New engine, won't run!
 

I finally got around to installing the big block in my 78, but can't get the darn thing to run. It is a completely rebuilt 427 tall deck motor. I have checked the distributor 5 times to make sure it is on top dead center of the compression stroke. Put in different plugs, new fuel pump, different plug wires, different cap and coil which i know is good. Adjusted the distributor every which way, Tried setting a tooth off in either direction. Cam was installed properly. Double checked valve clearances. I am out of ideas. It turns over fine and it will pop and sputter, no backfiring, but it will not run. I am out of ideas.

It's getting spark compression, and gas, and i am darn sure its in time. I have had a darn good mecahinc of 30+ years helping me and he can't figure it out either.

Any advice would be appreciated.

Re: New engine, won't run!
 

doouble check the distributor yet again... in fact pull it out and reset it.. I did this with my motor on the V6 i had and i had it out so it wasnt firing right..the stupid diagram in the Haynes manual was off so i had it firing on the wrong cylinder i know it sounds stupid but this is an error i made.... i had gone as far as to even think the fuel wasnt right and was going to put in a new fuel pump

Re: New engine, won't run!
 

Since you state you installed a different cap AND coil, Is it safe to assume this distributor is of the older style HEI ?

If so, There could be a problem with module or even the condenser. These older style pick-up's are known for breaking the lead wires up close to the pick-up housing from the vacuum advance moving the plate back and forth, The insulation may look good but the inner wire will be broken.

I mention the distributor components because it looks like you have most everything else covered, It's possible you have spark at cranking speed but loose it when it trys to start up (spins faster).

Just my http://www.xtremesystems.org/forums/...s/twocents.gif

Good Luck

Re: New engine, won't run!
 

If it is a tall deck block do you have a tall deck distributor? I dont even know if there is such a thing.

Re: New engine, won't run!
 

Pick up coil? Are you it has spark?

Re: New engine, won't run!
 

what about gas. are you using high octane. My friends big block would not fire on anything lower than 105 octane. Just another thought

Re: New engine, won't run!
 

The distributor itself is only about two years old, and the whole distributor setup that is on it now is the same one from the small block i pulled out of the truck and it ran fine. it is possible something could have happened when changing things over though. I know it has spark as we have checked it to make sure. The distributor has been pulled out and reset just about every time. Gas could be a problem as its just 87 octane, but have never had that problem before.

I won't be able to work on it again until sunday, but will check the distributor just in case for anything broke internally and maybe for kicks and giggles i will just drop the distributor in some random place and see if it will start.

Re: New engine, won't run!
 

Tall deck blocks require a tall deck distributor or machine work on the intake to allow the short deck dizzy to engage. All small blocks are short deck. Not all 427s are tall deck. Hope this helps Jay

Re: New engine, won't run!
 

I used the stock tall deck intake which allows for the use of a regular distributor. I mean it drops in all the way, connects to the cam fine, and engages the oil pump.

Re: New engine, won't run!
 

Is it a new engine or reworked engine some times the timing chain,gear could be aligned wrong ,just a thought but will cause the same problems.

Re: New engine, won't run!
 

Cool, I have seen the deck height gremlin fool more than one before. ;) Jay

Re: New engine, won't run!
 

I would put a compression gauge in a few holes and check em, hth.

Re: New engine, won't run!
 

Squirt a little oil into each cylinder and crank it over with the ignition disconnected to spread it around then reconnect the ignition. Sometimes new engines don't like to fire on dry cylinder walls. The rings aren't seated yet and leak down too much on the dry fit to build enough compression to fire the mixture.

The 400 in my Malibu was that way. I didn't believe it was the problem and pulled most of my hair out trying to get it to run until my 82 year old neighbor suggested the oil in the cylinder trick. It fired right up.

Re: New engine, won't run!
 

Water in the fuel? Had that once, finally pulled the fuel line off the carb and what spilled out beaded up on the intake. I was pulling my hair out too.

Re: New engine, won't run!
 

Thought about the timing gears being off. Going to pull the valve cover off and watch the valves when the piston is coming up to check that and see where the distributor is. I don't think there is water in the gas as i stopped and put gas in the truck right before i changed the motors and its only been sitting 3 weeks. I might try the oil in the cylinder trick. We did put a bunch of superlube down the cylinders before we put the motor in the truck and turned it over by hand to make sure it still turned since its been sitting a while.

