No start just Manifold backfire

Hey dudes its ya favorite Newbie. I have been messing with me Sbc chevy for the past 8 months and still cant get that distributor set up right i went from being 180 out to being a tooth off and thats were im stuck. So far i have got it to run at 1500 RPM and would die at idle. Now i have tried to rotate counter clockwise 1/24 (one tooth) and now all i get is a lil puff of smoke and no start....Any ideas will be helpful i would hate to pay someone to fix it. Ya hit me up!?!?

 

Explain what you have done. Tell us the exact order in which you are setting the distributor in.

 

Set it up at 10 deg. ADVANCED (@ the timing marks at the harmonic dampener) - be sure that it's on the COMPRESSION stroke (do this by removing the #1 plug and put your finger on the "hole" while you rotate it with a breaker bar (remote starter works too - so long as you keep your fingers AWAY from anything dangerous AND be sure to defeat the ignition so it doesn't start) anyways once it's set at the crank so it reads 10 deg advanced (just get it close) now check to see that your rotor is pointing to the #1 plug wire. Rotate (counterclockwise) the distributor until the points JUST OPEN -double check rotor - lock it down - It should start. If it's electronic the process is basically the same except you will be referencing what ever they use to trigger the ignition.

 

That stuff always happens to me and then I get to rediscover which way everything turns and why and how simple it was all supposed to be, like marriage and church and knowing when to stop.

 

find true top dead center, rotor will point at number one on distributor cap, thats where you start and wire it 1.8.4.3.6.5.7.2 I think. and to find top dead center, yank off drivers side valve cover, rotate crank till timing mark on harmonic balancer gets to TDC and check to see if both the #1 cylinder valves are closed, this should be TDC, if not closed, rotate around 1 more time till TDC mark and look again.

 

Oaky i had the car runing but only when i had the distributor turned all the way counterclock wise and only when i kept it at a low RPM. Well to try to fix that lil prob, so i pulled the distributor,set it to TDC on #1 cyclinder, turned the oil pump shaft by 5 degrees to adjust the advance curve, dropped the distributor back in with the rotor pointing to the number one plug, put the cap back on, tighted everything back up, hooked everything back up and tried to start with just one single manifold back fire then just cranking after that . it didnt seem to even want to start. So am i missing anything in there???

 

How do i know when both valves are closed?? Up or down?

 

Follow hemirambler's advice to a T. It won't fail

 

They will be up, the springs won't be compressed and rockers should be able to 'wiggle' a little......you may want to check your valve lash too....
You sure you got the firing order correct????

 

The way I figure out when #1 is at TDC is remove the spark plug and stick my finger over the hole. Then I have someone (or I use a remote starter button) "bump" the starter to rotate the engine. You'll feel a large burst of air when #1 is at the top. Otherwise you'll feel it sort of "pull" against your finger. When you feel the burst of air, check the positioning of the timing marks on the balancer versus the timing mark on the timing chain cover. You'll be able to zero it out after. If you have any doubt about the piston being at TDC, you can usually check it with a piece of welding rod or coat hanger and feel for the piston itself.

Figure out where the rotor is pointing. I think in this case it would be easiest to make that your #1 (rather than remove and try to drop the distributor in place) and then set the plug wires off of that #1 location.

While you are bumping the starter to find TDC for #1, remove the distributor cap and pay attention to the direction the rotor is turning, as this is the direction you will lay out the plug wires. I believe Turboroadster has the right firing order, but almost ALL sbc intake manifolds have it stamped somewhere on the manifold.

Also, I don't think anyone noticed or asked, but you do know that chevy motors have the even numbered cylinders on the right side (passenger) of the motor and the odd numbers on the left side (driver's) of the motor. I learned this the hard way about Fords once that they are numbered 1 thru 4 on one side and 5-8 on the other.

Let us know what you figure out!

 

Oh... another way you can check for exact TDC is if you have access to an air compressor and a compression tester. Screw the compression tester lead into the spark plug hole and then hook it up to the compressor. You'll hear the rush of air escaping the cylinder through the valves. Turn the motor until you hear the air stop. Make sure you turn down the air pressure on the compressor or as soon as you get #1 where you want it and turn loose, it will rotate itself back down due to the build up of air pressure.

