthefury
These screw in bleed tubes you're talking about, would they be something like what's on this page?: http://www.cantonracingproducts.com/...acc.html#tubes
"SBC lifter valley vent tubes are designed to be installed in the eight lifter valley drain back holes. These 2" tall vent tubes reduce crankcase pressure by allowing air to freely pass through but not allowing oil to drain directly onto spinning crankshaft absorbing horsepower and increasing temperature.
The oil is redirected to the sump through the timing cover and rear block holes. #22-220 SBC lifter valley vent tubes sold in a pack of 8 per set.
Recommended or related parts.
#65-061 Lifter Valley Baffle."
"SBC lifter valley vent tubes are designed to be installed in the eight lifter valley drain back holes. These 2" tall vent tubes reduce crankcase pressure by allowing air to freely pass through but not allowing oil to drain directly onto spinning crankshaft absorbing horsepower and increasing temperature.
The oil is redirected to the sump through the timing cover and rear block holes. #22-220 SBC lifter valley vent tubes sold in a pack of 8 per set.
Recommended or related parts.
#65-061 Lifter Valley Baffle."
i was told to envision a hand blender in a bowl of eggs when dealing with a spinning crank vs. oil. wouldn't dumping the oil out of the valley on to the chain & sprocket have a similar effect?
Mr. Fury
You got it. Anytime you can let air more freely move around in the engine(hence the big open holes at the top of the main webs on the LS6 block) you are in better shape. A piston going up and down moves air from bank to bank. The easier it moves the less resistance it has.
Vaccum in the crankcase is best but not an option on the street or in Stock. Less resistance will result and a light(less drag) ring package can be used.
The oil will go down the front or the back. Much better than on the cam and the crank.
Steve you bring up an interesting point. I never tried coating the cam and crank gears with oil shedding coatings to help prevent what you are talking about. I don't know if it would live in that environment. I also really don't know if it is a measureable loss like whipping oil on the crank. Maybe someone can add on to this part.
Rich
You got it. Anytime you can let air more freely move around in the engine(hence the big open holes at the top of the main webs on the LS6 block) you are in better shape. A piston going up and down moves air from bank to bank. The easier it moves the less resistance it has.
Vaccum in the crankcase is best but not an option on the street or in Stock. Less resistance will result and a light(less drag) ring package can be used.
The oil will go down the front or the back. Much better than on the cam and the crank.
Steve you bring up an interesting point. I never tried coating the cam and crank gears with oil shedding coatings to help prevent what you are talking about. I don't know if it would live in that environment. I also really don't know if it is a measureable loss like whipping oil on the crank. Maybe someone can add on to this part.
Rich
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Originally Posted by STOCK1090
Mr. Fury
Vaccum in the crankcase is best but not an option on the street or in Stock. Less resistance will result and a light(less drag) ring package can be used.
Rich
Vaccum in the crankcase is best but not an option on the street or in Stock. Less resistance will result and a light(less drag) ring package can be used.
Rich
Nate
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Originally Posted by Nate_Taufer
Why is a vacuum in the crank case not an option on street setups? I am thinkg about going with the moroso setup when i put in the 433.
Nate
Nate
? ? ? 
TECH Resident
Joined: Dec 2004
Posts: 845
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From: K-W, Ontario
I doubt a vac system on a street motor would serve any benefit.
THis sort of modification would probably make some power on engines spinning
6000-8500 RPM which make some serious cylinder pressure.
THis sort of modification would probably make some power on engines spinning
6000-8500 RPM which make some serious cylinder pressure.
Your definition of street and mine may be different but here goes.
Sealing up the engine so you can HOLD vacuum could be interesting. If you plan on pulling a heavy amount of vacuum oil seals are put in backwards so it does not try to fold them in. I'm guessing you will find a few areas that will leak vacuum but not oil.
The real gain from vacuum is the very light ring package and oil ring tension you can run. If your vacuum goes away you may not be able to control the oil getting past the rings. If you do not put the light rings in don't bother with vacuum.
I do not know the duty cycle of the pump you are planning to use. It may lose its effectivness in a short amount of miles since it was designed for racing. If you are going to run vacuum get an electric vacuum pump form a GM car. I cannot remember what they were used on. I think it was some Buicks and Pontiacs.
Oil tends to get pulled away from the piston pins on high vacuum situations. I don't know if that pump will get that high.
Save the aggravation and the time. Put the money into high dollar pistons and rings. Find the best machine shop and pay him to take his time to get everything right. Get a better set of heads or buy your next cam that you think will build more power for what you are doing. You first choice is usually not perfect. I have gone through four different tweaks to my original choice to get to where I am now.
My $.02
Rich
Top fuelers are street drivable if you like the turning radius of a bus, fuel mileage measured in feet per gallon and nowhere to put a friend.
Sealing up the engine so you can HOLD vacuum could be interesting. If you plan on pulling a heavy amount of vacuum oil seals are put in backwards so it does not try to fold them in. I'm guessing you will find a few areas that will leak vacuum but not oil.
The real gain from vacuum is the very light ring package and oil ring tension you can run. If your vacuum goes away you may not be able to control the oil getting past the rings. If you do not put the light rings in don't bother with vacuum.
I do not know the duty cycle of the pump you are planning to use. It may lose its effectivness in a short amount of miles since it was designed for racing. If you are going to run vacuum get an electric vacuum pump form a GM car. I cannot remember what they were used on. I think it was some Buicks and Pontiacs.
Oil tends to get pulled away from the piston pins on high vacuum situations. I don't know if that pump will get that high.
Save the aggravation and the time. Put the money into high dollar pistons and rings. Find the best machine shop and pay him to take his time to get everything right. Get a better set of heads or buy your next cam that you think will build more power for what you are doing. You first choice is usually not perfect. I have gone through four different tweaks to my original choice to get to where I am now.
My $.02
Rich
Top fuelers are street drivable if you like the turning radius of a bus, fuel mileage measured in feet per gallon and nowhere to put a friend.
