Any feedback on this idea? The entry angle of the injectors is not ideal coming from the runners as the port is almost blind to the valve. What if we were to sink the EFI bungs into the roof of the runner from the top of the head? A 3/4 drilled through hole at about a 15 degree angle? Then die grind the sockets flush with the roof. Sure they would go through the water jackets but if we were to epoxy them in, the water jacket would be sealed. You make the bungs from 1/2 inch AL pipe that has an OD of exactly 3/4, step drill out the inside to 13.5mm or 17/32 to seat the injector. This way you can run any intake you want with just the addition of a throttle body where the carb would go. You can buy them in .75 OD already step drilled for about $3.00 a piece in a 6 or 8 pack on Ebay. The fuel rail would go right across the top of the head. The colored lines are sight lines for various injector positions. Any opinions? How hard would it be to drill these on a press, or is it outsourced mill time?

Trying to use metals with different expansion rates is going to be a problem. Plus, epoxy is only so good, and expecting it to seal with this type of application, both heat and pressure, is asking a lot. A better alternative is to make some threaded bungs out of cast iron with a pipe thread that goes all the way thru both the exterior casting into and thru the port wall. This way you have a much better sealing potential with the pipe thread and along with a pipe thread sealer is going to be foolproof. I have actually done this on several race engines where I have tapped and plugged the spark plug hole on a set of angle plug V8 heads and redrilled them as straight plug. The rules said no angle plug heads allowed...hehe! But anyway, no problem sealing even with combustion pressure and water pressure.

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There's no such thing as too much cam....only not enough engine!

son of a gun, they nailed it! i guess ill search it next time....

Speaking with a professional fuel injection wizard regarding an EFI manifold I am designing an fixing to cast, he told me a problem with many carb type manifolds that are converted to EFI is that the injector is still placed too close to the head. For alcohol, the injector cannot be close enough, many aftermarket race heads actually have the nozzle plummed right into the combustion chamber. For gas however, to opposite is the best positioning. Placing the noozle too close to the valve creates a problem for gas that doesn't happen for alcohol, and that is you aren't giving the gas enough time to atomize and mix with air before it enters the cylinder, and the effect is spraying raw gas into the cylinders. He has seen a lot of gains with the nozzles on carb manifolds moved another inch or so farther away from the head instead of closer to it. He says many people try to copy what is successfully done with an alcohol based type of injection setup on a gas setup not realizing its not a copy cat kind of a process.

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There's no such thing as too much cam....only not enough engine!

Scott - I agree with that assessment for gas. I have also had injector heat soak issues after shutdown.

Lou

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Home of Slant6-powered fun machines since 1988

The school of thought I ran into on MPFI intakes was the closer to the valve, the tighter the emissions could be controlled. Unburned gas is a result of poor atomization, and the farther you are away from the port, the longer the time the fuel has to fall out of atomization. Realistically, anything past 2400 RPM is too too fast for the fuel to enter the cylinder through an open valve anyway. Fogging the head from injectors up in the runners is fine for F1 RPM running but for our low RPM slants, perhaps closer is better. It also comes down to design constraints. Washing the back wall with the injector cone from the runner is less desireable than hitting the back of a hot valve or an open port. Then again, they did this with TBI for years but emissions got tighter and could not be controlled with the long wet runners of TBI.

That might be true from an emissions standpoint. Seems like things that help emissions hurt performance and vice-versa. Try it and see, like you said in another post, all you have to lose is a cylinder head.

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There's no such thing as too much cam....only not enough engine!

Yes, and I now realized that I cant even do what I want to do. You need a serious drill press with a table that tilts away from the spindle or a DEEP swing on the spindle to set up a head at the correct angle and then drill that cast iron with a pretty slow spindle speed...out of my ability. And I dont have a hand drill thatll take the 1/2 shank 3/4 drill bit I bought, doh! So I just picked an 1962 cast AL 1bbl intake out of my stack and drilled a 3/4 hole as close to the flange as possible and leaned it over 60 degrees. It worked pretty good in soft AL, and I suppose thin wall EMT too; maybe not so good in cast iron. Got them all pretty close and it looks like I got a straight shot to the valve although the window is pretty small. Ill get my rail and mount the injectors and use the rail as the jig to epoxy the bungs. Grind flush inside and mount the TB where the 1920 1bbl used to go. Quick and dirty MPFI. bung in head officially abandoned unless I can get a machine shop to mill the holes for me for $5 a hole...wishfull thinking...Out.

Use a 3/4" hole saw with a 3/8" shank, it'll cut the cast iron better than the drill bit using a drill press or hand drill.....

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There's no such thing as too much cam....only not enough engine!

Good news, that Ill try. The OEM intake will be fine as is, but Im going to have to drill the head for my ram intake, turns out here is no room for the fuel rail with the plenum elbow Im using...The hole saw looks like a perfect solution. Tried to fanagle a jig so I could lean the head into the spindle but I dont like the way it sits. Oh well, a day in the garage beats a day working!

where did all the pics go? All my link are broken and when I try to edit them, the URL of my pics is not any of my photo sites...? Did the board host them and dump them?

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I didn' t buy it, I built it.....

The board doesn't host any pictures.


Where ever you had the pictures is where the problem is.

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

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The website declined to show this webpage

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes