patricklav

iTrader: (7)

Well, i finally got my engine rebuilt and installed, where i dealt with a multitude of issues to get it to the point where i can now fire it up.

When i turn the ignition, the engine turns over, but instead of starting up, all it does is backfire loudly. One of the headers actually had a very small fire on it. I waited about an hour before trying it again, in case it was flooded (im pretty sure it was) and got the same result. I held the throttle wide open for about 20 seconds before trying to start it to try and resolve the potential flooding but that didnt help.

Can you guys point me in the right direction here? This is my first build and im learning as i go but troubleshooting issues is more for the experienced and i dont wanna mess it up now.

thanks

dads old blue 9

distributer maybe 180 out . what eng do you have?

jermdm

Sounds like the timing is off. Could be the distributer not installed correctly like dads old blue 9 said or timing chain not timed correctly.

patricklav

iTrader: (7)

350 GM Goodwrench motor

patricklav

iTrader: (7)

Im sure the timing chain is installed correctly as i triple checked it before installing the cover, balancer and pulley.

How do i get the timing as close as possible to get it running where i can further get it timed properly?

thanks

dads old blue 9

find tdc ON THE COMPRESSION STROKE turn the dist til one pin is directly over the rotor thats #1 18436572 I still think your 180 out meaning when you lined up tdc timing marks you were probably on the exhaust stroke common problem for some dont keep trying to start it the way it is . leave the dist bolt just loose enough to hold it firm but still able to move it by hand have a friend turn key move the dist slowly one way 1/2 inch if no start turn other way 1/2 inch when it starts adjust by ear ,then timing lite .

patricklav

iTrader: (7)

Yup, i was on the exhaust stroke. I corrected that and tried firing it up and its no longer backfiring burt its niot starting either. The starter is cranking the engine but its not sputtering or doing anything. Im getting gas to the carb so its not a fuel supply issue.

Any idea what else may be preventing it from starting?

thanks

dads old blue 9

Is it getting spark ? crank and turn the dist just turn it very slow . could be flooded after all the unburnt fuel pull a plug see if its wet do not pump the gas just hold the pedal to the floor . .....let me know

sofakingdom

iTrader: (1)

This kind of thing isn't about "ideas"; it's about "get out there and look".

We can all sit here however many thousand miles away and play "maybe it's this maybe it's that" games. Without a doubt someone will pipe up with "timing" (invariably to tell you it's too far advanced) and someone else will tell you "EGR". That's about as valuable as any "ideas" you're going to get.

Use logic. Fuel/air in reasonable proportions; spark near the right point in the engine cycle (within 20 or 30° is close enough to run, even if not perfect); compression. Which one is missing? Pretty straightforward. So here ya go.

Make sure all the fluids are full before you start.

Pull the #1 spark plug. Disconnect the 12V wire to the dist and pull the injector fuses. Have your assistant bump the motor over while you hold your thumb over the #1 plug hole. When it blows your thumb off the hole, have them stop, and look down in the cyl with a flashlight or something; turn the motor by hand until you see the piston coming up. Stop before it gets to the top. Set the dist so that the star wheel teeth line up, and the rotor points just to the driver's side of straight ahead. Put the plug wires on the cap with #1 as described, then 8436572 from there around the cap clockwise.

Back all the rockers off one full turn.

Put in a new set of plugs.

Plug everything electrical back in. Reach in the window and fire it up. Before you put the valve covers back on, adjust the rockers by backing each one off until it starts to clatter, then tighten it until it shuts up. Do all 16 as fast as you can like that. Shut the motor off. Tigthen them all ½ more. Put the VCs back on. Close the hood. Crank it back up and go for a test drive IMMEDIATELY. No extended cranking, no sitting idling, DRIVE IT IMMEDIATELY.

patricklav

iTrader: (7)

I pulled the plug. It's bone dry. It is getting spark, as when I crank the engine it sparks. Is it possible for it not to fire if the carb is messed up and just floods it? When I prime the fuel pump gas comes right out the top of the carb (edelbrock 750). Seems like there's way too much fuel And its just flooding the carb and not spraying.

Thanks

sofakingdom

iTrader: (1)

<sing>one of these things is not like the other</sing>

Could be one, could be the other, CAN'T POSSIBLY be both.

If the carb shoots fuel out the accelerator pump, it should at least attempt to start.

At the right time? Specifically, as the piston approaches TDC on the compression stroke, not the exhaust stroke?

What happened when you backed the rockers off?

dads old blue 9

dont mess with rockers first off thats not the no start prob ,not with a new new long block .you say you have a carb so this isn't advisable by most but being that the plugs are bone dry pour a very small amount of fuel in yhe carb throught and crank it if it starts for a second let me know dont continue . also did the carb come from a running eng? you can use carb cleaner in lou of fuel one time only

dads old blue 9

I just re read your last post and see that you already tried fuel in the carb if thats what you meant by (priming the pump) and no the carb has no efect on weather or not the dist sparks .with exception to the vac advance (if you have one) but the car should start weather the advance is functioning or not . that would just make it run rough . by the way i'm not sure of your abilities so dont think i'm an *** If I tell you something that you already know. double ck for vac leaks ,especially at the carb.

sofakingdom

iTrader: (1)

Back the rockers off one full turn.

Object of the exercise being, make sure they aren't too tight. Because if they are, there won't be any compression. (among other NO-RUN symptoms... but that's the first most obvious one)

Vac leaks won't keep it from starting.

