Water Injection in Old/Tired Chevy 350 TBI

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I'm running some scenarios through my head regarding a water injection system on my oil burning Chevy 350 TBI.

My hope is to keep deposits down in the combustion chambers. I've gotten rid of bad pinging/detonation in the past giving the engine a steam cleaning by pouring water down the intake. But I'm still currently fouling a plug in #1 quite often and I'm tired of spending the money to keep PEA in my tank all the time and filling up with Premium gas as well.

I've read on line that you want to keep water to under 10-15% of fuel burning otherwise you risk contamination of the oil with water.

So, I have a 22 gallon gas tank. So one gallon of water/full tank of gas is the ratio I'm shooting for, which is about a 5% water/gas ratio. Should be safe, right?

I'm thinking of using a hyperdermic needle perhaps to create an inlet in either my brake booster hose or into the PCV line....just before either line connects to the intake. What do you think of this idea?

Lastly, do you think either of these vacuum sources will have enough force to suck water out of a gallon jug through some tubing? Or am I wasting my time?

Thank you in advance.
 
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Self-activiated (vacuum) water injection rarely works quite the way you hope it will. For one thing, you really only need to be injecting water under heavy load / high RPM where the pinging occurs, and that's where vacuum is NOT going to help you! You'll be injecting the most water when you're coasting or idling, and that's going to a) not help pinging, and b) contaminate the oil the most.

Effective water injection uses a pump, controller, and solenoid shutoff valve to atomize the water and deliver it only when the RPMS are up and the vacuum is down (manifold absolute pressure is the highest, in other words).
 
Originally Posted By: 440Magnum
Self-activiated (vacuum) water injection rarely works quite the way you hope it will. For one thing, you really only need to be injecting water under heavy load / high RPM where the pinging occurs, and that's where vacuum is NOT going to help you! You'll be injecting the most water when you're coasting or idling, and that's going to a) not help pinging, and b) contaminate the oil the most.

Effective water injection uses a pump, controller, and solenoid shutoff valve to atomize the water and deliver it only when the RPMS are up and the vacuum is down (manifold absolute pressure is the highest, in other words).

Excellant answer. +1
 
Go up heat range on the spark plug for that cylinder. It will help lengthen the time between foulings.

You may want to look into replacing the valve seals too. They're cheap and not too difficult to do on a SBC. You can use a piece of rope in lieu of air to the cylinder to keep the valve from falling in.
 
Have you ever checked the ignition timing? It is adjustable and must be set on these engines. If it is set to far advanced the engine will tend to be pingy.

Also have you replaced the intake gaskets. These engines are notorious for leaking water into the oil from bad intake manifold gaskets but sometimes there will be a leak from an intake port to the lifter valley and it will suck in oil. I have seen these engines go 250k without using oil so it could be an intake leak instead of piston ring wear especially since it only fouls one plug.
 
The timing is correctly set. I've done it myself a few times, and check it occassionally. It's dead nuts on.

This cylinder always burned out. It did have a leaky intake maifold gasket. It was replaced. Nothing changed as far as oil consumption or that cylinder slowing down it's oil burning either. I think it's possibly a worn out/broken valve guide. Doesn't matter, because I'm not throwing any more money in this engine. When it dies, I'm installing a new GM crate engine for this truck. They are cheap. So, I'm gonna run this one out until she dies.
 
Originally Posted By: 440Magnum
Self-activiated (vacuum) water injection rarely works quite the way you hope it will. For one thing, you really only need to be injecting water under heavy load / high RPM where the pinging occurs, and that's where vacuum is NOT going to help you! You'll be injecting the most water when you're coasting or idling, and that's going to a) not help pinging, and b) contaminate the oil the most.


I'm not too concerned about having water in the combustion chamber when under high RPM load. My pinging is due from piston deposits, not high compression/performance mods. So, even if the engine is drinking some water only when it's idling or coasting....that's fine with me. Honestly. I just want to de-carbonize the pistons one more time by steam cleaning (pouring water down intake), and then hopefully use this water injection system as maintenance....instead of putting PEA in my tank constantly and buying 93 octane fuel.

If the piston tops are relatively clean from the water injection all the time I'm idling and coasting, it won't ping when I'm under load at high RPM's and with no water.

See what I'm saying?
 
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I would skip the water injection idea and try this:

1. Switch to 15w40 HDEO
2. Clean the TB and do a piston soak overnight with B12 Chemtool or similar.
3. Do a complete tune up (wires,cap, plugs,timing) and find a higher heat range spark plug and if possible a low voltage platinum style for the fouling cylinders.
4. Try MMO or Lucas upper cyl lube in your gas and see what happens.
5. Check your coil output
 
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Originally Posted By: Phishin
Originally Posted By: 440Magnum
Self-activiated (vacuum) water injection rarely works quite the way you hope it will. For one thing, you really only need to be injecting water under heavy load / high RPM where the pinging occurs, and that's where vacuum is NOT going to help you! You'll be injecting the most water when you're coasting or idling, and that's going to a) not help pinging, and b) contaminate the oil the most.


