Engine idiot that wants a change.
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Joined: Nov 2002
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From: Columbus, Ohio
Engine idiot that wants a change.
That's me. I am an idiot and I know very little about engines. I can change my oil, done a couple of water pumps, alternator (who can't do that), and that is about it. I know my car has a carb. and I was thinking about changing to fuel injected. Is this possible on a 1984 Z with the stock 305 4bbl? I am sure it is possible but is it worth the money and time? Would this be something I could do or would I have to take it to a mechanic? I don't care to much for the carb. Would my car run differently being injected verus carbed? Would I solve all my problems by just buying a crate motor and building on it? If you think I would be better off buying a new engine what size do you suggest, and anything else I should look into before doing so? Thanks for your help.
Joined: Mar 2000
Posts: 43,187
Likes: 42
From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Nobody can really answer all of these questions for you, but we can establish a few groundrules.
1st, there were two different carb'd engines in '84, the LG4 and L69. Look at the 8th character in your VIN - if it's "H", you have the lower-performance LG4. A bunch of things can be done to improve its performance, none of which requires the switch to EFI. My sig lists what I did, but yours (if LG4) would have lower compression, no knock sensor, and a motor-driven fan rather than electric.
EFI tends to improve fuel economy, driveability, and emissions. But, there's no free lunch. More can go wrong with EFI, although the computer-controlled carb you now have (assuming this isn't a Canadian car) is almost as complicated. And, the expense of conversion would take a long time to recoup through improved fuel economy.
The majority of conversions done by people are from EFI to carb, not the other way around. That's because it is cheaper to get more performance out of a carb'd engine than it is out of an EFI engine. Of course, fuel economy suffers more with hopped-up carb engines than it does with similarly improved EFI engines.
Now, how much of this can you do? I don't know, but I'd highly recommend that the answer be "all of it". The type of things you are talking about are not the "normal" work of mechanics, and they could take forever doing it and you'll be missing an arm or leg when it's finally done. This is more along the line of "hobbyist" work for that very reason. My brother did a V6 to V8 conversion almost 10 years ago, had a shop help him with the final wiring. But, had he spent a little time with a shop manual, I'm sure he could have figured it out himself. And, that was 10 years ago.
My advice? Start by improving what you've got. If LG4, the exhaust on that thing is terrible. Replace it all, from heads to rear bumper, with headers, high-flow y-pipe/cat/cat-back. The air cleaner is also terrible (if LG4 single-snorkel), find or make yourself a dual-snorkel (check the tech article for how to make one). The ignition typically needs some help, coil and module do the trick there. Those upgrades alone will do wonders. After that, you're looking at cam, heads (porting at least), higher stall torque converter, gears, subframe connectors, etc.
When that all gets too tame for you, now you can consider a 350, 383, or 400. All of the above will transfer over to the new engine except the porting work (although you can make ported 305 heads work on a 350, if you go about it right).
Oh, more problems tend to be caused by crate motors than solved...
1st, there were two different carb'd engines in '84, the LG4 and L69. Look at the 8th character in your VIN - if it's "H", you have the lower-performance LG4. A bunch of things can be done to improve its performance, none of which requires the switch to EFI. My sig lists what I did, but yours (if LG4) would have lower compression, no knock sensor, and a motor-driven fan rather than electric.
EFI tends to improve fuel economy, driveability, and emissions. But, there's no free lunch. More can go wrong with EFI, although the computer-controlled carb you now have (assuming this isn't a Canadian car) is almost as complicated. And, the expense of conversion would take a long time to recoup through improved fuel economy.
The majority of conversions done by people are from EFI to carb, not the other way around. That's because it is cheaper to get more performance out of a carb'd engine than it is out of an EFI engine. Of course, fuel economy suffers more with hopped-up carb engines than it does with similarly improved EFI engines.
Now, how much of this can you do? I don't know, but I'd highly recommend that the answer be "all of it". The type of things you are talking about are not the "normal" work of mechanics, and they could take forever doing it and you'll be missing an arm or leg when it's finally done. This is more along the line of "hobbyist" work for that very reason. My brother did a V6 to V8 conversion almost 10 years ago, had a shop help him with the final wiring. But, had he spent a little time with a shop manual, I'm sure he could have figured it out himself. And, that was 10 years ago.
My advice? Start by improving what you've got. If LG4, the exhaust on that thing is terrible. Replace it all, from heads to rear bumper, with headers, high-flow y-pipe/cat/cat-back. The air cleaner is also terrible (if LG4 single-snorkel), find or make yourself a dual-snorkel (check the tech article for how to make one). The ignition typically needs some help, coil and module do the trick there. Those upgrades alone will do wonders. After that, you're looking at cam, heads (porting at least), higher stall torque converter, gears, subframe connectors, etc.
When that all gets too tame for you, now you can consider a 350, 383, or 400. All of the above will transfer over to the new engine except the porting work (although you can make ported 305 heads work on a 350, if you go about it right).
Oh, more problems tend to be caused by crate motors than solved...
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Joined: Nov 2002
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From: Columbus, Ohio
Hey thanks for all your input. :hail: 
I will have to check and see which carb I have. I think I might be able to tackle some of those things and I have people that would be able to help with the others. I guess I will keep the carb. I just don't like it taking off on me when it is warming up. It idles in the mornings at about 2000-2500rpm's. I think a crate might be needed in my situation because it is burning oil (well at least it smells that way). It could be from me getting it on the engine when I was doing oil changes. I guess just burning a little bit of oil isn't too bad for a car that is all most 20 years old. Anyone else have any ideas? Thanks again for your input it will defenitly be considered.
