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Discussion Starter #1
Hello all,

I recently got my engine broken in, and have been working on getting it to idle-- however, I'm having trouble with this. I had the engine between 2,000 and 2,500 RPM for break-in, but when I fire it up and try to get it down to under 1,500 or so, the engine sputters out and dies. I've been messing around with a timing light and nothing seems to be coming together-- I'm hoping somebody can direct me or give me a procedure to follow that will get my engine down to idle. Here's what I've done:

  • I've checked for vacuum leaks (289 four speed has 1 vacuum from dizzy to carb, and neither the carb spacer or intake is leaking).
  • I've set the carburetor mixture screws 1.5 turns out from seated.
  • When using the timing light, I can't get the distributor advanced enough to get to my timing marks-- it runs out of space to turn. Turning it the other way (retard) causes the engine to weaken and even backfire. I've tried popping the distributor out and relocating it a couple of gear teeth to give me more room to work, but it seems like it doesn't help.
  • I'm pretty sure my basic timing is right. I set the engine TDC and lined up the rotor and cap to the #1 plug wire. The engine sounds great over 2,000 RPM; it sounds smooth, no sputtering or stumbling, etc.
Basically I'm wondering if anybody can give me a list of things to check or adjust in sequential order, or any other general advice on how to get this engine to at least idle roughly. I'm really struggling! All input is appreciated.

Cheers!
Alex
 

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Discussion Starter #2
I should also mention that the carburetor has been completely rebuilt and is clean!
 

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Re: "...When using the timing light, I can't get the distributor advanced enough to get to my timing marks-- it runs out of space to turn. Turning it the other way (retard) causes the engine to weaken and even backfire..."

The only thing that comes to mind is that your TDC might not be correct. Have you confirmed that the timing marks on your balancer actually match TDC?

Edit: Also, when lining up timing marks on the balancer with the pointer before stabbing your disti, make sure you are turning the crank clockwise when coming up on the mark. Otherwise, you are not accounting for slack in the timing chain.
 

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Discussion Starter #4
Re: "...When using the timing light, I can't get the distributor advanced enough to get to my timing marks-- it runs out of space to turn. Turning it the other way (retard) causes the engine to weaken and even backfire..."

The only thing that comes to mind is that your TDC might not be correct. Have you confirmed that the timing marks on your balancer actually match TDC?
When the TDC mark is lined up with the indicator on the water pump, the piston is definitely at the top of it's stroke. However, after messing with the timing and all, I'm not sure whether it's on the compression or exhaust stroke.

Edit: All fiddling with the crank has been done clockwise!
 

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When the TDC mark is lined up with the indicator on the water pump, the piston is definitely at the top of it's stroke. However, after messing with the timing and all, I'm not sure whether it's on the compression or exhaust stroke.

Edit: All fiddling with the crank has been done clockwise!
I doubt if you were off by 180 degrees that the engine would run at all (but I could be wrong). It certainly sounds like you're doing things correctly.

Some real shots in the dark here...
(1) Just to confirm, when you are trying to set your timing do you have your vacuum advance disconnected and the port plugged on the carb?
(2) Is your firing order correct? If you did a cam swap does it have the original stock 289/302 firing order or a newer 351 firing order?
 

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Discussion Starter #6
I doubt if you were off by 180 degrees that the engine would run at all (but I could be wrong). It certainly sounds like you're doing things correctly.

Some real shots in the dark here...
(1) Just to confirm, when you are trying to set your timing do you have your vacuum advance disconnected and the port plugged on the carb?
(2) Is your firing order correct? If you did a cam swap does it have the original stock 289/302 firing order or a newer 351 firing order?
Yes, I had the vacuum advance disconnected and plugged!

My firing order remained the same for the rebuild; 1-5-4-2-6-3-7-8. I will double check that I have the wires correct and that I didn’t cross some, but I don’t think that’s the issue!


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Your engine will not run if you are 180* off. I would double check the 0* mark on the balancer. Best would be a piston stop. Do you know how to use it? If not even a straw can do the trick.
You wrote you are running out of space to turn the distributor. This means you might be off by one tooth. Pull the distributor and put it back by one tooth. This gives you enough room.

