A very challenging no start situation

[dakattack7]

74 c10, 350 engine.
This engine ran great before, though it had been sitting for 10+ years and smoked.

I pulled the engine and resealed the entire thing including the valve seals which were hard and crumbled. New head gaskets AND bolts torqued in 3 stages in the correct sequence.

Reinstalled with a 4 barrel manifold (2bbl originally) and for the life of me I cannot figure out (Nor anybody who's brain I've picked) why I can't get this thing to run.

Diagnostics done:
Compression: 100 ish psi across the board at 7500 feet (Not great but plenty to run)
Fuel: It has a freshly ultrasonic'd rebuild quadrajet, though starting fluid is being used to rule out fuel
Timing: distributor is set correctly with the rotor at the number 1 terminal at top dead center of the compression stroke of cylinder 1.

All components of the distributor were replaced to no avail, including pickup coil.

I installed a double roller timing chain so I verified it was set right. I also have watched rotor and valves as I hand crank it and have verified valve timing is correct.

The spark plugs, wires, cap and rotor are new. The rotor and cap have been tripple checked for any holes or arcing and the pin is making contact and has dielectric grease.

The distributor (hei) has a new wire to the fuse box for true 12v and is receiving it during cranking and run position.

The distributor clamp was sanded along with the intake to insure a solid ground.

Spark was tested primitively by grounding a plug to the block but a bright blue spark was observed. I watched my timing light from the cab on #1 and it is consistent while cranking.

Valve lash has been reset 3 times including one time very loose to insure the valves weren't hanging open. I cleaned the carbon off the valves when it was apart.

I just removed the intake and made sure the gaskets were installed correctly and reinstalled it. I put new plugs in case the old ones were acting up from washing the cylinders initially.

The engine would sputter as if barely trying to start, and I had a few times where it sounded like it fired for the shortest instant. No backfires, timing is correct.

Distributor shaft is tight and not worn, and this is the distributor it was running well with before the reseal.

Any ideas would be greatly appreciated!

[geezer#99]

Swap your #1 wire over to #6.
Sounds like you’re 180 degrees off even though you said you’re on tdc compression.
Takes but 10 minutes for the swap.

[Dead Parrot]

Pour a small splash(not much) of gas down the carb, wait a minute and crank. If you get fire, fuel flow problem. Otherwise most likely spark/timing.

I read you are using spray start but I have seen a few times that for some unknown reason, that stuff didn't work. Might have been some new fangled EPA approved stuff.

[AussieinNC]

Remove spark plug #1....
Hand turn the engine in correct rotation with your thumb over the #1 plug hole...
When you feel compression building in #1 cylinder, continuing turning engine by hand and align timing mark on balancer to 12 degree mark on tab.
Remove distributor cap and note where the rotor arm is pointing....should be just about pointing at #1 cylinder....
If its pointing to the rear of the truck, you have the distributor in 180 out....
You can either just move the plug leads around on the cap or pull the distributor and reinstall with rotor pointing at #1....
I am assuming you know the firing order and cylinder numbering...18436572 with drivers side cylinder being 1,3 5 and 7 front to back and passenger side being 2.4.6.and 8 front to back.
Once you get the distributor setup correctly....go to next step...
With engine still at 12 degrees on timing tab....loosen distributor and rotate the distributor clockwise about 20 degrees,,,,place a spark plug in # 1 plug lead and ground the plug....DO NOT HOLD THE PLUG !!!
Turn on ignition but do not crank...
Rotate the distributor body counter clockwise until the grounded plug fires....lock down the distributor...
Turn off Ignition
Replace #1 spark plug and install #1 plug lead....

Start the truck...

I have used the above process for over 50 years...assuming you have not made any internal assembly errors the engine should start...

You mentioned installing new timing set....I assume you matched the dots up correctly when assembling the gear set,,,,100 PSI seems low for a new rebuild....

Let us know how it goes...

[Wgesnerjr]

Check spark plug wire routing. It never fails, I have taught my nephew to replace one wire at a time and he can still get one swapped. His skills and fudging up spark plug wires amaze me.

[cadillac_al]

I'm with the other guys, you're 180 out or your timing marks aren't lined up right. I messed up some timing marks once, didn't get my squares and triangles lined up right because I was too lazy to go get my glasses.

[dakattack7]

Hi guys, thanks for the replies.

The distributor is 100% set correctly. It is not 180 degrees out. It was the first thing that was checked and then triple checked. I’m setting it with the vc off watching the valves, using a Allen key as a piston checker and the balancer marks..

I also said there is no backfiring. If it was 180 out it would backfire.

As for the starting fluid being bunk, the Quadra jet has a working healthy accelerator pump, so it is getting at least sufficient fuel to start. (I’m using starting fluid to rule out fuel though)

The spark wire routing has been triple checked and is correct.

This is not a new rebuild just an old engine that ran good so it was resealed.

The cloyes double roller chain is only keyed one way and was verified to be installed correctly with the dots at 6 and 12 aligned perfectly.

