Hi I'm looking for any information or literature on reverse flowing a nail head or any v8s. I've did a search but no tech articles surfaced. Thanks guys!
http://www.jalopyjournal.com/forum/showthread.php?t=716655 Not a TON of hard tech, but it seems to be coming up more and more lately. How about an iron "intake" with a turbo bolted directly to it?
Well, years ago Smokey Yunick developed and built reverse-flow system for some of his Trans-Am race cars – but then again Smokey had pretty much unlimited resources. Several independent engineer / engine builders have toyed with reverse cooling but as you already know the LT1 was the first “mass-produced” engine with reverse-flow cooling. There are differing opinions on the effectiveness of reverse-flow cooling. It would appear to be better than standard-flow systems but it certainly requires additional engineering to make it work properly. In a “standard flow” engine the coolant is typically boiling somewhere in the engine – more than likely in the coolant passages within the cylinder head as this is the hottest point the “coolant” comes into contact with. The temperature of the interior engine walls surrounding the combustion chambers are far above the boiling point of any known coolant. The coolant directly in contact with the back-side of the combustion chambers, particularly near the spark plugs and exhaust valve seats, turns to vapor. This forms a turbulent natural convection where the vapor forms bubbles that collide causing a condition known as “nucleate boiling”. This condition is not harmful as long as the vapors are continually moving and not allowed to accumulate (like when an engine runs cry – very bad things happen). Under normal engine operating conditions, the coolant flow rate is sufficient to move the vapors along while continuing to flood the area with a steady stream of liquid coolant. As the liquid hits the vapors, any of the above mentioned “bubbles” that may have formed condense back into the coolant stream. If a steam pocket forms, the vaporized coolant may prevent the flow of the coolant to that area of the water passage and a hot spot will develop on the inside of the chamber. This condition can cause detonation and potentially lead to engine failure. Vaporized coolant cannot transfer heat as efficiently as liquid coolant so in essence, it acts as an insulator, allowing the temperature to go into the stratosphere. In a reverse-flow system, the coolant flow not strong enough to expel the vapor from the cylinder heads down through the engine block and out to the radiator. The vapor, instead, will remain trapped around the cylinder head, where it will become super heated and in all likelihood - melts your engine. GM came up with a solution to this problem. They vented the cylinder heads where coolant vapors would normally collect. On the Gen II engines, these vents are on the rear side of the cylinder heads. Steam and trace amounts of liquid coolant escape through a banjo fitting into a tube that goes into the coolant overflow reservoir. The opening of the banjo is small enough to limit liquid coolant from flowing through it, but allows steam to easily pass. As the steam travels through the little hole in the banjo fitting, the pressure drop and it condense to a liquid state as it returns to the overflow reservoir. So to “convert” from standard to reverse flow cooling, you’ll have to have the steam holes and a means to regulate / restrict the passage of steam vapor and fluids. You’d also need to capture and return to the cooling system.
Didn't I just see a pic of a reverse induction nailhead on here the other day? Or was it something else? Rich
Likely there will be very little actual info. A few have tried to make a reverse flow engine work typically using a supercharger to force air through the smaller exhaust ports/valves and use the larger intake ports/valves for the exhaust. However, no one has had enough sucess with this (or any notable sucess at all) to make it a common practice. I can tell you for a fact that the biggest increase in a Nailheads performance is actually getting more air into it, not the exhaust like commonly thought. Not to say you should neglect port work, but when more air is allowed in the Nailhead makes more power than if more exhaust is let out-all other things being equal. If you decide to use the reverse flow on the Nailhead, supercharging is the best bet as the exhaust ports have a bad short turn radius which would not likely do well if just using engine vacuum to induct air and fuel. But if power is what you want not just a freakshow, I would set the supercharger up conventionally for induction weather it is front mount or top mounted.
You will have to swap the intake and exhaust lobes on the cam. In order to do this You will need an unground cam blank. As mentioned earlier to get any benefit from this you will have to supercharge it. I am doing the same thing with a flathead V8 and a front drive blower. Check out my thread front drive blown reverse flow.
What is the pay off for doing this to an engine? What are the reasons it would be desirable? I've never really learned much on this particular subject.
People, (Craiger, Bill Kenz, and others I'm sure) did reverse cam MODEL A'S because there are four exhaust and only two intake ports, effectively doubling their fuel intake.
While it is apparently not what the OP was looking for, I would like to thank you for this explanation on the cooling system. Most thorough I've ever read.
I read through the T bucket page a little. Apparently, he made the "reversed" cam by turning the lobes round and then metal spraying the blank back up to create new lobes in the right area. Wow, hot rodding at it's finest.
Besides the cam, Just basic plumbing. Make an intake and exhaust, but use the opposite gaskets for patterns.
Nielson Vintage Racing Cams http://www.nielsoncams.com/ They priced me a custom ground Pontiac hemi roller cam .
How about disecting a hilborn fuel injection and fitting to the sides of the motor, That would look cool
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