Re: New engine, won't run!
 

That superlube might have been too thin to oil up the rings. A little motor oil won't hurt anything. It will just smoke a bit until it burns off.

It's possible the timing set got put in with the dots incorrectly oriented. Some engines set the dots both facing up and some point the dots together in the middle. Maybe the mechanic who put it together used the wrong method. Only way to tell it to pull the timing cover off. Chevy V-8's put the dots together in the middle.

Re: New engine, won't run!
 

I'm not saying that there isn't a valve timing issue here, but the above statement is completely un-true.
The crank gear is exactly half the size of the cam gear, so the "dots" will not always meet in the middle when the crank's "dot" is up. If you start out with the "dots" in the middle and turn the crank exactly one revolution....the cam's "dot" will not be at the bottom anymore, it will be at the top.
This BTW is TDC of the compression stroke for the #1 cylinder

Re: New engine, won't run!
 

The timing marks on a chevy small block V8 neet to be together when installing a timing set. It has been a few years since I have replaced a timing set and was a little unsure after reading the last two posts, so according to my 1974 Chevrolet Light Duty Truck Servive Manunal Section 6 page 58 "Hold the sprocket vertically with the chain hanging down and align marks on camshaft and crankshaft sprockets."

Re: New engine, won't run!
 

No, he is right, it won't matter where the dots are as long as they are both up or both together in the middle. Since the crank spins twice as fast as the cam it will work either way. Now if they were off a tooth or two it could make a big difference.

Forgive my slow thinking. I've been working 20 hour days for the past week so my brain is a little slow right now. I can sleep in February when this project is done.

Re: New engine, won't run!
 

Distributor is 180 degrees out.

Re: New engine, won't run!
 

Duh. Why didn't I think of that. It is the easiest thing to do wrong.

Re: New engine, won't run!
 

That is what I was thinking after you said the location of the timing marks didn't matter. If the cam sprocket was installed with the the dot at the 12 o'clock position the distributor would be off 180* making the number one terminal on the back dist cap. Talk about confusing.

Re: New engine, won't run!
 

Well, Let's add to it. The distrubutor can be installed in any position you want, As long as you put #1 plug wire in the proper position on the cap (where the rotor points) while #1 piston is at TDC compression stroke.

Re: New engine, won't run!
 

How are you checking TDC ? The way I do it have one person put place their finger firmly over the #1 spark plug hole so it seals, then have someone spin the engine over by hand. When you feel pressure build up against your finger, watch the timing mark and stop when it gets to TDC. The finger is necessary because the timing mark on the balancer will show #1 OR #6 at TDC firing, because it takes two full revolutions of the crank to fire all 8 cylinders. The pressure against your finger means there's compression building in the #1 cylinder and when the timing mark gets to TDC, the motor is on #1 TDC firing for sure.

After that, check the rotor position and see if it's point to terminal on the cap that your #1 plug wire is connected to. I assume you have the wires connected in the firing order clockwise around the cap ?

Tighten the distributor down to where it's snug, but still can be moved by hand. Have one person crank the engine over, and one person slowly moving the distributor a small amount in either direction till it fires.

Don't know if you've already done all this but that's all I've got.

Re: New engine, won't run!
 

Everything you all have said about the distributor i have tried. I cput the distributor right on and 180 off, moved it a tooth either way from those positions and nothing. I check tdc just like you all have posted. But now on to something new.....

I've been thinking about the dry cylinder deal with puting oil in the cylinders. I had forgot that when i was checking the starter out i sprayed a ton of wd 40 down the spark plug holes. I would almost bet since wd 40 does evaporate quickly especially with the plugs in the motor, that when gas hits the plugs its more or less flooding the engine. So i am thinking that if i pour some regular motor oil down the holes and crank that thing over alot and clean the cylinders out, that it may run. What do you guys think?

Re: New engine, won't run!
 

