Timing problem?

[nlreb54]

I just installed a new Performer manifold. After installation the engine cranks fine but when I place the car in drive it bogged down. I advanced the timing and the engine will run but very sluggish in drive. Could I be one tooth off when I reinstalled the distributor? I do not think I have a vacum leak from the intake installation.

 

[mike weyman]

i do,think it's vaccum.

 

[vette-dude]

What does your timing light tell you? Are you on the mark on the dampener? It is possible to be one tooth off and the car will run but you should not be able to acheive the optimum timing with a timing light. Did you time it like the maint. manual instructions say or are you doing it by ear? I'm not sure on yours but I think to time it you have to disconnect the electronic timing connector. If not you at least have to disconnect and plug the vacuum line if it has a vacuum advance. This will allow you to get the initial timing set if the dist. was installed correctly. If all this checks then you must have a vacuum leak somewhere.

Randy

 

[The73vetteman]

Did you change the carb at the same time as the manifold? If so, do you know that you have everything connected properly?

Have you checked that the manifold gasket is sealing properly? Everything torqued down properly?

'73

 

[GerryLP]

I just installed a new Performer manifold. After installation the engine cranks fine but when I place the car in drive it bogged down. I advanced the timing and the engine will run but very sluggish in drive. Could I be one tooth off when I reinstalled the distributor? I do not think I have a vacum leak from the intake installation.

If while idling you spray some WD-40 beween the head and intake, and if the rpm goes up, then you have a leak. Also remember that the idle setting on the carb is set with a manifold vaccume gauge. You aim for the best vaccume setting at idle (highest vaccume reading). If the rpm goes higher than the setting you need, then back-off alittle from the throttle idle adjustment screw, and check it again. If you're carb has vaccume advance connected to the cannister on the distributor, then disconnect it and plug the carb side of the hose to adjsut the idle.

The final idle setting on an auto transmission car is usually set with the car in "drive". Make sure you block the wheels, set the emergency brake, and have no one or nothing in front of the car.

 

[nlreb54]

I am going to check for vacum leaks with the WD40. I torqued the bolts to 30 ft lbs. I did not change the carb. It is a 1406 eldebrock. I have been able to set the timing to 8 degrees BTDC with the timing light however unless I idle it to 1500 rpm in park it will not idle in drive and then it is rough. I also had some light back firing through the passenger side muffler. It does have a vacum advance and I have disconected the hose when setting the timing. Any ideas will help.

 

[bossvette]

the rings on the balancer have been known to slip, putting the timing mark in the wrong place. I had it happen to me once when I checked it with a degree wheel it was 8 degrees advanced

 

[GerryLP]

... I also had some light back firing through the passenger side muffler. ...

Ok...maybe you have a spark plug wire on the even side of engine (RH side cylinders 2-4-6-8) in the wrong cylinder -specially if the engine has idled for 15 - 20 minutes. The ignition wires can be tricky. Double check. Tripple check.

To help you set the idle, screw-in the throttle lever idle screw to maintain enough speed on the engine so it won't die on you. Hook-up the vaccumme gauge. The carb should have idle mixture screws. Disconnect vaccume advance and plug carb side. Set the idle mixture screws between 1/8 to 1/4 turn at a time. If the vaccume drops going one way, then reverse the direction on the screws. Aim for the highest vaccume reading. At this time the engine speed should be increasing. back-off the trottle idle screw enough to bring the idle to about where you started. Keep fine tuning the idle mixture screws with the vaccume gauge. Repeat until you can get the idle speed to about 900. At this time, place the car in drive following the precautions in third previous post. With your foot on the brake pedal, you should feel the engine turn steady with barely any misses or trembling.

I have been able to do this even with my XE268H cam. Take your time, and progress slowly. It is tempting to turn the idle mixture screw more than 1/4 of turn, but then you'll end-up chasing your own tail. Check for gasket between carb and manifold. Check for vaccume hoses leaks....check...check...10-4

 

[JohnZ]

Disconnect vaccume advance and plug carb side. Set the idle mixture screws between 1/8 to 1/4 turn at a time.

The idle mixture adjustment should be done at normal idle, with the vacuum advance connected; it's only disconnected when setting initial timing.

 

[GerryLP]

I hear you, John.

Is just that I usually leave the vaccume advance for last (specifically on a carb/manifold/distributor swap). I feel that if one has not matched a particular carb to a specific engine, this way saves more time and avoids problems. The only exception I can think of is a wet-flowed carb from the factory (an out-of-the-box Street Avenger or the like).

You're right, if done the way I explained, then once everything is done, and the advance hose is hooked-up, the engine will tend to speed-up the idle speed. I just take care of that minor adjustment with the trottle idle screw, if needed, after I finally set the vaccume advance.

In my car, I tend to adjust the vaccume advance slightly off idle. My car idles on "drive" at 750 - 800 rpm's. Off drive it idles at around 950 - 990. So I tune the vaccume advance for about 1050 - 1100 rpm.

I don't know if what I am writing makes sense to anyone, but it works real good in my car. So described in shorthand it would be as follows: Initial timing, mechanical timing, carb idle mixture for best vaccume, idle speed in drive (this works closely with idle speed off drive), vaccume advance. Not exactly text book, but it works in my car.

p.s. Am I mispelling vaccume? I don't know how to work the website's spelling checker

 

[nlreb54]

Headlights are not opening so I can feel sure I have a vacume leak? They were working fine before the change.

 

[The73vetteman]

If the headlights aren't opening then it sounds like you've left a hose unconnected and are losing vacum.

'73

 

[nlreb54]

I have repaired the headlight problem. Leaking hose. Sprayed WD40 to check for manifold leaks and everything is fine. Rechecked plug wires. The engine runs fine at idle but bogs down in drive. Any ideas?

 

[GerryLP]

I have repaired the headlight problem. Leaking hose. Sprayed WD40 to check for manifold leaks and everything is fine. Rechecked plug wires. The engine runs fine at idle but bogs down in drive. Any ideas?

Does it smell like fuel-rich exhaust? What was your idle and drive vacume reading?

 

[nlreb54]

After a couple of hours of adjusting, I have the engine running fine now except for a small miss at idle in drive. More like a cough. One of the lines is diconncected from the charcoal cannister. Where do the lines go? One to the tank and the other?

 

[curtis]

A stuck EGR valve will cause many of the problems you have. Long time ago when I took all that stuff off for smog, but seem like the charcoal can was hooked to a ported vacuum fitting onthe carburetor. right now on my 76 that line is justnot hooked to anything.