oldcutlass

Have you set your timing, carb air/fuel mixture, and curb idle.? Sounds like you cured your vacuum leak.

Sampson

As others have said it still sounds like you need to dial in the timing. It shouldn't take 3 hands. Snug down the distributor until it will still turn but is not loose. Start the car and run at high idle until it is warmed up and you do not need the choke. Choke should be open. Reduce engine speed to the lowest level the car will run. Slowly rotate the distributor. If the engine Rpm starts going up and running smoother reduce idle speed. Keep going until the engine starts to run poorly and then back it up again to the point where it runs the best. If the engine stumbles and dies rotate back to the point it last ran and restart the car. Slowly rotate the distributor the opposite direction. This will get you close.

1976Oldswagon

wow, fast responses.

the engine will not idle, even with the idle screw all the way in..but luckily I can get 3 hands, so I can get that taken care of. good to know its timing and not carb related.

so, if I take anything away from this project, its this: if you are looking at intake manifolds, and you KNOW you will have distributor clearance issues, don't just think "ahh well, I'll just pull the distributor out and reset the drive gear on the cam, once I get close I'll have it!" because it's just not that easy.

1976Oldswagon

okay, it will start, idle/run for a few seconds, then it backfires (out of the carb) and dies.

I've adjusted the timing all over the place, and this seems to happen no matter if where it is.

the timing order is correct.

also, I've been adjusting the timing with the vacuum advance line plugged. should I have that hooked up or not?

and when I do get it to run, I adjust the timing with the vacuum advance unhooked, with the RPMs above where the mechanical advance is, right?

oldcutlass

Ok let's go over a few things. Did you get full voltage at the coil? Did you get your carb rebuilt? What rpm are you trying to set timing and what setting are you using? Are you sure the firing order is correct? Yes, the timing is set with the vacuum advance line disconnected and plugged.

1976Oldswagon

okay. when I'm not cranking, there is 3.7 volts at the coil...the engine has ran while not on the starter, I have ignition.

no, I haven't rebuilt the carb, but I did confirm its function on a friend's truck.

yes, I'm sure the firing order is correct.

oldcutlass

Can you get a voltage reading while running on the coil +? It needs to be full battery voltage. 3.7v is wrong.

1976Oldswagon

depending on where I ground out, I get 3.7-4.5 volts.

when cranking, I got full battery voltage.

I thought that the engine cuts down on voltage to the coil while running (via the resistance wire) to keep from burning the points up??

oldcutlass

If you are running an electronic ignition, you don't use the resistance wire. Also if you were using the resistance wire the voltage should be around 8-9v.

1976Oldswagon

its an MSD blaster 2 coil, everything else is stock.

I will put a jumper line in from the battery to the coil and try again.

1976Oldswagon

jumper line from battery to coil, did the same thing.

whatever is making it backfire isn't the coil/spark.

might be timing.

oldcutlass

A pointless kit is not stock and most require the removal of the resistor wire.

MDchanic

Some are, some aren't.

We'd need to know the exact make and model to be able to look up the instructions.
The Crane sensor that came on my 350 requires the original resistor.

We return again to the place we always end up: Without getting good information, we can't provide good information.

- Eric

1976Oldswagon

I have no clue what brand/model it is, it was in the car when it got to me..that being said, it ran fine with the resistance wire before all this.

MDchanic

Okay, so let's bark up a different tree.

You have a car that runs, but doesn't idle, with a used, non-rebuilt carburetor that you observed to work well on the vehicle it was on before.

I agree with the others that you HAVE to get this engine times correctly.
Connect timing light, vacuum gauge, and tach, place each in safe place, clean and mark balancer slot and timing tab with chalk, paint, or whatever you'd like, so you can see them clearly, start car, grab timing light, point and shoot, slowly drop RPMs and watch advance drop, then raise RPMs to about 3,000 and watch the advance climb. Set to about 35°BTDC at 3,000 RPM. Then see where the timing goes as you reduce the RPMs again. Watch it so you can note the advance at the lowest RPM you can get.

You have a new, non-factory cam, so you don't have any timing guidelines for this engine - you will have to establish your correct timing from scratch, and probably recurve the mechanical and vacuum advance of your distributor to get the car to run right.

But first, let's get the timing in the ballpark.

If it won't idle with the timing set to 35° at 3,000, then connect the vacuum advance and see if it idles better that way.

This is going to be very hit or miss because, since you have a new cam, you're making up your timing specs as you go along.