What is your vacuum and how stable is the needle?


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Discussion Starter #9
Your engine will not run if you are 180* off. I would double check the 0* mark on the balancer. Best would be a piston stop. Do you know how to use it? If not even a straw can do the trick.
You wrote you are running out of space to turn the distributor. This means you might be off by one tooth. Pull the distributor and put it back by one tooth. This gives you enough room.

What is your vacuum and how stable is the needle?
Thanks for the reply! I messed with the distributor a bit and she runs well enough to work with now. I also have more room to adjust it. I don't have a vacuum gauge, but it sounds like I'm going to need one.
 

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Discussion Starter #11
Okay, so I'm swinging back around with some updates. I got the engine running semi-smoothly again. I can get it down to about 900 RPM and leave it unattended, and it will idle.

I've been adjusting the timing, and I'm at about 30* of advance-- this is way too much, isn't it?

I'm worried I might have a bad carburetor/timing relationship; one is extreme because the other is unadjusted, etc. How can I go about "resetting" these factors or isolating them?
 

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Maybe a dumb question... but how do I do that? If I try to turn the distributor to get to that point, the engine really struggles. Hence my concern with the carburetor?

Thanks for pitching in :)
- Alex
You'll have to up your idle first, it's a balancing act..

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Maybe a dumb question... but how do I do that? If I try to turn the distributor to get to that point, the engine really struggles. Hence my concern with the carburetor?

Thanks for pitching in :)
- Alex
Well, if it runs smoothly at 30 deg. btdc, but not 10 deg. btdc I'd guess you're either you're not using #1 spark plug wire or your timing marks are off (timing gears and/or harmonic balancer and pointer).
 

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Well, if it runs smoothly at 30 deg. btdc, but not 10 deg. btdc I'd guess you're either you're not using #1 spark plug wire or your timing marks are off (timing gears and/or harmonic balancer and pointer).
Ok, you mention 30º. Is this at the 900 Rs the engine, finally, settled at and is this "without" the Vac disconnected and plugged?
 

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Sounds like you may have a vacuum leak, I had a similar problem after swapping the intake manifold. Eventually had to pull it and reinstall. 2nd time engine ran perfect. I can only assume I had a vacuum leak somewhere along the manifold.
 
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To elaborate on what Flade said above... if it is a vacuum leak it could be coming from a leak from the crankcase/lifter valley into one of the intake runners past one of the intake gaskets. You'd never see that by checking around the outside of the engine (eg by spraying carb cleaner around the gaskets). But I would think a vacuum gauge should show a problem (either low or bouncing vacuum).

Edit: BTW, you don't need to spend a lot on a vac gauge. I bought a HF one and it works fine. You can find similar ones on Amazon and Summit for similar $'s

 

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What post on the distributor cap are you using for #1 cylinder? I suggest you follow an earlier post and use a piston stop to determine true TDC on your balancer. Also are you using a 4 hole balancer vs a 3 hole balancer? That makes a difference. The 4 hole has the marks like 65 degrees off. It's meant for a pointer on the passenger side. I have a 4 hole balancer on my 289 that I had to make a timing tape for. TDC is @65 degrees on the old marks. Also vacuum leaks are not just at vacuum sources. Your intake or carb could be loose. I have started using only Gasgacinch on my intake gaskets. No RTV in the water jackets. Use 4 studs on the corners, Lay a bead of Right Stuff at the end rails and set your intake down. Use lubricant on your intake bolts. Torque in the correct sequence. Run the engine a few times,and torque them again. Oh and 1.5 turns on the idle mixture screws is just a starting point. You can't just set them there and say I'm good. Once you start and warm up the engine you tune the mixture screws to highest engine vacuum that could be 1.5 turns, could be 1, or could 2. Could be anything based on what your engine wants to run well. I see tons of people in different forums say exactly what you said. "I set my mixture screws to 1.5 but the engine doesn't idle. I don't understand why."
 
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