Well...I agree with Pyrotechnic. That's how we always did it with engines that may have been assembled a little different than factory specifications. However, first and foremost you must have compression. After you verify you have adequate compression, then do the finger in the hole trick to validate that you are on #1 COMPRESSION STROKE. Also, validate that the timing mark is coming to alignment with the TDC indicator. If it's not, the damper is defective, installed wrong or the wrong one. If necessary, make a TDC locator out of an old spark plug with the porcelean removed and a rod welded through the middle. Remove the plugs and rotate the engine through by hand with a torque braker bar and socket on the crankshaft bolt to validate the TDC mark. Once TDC is validated, get on the compression stroke and wire the distributor cap so that the next plug wire the rotor gets to is #1, followed by 8,4,3 etc. Be SURE you don't have a distributor cap that has the internal jumpers so that all the plug wires come out on the same side of the engine that they go to. This will screw you all up. If it still won't run, leave the plugs in and hook a timing light to the #1 cylinder wire. While cranking, see where the spark flashes the light on the vibration damper. If it's right, and you have compression and fuel, it must run.

Re: New engine, won't run!
 

Sorry guys. I thought about what was posted last night while I was at work. If the timing set is off 180* then the dist will be off 180* And as someone said it won't matter. The dist just needs to be turned 180*. I don't know what the hell I was thinking.

Billnorman may be on to something here. The balancer could have the wrong markings, and if that is the case you might want to make sure it has the correct balance for the engine. I believe the 396 is internal and the 454 is external.

The spark plugs probably are not the problem. Even if they did get wet from the wd40, I would think they would be dry after a day of sitting. How are you testing spark? You should use a spark tester. Arcing off a screw driver can give too small of a gap. So there may be enough spark to jump a small gap, but not enough to jump the gap on the spark plug in the cylinder. Do you have a full 12 volts to the coil? Could it be the ignition module?

Re: New engine, won't run!
 

That one has bit a few people.

Re: New engine, won't run!
 

Worth a try. WD40 is pretty thin and displaces other fluids plus it dissipates pretty quickly. The cylinders could be dry by now.

I would change your oil too as all that gas and WD40 has run into the oil pan and contaminated your oil by now. No sense taking the chance on hurting a fresh engine over $15 worth of oil and filter.

Make sure you have a fully charged battery too. HEI's don't like to fire when the voltage is low.

Re: New engine, won't run!
 

Uhh...are you absolutely positive you're getting fuel?
Will it start and run when a dab of fuel is poured down carb?
I've seen guys chase problems only to find out that either the fuel pump isn't pumping, clogged filter, vaccum leak or the carb has a stuck float.

Re: New engine, won't run!
 

Or there is air in the fuel line and the pump isn't getting any fuel to the carb.

Re: New engine, won't run!
 

hmm, - if the timing`s correct - and the distributor positioned corecctly, too. Fuel is there, - THEN I think it should be a defective spark module in the dizzy.

I have had exactly the same prob - I couldn`t imagine that I might have problems with the distributor because I actually HAD SPARK on the plug....

After I replaced the module it ran....... :metal:

Re: New engine, won't run!
 

Status report requested.....

Re: New engine, won't run!
 

Especially if it's a dual tank truck....if the fuel valve has a small, internal leak and one tank is empty, it's basically a vacuum leak and no fuel is drawn from the tank with fuel....
I just fixed this problem on my own truck after much frustration trying to find the issue...:lol:

Re: New engine, won't run!
 

Wow Damien, that's pretty harsh....especially when I am not.

Re: New engine, won't run!
 

Its got gas, I checked this by pulling he screw out of the side of the bowl. If your pour gas down the engine it quits firing all together. I tested the spark by pulling the plugs out and laying them on the frame rails and had somebody turn the engine over and watched them all spark a pretty blue spark. The balancer is new and it is right on the money for when the cylinder is on tdc. Still don't think it would be the distributor as it's only been off a running engine for about 3 weeks.

Re: New engine, won't run!
 

octane, octane, octane

Re: New engine, won't run!
 

I find it hard to believe that "low octane" would make the motor fail to fire completely. It may not be optimal, but it should fire up just the same.
Octane rating does not relate to the energy content of the fuel. It is only a measure of the fuel's tendency to burn in a controlled manner, rather than exploding in an uncontrolled manner. So a lower octane fuel may be a lot more suscpitable to pinging, but it should start in at least idle just fine.
Higher octane actually supresses the flame to a more controlled burn.

They do start Nitro-Methane powered engines with a squirt of gasoline after-all....

Re: New engine, won't run!
 

I agree with longhair on the octane rating. The compression ratio on a tall deck at most is usually only 9:1

Re: New engine, won't run!
 

Have you checked the valve adjustment? I know big block valave trains are critical