Remember, we're troubleshooting a NO-START, not a RUNS LIKE CRAP. Vac leaks will DEFINITELY cause a runs-like-crap; CAN'T POSSIBLY cause a no-start.

Fuel/air, spark at the right time, compression. Focus. Concentrate. Zero in. First things first. Eliminate a bunch of "maybe it's this maybe it's that". Think of things that can KEEP THE ENGINE FROM STARTING; once you get it to start, THEN AND ONLY THEN go to work on things that might make it not run right. (if it even still needs that)

patricklav

iTrader: (7)

Ran out of time today before I seem your post. I will try that tomorrow night and let you know what it does.

Thanks

sofakingdom

iTrader: (1)

Good luck!!

Clear your mind of everything except logic when you get back after it. Concentrate on the "magic 3" ingredients; air/fuel, spark at the right time, compression. Verify each one, one at a time, until you are completely satisfied it is perfect. Don't let yourself get pulled into tail-chasing, dinking around with random stuff that CANNOT CAUSE the symptom you are observing, "maybe it's this maybe it's that", twiddling things that aren't related to NO-START, and all that other non-productive stuff that leads nowhere. I hate to have to tell people this, but about 95% of the time the cause of a new-motor no-start is something blatantly obvious that was done wrong during assembly. Over-tightening the rockers because somebody "said" you were supposed to "torque" em to 30 ft-lbs or whatever or because the "twist the push rod" method was used, and setting up the dist on the instance of #1 TDC that's not the firing one, are BY FAR the 2 most common causes of a new-motor no-start. Begin your work there. Apply the Pareto Principle: 80% of the problems are caused by 20% of the explanations. Logic, reason, rationality, orderly mental process, all those things will lead you straight to the problem. "Maybe it's this maybe it's that" will keep you out there frustrated for who knows how long until you accidentally stumble across whatever was done wrong. Study my signature and let it sink in thoroughly.

dads old blue 9

good luck . hope what ever you decide to try works . not sure about hamlets advise about the rockers. with a good wrench motor . but stranger things have happened , and he doesn't sound stupid , just a little....... off LOL

dads old blue 9

I just thought of something ,your first post you said ''car wont start keeps backfiring'' if it was backfiring when it was 180 out that means it was getting fuel and spark , just at the wrong time. one more thing to check before you start messing with valves tripple check the plug wire routing . and some will not agree with this , but if you have an old dist cap ,break off the #1 so theres a hole place broken cap onand look straight down till you can see rotor tip (obviously align tdc) that will get you as close to eyeball time as possible .

patricklav

iTrader: (7)

Good stuff!

Reading that just gave me the motivation to get back out there and keep going but ......... It's 20 degrees outside and my garage isn't heated so tomorrow night will have to do.

Thanks

patricklav

iTrader: (7)

I do have an old cap so I will give that a try as well.

Thank you for all the help.

patricklav

iTrader: (7)

Tried again tonight. Backed off the rockers. Set piston #1 to TDC, set the distributor, cap and wires and still nothing. It's turning over pretty well but still no sputter or anything that tells me it's firing.

I checked the power feed to the coil and its reading 12 volts with key turned forward so I'm getting power to the distributor. Could it be the distributor is bad? I bought it used and haven't seen it ever run. I have another one that was on the car before, which I have never seen run either that I can try.

I feel pretty confident that I hit TDC because I could fee the piston at the top of the cylinder with an engine mount tie wrap and the rocker arms were not moving as I came up to TDC which tells me their closed for the combustion. Once I got that set I installed the distributor with rotor pointing at #1 cylinder. I put the cap on and installed the plugs with valve covers still off.

Not sure if this matters but I notice many of the rockers are loose on part of the crank rotation but are very tight on another part of the rotation.

I'm not sure what else to try.

dads old blue 9

I kinda wish you didn't mess with the rockers . if you remember exactly what you did with them .... undo it . when you found tdc you did align the timing mark on the harmonic balancer rite? did you use the hole in the cap trick ? double check the order of the wires make sure the rotor rotatoin coinsides with the firing order 18436572 dont go by the # printed on the wires . if you have a timing lite clamp it on a plug wire just to see if it flashes .if your not getting spark a good GUESS would be the coil. this is common on these cars . make sure the batt ground goes to the engine ....not the body check the ground on the firewall (copper braided line) about 4 inches to the left of the dist. (when replacing an engine its easy to forget this ground) . double check for any thing that might have been missed during installation. I think its the coil if everything else is ok remove coil and closley inspect for discoloration and hairline cracks. also the ground there too remember there are rubber mtr mts so the ground path must go... bat to eng eng to firewall .

dads old blue 9

Patric heading out for the day , hope everything goes well . I bet you'll have it running today. please keep me posted .

aremy10

iTrader: (3)

i had built a motor years ago and had the distributor in 180 degrees. same thing, popping etc, followed by a big load band! put it back in the right way, and ran good for a week, then wouldnt start, replaced coil, ran for days, wouldnt start , etc,
check for spark again, check capacitor in distributor for damage (should see if it is cracked, etc) if no spark. if it is damaged you may have damaged the distributor. after i replaced capacitor in mine it still would keep blowing coils , only after changing the distributor it worked right again. just another idea from an experience i had. i do not know how common a thing this is , first time i have seen it, but doesnt hurt to check

patricklav

iTrader: (7)

Thanks guys. Have two sick kids and sick wife with the flu so haven't been able to get back out there. Hopefully in the next day or two.