Ok, I have asked about this on the tech/general engine board and have tried several things, but have not been able to figure out what is causing it. Here is my other thread: https://www.thirdgen.org/techbb2/sho...postid=1140829 Let me start by telling you what is happening and what I have done so far.

First of all, I started up my car recently after just getting the motor and many other things done to it. I was trying to adjust the timing and it doesnt want to go down to where it is supposed to. When I get it down to around 8* it backfires and dies. I do have the 4 wire connector disconected. It is a computer controlled carb and distributer setup on a 350. Specs are in sig.

I tried just leaving the timing up where it would run good(advanced enough it was off the tab). It ran good and would idle but after running it at 2000 rpms for a couple of minutes the #7 primary began to glow red so we shut it down. It appears that the #1 may have been beginning to get hot also but it wasnt glowing.

I had my cousin come over and reset the valve lash for me because I thought that maybe I didnt get it quite right since it was the first time I had done it. Unfortunatly it did the same thing after he had set it.

I checked the compression on both of the primarys that got hot and one on the passenger side that didnt and they all read at right about 150 psi.

I also checked to see if my timing mark was decently accurate and from what I could tell it was. If the keyway in the crank it 45* from the top the timing mark is at 0 and the rotor is in the right spot(it was pointing at #6 which would be exhaust stroke for #1). One thing here that I am not sure about is how much 1 tooth off will move the rotor. It appeared to be closest to #6 but was a bit clockwise of it. Could the dist be off a tooth?

It was suggested to me over on camaroz28.com that maybe one side of the carb was running to lean. That is why I brought this post over hear. I looked and did notice that the idle adjustments in the base arent angled the same direction. What kind of tool do I need to adjust these. I figure that the #7 cylinder is the farthest away from this primary so it could have been slightly leaner than the other fed by this primary. #1 also looked hot but didnt glow and it appears to be the next furthest from this side of the carb. If this was adjusted wrong could it have caused the motor not to run when I got the timing set correctly?

One last thing. I realized that I had been trying to set the timing with it running at 2000 rpms. At first I thought maybe if it had mechanical advance that was what was throwing it off but I was informed that it didnt. It just hit me though that if it was at 2000 rpms when I was setting it it could require more advance up there to run correctly since it is supposed to be set at idle in drive so that could be why it was dying when I brought the timing down. Maybe if I set it at idle in drive and then pluged in the connector and brought it back up to 2000 it would make a difference.

Thanks for taking the time to read this and if you noticed what I am doing wrong or have an idea let me know. I will probably try setting the timing with it at idle no matter what but I would like to know how to adjust the idle screws(what tool is needed) so that I can do that and adjust the idle air bleed also so that hopefully I can get this all worked out soon.

Ben

 

A few things can cause that, and the carb is way down the list. The fact that it backfires and stalls at 8 degrees is a huge red flag that the problem is elsewhere. Re-do the valve lash. Do it with the car running if you have to to get it right. Make sure you don't have any plug wires crossed. Try that first, if it doesn't work we'll go a little further down the list.

 

I will double check the plug wires. I was told that a vacuum leak could cause this. I dont think it is the valve lash. I did it(it was my first time) and it did this. That is what I thought it was at first, and I had my cousin come over and redo it for me. It still does it after he reset it for me. I dont think the plug wires are crossed but like I said I will check when I get a chance. I have some carb cleaner so when I have a chance to start it I can check for vacuum leaks.

Thanks

Ben

 

Oh, also I did realize that I was trying to set the timing while the engine was at 2000 rpm so that might be part of my problem with the timing but I dont know if it was all of it. Also, I just double checked the order of my plug wires and they are right.

Thanks for the help

Ben

 

set the timing at idle and go from there. And then see how it goes. although i would listen to jester like gospel.

 

Thats what I plan on doing, but vader didnt reply to this. Jester I am very interested in what is next on the "list".

Thanks

Ben

 

Well....just because you set the lash twice doesn't mean you set it right the second time either. I can't stress enough how often people mess that up and spend forever chasing other ghosts. Did you set it with the engine running or turned off...using what method?

A complete ish list, is rough order of likelyhood is:

1. valves too tight.
2. Timing is way off. Even tho the gun says it's right, the mark could be off.
3. crossed plug wires
4. vacuum leak
5. cam is degreed/ground/installed wrong
6. Carb has an fault in the idle circuit, usually a blockage somewhere.
7. damaged exaust valve

 

1. I set the valve lash with it off. My cousin came over and reset it for me. He also set it with it off. It is doing the same thing on the same cylinder. I wouldnt have thought that would be the case since we both set it at different times. I tried to set it running before he redid it for me but have never done it this way, and didnt want to mess anything up. How loud will it be if I back it off while running because the car isnt quiet. Should I be able to hear the rocker over the exhaust?