I will have to check and see which carb I have. I think I might be able to tackle some of those things and I have people that would be able to help with the others. I guess I will keep the carb. I just don't like it taking off on me when it is warming up. It idles in the mornings at about 2000-2500rpm's. I think a crate might be needed in my situation because it is burning oil (well at least it smells that way). It could be from me getting it on the engine when I was doing oil changes. I guess just burning a little bit of oil isn't too bad for a car that is all most 20 years old. Anyone else have any ideas? Thanks again for your input it will defenitly be considered. Joined: Mar 2000
Posts: 43,187
Likes: 42
From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Well, I'll chime in again, even though you asked for someone else...
The fast idle speed (what it idles at when the choke is on) can be adjusted. 1st, it should only go that high when you first start it. Then, the choke pull-off should open the choke enough for the fast idle to drop down one notch when the throttle is tapped. If it idles at 2000-2500 RPMs when cold, it really is adjusted too high, as that is about what it should be when you do the adjustment (which is to put the fast idle cam up when the engine is warm and set the adjustment). Personally, I prefer to adjust those things so the engine runs right, not some pre-set adjustment (a trial-&-error thing).
It could also be that your fast idle cam is gummed up, and just needs to be squirted with some carb cleaner.
On the oil burning, these engines are notorious for valve stem seals going bad. From the factory, they are little o-rings that go between the valve retainer and keepers. They only control the oil that would get by that spot, not the oil that splashes under the spring. The o-rings get hard with heat and age, crack, and no longer do the job. Most people replace them with umbrella-type seals. It's not too hard of a job - you don't have to take the engine apart - but if you're new at all this, you might want to try to get someone with some experience to give you a hand. Just doing that changed my 123k mile engine from burning a quart every 600 miles (and a smoke cloud at start-up) to a quart in 2000 miles.
The fast idle speed (what it idles at when the choke is on) can be adjusted. 1st, it should only go that high when you first start it. Then, the choke pull-off should open the choke enough for the fast idle to drop down one notch when the throttle is tapped. If it idles at 2000-2500 RPMs when cold, it really is adjusted too high, as that is about what it should be when you do the adjustment (which is to put the fast idle cam up when the engine is warm and set the adjustment). Personally, I prefer to adjust those things so the engine runs right, not some pre-set adjustment (a trial-&-error thing).
It could also be that your fast idle cam is gummed up, and just needs to be squirted with some carb cleaner.
On the oil burning, these engines are notorious for valve stem seals going bad. From the factory, they are little o-rings that go between the valve retainer and keepers. They only control the oil that would get by that spot, not the oil that splashes under the spring. The o-rings get hard with heat and age, crack, and no longer do the job. Most people replace them with umbrella-type seals. It's not too hard of a job - you don't have to take the engine apart - but if you're new at all this, you might want to try to get someone with some experience to give you a hand. Just doing that changed my 123k mile engine from burning a quart every 600 miles (and a smoke cloud at start-up) to a quart in 2000 miles.
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Joined: Feb 2003
Posts: 19
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you can do anything you want. you have to buy all of the parts to make the car injected compatible. the car will sound different. it is an expensive swap if you do tpi. you are better off buying a wreaked parts car to pull the motor and all other necesary parts you need.
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Member
Joined: Nov 2002
Posts: 139
Likes: 0
From: Columbus, Ohio
Originally posted by five7kid
1st, there were two different carb'd engines in '84, the LG4 and L69. Look at the 8th character in your VIN - if it's "H", you have the lower-performance LG4. A bunch of things can be done to improve its performance, none of which requires the switch to EFI. My sig lists what I did, but yours (if LG4) would have lower compression, no knock sensor, and a motor-driven fan rather than electric.
My advice? Start by improving what you've got. If LG4, the exhaust on that thing is terrible. Replace it all, from heads to rear bumper, with headers, high-flow y-pipe/cat/cat-back. The air cleaner is also terrible (if LG4 single-snorkel), find or make yourself a dual-snorkel (check the tech article for how to make one). The ignition typically needs some help, coil and module do the trick there. Those upgrades alone will do wonders. After that, you're looking at cam, heads (porting at least), higher stall torque converter, gears, subframe connectors, etc.
1st, there were two different carb'd engines in '84, the LG4 and L69. Look at the 8th character in your VIN - if it's "H", you have the lower-performance LG4. A bunch of things can be done to improve its performance, none of which requires the switch to EFI. My sig lists what I did, but yours (if LG4) would have lower compression, no knock sensor, and a motor-driven fan rather than electric.
My advice? Start by improving what you've got. If LG4, the exhaust on that thing is terrible. Replace it all, from heads to rear bumper, with headers, high-flow y-pipe/cat/cat-back. The air cleaner is also terrible (if LG4 single-snorkel), find or make yourself a dual-snorkel (check the tech article for how to make one). The ignition typically needs some help, coil and module do the trick there. Those upgrades alone will do wonders. After that, you're looking at cam, heads (porting at least), higher stall torque converter, gears, subframe connectors, etc.
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