This is the way I learned to change valve guide seals on a motor without removing the heads!

 

did you set the valves correctly. i was glad too see that somebody mentioned that rotor should be pointing to #1 on distributer cap. i do recall the confusion of people saying: rotor should be pointing to #1? wtf! until physically seeing it done i was allways under the impression they meant # 1 cylinder and after trying to get a sbc running after a manifold swap i thought i was going to go fucking crazy trying to get it running. lucky for me a 6 pack later i found someone that recognized what i was doing wrong by making me physically go through the motions. believe me that flash of embarassment of doing it wrong was well worth the knowledge i gained

 

Just a question but has the motor been tore into or rebuilt? If not by you, by someone else? The reason I ask is that I bought a motor from someone and they said it was fresh and I couldn't get it to run at all. Several weeks, alot of friends/beer later, we took the timing cover off and realized the guy didn't put the timing chain on right. It didn't matter what I did, the cam was dialed in wrong in relation to the crank and pistons. If it is stock then find TDC and go from there. If it still won't run check your distributor for flaws. i.e. coil, module, stuck open/bad vacuum advance. Stock chevy distributors have a total of 24 degrees of advance built into them and most chevys are happy starting at 36 degrees of total advance @3000 rpm. get it running and start by putting your timing mark on the balancer @ 10-12 degrees thus giving you a total of 36 degrees. Also if you are using a timing light remember to disconnect your vacuum advance tube to the distributor before you try to adjust. (I normally forget to do that lol!) You never specified if it was HEI or points but it should all be realitively close either way. Good luck and keep us informed.

 

Well when i bought the motor i was told it was bored out and rebuilt. It ran fine until one day let my friend barrow it, few days later it started to backfire, then run rough, then wounldn't even start! Since then i have replaced everything but the heads and block(havent touched the valve train ) ... And its a HEI accel distributor...ya keep throwing those ideas this way

 

timing chain -gears its off on the cam gear..
your buddy pounded it
now its outa time and it needs new gears and chain
every time you get it close the compression is backing up the chain on the gear ... move #1 cylinder it kinda fires then .. nuttin try resettin it fires then .. over ,over again
paperdog

 

Are you using a timing light to set the distributor after it's started?...It doesn't sound like it.

Just snug the distributor holddown bolt. While cranking the engine, slightly rotate the distributor one way then the other untill the engine fires and runs smoothly, then, if it's not already hooked up, shut off the engine, hook up the timing light, start the engine and set your timing (by rotating the distributor) to the factory specs for your engine...probably around 8 degrees BEFORE top dead center. It's been awhile since I've been around SBC but the harmonic balancer probably has a 0 or is marked TDC...You want the light to blink BEFORE TDC.

Timing is set? Tighten the holdown bolt disconnect timing light, enjoy.

 

HEIs (even aftermarket ones) have a tendency to kill the little ceramic brain in them, you can try replacing it. I had a 350 with an HEI that started missing occassionally, like a broken wire, just once every couple of minutes did that for about a week while I was trying to find the intermitant wiring problem. Then it died completely It would pop a little when cranking but wouldn't run, changed the brain, no help, swapped another coil into it and it fired right up. One of the two should help maybe. Good Luck. Jaysin

 

Im ordering a HEI upgrade to replace all the moving parts, module, coil and vacuum advance. My distributor is just worn out and vacuum advance filled with gas. Ill install the upgrade and let ya know.

 

This is key bit of info and could mean many things. Where is it coming from? If there is a liquid in the advance mech and line, then it won't work or work sluggish and screw with the timing, also could indicate carb problem and flooding, could mean vacuum leak too. Keep in mind the HEI may not solve the problem.

FWIW...

 

gee sounds like you buddy may have blown a head gasket. drain the cooling system and see if their is a change in the rough idle. pull the plugs and check for any signs of moisture. compression check? last thing get a new buddy, he should be helping you pay for this bullshit! good luck and let us know what you find. god luck.