- Eric

oldcutlass

Eric, I'd leave the vacuum canister disconnected as it will advance the timing way to far and he will get detonation. Also once it's set he needs to make sure that he gets no advance past 3000 rpm. It's a modified points distributer not an hei.

MDchanic

Okay, but with a cam, he may need extra advance at idle to idle smoothly.

I agree that this may require distributor adjustments to get it dialed in, but hooking the hose up and seeing whether it helps will at the least be instructive, and may move us further along.

- Eric

1976Oldswagon

okay, so today I fooled around with the timing some more, and it seems no matter where I put it it does its start-putt-putt-BOOM-stall routine. I will take a video and post to explain what I mean.

is 0 degrees straight up on the balancer, or at the beginning of the timing tab?

all vacuum lines are plugged, except for the one going to the distributor, and the brake booster.

oldcutlass

I'm starting to think that if the firing order is wired correctly, that perhaps the timing gears were installed wrong. Do you think that's a possibility?


It should not backfire.

1976Oldswagon

ok, worked on the car some.

if I back the distributor off, it will run without backfiring, but will not idle. at a certain point, the engine will no longer crank over. it will pop and fire all the way in this range, if I hold the throttle open it will run.

going the other way, eventually the engine will backfire. somewhere in the middle I got it to run okay with the idle screw all the way in, with a piece of tape jammed between the adjuster/throttle lever. but I can't seem to find that sweet spot again. it wasn't what I'd call a smooth idle, it sounded like it was way retarded.

when I installed the cam timing gears, I used the old timing chain, which was replaced when the entire motor had a stock-rebuild maybe 40k miles ago, so I did not account for stretch and installed it with both dots straight up. I know some people install them with both dots facing each other, but since I had set the motor to TDC before this, and both dots were up, I put it back together this way.

I think its running lean, (305 carb on cammed 455 problem) and tomorrow I'm going to see if I can find the sweetspot where it would idle roughly, and mess with the mix adjustments on the carb to see if I can smooth it out.

if that doesn't work, I'll borrow a carb from my friend (stock pontiac 400 qjet) and see if I can get better luck with a carb set up for a larger motor.

here is my cam.

QHCLbPw.png

1976Oldswagon

http://www.youtube.com/watch?v=Xvq-a...ature=youtu.be

it does run great, just doesn't want to idle where the carb does.

I don't have a tach to check my RPM.

oldcutlass

It's hard to make out anything on the short video, but apparently your close. What did you do?

1976Oldswagon

I know the video is crappy, if it was any longer it wouldn't upload.

I'll see if I can do better tomorrow in the light.

I took the throttle return springs off, and set the throttle a little ahead of the idle screw. tomorrow I will take the spring off of the adjuster screw, screw it in far enough that it will idle, and see if I can tune it effectively.

the water pump is leaking, so I've got to deal with that too.

oldcutlass

The old one thing leads to another routine. What is your timing set to?

1976Oldswagon

I took the water pump off, and decided to look at the timing without the pump in the way.

its WAY to the passenger side of the vehicle (retarded?) and when I tried to advance it to the driver side, the engine died.

oldcutlass

Is there not a timing tab on there? The passenger side would be advanced.

1976Oldswagon

hahaha well then I got this figured out, I had it mixed up. I have the stock pointer on it, and I have no clue where actual TDC is. is it the notch at the drivermost side of the pointer?

oldcutlass

There should be multiple lines and some numbers on it if you clean it off.

Sampson

So if you used your old chain and installed the dots straight up.....is it not possible that the slack was on the back side of the cam. Meaning the crank would turn several degrees before the cam started turning. This would effectively be the same as installing the cam a tooth or 2 off. Eric & Eric your thoughts?

MDchanic

There shouldn't be that much slack, and if there is, he needs another chain.

- Eric

billmerbach

If he gets a new chain I'd do a double roller like I just got done doing to my dads plymouth

oldcutlass

I agree with Eric, probably minimal slack. I'm just waiting to hear what his timing is set to.

1976Oldswagon

its about 2/3ds of an inch to the passenger side of the timing tab, this is at idle, with the vacuum advance hooked up.

MDchanic

Oh for the love of Pete.

Nobody measures anything in thirds of an inch.

And, I'm sorry, but my photographic memory isn't that good.
If you are going to be adjusting the timing this way, please either get a dial back timing light, get a timing tape, or just measure and mark your balancer so that you can read off the timing past the normal markings.
The measurements are:
20°=28.8mm
30°=43.3mm
35°=50.5mm
40°=57.7mm
50°=72.1mm

- Eric