2. Well, I know the timing was off, but not sure how much because I was trying to set it at 2000 rpm and it wouldnt get below 8*. I plan on trying to set it at idle this weekend and see what happens. Do you think this could be the cause since it is not all cylinders?

3. Double checked and plug wires are in right order.

4. Plan on checking for vacuum leak when I start it next after I set timing.

5. Sure hope not. I just installed it straight up with 2 dots on timing set.

6. The carb did have the idle screws set to different amounts on oposite sides of motor(computer quadrajet)

7. Also hope not. Also I checked the compression and it seemed the same as the others I checked(150 psi). Also while I had the plugs out all of them I pulled were black, but I also just swithced from a different carb that was bad enough it would barely run the motor.

Thanks for the help, and I think Iwill try setting the timing and checking for vacuum leaks because those are the easiest things to do. If that doesnt work I guess I will try to readjust the valve lash on the cylinder that is giving me problems with it running. I hope I can get this straightened out pretty quick.

Ben

 

If you are setting the timing at 8 deg @ 2000 rpm, that is your problem right there!

Retarded timing will cause headers to glow red hot, and 8 deg at 2000 rpm is definitely retarded (no pun intended)!

Set it to 8 deg at idle, and plug the connector in, and your problem may go away. Also, make sure #5 & #7 wires are not crossed, as this is easy to do.

 

Yes, I realized that that was A problem, and plan to fix that, but dont know that it is my only problem because only one of the primarys got hot enough to glow. Also just to make sure by crossed you mean switched right. They can lay over each other right? I have already double checked to make sure they were in the right position.

Ben

 

As gone over many times now, start with the basics.
when you instlalled the cam wer the two dot's at 12 on the crank, and six on the cam? That's how they are supposed to be.

and were they exactly correct as in if the gears were any bigger the marks would touch. if so you got it right.

Second. set the timing farther advanced mementarily to see how it "sounds". if you've got an intake rocker down too tight, it won't sound right. will sound sort of hollow.

If it doesn't, sound odd, and spit fuel out the carb it probalby isn't a vavle down too tight.

Now for the timing. like they said. fire it up, get it to idle around 800-1000 rpm, and set the timing at around 6-10 degrees. or whatever the chip your running calls for.. .

if it's still funky check your firing order AGAIN. 18436572 just incase you forgot

if your still in good shape, check that #7 wire for faults, IE high resistance, ohm meter it, check for breaks in it, or bad connections.


Make sure your timing indicator is correct.

Then to the carb. it's really dependant on the carb, but you'll proably need about 6 turns out on each side, check it with a dwell meter, try to get it as close to the middle as you can

As far as the header glowing.. it's not uncommon, i've had it happen on every car i've fired up the first time with new headers, typically you start em late and fat to be safe, get it going then advance the timing some, and it will lean out some.

so it's not that uncommon.

but it only lasts a minute or two, if yours is persistent go down these lists.

 

Thanks for the help. I will check the stuff eventually but it is icy and snowing outside right now and I cant run the car in the garage. That is how my timing gears were. I have double checked the wire order. I also adjusted the idle mixture(it was different on both sides). I need to adjust the timing and check for vacuum leaks. Then if that doesnt fix it I will try some of the other stuff you said.

Thanks

Ben

PS: If I forget the firing order with it stamped on the manifold right in front of me I have problems other than the car.

 

Man this is pissing me off. I just tried to start it and get the timing set. It still didnt want to run very well with the timing down but I was able to get it set lower since I wasnt holding the rpms up. I plugged the connector back in and it still didnt want to run unless we kept the rpms up. Well, I do have to mention that it is currently like 25 degrees out. This time all 8 primarys started to glow and did it all at the same time. I couldnt even really check for a vacuum leak because it wouldnt idle well enough.

I dont know what to do next. I this is the first time that I have ever had to start up a new motor like this and I dont have anyone experienced around to help out. The thing that keeps sticking out in my mind is that it still wanted to be very advanced in order to start and run, though I was able to get it down more since I was setting the idle at a lower rpm.