 

Vacuum is supposed to suck, yours is blowing...HEI ain't your problem.

Are you sure it's not backfiring through the carburetor?...It sounds like an intake valve isn't sealing/closing.

The last time I had gas in a vacuum line coupled with backfiring I had a (really) bad intake valve seat.

Do a compression test.

 

UPDATE Okay heres what i got, when i set the distributor in at set it in 10 degrees before TDC and now i can get it to run still at a low RPM not at idle though. Its a chevy so the rotor rotates clockwise, so counter clockwise (advance) and i can get it almost to idle. Now if that sounds like a vaccum leak let me know. Oh ya can someone tell me how to do a compression test and what tools i may need also. No shop avalible or compresor. Thanks guys

 

Dude, you mentioned it was supposed to be rebuilt and ran fine until a buddy drove it. I vote for timing chain has slipped a tooth, retarding the valve action. Just because somebody rebuilt it doesn't mean they replaced the timing chain.

Easy way to check to see if the chain is stretched:
1) remove distributor cap
2) with a breaker bar in the balancer rotate engine BACKWARDS (counter-clockwise looking from front of car) until you see distributor rotor move
3) slowly rotate engine FORWARD until distributor rotor moves. It should move almost instantly - up to 1/8 revolution is OK

If the crank has to move 1/4 revolution to move the distributor the timing chain has too much slack and has probably jumped timing. This has all the valves opening and closing late. The timing chain needs to be replaced before doing anything else.

Tracy

 

PAPERDOG and DIDGEYTRUCKER are probably right on this one...

Put a new timing set in it.

They usually go to shit right when you start the engine. It could have been running fine when it was shut off.... then...phhhhhht...



JOE

 

Sweet guys i will order one and put it on should use gear driven or chain?

 

Use a chain. the gear drives sound good for the first half hour, then the noise just makes you crazy!!!!

 

Dang ok i took the distributor cap off and hand cranked the motor till i saw movement and cranked it back . The was almost no play as in as soon as i cranked it the rotor turn both ways with no delay. Show what does that mean??? a buddy said it sounded like it was getting too much air...

 

you know what would help is a few pics, its hard to tell if you even know what top dead center is, are you sure its getting gas? its not that hard to get and engine to fire just a few simple steps. so the engine ran fine then your buddy took it for a drive and came back and parked it and it never ran good again?

 

I had a similar problem with a 302 I just put in. It would crank, and hit for a second, then BANG!!! Flames and all.

Turned out I used the wrong firing order. Leave it to Ford to have like 30 different firing orders for the same year engine... HO/non HO, etc...

Your problem sounds entirely different though. And I bet it's something simple.

An engine needs 3 basic things; air, fuel and spark. They need to be happening at specific times. Start with the simplest one and go from there.

Does the engine spark? Does it spark at the right time? Are you SURE the firing order is right? Once you've eliminated the ignition system (including battery voltage, firing order, etc) then move on.

Is the air system restricted? Is the cam timed right (thats where the TDC stop comes in) Do you have any visible vacuum leaks? (A buddy of mine and I did an intake gasket on a 351W a while ago. It started fine, ran ok for a minute then died. Couldn't figure out why until we looked and saw a major leak on the back of the block. He forgot to silicone, or seal at all, the back face of the intake to the block... had one HELL of a vacuum leak!)

Once you've nailed them, go for fuel.

I've found breaking it down to the simplest elements usually yields the best results.

Good luck, keep us posted.

Jay

 

Well when my buddy drove it, the car slowly lost all performance within a weak then it wonteven start, it had back fires and couldnt take it past 4000 RPM. So it sat for 2 years then i replaced battery, carberator, intake gaskets, distributor, plugs, wires, coil, rewired inginton, damper cover to ensure no slipage, i havent pulled the heads yet (dont know how) so i dont know how the valve train looks and head gaskets. When i pulled the Intake off it was filty cleaned it out very well. Now we are to this point and it seems to me that maybe a valve has been burned up or something wrong in that area. What do ya think of this ?