I'm not too concerned about having water in the combustion chamber when under high RPM load. My pinging is due from piston deposits, not high compression/performance mods. So, even if the engine is drinking some water only when it's idling or coasting....that's fine with me. Honestly. I just want to de-carbonize the pistons one more time by steam cleaning (pouring water down intake), and then hopefully use this water injection system as maintenance....instead of putting PEA in my tank constantly and buying 93 octane fuel.

If the piston tops are relatively clean from the water injection all the time I'm idling and coasting, it won't ping when I'm under load at high RPM's and with no water.

See what I'm saying?



It still cleans better under load, so how about rigging a windshield-washer pump to squirt down the TB when you push a button? That way you could hit the button under load to clean it, then not be drinking water when its unloaded?
 
Originally Posted By: Doog
I would skip the water injection idea and try this:

1. Switch to 15w40 HDEO
2. Clean the TB and do a piston soak overnight with B12 Chemtool or similar.
3. Do a complete tune up (wires,cap, plugs,timing) and find a higher heat range spark plug and if possible a low voltage platinum style for the fouling cylinders.
4. Try MMO or Lucas upper cyl lube in your gas and see what happens.
5. Check your coil output


Already done all that. Done so many piston soaks on that one cylinder, I should be locked up.

Never tried MMO or Lucas UCL in my gas tho. Sure, I'll give that a shot.

Coil is good too.

But thanks for the suggestions Doog.

Originally Posted By: 440Magnum
how about rigging a windshield-washer pump to squirt down the TB when you push a button? That way you could hit the button under load to clean it, then not be drinking water when its unloaded?


Genius!! Except my washer pump isn't working...but now I have a legit reason to trouble shoot it. Sweet. Thanks 440!!
 
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This all looks good, but yes, I agree with some of the others.. you have got something going on there that water injection is not really the right solution to I believe. Valve seals, rings, whatever - and actually the sad irony is the high octane fuel isn't helping ur carbon buildup one bit either, other than minimizing the ping - if it even does THAT.
 
You can even do the valve seals without pulling the head with compressed air and the cyl locked to TDC.
 
I've followed this truck for a while now. You gotta fix it or part ways with it. You coulda had that engine rebuilt for the oil and additives your dumping into it.

Seriously if you replaced the rings, quick hone, and some valve seals all would be fine. Take a couple of days. Do it. We will help you.
 
Washer pumps work great and were used before the commercial water/meth injection kits like the overpriced Snow stuff... The trick is getting a nozzle that will create a fine mist into the intake tract. With todays elaborate intakes you dont want water puddling anywhere, it needs to be atomized to be properly distributed.
 
Originally Posted By: LeakySeals
Seriously if you replaced the rings, quick hone, and some valve seals all would be fine. Take a couple of days. Do it. We will help you.


+1 Probably the best advice.
 
Originally Posted By: Doog
I would skip the water injection idea and try this:

1. Switch to 15w40 HDEO
2. Clean the TB and do a piston soak overnight with B12 Chemtool or similar.
3. Do a complete tune up (wires,cap, plugs,timing) and find a higher heat range spark plug and if possible a low voltage platinum style for the fouling cylinders.
4. Try MMO or Lucas upper cyl lube in your gas and see what happens.
5. Check your coil output


Dumb question. Why would you switch to 15w40 for this vehicle ? Ring sealing ? Not sure what the gain is there...
 
I might look into a non-extended tip plug (fully recessed gap)for the fouling cyl. Extended tips are way overrated anyhow
smile.gif

REally, I would do the VG seals -cheap and easy. This sounds like you got piston/cyl danage wear in the cyl that was eating coolant. If worse is really worse, You may wish to consider pulling the lifters + pushrods for that cyl and shut 'er down.
"V7 because eight is too big, and six is too small"
 
Originally Posted By: LeakySeals
I've followed this truck for a while now. You gotta fix it or part ways with it. You coulda had that engine rebuilt for the oil and additives your dumping into it.

Seriously if you replaced the rings, quick hone, and some valve seals all would be fine. Take a couple of days. Do it. We will help you.


Honestly. I haven't spent that much. $15-20/month for PEA. A couple quarts of Kreen....but it was sludged up when I got it. Oh, and I recently bought some Restore additive.

I am inexperienced and doubtful I could replace rings and hone. That is out of my comfort zone. Maybe valve seals are next. I can do that. Or have a buddy do it for some beer.

Always reluctant to do it because compression was down to 100psi in that cylinder and all the other cylinders appear to be burning minimal oil.
 
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