6 cylinder to 5 cylinder conversion

M

Mydogisshaggy

Well-known member
What are the options to "disable" one cylinder, probably #1 for a few reasons.

Would the easiest way be to change the firing order and tuning it? Disable the port fuel injector. Or less lazy, custom intake amd exhaust. And cover the #1 ports.

What about filling in cylinder #1? Running a custom 5 cylinder cam.

How hard is this?
 
This is a v8 turned into a v6, but will give you an example some of the principles involved.
A 5 cylinder version of the ford 6 would definitely have a unique sound, but without a custom crank and cam, it may just sound like a misfiring 6.
The easiest way is the way you described, block the ports and disable the injector.
You could also remove the rockers and pushrods and hose clamp the lifers just high enough to clear the lobes, but still cover the oil gallery.
 
I missed that trip, but two school buddies/housemates of mine drove Tom's 60's F100/240 up north hunting, and developed a bad rod knock. He limped it to the cabin, straddled the ditch, dropped the pan, cut the rod beam, shoved the slug up the bore, hose clamped the journal to cover the oil hole, buttoned it up. They shot a few birds in the morning, loaded up and drove the 130 miles home. They swore that besides the miss, it ran fine, didn't shake appreciably. I always chuckled when firing up the 2.0L Pinto based 2+2 air compressor he built in HS shop. He was pretty handy.
 
I once considered disabling #1 injector to use cyl 1 as an off road air compressor.
Compressed air to run through spark hole adapter and check valve during compression stroke.
I decided not to based on the hard vacuum that cylinder would pull on the downward power stroke, once I had stolen all the air during compression.
I probably could have worked some sort of double check valve to relieve some of that through the same sparkplug adapter, but assuring clean, filtered, non-check-valve-internals-containing air supply, made this seemingly simple hack less simple and portable than I wanted.

Just leaving the plug in and disabling the fuel injector should work OK, as the compression-power strokes just become an air spring.
The computer is not going to be happy with what the O2 sensor is telling it once all the non-combusted air goes into the exhaust. It will probably go all Limp-mode and richen up the mixture. That AND the extra oxygen would not be healthy for the Cat either.

I suspect the simplest way to make it a reliable 5 cyl would be to throw in one of the old GM 3.5L Canyon i5s. Or else a Mercedes OM617.
 
The best and easiest way is to send your cam to Schneider and have them grind the intake and exhaust lobes off of the one cylinder so the lifters can stay in place and the valves stay closed.
 
Bronctopia said:
I once considered disabling #1 injector to use cyl 1 as an off road air compressor.
Compressed air to run through spark hole adapter and check valve during compression stroke.
I decided not to based on the hard vacuum that cylinder would pull on the downward power stroke, once I had stolen all the air during compression.
I probably could have worked some sort of double check valve to relieve some of that through the same sparkplug adapter, but assuring clean, filtered, non-check-valve-internals-containing air supply, made this seemingly simple hack less simple and portable than I wanted.

Just leaving the plug in and disabling the fuel injector should work OK, as the compression-power strokes just become an air spring.
The computer is not going to be happy with what the O2 sensor is telling it once all the non-combusted air goes into the exhaust. It will probably go all Limp-mode and richen up the mixture. That AND the extra oxygen would not be healthy for the Cat either.

I suspect the simplest way to make it a reliable 5 cyl would be to throw in one of the old GM 3.5L Canyon i5s. Or else a Mercedes OM617.
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I don't know how you'd manage doing it with one cylinder and a stock head, but using an auto engine with a special head for a compressor isn't unheard of. I had an old tow behind air compressor that was a 302 V8, with a special head on one bank of cylinders. 4 on the left fired, 4 on the right compressed air. Worked well and had incredible flow rates, but we had tons of issues with moisture in the lines - not great for running a sandblasting cabinet like I was. You could always go the route of converting an A/C compressor into an air compressor, or try and use a PTO driven one if you have provisions. I am going to try the PTO route myself with a compressor I picked up a couple years ago.
 
Firepower354 said:
I missed that trip, but two school buddies/housemates of mine drove Tom's 60's F100/240 up north hunting, and developed a bad rod knock. He limped it to the cabin, straddled the ditch, dropped the pan, cut the rod beam, shoved the slug up the bore, hose clamped the journal to cover the oil hole, buttoned it up. They shot a few birds in the morning, loaded up and drove the 130 miles home. They swore that besides the miss, it ran fine, didn't shake appreciably. I always chuckled when firing up the 2.0L Pinto based 2+2 air compressor he built in HS shop. He was pretty handy.
Click to expand...
Saw the same done on a 6-71 DD. 50 miles offshore, #5 rod threw. Drove it on 5 without issue to the port at Brunswick, 105 miles.
 
Mydogisshaggy said:
Displacement, transmission options... Parts availability, knowledge of i6, its ford, Its just an idea really.
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Inline five and V10 are among the worst balanced engine configuration, without counterbalance shafts they'd be shaken to death in short order. Instinct would think it would be pretty good, but nature does not like 72 degree and 144 degree patterns. Inline sixes- exact opposite.
 
Frank said:
Inline five and V10 are among the worst balanced engine configuration, without counterbalance shafts they'd be shaken to death in short order. Instinct would think it would be pretty good, but nature does not like 72 degree and 144 degree patterns. Inline sixes- exact opposite.
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So keep it a 6 cylinder but disable an injector and tune it for 5 cylinders and that will keep the balance?
 
You have the most perfect balance with an inline six already..
As pmuller suggested, you should grind off cam lobes to disable the valves.
That turns your de-activated cylinder from an air pump (sucks energy, screws the exhaust) into an air spring.

There will be crankshaft torque harmonics penalties for doing this due to the missing power stroke. Don’t spin it fast, dump clutch on it, and make sure your harmonic damper is in order.
 
my uncle had a 1947 chevy broke a rod and knock a hole in cylinder wall they drove a cedar post into bad hole took push rods out and drove two more years!! poor boys
 
benchracer said:
my uncle had a 1947 chevy broke a rod and knock a hole in cylinder wall they drove a cedar post into bad hole took push rods out and drove two more years!! poor boys
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That was not an uncommon occurrence and fix during the Depression Era.
 
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