Big redo of the old bucket
- Thread starter PotvinGuy
- Start date
I am a boilermaker. Four long hard years to get the degree I needed to become rich and powerful. That didn't work out, so I became an engineer.
EWTALLEY
Active Member
My hometown is just down the road in Greencastle " home of Depauw.U." I almost went to Purdue, my first Father-in-law offered to pay my way through the four years,,but like Indycars post that was me back in 1963. So having a "wild hare" I joined the Navy instead. This guy was an Electrical Engineer and worked for Public Service Co. of Ind. and also boilermaker. Thanks for the info.
I grew up in Warsaw. PU 1963-1967. EE, and NASA wanted me for the Apollo program, but, being smart, I went to TX for more money.
When I first built my car I used a "fuel injector sizing" site to pick 36lb injectors. But I noticed that the idle injector duty cycle (as indicated on the FAST handheld) was less than 1% (it fluctuated between 0 and 1 because the handheld only displays to the nearest percentage). I figgered the mildly rough idle and rather poor off-idle response was due to the injectors being too big. So I swapped them for 24# units. Here is with the wiring disconnected:
...and with the left log off:
The log and injector assembly:
Here's the new 24# injector:
..with a nicked O-ring...ack!
How did this happen? And how did I find out? When I put it all back together 3 of the injectors were spraying from the top end. Looking at the fuel rails:
I could see that the rail had drilled holes with sharp edges, and the O-rings were being nicked while coaxing the injectors into the rail. So I used some fine sandpaper to ease the edges, used plenty of grease, and no more leaks. And here we are buttoned up with the wiring still exposed:
Went for a ride. The idle duty cycle is now 3-4%, cruise is about 7% and WOT is 40%. That's with the blower undriven. Idle is smooth and throttle response is smoother too. Now I need to find a big open space to test with the blower engaged.
What have we learned today, boys and girls? Picking the right size injector will make your ride happier. Too big and your motor will be rough. Too small and you could lean out at WOT. And don't be tempted to put big HP numbers in the sizing calculators. I used 500, which I will never see.
...and with the left log off:
The log and injector assembly:
Here's the new 24# injector:
..with a nicked O-ring...ack!How did this happen? And how did I find out? When I put it all back together 3 of the injectors were spraying from the top end. Looking at the fuel rails:
I could see that the rail had drilled holes with sharp edges, and the O-rings were being nicked while coaxing the injectors into the rail. So I used some fine sandpaper to ease the edges, used plenty of grease, and no more leaks. And here we are buttoned up with the wiring still exposed:
Went for a ride. The idle duty cycle is now 3-4%, cruise is about 7% and WOT is 40%. That's with the blower undriven. Idle is smooth and throttle response is smoother too. Now I need to find a big open space to test with the blower engaged.
What have we learned today, boys and girls? Picking the right size injector will make your ride happier. Too big and your motor will be rough. Too small and you could lean out at WOT. And don't be tempted to put big HP numbers in the sizing calculators. I used 500, which I will never see.
CheapT
Active Member
Potvinguy, glad your ride is running better! It''s funny that you mention that about the horsepower. Back in my high school days a gear head friend of mine asked me how often and when would my car see X horsepower. I said it would be every once in a while. He suggested a smaller carb and as it worked out he was correct. I wanted a 750 double pump for a small block ford and he suggested a 600 vac sec. (Bigger is always better!) He was right. Giving the specs to the holley people they said too much fuel. Use the 600. Car ran great
A lot of people wouldn't catch the O ring damage. My son tried to put an injector with a damaged O ring back into his buick. We ended up changing out all the O rings since a few more were nicked.
I know it's all together now but maybe next time have someone put a small chamfer to ease the corners of the rail
A lot of people wouldn't catch the O ring damage. My son tried to put an injector with a damaged O ring back into his buick. We ended up changing out all the O rings since a few more were nicked.
I know it's all together now but maybe next time have someone put a small chamfer to ease the corners of the rail
Mercy, a year has gone by since my last letter from the front. I've been using a pair of motorcycle steering dampers to tame the manual rack and pinion steering.
Here's what one looks like:
..with one on each side, set to highest damping. But I've found a bigger version:
The new ones have a longer stroke, which will allow more wheel movement and tighter turn radius. And hopefully the new ones will have more damping. They are adjustable like the old ones. I imagine really big industrial dampers have some damping spec, but these don't. Stay tuned for the thrilling conclusion.
Here's what one looks like:
..with one on each side, set to highest damping. But I've found a bigger version:
The new ones have a longer stroke, which will allow more wheel movement and tighter turn radius. And hopefully the new ones will have more damping. They are adjustable like the old ones. I imagine really big industrial dampers have some damping spec, but these don't. Stay tuned for the thrilling conclusion.
Good question! I'll jack it up and see. Stay tuned.
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