318 Motor, please help

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insidegroove

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Hello, I just joined this forum because i'm at my wits end and i'm hoping you guys can help me. I have a 1969 318 LA engine with a 904 automatic transmission. i just put new points in the ignition, brand new plugs and wires and brand new coil. it has a Holley 650cfm 4bbl carb. I have a 4.5 power valve installed because the vacuum reading in gear is 10. (at idle in park its at 20). The motor fires right up and idles great. i let it get to operating temp (190) and as soon as i put it in drive it wants to stall out....if i play with the gas pedal a bit it will come up to a steady idle after a few seconds. if i stab the gas it falls on it's face and most times will pop from the carb and stall. so i have to carefully play with the gas pedal to get rolling without stalling. once its rolling it drives nice and smooth. what am i missing???
 
1...Do you know general condition of engine, does it burn oil, have you run compression/ leakdown check?

2....Where is the timing set, and do you know how to check accuracy of timing marks with piston stop?

3...Do you understand and know how to adjust carb idle mixture, aka, retarded timing and or lean idle mixture will tend to amplify what you describe

3...Do you understand what the carb accelerator pump is and what it does, and have you checked that?
 
67Dart273 said:
1...Do you know general condition of engine, does it burn oil, have you run compression/ leakdown check?

2....Where is the timing set, and do you know how to check accuracy of timing marks with piston stop?

3...Do you understand and know how to adjust carb idle mixture, aka, retarded timing and or lean idle mixture will tend to amplify what you describe

3...Do you understand what the carb accelerator pump is and what it does, and have you checked that?
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1. its an original 318, probably tired and down on compression but i dont know how to check that. it doesnt burn oil though and doesnt run hot.
2. i have a timing light but havent tried it yet. i pretty much set the timing by ear and watching for the sweet spot at idle.
3. i adjusted the air/fuel mixture settings on the primary side (seconday doesnt have the adjustment screws) using a vacuum gauge. turned them all the way in, backed them out 1.5 turns to start and then kept making small adjustments to get the maximum reading on the gauge. are you talking about the screw on the drivers side that most people say is the "idle adjustment screw"?
4. the accelerator pump is in the front on the drivers side, i watched several videos on adjusting it so that its engaging right away when the throttle moves, i believe i have it set perfect (used a feeler gauge at .014 i belive it was )
 
ok i just went outside and hooked up the timing light. it's past the 10 on the "below" side, so im guessing roughly 12. is this bad? it idles smooth and i can stab the gas in park with no hesitation........just when i drop it into gear

358031222_1432870597492443_2892452611676087957_n.jpg
 
It will be "before" or "After" you want your spark to occur before TDC and yes 10-12 sounds in the "ball park". How about Idle speed do you know what RPM its idling in drive?
 
Dartswinger70 said:
It will be "before" or "After" you want your spark to occur before TDC and yes 10-12 sounds in the "ball park". How about Idle speed do you know what RPM its idling in drive?
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im actually going to purchase a tach hopefully this weekend. in park it's idling a little higher than i like to hear.....if i had to guess the idle in park is around 1000-1200, when i drop it into drive the RPM's go way down for a moment and then evens out where i would say about 800. my original guess a while back was a vacuum leak where the intake meets the heads but i sprayed around the perimeter with carb cleaner and there was no RPM change
 
Dartswinger70 said:
Does it have power brakes? possible leaky booster? vacuum?
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manual brakes. i hope i dont sound like a moron but im learning....im far from a motor guy. one thing i was thinking but not sure if its an issue. there's a large port coming out the back of the carb, i have a rubber hose going from that port to the breather on the driver's side valve cover. i think people with power brakes plug into that port dont they?
 
insidegroove said:
im actually going to purchase a tach hopefully this weekend. in park it's idling a little higher than i like to hear.....if i had to guess the idle in park is around 1000-1200, when i drop it into drive the RPM's go way down for a moment and then evens out where i would say about 800. my original guess a while back was a vacuum leak where the intake meets the heads but i sprayed around the perimeter with carb cleaner and there was no RPM change
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Engines will often idle fine but have problems when in gear. When going into gear, there is a load on the engine so it needs to make more power to handle that. I would suspect your timing is a bit too retarded so you might want to loosen the distributor and move it slightly counter clockwise. That will raise the idle speed some so you might want to adjust that. If that helps, you might want to move the distributor a little more until it no longer stalls going into gear. All it takes is a little change like this to make your engine happy.

