HEI Ignition Problem

[nrb's70gmc]

ok i checked the #6 and the screw driver is also touch the #6 piston and like i said the rotor is leaning tords the #6 post on the cap

[Sinister]

Like I said, I think you're at TDC for #6.

[rsavage]

If your rotar is off by 180 degrees, you are on the exhaust stroke. Continue turning the motor until your timing marks line up and you are on the compression stroke. Best way to insure is as indicated above - pull the valve cover and check that both #1 valves are closed. I would actually pull both valve covers and check to make sure that you haven't jumped a pushrod off a rocker. You indicate that you are back firing when running. If your rockers are all working correctly, distributor in correctly, wires on the distributor correctly, then you might have jumped a tooth or so on your timing gear/chain. Dead giveaway would be an inability to fire it up, get it to run, when it is timed correctly.

[nrb's70gmc]

The #6 is also at the top (screwdriver was touching the piston) and like i said the rotor is leaning tords #6 post on the cap.

[nrb's70gmc]

ok i pulled the valve cover rotated the motor untill both valves are down-the balencer mark is set at 0 degrees on the timing tab--#1 piston is at TDC---rotor is almost dead on #1 post now (before it was facing #6 now its 180 degrees facing #1)

what does this mean now??

[Sinister]

Both valves are down? They should both be up, no compression on the valve springs. What is it you're trying to do?

[nrb's70gmc]

they should both be up? ok i will go out and rotate the motor again

[nrb's70gmc]

im trying to get #1 at tdc so i can get it timed correctly

[nrb's70gmc]

Originally Posted by rsavage

If your rotar is off by 180 degrees, you are on the exhaust stroke. Continue turning the motor until your timing marks line up and you are on the compression stroke. Best way to insure is as indicated above - pull the valve cover and check that both #1 valves are closed. I would actually pull both valve covers and check to make sure that you haven't jumped a pushrod off a rocker. You indicate that you are back firing when running. If your rockers are all working correctly, distributor in correctly, wires on the distributor correctly, then you might have jumped a tooth or so on your timing gear/chain. Dead giveaway would be an inability to fire it up, get it to run, when it is timed correctly.

ok the #1 valves are closed the balencer lines up with 0 degrees on the timing tab-the #1 piston is on tdc and the rotor is facing near #1 post on the cap

is this correct? what should i do next?

[Sinister]

Fire it up and throw a timing light on it.

[nrb's70gmc]

my garage time ran out today i have other things to get done but i will keep you all posted

[nrb's70gmc]

on a side note the thing about the timimg chain skipping/jumping a tooth is this a commom problem? i have never heard of this happing before. i have heard of chains streching but i did not know they could skip in the gears

if it turns out that the chain skipping a tooth is the problem i wil be having a edelbrock accu grive hear right quick.

[neba]

sent you a message

[rsavage]

Not a common problem but a possible. However, I would pull both valve covers and check every rocker before going to timing gears. Jumping a pushrod off a rocker can happen on a tired engine if you rev it too high too often. Did you triple check your wires to make sure that they are on the right post and plug?

[nrb's70gmc]

Originally Posted by rsavage

Not a common problem but a possible. However, I would pull both valve covers and check every rocker before going to timing gears. Jumping a pushrod off a rocker can happen on a tired engine if you rev it too high too often. Did you triple check your wires to make sure that they are on the right post and plug?

i only have 15,000 miles on this engine (bought new in 04) i dont think its to tired yet

i have the cap off right now but i will check the wires when i put the cap back on

[nrb's70gmc]

i went ahead and pulled both valve covers anyway (all pushrods are fine)

[nrb's70gmc]

update
i put everything back together fired it up
it died one time other than that it ran the 7 minutes i was playing with the dizzy
it idles but the motor viberates speraticly (when you touching the truck you can feel it)

when you give the motor throttle the carb backfires as well as the exhaust pipes

[monte0185]

Throw a timing light on it and set it about 14 to 18 degrees with the vacuum advance pulled off the dizzy and plugged.

