help my engine gets to hot

[roadblaster]

You set the timing to 8 degrees AFTER Zero?

Timing is ALWAYS before Top Dead Center, before the Zero mark on the timing tab.

[beardy2]

my carb is a rochester manual choke from the 70's i believe and we set it to what my repair manual said but i might have read it wrong. but if we turn the dist to make the line on the balancer go up then it runs on a real high idle and if you give it gas it back fires badly

[roadblaster]

The idle mixture on a Quadrajet is set by 2 screws at the bottom front of the carb. The screw may be covered by no-tamper caps but if they are uncovered:

Run the screws all the way in then back them out an equal number of turns. Begin with 3 whole turns. Start the motor and turn one screw out one turn to see if the engine runs smoother if it does, turn the other screw out to the same position.

When the engine stumbles while turing the screws in,, counterclockwise the screws until the idle smooths out. The goal is to have both screws turned IN (an equal number of turns) as far as they can before the engine starts to stumble.

Now for the timing: Turning the distributor counterclockwise advances the timing. If the timing is advanced to far, the cylinders will fire so soon the (warm) engine will be working against itself when it is cranking and trying to start. When it is too far advanced, the engine will make a straining,hesitating sound when EACH cylinder fires.

So, advance the timing and try to start the engine. If it cranks ok, shut it off and advance the timing (counterclockwise distributor) and see how it cranks. Repeat the process untill you reach the point where it starts working against itself, THEN back the timing off with a little clockwise distributor until the straining goes away. Now the timing will be close enough to take it out for a little drive. When you are on the road, in gear, give it soem gas and listen for spark knock. It will make asound like marbles rattling. If you are getting spark knock on the road you MUST back off the timing or you will ruin the motor. The best scenario is to run as much advance as you can without spark knock.

Now then, for the backfiring, i suspect that your timing light is attached to the wrong plug wire. It should be attached to the front plug wire on the Driver's side for a small-block Chevy V8. Timing should be 8-12 degrees BEFORE Top Dead Center, depending on what GM decided was right

[my95z28]

plugged cat?

[beardy2]

plugged cat?

i dont have a catalatic converter its strieght piped.

roadblaster i will try what you said to do.

i think i might have a good idea on what could be wrong my neighbor ( big car nut) said that it sounded like the egr valve was sucking air around the gasket so i took ether or starter fluid and spraid around the gasket and nothing happend so i spraid it around the back of the carb and it reved up so it needs a gasket kit and it needs a new fuel line because the started dripping and running down the engine. so conclusion carb was sucking air so there for it was putting to much fuel into the engine so those cylinders were getting to much gas when it ignited there for was getting to hot. now can you guys tell me if this sounds right or possible.
thank you

[81DaytonaPaceCar]

i dont have a catalatic converter its strieght piped.

roadblaster i will try what you said to do.

i think i might have a good idea on what could be wrong my neighbor ( big car nut) said that it sounded like the egr valve was sucking air around the gasket so i took ether or starter fluid and spraid around the gasket and nothing happend so i spraid it around the back of the carb and it reved up so it needs a gasket kit and it needs a new fuel line because the started dripping and running down the engine. so conclusion carb was sucking air so there for it was putting to much fuel into the engine so those cylinders were getting to much gas when it ignited there for was getting to hot. now can you guys tell me if this sounds right or possible.
thank you

I guess I'm a little confused...that doesn't sound right.

I'm with Roadblaster...it definately sounds like timing is at least one of your problems. EGR could be a contributor, but not the root cause.

It's likely a combination of timing and cooling...it almost sounds as if the cooling system is not working at all.

Another contributor could be the 4 barrel carb itself. If that motor came with a 2 barrel originally, the combustion chambers of the heads are set up for the fuel volume that a 2 barrel can deliver...slapping a 4 barrel on there can drown the motor out in fuel. But this should not make it run hot...just run like crap, especially under load.

But if your headers are turning red after only 3 minutes of idling, there is a serious issue or two there.

[roadblaster]

Like I said. Rich condition (too much fuel) does NOT make cylinders run hot. Lean condition ( not enough gas ) DOES make cylinders run hot. Sounds bass-ackwards but that's the way it is. Too much gas cools things off in the combustion chamber.

If you are sucking air around the carburetor-to-manifold gasket, you will have a lean condition. (Too much air for the amount of gas that the carb is delivering.) The carb meters the amount of fuel by sensing the pressure drop from the air passing thru it. If air is getting in elsewhere, the carb is not 'seeing' it and is not giving extra fuel to compensate.

I still say you need to get the ignition timing worked out. If you can't time it correctly with a light, use the trial & error method i described before.

I suggest you find an old timer, age 40 or older, who knows a little about old-school engines, to have a look at it if you can't figure it out. These engines are easy to tune if you grew up with them

[roadblaster]

"Another contributor could be the 4 barrel carb itself. If that motor came with a 2 barrel originally, the combustion chambers of the heads are set up for the fuel volume that a 2 barrel can deliver...slapping a 4 barrel on there can drown the motor out in fuel."

HUH? *****

[81DaytonaPaceCar]

"Another contributor could be the 4 barrel carb itself. If that motor came with a 2 barrel originally, the combustion chambers of the heads are set up for the fuel volume that a 2 barrel can deliver...slapping a 4 barrel on there can drown the motor out in fuel."

HUH? *****

Yep...

A guy in high school had a 70 Camaro with a 307 2-barrel and decided to get cute and slap a Holley 750 on there. Ran great as long as you never opened up the secondaries. Open up the secondaries, and it would just bog right down.

Also saw a 327 with (again) a Holley 750 on it...exact same issue...

Idled great, but horrible under WOT...

[tf34mechh]

Also try and get some sort of temp gauge. Either a gauge hooked up or one of those remote temp guns. You might want to look into getting a electric fan down the road as well. I hope you get it figured out.

[beardy2]

i wanted electric fans but my wiring was butched by the previous owner it's a pain like the gaige lights hook to the hot and negitve wires on the radio the previous owner really screwed up the wiring. the only thing that might not work could be a water pump. it's a 305 out of like a early 80's truck. when i timed it i have it running perfect sounds great all the cylinders are firing in order exhaust sound great but now you can here it suck air like crazy and the only spot i can find the reacts to the starter fluid is the carb. did any of you have a water pump that works cheap. there are brand new ones on ebay for $28 plus shipping. i plan on getting a carb kit and a new fuel line. also on the back of the carb there is a meatl line that screws into the carb and hooks to the vacuum over by the brake master cylinder, when it is all the way screwed in the the carb it runs like crap but if it is abou 3 quaters of the way screwed in it runs great what is up with that.

[81DaytonaPaceCar]

Start her up with the radiator cap off...can you see coolant flowing?

Can you see if the radiator is corroded and plugged?

[MP81]

Is there even a radiator?...

[81DaytonaPaceCar]

Is there even a radiator?...

No radiator would be a problem...lol...

[JoeliusZ28]

actually they made a few rare Air-cooled small blocks with the huge aluminum fins on the cylinder heads. It saved about 10 hp deleting the water pump.


jk