Thread: got gas, got spark, got fire but not the kind i want

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so i just got done installing my 355 into a 1978 volvo, we are trying to get it to fire up but all that happens is it ends up shooting flames out of the carburetor. the car has gas and spark, and it sounds like its only firing on one cylinder. we set TDC and got it all lined up. what would cause it not to fire over or even worse, why is it jetting fire out of the carburator? could it be the cam is off timing?

did the engine run before the swap ? .. it must be timed wrong ..

Double check your firing order,pull #1 up to TDC ,(pull the left valve cover to check that both valves are closed) Was this rebuilt and is this the first time it was fired up?

Make sure your distributor is not 180 degrees out.



Bill S.

distributor is set right, firing order is good, the engine ran before it was installed, all i did was put 305 heads on it and a new carb, but every thing was drained from it and nothing other than the heads were touched. and intake were touched. the engine was rebuilt once before, but had been run since. what am i missing?

This happened to me once when I put the fuel line on the vacuum port and the vacuum on the fuel port. I was swapping from a two barrel to a four barrel and the carter carb fuel port was opposite of where the original fuel line was. Maybe?

Originally Posted by volvaro

distributor is set right, firing order is good, the engine ran before it was installed, all i did was put 305 heads on it and a new carb, but every thing was drained from it and nothing other than the heads were touched. and intake were touched. the engine was rebuilt once before, but had been run since. what am i missing?

What are you missing?? From the way you descripe your problem it sounds like you have either miss timed the motor, or dropped the dizzy in and missed the timing that way. If the engine ran before and you have done only the things you mention it will run again. Don't "ASSUME" the dizzy is correct. Check it! Dont "ASSUME" it has the correct firing order. Check it! If you have already checked those things and it seems correct- Do it again. the problem is in the timing some way some how, I just bet.

RS

Head swap, did you check for proper push rod length? Did you adjust the valve lash? What about rockers, are they properly adjusted? Could a head gasket slipped while installing? Then again, did you torque down the head bolts properly and in the correct order? New head bolts? Way too many things come to mind that could go wrong just with the head swap. I'd still double check the distributor as the first thing, then work your way down my list.


Bill S.

proper pushrod length is good, valve lash is set to 0 like factory said, rockers are good and torqued, headgasket didnt slip when installing, head bolts are torqued. fuel lines are hooked up and vacuum is hooked up properly. gonna check to see about if we got TDC right or if we made a dumb mistake. its all back together and the cam is timed right, checked that too. probably just got TDC wrong. not the first time, or my distributor might be backwards. ill let yall know.

A couple of years ago I was building a Pontiac powered 4x4 1953 Ford truck. I had spent a ton and a half of money on that HO 421 and finally the day came to fire her off. She spit and puked a couple of times backfired through the carb but no go. I went back to my Motor Manual for the Pontiac. I had ther cylinder numbering sequence right, I had the firing order right 18436572 same as most Gm's. I pulled and checked the distributer and everything was good to go. Still spit, puke, backfire, I go back to the book and pull the dizzy redo everything 18436572 sequence is correct turn the key-- spit, puke, backfire. Man what could be wrong????? Back to the book FIRING ORDER Pontiac 421 HO 18436572-- Check, Cylinder # Sequence Check. Turn motor over #1 cylinder in correct location, turn the key SPIT, PUKE. BACKFIRE....
Pull the intake, pull the timing cover, reset the valves, check timing marks for timing chain, Everything and I mean everything is as its supposed to be. I redo everything for the 6th time, before I turn the key I go and recheck the BOOK.. Firing Order 18436572, Cylinder # sequence, Man what is this in the third column?? Engine rotation Pontiac all V8's "CCW", Can it be that simple? Or maybe the question should be --Can I be that stupid?

Rewire the dizzy--- 18436572 this time CCW-- Turn the key, Varoooom I had me a gen-u-wine fire breathing monster on my hands. I felt real silly for doing that 6 times before I finally got out of my own way.

Morale to that story is check everything and ASSUME nothing..

