Thread: Chevy 283 all messed up.....Need advice

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Here's a little background on the engine.

It's a 1967 chevy impala 283 that is now in a 1950 chevy truck. It has been completely rebuilt. From the best of my knowledge it was bored 40 over and I put an edelbrock rpm intake and I believe a 650 edelbrock carb on the engine as well as an HEI distributer.(Could be a little off on the carb size, after all it's been 15 years). Also it has roller rockers on it plus new push rods, although only 7 out of 8 are new b/c at the time I lost one. I also put the rubuilt heads, intake and carbon myself.
The truck started out as a father son project back in 1995 and very shortly afterwards turned into just my (sons) project and unfortunatlely with school and work it kept being put on the back burner. Now that I have had a litle time and money I have started to work on the engine again and here's my issue, mind you the engine has been ran off and on here and there and even put under load throughout the last 15 years in order to pull the truck in and out of garages and storage units.
Ok so the engine ran pretty dam awesome before it was rebuilt and after we rebuilt it, it never ran the same and up until this point I felt all it needed was for the valves, carb and timing to be adjusted. For the last 3 weeks I have been attempting to adjust the valves and carb using the advice of a neighbor who used to work for edelbrock and it seemed to start up pretty well but it would backfire through the carb a lil bit and would putter out and die as soon as it was put into gear or accelerated whatsoever under load. Ok not a big deal thinking it needs more adjustment but today I started it up and out of nowhere it backfired louder than a shotgun out of the exhaust and sputtered out and died even faster than before under load but what worries me most is that out of the right side exhaust (it has dual exhaust no y pipe) there is white billowing exhaust fumes. Any help or advice would be greatly appreciated. I just want to make this thing run decent so that I can be excited again about working on it. As I sit here the truck is stuck in the drive way unable to move under it's own power and the rain is coming again, mind you I was able to drive it slowly up and down the street the other day without to much of an issue until I pushed to much on the accelerater and it would sputter out and die.

Thanks again for the help..

I ran into a guy at one of my customers shops several years ago that did the same thing you did and had the same result as you.The RPM intakes large ports are too much for your 283 heads and the Carb is too much also.I suggested He use a Std. Performer intake and a 500 CFM Edelbrock Carb,as soon as the switch was made it ran like a striped ass ape! Your engine is loading up from a lack of low speed velocity due to the large runners in the RPM intake,I would also suggest you change the oil and filter again as you probably have raw fuel in the pan.Since you are not sure of the Carb do this,looking at the front of the carb there are numbers stamped on the front left mounting tab so post those and we can verify the Carb size.

So many possible things could be causing this. I would start with the easy stuff. Make sure your valves are adjusted properly, better to be a little on the loose side to start than too tight. Check the timing to make sure the cam is in phase with the crank. Make sure the distributor is close to where it should be.

A vacuum leak can cause some goofy stuff. Try idling the engine while you spray starting fluid all around the gaskets on the intake manifold. If it speeds up while spraying part of it, you have a leak. Make sure all the vacuum ports are plugged or have the appropriate hose on them. All of us have forgotten to plug a hole or two on the intake or carb at one time or another.

Just start at ground zero and work up from there.

Don

Thanks so much for the info and advice as to what I should do next. I checked the front of the carb and the numbers look like they are 1405 0079, (I'll check when it light out just to be certain it's not 1406 b/c that carb doesn't run as rich) and after a little research I found out that I have a 600 cfm carb on my engine. Although I don't yet know what the 0079 means. I was pretty close guessing it was a 650 instead of really being a 600, but where I was wrong was that the intake is a just a edelbrock performer as opposed to a rpm like I stated before. Now I don't know if that makes a difference in consideration to Jeffs advice, being that I might just need a smaller carb to run better. Is there a way to adjust the carb to work with my application by changing the metering rods in the carb? Also I will for sure change the oil and filter, that has totally skipped my to do list as I was just trying to get it started. Good looking out.
As for your advice Don, I'll try that out tomorrow or the next day, I didn't know I could find a leak that easily, kinda like putting soapy water on a residential gas line looking for a leak--Thanks. And hopefully my attempts to adjust the valves along with time the engine will soon pay off and I'll get it just right. To be completely honest I'm trying my best to do it myself and get the satisfaction of making it run but I'm starting to worry that I have messed it up.