On the quadrajets idle mixture, is farther in or out richer or leaner, and does this effect rpms above idle also? I set them to almost 7 turns out because that is what I read to set them to on these boards and they were both set at different amounts before. I did notice a black puff of smoke when the thing would first start each time but didnt seem to do it while running. I know that black smoke indicates a rich mixture, but glowing primarys is supposed to indicate a lean mixture.

I would really appreciate any more suggestions and will answer any questions to the best of my ability.

Thanks

Ben

 

a Quick eyeball on the timing at idle with the lg4 should be around 30-34 degrees with the computer hooked up. so if your in that ballpark good.

is the MC solenoid working in the carb? ie turn it on hear it clicking?

 

Yes you hear the mcs clicking when you turn on the ignition.

I just talked to my friends dad again and he said that he thought he would guess that the carb was at fault but obviously he isnt hear to see it either. He said that he doesnt know that the carb with the stock settings would be able to compensate for the extra 45ci and the cam/exhaust and everything else. So I was wondering if someone had the specs that the ccc setups on the 350's in other vehicles used so I could work from there. He said that he has drilled jets out on them slightly when going from a 305 to a 350 in the past.

I might try checking the timing with the connector connected tomorrow if I have time and see if I can see about where it is.

Another note, if the computer is setup for a 305 it wont richen up the mixture for my motor till it goes into closed loop right? I may have to move the heated o2 sensor up on my priority list because I have long tubes and it may not be heating up the 02 sensor(although with the primarys starting to glow it may be) to operating temp soon enough to adjust the mixture. It may help me get it running well enough to adjust stuff properly but I would still like to know what is set different from factory for the 350's as far as the primarys so that I might be able to get it close before running it again.

Thanks

Ben

 

Do you have the stock timing cover?
The LG4 timing tab is on the cover about the 12 0'clock position and you have to look behind the water pump to time the motor.

If you are using an aftermarket cover and timing tab that is located around the 2 0'clock position, your timing will be grossly retarded.

Good luck.

 

Do you have the stock timing cover? The timing tab is around the 12 o'clock position and you have to look behind the water pump to set the timing.

If you have a timing tab at about the 2 0'clock position the timing will be severly retarded.

Good luck.

 

I have a aftermarket timing tab, but I also have a replacement balancer that is for the older 350, and I think the motor actually is at tdc when the timing mark lines up at 0 because when I first set the valve lash I also was told to watch which valves were where in there travel on the # 1 cylinder and they appeared to be in the right place at tdc. Also, on another thread I had about this problem I was told that the keyway in the crank should be 45* from the top when at tdc and that is where it was when the timing tab said 0*.

Ben

 

Oh, but jeff, that has crossed my mind because it does seem that the timing wants to be set up more like it would be on the stock timing tab, but if I have the other balancer it would need to be set where the aftermarket tab is right?

Ben

 

Depending on the year of the 350, its timing tab may very well also be behind the water pump.

Before you dismantle anything or spend more money, try setting the timing using the tab behind the water pump.
It will only take a few minutes of your time and if it doesn't help, you aren't out anything, but if it does correct your problem, you will have saved yourself more aggavation and money.

 

Well, I just looked at a 305 balancer in the garage and the keyway is definately in a different position compared to the timing mark than the 350 so I dont think that is the problem. I may try setting the timing up there like that but cant I damage the motor if I advance it to much?

Ben

 

Does anyone know what years were what way anyway?

Ben

 

if you advance the timing and the engine starts backfiring, then I would stop advancing the timing.
If, while you are advancing the timing and the engine rpm increases, then, turn the curb idle screw to decrease the rpm and turn the distributor some more, balancing the timing adjustment with the idle set screw untill you are idling around 600 rpm and 6 - 10* before top dead center on your tab.

 

Older smallblocks have the timing tab at 2 o'clock. I forget when they moved it to 12 o'clock, but having a mismatched balancer/timing cover could do that.

 

Yes, but I have already checked the keyway on the crank compared to where my timing mark was and it was correct for the older style timing tab.

If the distributer was a tooth off it would only cause you to have to move the dist more to get it to timing right correct, or would it actually cause the timing mark to show up in the wrong place? I know that I have plenty of room at the dist to adjust, it just doesnt like to run down there very well.

Ben

 

Rather than speculate about it, just do a #1 TDC location check.

 

How can I do this other than pulling the head? Can I just stick a screw driver or something in the spark plug hole and wait till it gets to the top? I did a check that RB83L69 suggested which was to turn the motor until the crank keyway was 45* from the top and it should be at 0 degrees and it was so I think that the timing mark should be correct, but if I can test it another way I will just to make sure.