Roland

i will definitly have to try that. cause i always thought it was clockwise that u do the firing order but if its supposed to be counter on this thing then so be it. thx for the advise.

Originally Posted by Hombre259

A couple of years ago I was building a Pontiac powered 4x4 1953 Ford truck. I had spent a ton and a half of money on that HO 421 and finally the day came to fire her off. She spit and puked a couple of times backfired through the carb but no go. I went back to my Motor Manual for the Pontiac. I had ther cylinder numbering sequence right, I had the firing order right 18436572 same as most Gm's. I pulled and checked the distributer and everything was good to go. Still spit, puke, backfire, I go back to the book and pull the dizzy redo everything 18436572 sequence is correct turn the key-- spit, puke, backfire. Man what could be wrong????? Back to the book FIRING ORDER Pontiac 421 HO 18436572-- Check, Cylinder # Sequence Check. Turn motor over #1 cylinder in correct location, turn the key SPIT, PUKE. BACKFIRE....
Pull the intake, pull the timing cover, reset the valves, check timing marks for timing chain, Everything and I mean everything is as its supposed to be. I redo everything for the 6th time, before I turn the key I go and recheck the BOOK.. Firing Order 18436572, Cylinder # sequence, Man what is this in the third column?? Engine rotation Pontiac all V8's "CCW", Can it be that simple? Or maybe the question should be --Can I be that stupid?

Rewire the dizzy--- 18436572 this time CCW-- Turn the key, Varoooom I had me a gen-u-wine fire breathing monster on my hands. I felt real silly for doing that 6 times before I finally got out of my own way.

Morale to that story is check everything and ASSUME nothing..

Roland

LOL, Yup sometimes we just "over think" it!

I'd bet that every person on here has a story of one of their screw ups. Every time one of my service techs has a problem I tell them go back to the basics, start from the begining and when you find the problem its going to be something simple and/or stupid that was wrong.

My last "dumb one" was on a small block Chevy engine that I had out of my roadster for a year while the car was painted. It's got some nice Moon "no name ribbed" valve covers that I polished up before I put the engine back into the car. Well.......I had the same backfire problems as stated above. Checked TDC, #1 plug wire location, firing order, checked my new MSD distributor, etc. Well I hate to admit it but what it turned out to be was I installed the "valve covers backwards" and they lightly rubbed the valve retainers preventing the valves from completely seating at cranking speed. The covers have a taper "more on one side than the other" and without any lettering it was easy to invert them and it will not work.

A quick compression check would have saved me some time.

Originally Posted by volvaro

proper pushrod length is good, valve lash is set to 0 like factory said, rockers are good and torqued, headgasket didnt slip when installing, head bolts are torqued. fuel lines are hooked up and vacuum is hooked up properly. gonna check to see about if we got TDC right or if we made a dumb mistake. its all back together and the cam is timed right, checked that too. probably just got TDC wrong. not the first time, or my distributor might be backwards. ill let yall know.

We assume those are mid 80's 305 heads. If so, your valve lash is off.
Rocker arms are not "torqued" on these.
The book wiil call for 1 full turn past zero lash. A lot of guys will have a preference of 1/2 turn past zero to 3/4 turn past zero lash.
The engine will run at zero lash, but you won't be happy.
I'm concerned about the rockers being "torqued".
Firing order will be clockwise on a SBC.

and of course the other remaining thing-----cylinders are numbered different ly on different brand engines---GM are 1357 down the left side, Ford 1234 down the right side---now is that facing the motor or the direction of travel???

Spitting fire definately sound like a timing issue, either wires off, distributor off, distrib set in 180 degrees off i.e. dropped in at TDC but on exhaust stroke, not compression(easy to check with a compression guage on #1 cyl. , slowly hand crank the engine until you see TDC on the flywheel pointer. Then look at gauge, is pressure increasing or doing nothing, should be going up if compression stroke. Next pull cap and see where the rotor is pointing. Should be on number one. This may be obvious to you or not , so I'm posting just in case it helps, otherwise, maybe some of the other stuff mentioned above.