[Wgesnerjr]

Engines just need fuel, air, spark and compression all at the right time to go BANG!!

Sounds like you are checking all the right items, but something is just not right.

A couple of more thoughts:

You say compression is 100. did you see if the pressure leaked down over time? If pressure is leaking out, the head gaskets might be sealing just enough to give you 100 but then not enough for detonation.

Before ripping it apart, try running a straight wire from Battery Positive to HEI.

[Dead Parrot]

If my math is close, 100psi @ 7500ft is roughly the same as 130psi at sea level. Probably fairly good assuming a standard low compression 350.

Plug gap at .045?

If the accel pump is squirting good, crank while holding the throttles wide open. Possible the Q-jet is way rich for the altitude and you have too much fuel. Make sure the choke is wide open during this test.

[AussieinNC]

Originally Posted by dakattack7

Hi guys, thanks for the replies.

The distributor is 100% set correctly. It is not 180 degrees out. It was the first thing that was checked and then triple checked. I’m setting it with the vc off watching the valves, using a Allen key as a piston checker and the balancer marks..

I also said there is no backfiring. If it was 180 out it would backfire.

As for the starting fluid being bunk, the Quadra jet has a working healthy accelerator pump, so it is getting at least sufficient fuel to start. (I’m using starting fluid to rule out fuel though)

The spark wire routing has been triple checked and is correct.

This is not a new rebuild just an old engine that ran good so it was resealed.

The cloyes double roller chain is only keyed one way and was verified to be installed correctly with the dots at 6 and 12 aligned perfectly.

180 out will usually simply just not start....hardly ever backfires....

TDC on compression ???? Did you feel the compression build on cyl #1?

TDC number 1 occurs twice...once on compression, once on overlap....

Timing dots 6 on cam gear and 12 on crank gear means that engine is on overlap on #1...not on compression...thats why I always use my thumb over the plug hole to establish compression build on cyl #1....

[dakattack7]

The wire is a new wire from the fuse box to the dizzy and has 12.6v run and start

Don’t have a leak down tester unfortunately

I tried all different combos of throttle position and choke position

I didn’t set the distributor when the cam and crank gear marks were at 6 and 12, just confirming timing chain is installed correctly.

The distributor is set correctly and not 180 out without question. I watched the intake rocker open and then felt the piston with an Allen key and used the marks.

Every time I’ve stabbed the dizzy 180 it backfires. But anyway, still no luck. Haven’t touched it, pretty tired of it

[dmack91]

Any chance the new i take mating properly to.the heads? If the angles are off from.machining , I have heard of the bottom of the intake tract not sealing.

If it was running before, I would consider swapping the original 2 barrel intake and carb back on. If it runs, that would narrow it down to the intake and carb.

How about the balancer outer ring slipping on the inner? They will wear out at times,causing the timing marks to be off significantly.

[mongocanfly]

im curious to see what you find....if you got fuel ,compression,and fire, it should crank,,,or at least hit...I would be guessing timing...but you ruled that out in many of your posts...
just for funzzies you could swap the wires around 180deg on the distributor and see if itll hit though...

[cadillac_al]

I would say the valves are too tight but you said you adjusted them 3 times. I hope you don't use the twist the push rod method.

[Greasey Harley]

Okay, back to high school auto shop.


You have verified spark. Good, your ignition makes sparks.
You have verified compression. Good, your engine makes compression.

Have you tried squirting gas down the carb? I like to use an old spray bottle full of gas.
Have a friend crank the engine and hold the throttle wide open, while you spray raw gas down the venturi.

Did it try to pop?
Yes= fuel issue, No= something else

If it tried to pop while squirting gas:
check fuel pressure/flow? ...you haven't ran out of gas, right?
Fuel filter isn't clogged?
---Check Fuel lines, fuel pump, fuel filter
Fuel Pump installed properly?
100% sure the carb is properly rebuilt, adjusted and tuned?

If all that checks out,



What next?

-Remove #1 plug.
-insert finger
-Have a buddy bump the starter (one bump at a time till you feel compression) STOP AS SOON AS YOU FEEL COMPRESSION
-Insert an object [like a screw driver] into the plug hole
-Hand rotate the motor (clockwise from the front) 'till the piston stops moving upward
-Verify that the timing mark on the balancer is (at least) close to zero.
Because:

Originally Posted by dmack91

...how about the balancer outer ring slipping on the inner? They will wear out at times,causing the timing marks to be off significantly.

Balancers DO slip.

Once you have physically verified that the engine is indeed on #1 TDC Compression,
..go ahead and take a look at where the rotor is pointing.
(I like mine pointed toward the number one cylinder, but you may like it somewhere else).

Triple check your plug wires and firing order.
18436572, Rotor spins clockwise

...still nothing?
pull and inspect every plug.
check compression on every cylinder.

All good?

start swapping parts.

[dakattack7]

The cloyes timing set I purchased had the alignment dots marked incorrectly.

It finally started when I clocked the dizzy about a whole terminal advanced. Runs great, but gutless..

New timing set and all is well.