Did it run well before changing your points? If the dwell is not set properly the engine will run poorly. Newer point & condenser sets are of questionable quality so just because it is new does not mean it is good.

By the way, the power valve # may be too low. Rule of thumb is to start the PV rating at 2 inches below cruise vacuum and adjust #'s as needed. Based on what you said, I would try an 8.5. The old myth of running a PV at 1/2 of seen vacuum is just that.
 
Get rid of the Holley carb and much of your headaches will disappear. Carter/Edelbrock have better options......
 
Ultimately IMO you want more than 10 in hg of vacuum you should be near 15. That's why Timing and vacuum leaks are coming to mind. I've had good luck with Holley but they do drink fuel...LOL!
 
insidegroove said:
manual brakes. i hope i dont sound like a moron but im learning....im far from a motor guy. one thing i was thinking but not sure if its an issue. there's a large port coming out the back of the carb, i have a rubber hose going from that port to the breather on the driver's side valve cover. i think people with power brakes plug into that port dont they?
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Post a picture of that connection at the valve cover. The hose should have a pcv valve, not just a breather. If it goes straight into a breather it is acting like a huge vacuum leak.
 
Just pull the hose off the carb and stick your thumb on it and see what happens.
 
volaredon said:
Get rid of the Holley carb and much of your headaches will disappear. Carter/Edelbrock have better options......
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Simple bolt on Edelbrock 1406 with the electric choke.

They run nice on the 318s. Pretty much bolt on and go.

☆☆☆☆☆
 
Bobzilla said:
Post a picture of that connection at the valve cover. The hose should have a pcv valve, not just a breather. If it goes straight into a breather it is acting like a huge vacuum leak.
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Holy smokes you may have figured it out!!! I’m not home right now to check but I can say that there is no pvc valve….just the breather. I’m an idiot! I’ll test it when I get home thank you
 
Ricks70Duster340 said:
Engines will often idle fine but have problems when in gear. When going into gear, there is a load on the engine so it needs to make more power to handle that. I would suspect your timing is a bit too retarded so you might want to loosen the distributor and move it slightly counter clockwise. That will raise the idle speed some so you might want to adjust that. If that helps, you might want to move the distributor a little more until it no longer stalls going into gear. All it takes is a little change like this to make your engine happy.

Did it run well before changing your points? If the dwell is not set properly the engine will run poorly. Newer point & condenser sets are of questionable quality so just because it is new does not mean it is good.

By the way, the power valve # may be too low. Rule of thumb is to start the PV rating at 2 inches below cruise vacuum and adjust #'s as needed. Based on what you said, I would try an 8.5. The old myth of running a PV at 1/2 of seen vacuum is just that.
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I would hit the THANK YOU button 475 times if I could.

Thanks
 
I see the edeljunk crowd has chimed in with bad information.

Damn guys, it’s a CARB. If you can’t tune a Holley that’s fine, but don’t screw this guy up.

And look, what has RB been harping on for a long time now. The PV opening LIE.

This poor guy was either told or found on the internet the same stupid tuning information that Holley and the uninformed have been pushing forever.

No wonder some guys can’t tune one. You‘ve never been taught how.
 