[highperf4x4]

On these trucks there's really only so many things that can affect the motor like this. Fuel, ignition, valvetrain. I wish I was closer, I would stop by and give you a hand with it. I think we've pretty much covered everything you'd need to check. Sorry I couldn't be more helpful.

[nrb's70gmc]

Originally Posted by highperf4x4

On these trucks there's really only so many things that can affect the motor like this. Fuel, ignition, valvetrain. I wish I was closer, I would stop by and give you a hand with it. I think we've pretty much covered everything you'd need to check. Sorry I couldn't be more helpful.

thanks man- ya i have tried eveything (except a new module) so im going to buy a new one tomarrow--even though the 2 i have tested ok


this whole mess is probably(either a module or im not timing it right or somthing STUPID like that)

im exhausted working on my truck the past week its depressing becauise i have tried everything you guys have suggested.

[highperf4x4]

Yeah I hear ya. I know it's frustrating sometimes. I've been doing this stuff for alot of years and once in a while something will stump me for a bit and cause me to say "man that doesn't make sense". However, it always comes out in the wash one way or another. Don't let it get the best of you.

And just for the record, the easiest way to tell when you're on the compression stoke for #1 is to spin the motor with the valve cover off and watch the rocker arms. You can tell which valve is which by looking at the exhaust manifold and intake runners. The exhaust valve will be the one closer to the exhaust port and the intake valve will be closer to the runner on the intake manifold for that cylinder. Spin the engine until you see the exhaust valve open and close and keep spinning while the intake valve opens and closes. After the intake valve closes, you are on the compression stroke so bring the balancer around to 0 and you are at tdc.

I think earlier when you said both valves were down you were probably referring to the lifters right? When the lifters are down, the valves are up (closed)

[nrb's70gmc]

yes i was watching the lifters

can you explain the intake/exhaust valve thing again

lifters up mean open???
exhaust valve closest to exhaust port???

the intake valve will open then close---then the exhaust valve will open and close--then the motor will be on the comp stroke???? for #1

then line the balencer up to 0 degrees??

[highperf4x4]

Sure. The lifters are actually under the intake manifold. They ride on the camshaft. The pushrods sit on top of the lifters and stick up through the head and they "lift" the rocker arm which then pushes the valve spring down which "opens" the valve. I'll show a pic of the rocker arms from my 4x4. Mine have roller tips so yours may look slightly different but the principle will be the same. The roller tips on my rockers are sitting on the valve stems which are inside the valve springs.

The second valve from the front of the engine will be the intake valve for #1. It's really the only valve you need to watch. The intake valve will open on the down stroke of the piston and it will close as the piston starts to come up for the compression stroke. So, after the intake valve closes continue to spin the balancer until it gets to 0 and the #1 piston will be at tdc.










This is a pic of the passenger side of the engine so it's actually the #2 cylinder I'm pointing at but it will be the same on the driver's side for the #1 cylinder.

[nrb's70gmc]

Originally Posted by highperf4x4

Sure. The lifters are actually under the intake manifold. They ride on the camshaft. The pushrods sit on top of the lifters and stick up through the head and they "lift" the rocker arm which then pushes the valve spring down which "opens" the valve. I'll show a pic of the rocker arms from my 4x4. Mine have roller tips so yours may look slightly different but the principle will be the same. The roller tips on my rockers are sitting on the valve stems which are inside the valve springs.

The second valve from the front of the engine will be the intake valve for #1. It's really the only valve you need to watch. The intake valve will open on the down stroke of the piston and it will close as the piston starts to come up for the compression stroke. So, after the intake valve closes continue to spin the balancer until it gets to 0 and the #1 piston will be at tdc.










This is a pic of the passenger side of the engine so it's actually the #2 cylinder I'm pointing at but it will be the same on the driver's side for the #1 cylinder.

thanks for all that ( i ment to say rocker arms instead of lifters lol) i may take a day of rest so i can recupe and get my bearing back but i dont know im going to buy a new module tomarow and will def. look at this again in the near future.

[nrb's70gmc]

by the way is it hard to rotate the oil pump?? i stuck a flat head down in there and the screwdriver would'nt move either way. i dont know if its possible to get the screwdriver stuck in the cam gear or not but that is what it feels like.