Ben

 

if you know the timing is out advance it to somewhere where it will run consistently enough for you to find what's wrong with it.
you may have a wrong timing mark on the cover, or the ballancer you don't know. are you on the correct plug wire when you are timing it? silly question but i've done it before once or twice. leave the computer attached fire it up and get it running to where it'll stay running.

has a lot of signs of having a bad ignition coil.

if you've got a bad ignition coil, it wont' fire up with the timing set right, back fires when you hit the gas, doesn't burn completely

And yes. an lg4 running on the EST will have a no load timing that high.

 

Well, I have already checked top dead center and it matches up with the timing mark as far as I can tell. Yes, I am on the right plug wire. I double checked that and connected down near the actual spark plug.

As far as the igningion coil, I think i will have it tested. They can be tested right. I guess that coil was old when I had the 305 and then it sat a little over a year so it is very possible it is having issues. All of the plugs are new along with wires cap and rotor though. The plugs appeared black when I pulled them. That would make sence if it wasnt burning the fuel completely wouldnt it. But if that was the case would the headers glow like it was lean?

Also it did puff black smoke on startup but not while running.

Ben

 

Ben use a vacuum guage to set timming. Plug it in to a full time vacuum port advance it until it peaks and starts to drop off then bring it back to peak and drop it 2in. That will get you very close to where you want and it doesent matter if the ballancer is funky, you dont use it. The mixture screws do do in a CCC and arent worth the effort to even pop out, no difference that would cause a 50ci probelm with the carb either. The ecm may not like the new setup I know my CCS dident like a big cam but theres people here running huge cams with no problems. It just sounds like typical first time bugs to me good luck!

 

Actually, my friends dad said to set the timing that way but havent got a chance yet. I think I am going to have the ignition coil checked out first.

Thanks

Ben

 

I just went to autozone and tested the coil. It said that one of the resistances was fine. The one that goes from the bottom of the coil to the black wire with the loop was out of the meters range though. They said that they had seen them do this and be good before though. Do you think that this is my problem or part of it?

Thanks

Ben

 

ttt

 

quickets way to check a coil is to get a spark tester.... you can pick em up at pep boys...

you want the type where you can adjust the gap it's gotta jump inside the tube. to simiulate jumping the gap in the chamber.

set the gap to what your plugs are at, and have someone crank it and see it it jumps the gap, attached to the end of a plug wire, and grounded(just follow the directions)

if it does open the gap up to the mark for .060" and test it again.
if it fails the first one.. it's outright bad. if it fails the second one. it's week. I'd replace it either way.

 

I won an auction on ebay for a new Accel coil for it so I will be replacing it. I hope that is the problem.

Ben

 

Dont forget to give us feedback, i'm realy curious to know what is the problem. When will you receive the coil? about a week maybe?
good luck

 

I will. I dont know how long it will take to get the coil. I emailed the guy and asked how long and if he could get me a tracking number. I really hope that is the problem, but with my luck it probably wont be.

Ben

 

I got her fixed. I think it was a combination of 2 things. I put a new ignition coil on and it started up a hell of a lot better, but the timing still didnt want to set down to where I thought it was supposed to. Anyway, I was looking at the old 305 balancer which I knew had the timing mark up behind the water pump and it got me thinking about how it compared to the keway vs how the one on the motor was. Well, I decided to go to the parts store to check out one like I had on the 350. I asked the guy to see it to see if the 78s was like that or if it used the old timing mark location. He tried to tell me that I needed to get rid of the computer because it was definately the problem and I wouldnt be able to figure out anything by looking at the balancer. He tried to tell me that my carb and my balancer was conflicting. What a jackass. I told him to just bring it out and he did. Well turns out that the balancer for the 78 truck motor used the same timing tab as my 305 and I was trying to set it with the other style. Runs great now.

On the other hand, I think that I really do need to set my valve lash now(at the real top dead center). I think I was getting some valve train noise.

Ok, now I am thinking about it and I dont understand why it runs when I set the timing there though unless I just got lucky. I put the distrubuter in with it at the other top dead center. It didnt seem to me like it was aiming exactly where it should have, but as close as I could get it. Do you think that it was on the right tooth and setting the timing to the right mark would line it up? It wouldnt run otherwise would it? If anyone has an explination I would really appreciate it.

I really appreciate everyones help, and do have to say it has quite a bit more get up than the wimpy lg4.

Ben