I'll keep this thread updated and thanks again for the help.

Originally Posted by boarders123

but today I started it up and out of nowhere it backfired louder than a shotgun out of the exhaust and sputtered out and died even faster than before under load but what worries me most is that out of the right side exhaust (it has dual exhaust no y pipe) there is white billowing exhaust fumes.
Thanks again for the help..

Billowing white smoke is usually a sign of a bad head gasket. Read the plugs and also check the radiator and verify it is full and maybe do a pressure test on the cooling system with the spark plugs out. If you can't build pressure check the cylinders on the side making smoke. Hope it helps.

That carb is an Edelbrock 600, as you have found out, and while it is maybe just a tad big for a 283 it should still be fine. Edelbrocks are designed to be fairly user friendly, and are jetted on the economy side somewhat. Great street carbs. A 500 cfm would have been just about a perfect match, but you are still in the ballpark............we all overcarb a little......I have two 600 Edelbrocks on my 331 Ford, and they run good.

The nice thing about a project like you are doing is that it is a hobby motor, and while you want to get it running, it isn't like you need to get it done right today so you can go to work driving it tomorrow. That takes some of the heat off of you and will let you take your time to figure these problems out.

I would do a compression test and leak down test to get some baseline of how the cylinders are holding pressure. I should have mentioned that earlier. Just keep playing with it, you'll get it.

Don

Originally Posted by boarders123

.
As I sit here the truck is stuck in the drive way unable to move under it's own power and the rain is coming again,

i thought it never rains in california .. ( are you running on 15 year old gas ?)

Since you do have the regular Performer intake you should be OK,do the compression check as advised but if you are running an Edelbrock or Carter AFB it is important that you keep the fuel pressure at 5-5 1/2 psi at max,here is something that may help: http://www.fordmuscle.com/archives/2...etor/index.php

Welcome to CHR!

Sounds like you’re getting around to a project that’s been “dormant” for a while. Lots of us here have worked through finances, kids, kid’s college (all finance related), etc. while wanting to get to our hot rods so you’ll fit right in.

The carb and intake combination you have should be just fine for your 283. We used to run the Edelbrock Torker and 650-750 CFM carbs on these little motors with a little bigger cam, some tuning, and headers and they ran pretty good. That big ol’ puff of white smoke could just be a lot of un-burned gas or it could be something serious. In that this one has sat for a while, you may want to back up a bit and take things in order. My recommendations:

As mentioned – run a compression test. Take all the plugs out and start with #1 cylinder and write the results down as you go. Be sure to pull the coil wire to eliminate the possibility of a nasty shock while performing the compression test. Squirt a couple shots of 30 weight oil in each cylinder before you crank the engine (this will make a mess – might want to put rags in strategic spots). Look for compression in the 145-160 range. The numbers should also be within 10 PSI of each other. You will need to retest any cylinder with a low reading. Low compression could be caused by a number of things: Valves too tight, bad head gasket, bad rings, cracked or burned piston, cracked head or block (hope not). Once you get the results, post them and we can advise.

Valves have also been mentioned – adjust them. I’m assuming hydraulic lifters and I like to start at ½ to ¾ turn from zero lash – no tighter.

Drain the fuel tank completely and put five gallons of premium fuel in the tank. Disconnect the fuel inlet at the carb and pump about a pint of gas through (with the coil wire disconnected - careful here - even bad gas burns!). Change the fuel filter.

Let’s assume the compression is good – next step, put in a new set of plugs and unless the plug wires were a premium 7/8mm silicone set, change them too.

Now – start er up and check the timing. Initial on a 283 should be about 8 degrees (with the vacuum advance disconnected and plugged). In that you’ve done recent work, we’ll assume the timing chain is good and the distributer is in the correct spot (it has started and run).

Once the engine is running spray carburetor cleaner around the base of the carburetor and along the edges of the intake manifold. Any (and I mean ANY) change in the RPM indicates a leak and that’s a problem. If you find such, I would pull the manifold and get new gaskets. I like black silicone at the ends and use Permatex to coat both sides of the gaskets for the heads.

Work on the above and you’ll probably have a sweet running little motor. Keep us posted and we can certainly offer up lot’s more “advice”.

Regards and Good Luck,
Glenn