Bobzilla said:
Post a picture of that connection at the valve cover. The hose should have a pcv valve, not just a breather. If it goes straight into a breather it is acting like a huge vacuum leak.
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FOR THE WIN!!!! I just got home, practically ran my wife over to head out to the garage and try this out. i pulled off the breather with the hose attached, crewed on a basic oil cap for now and plugged the hole on the back of the carb. fired it up, dropped it into gear without even letting it warm up and it stayed running!!! now i know there has been a vacuum leak this whole time so all my tweaking has been for not. now i can start all over and get this bad boy running strong. i cant believe i didn't think of this. i'll be going to NAPA tomorrow for a PVC valve. Thank you Bobzilla!!! Thank you everyone else for the help, ill keep you posted. and no.....i wont get rid of my Holley, i think they look 10x better than the Edelbrock and much more tunability.
 
insidegroove said:
FOR THE WIN!!!! I just got home, practically ran my wife over to head out to the garage and try this out. i pulled off the breather with the hose attached, crewed on a basic oil cap for now and plugged the hole on the back of the carb. fired it up, dropped it into gear without even letting it warm up and it stayed running!!! now i know there has been a vacuum leak this whole time so all my tweaking has been for not. now i can start all over and get this bad boy running strong. i cant believe i didn't think of this. i'll be going to NAPA tomorrow for a PVC valve. Thank you Bobzilla!!! Thank you everyone else for the help, ill keep you posted. and no.....i wont get rid of my Holley, i think they look 10x better than the Edelbrock and much more tunability.
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PCV is a misunderstood and often overlooked thing.. don't sweat it...

Also... you are wrong about holley being better or more tunable than a carter/edelbrock but that's another discussion :) The main thing bout a carter is they are pretty dummy proof where a holley can be your worst enemy if you don't know what you are doing.

Have a awesome day! :)
 
insidegroove said:
FOR THE WIN!!!! I just got home, practically ran my wife over to head out to the garage and try this out. i pulled off the breather with the hose attached, crewed on a basic oil cap for now and plugged the hole on the back of the carb. fired it up, dropped it into gear without even letting it warm up and it stayed running!!! now i know there has been a vacuum leak this whole time so all my tweaking has been for not. now i can start all over and get this bad boy running strong. i cant believe i didn't think of this. i'll be going to NAPA tomorrow for a PVC valve. Thank you Bobzilla!!! Thank you everyone else for the help, ill keep you posted. and no.....i wont get rid of my Holley, i think they look 10x better than the Edelbrock and much more tunability.
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Get a vacuum gauge if you don’t have one. Hook it to manifold vacuum and take it for a drive.

Look at your CRUISE vacuum. Whatever that number is, let’s say 15 inches you’ll need a 10.5 power valve. That’s where I would start.

Of course, this depends on your emulsion stack and main air bleed sizing but you can’t get anything that opens sooner than 10.5 inches.

If you are making a lot of power the quicker opening power valve may be the best option. If you’re not making a ton of power you may be able to open the power valve later without causing a stumble.
 
insidegroove said:
FOR THE WIN!!!! I just got home, practically ran my wife over to head out to the garage and try this out. i pulled off the breather with the hose attached, crewed on a basic oil cap for now and plugged the hole on the back of the carb. fired it up, dropped it into gear without even letting it warm up and it stayed running!!! now i know there has been a vacuum leak this whole time so all my tweaking has been for not. now i can start all over and get this bad boy running strong. i cant believe i didn't think of this. i'll be going to NAPA tomorrow for a PVC valve. Thank you Bobzilla!!! Thank you everyone else for the help, ill keep you posted. and no.....i wont get rid of my Holley, i think they look 10x better than the Edelbrock and much more tunability.
Click to expand...
Welcome to the site !!! As you already can tell, many here will post what's not their personal preference as the problem... LOL. I've owned (and currently own) eddies, Holley's, bbd's, and all of my cars run really good. I'm glad you found the fix, that is always fun and rewarding. I'll throw out this, though, you might even like it better if you go up on your power valve.
 
318willrun said:
Welcome to the site !!! As you already can tell, many here will post what's not their personal preference as the problem... LOL. I've owned (and currently own) eddies, Holley's, bbd's, and all of my cars run really good. I'm glad you found the fix, that is always fun and rewarding. I'll throw out this, though, you might even like it better if you go up on your power valve.
Click to expand...

Could not agree more with this post. Wish I had said it.
 
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