Broken starter bolt

[Schurkey]

97 k1500 burb w 5.7.

Distributor timing was too advanced. moved it back a tooth and changed out timing set. Involved job but car deserves it

Distributor position does not change timing on a Vortec 5.7L.

What is the "Cam offset" showing on the scan tool?

Was the new timing set installed with a degree wheel 'n' dial indicator, or just crammed-in "dot-to-dot"?

 

[JalopiedAllOver]

Distributor position does not change timing on a Vortec 5.7L.

What is the "Cam offset" showing on the scan tool?

Was the new timing set installed with a degree wheel 'n' dial indicator, or just crammed-in "dot-to-dot"?

Did dot to dot. Not sure what you mean on distributor since previously it was halfway to the next cylinder and now it was pointing at the 1st cylinder for TDC. No longer have rough starts

 

[JalopiedAllOver]

Also, I have not yet used a scan tool on the current setup.

 

[Schurkey]

Also, I have not yet used a scan tool on the current setup.

Scan tool is the only way to assure you've got the distributor positioned properly. Everything else is just guesswork.

However, unless the spark is jumping to the wrong terminal, turning the distributor does not change ignition timing. It changes the synchronization of the cam sensor signal to match the crank sensor signal; and it aligns the rotor tip with the terminal on the distributor cap, potentially reducing the voltage required to jump the gap.

 

[JalopiedAllOver]

Scan tool is the only way to assure you've got the distributor positioned properly. Everything else is just guesswork.

However, unless the spark is jumping to the wrong terminal, turning the distributor does not change ignition timing. It changes the synchronization of the cam sensor signal to match the crank sensor signal; and it aligns the rotor tip with the terminal on the distributor cap, potentially reducing the voltage required to jump the gap.

Ok well im talking specifically about the cmp retard not the ignition if you want to be strict. It's -34° which makes me scratch my head since it starts up much better than before. I'm talking horrifically bad starts before. It was halfway to the next post at tdc. Gonna get it to 0 tomorrow.

The actual timing at the time set is just fine. There was slack before and now there's not

 

[Road Trip]

The correct bolts have a step in their shanks, and knurling on both the larger and smaller part of the shank. This helps locate the starter properly and hold it in place. You DON'T want the starter to "walk around" on the transmission or engine block mounting pads, because that can lead to cracks in the block there, and damage to the transmission or flexplate. And that's a whole lot more of a repair job, than swapping out a starter.....

Hello JalopiedAllOver,

HotWheelsBurban is on the money with all this. There are some critical details that
we 21st century DIYers have to pay close attention to.

The length is important for proper clamping, and in the good old days everything came
together easily due to the fact that everything involved was designed/manufactured in SAE 'standard' dimensions.

However, the new PMGR starters that everyone is upgrading to are a metric design, and the holes that the 2
starter bolts go through will have excess clearance if English bolts (that thread directly into the block)
are utilized. In other words, the starter can twist or misalign unless you use the exact right conversion bolts.

Here's a couple of threads where a good description of all this has happened:

(Big and little starters + special metric shank/english thread bolt details)

and

(Schurkey shares starter & conversion bolt photos & details)

****

Don't know if you have already extracted the snapped off part of that starter bolt.
If you haven't, I've actually found these affordable left-handed drill bits at the local
Harbor Freight to work much better than their price would lead you to believe.
(See attached.)

Here in the rust belt plenty of bolts snap off despite all the normal efforts to ease
this stuff apart. Once I started using these, after stepping up in size a few times,
often the drill bit will catch, and instead of trying to send the remnant further down
the hole, when the left-handed bit spinning CCW it catches and threads it out for
you as neat as you please. (!)

I buy these kits 2 at a time, always have a fresh kit in the traveling SNAFU bag, give
them to my motorhead buddies at Christmas, etc. It's become an essential lifestyle
thing in the old car/truck hobby. :0)

As always, the trick is to to get that first hole started as close to the center of the
bolt/stud as possible. If you are lucky, within 2 or 3 drill size steps it spins out.
Other times I'm pretty close to the threads themselves before the drilling function
relaxes everything enough for it to come out. (We used to have a small 'wailing wall'
in the shop, and some of our prized items on display were snapped off bolts that
looked like heli-coils because this is how we got them out. This wall often gave us
inspiration/reassurance by showing us that removing snapped off bolts *is* possible. :0)

Hope this is helpful. Getting these starters really right & factory reliable *is* possible,
and is well worth the extra effort.

Best of luck --

 

[HotWheelsBurban]

If anyone is wondering in the future - Distributor timing was too advanced. moved it back a tooth and changed out timing set. Involved job but car deserves it

Interesting that you mentioned that....we had a problem with Burb when we first got it, that the starter would sometimes not catch, and you'd have to bump the key to get it past the bad spot. Flexplate had some damaged teeth, and the truck ate several starters over about two years. I think it started with the notorious Vortec cap crossover firing, because after a new starter, flexplate and cap and rotor, and new appropriate starter bolts, problem is fixed!

 

[JalopiedAllOver]

Hello JalopiedAllOver,

HotWheelsBurban is on the money with all this. There are some critical details that
we 21st century DIYers have to pay close attention to.

The length is important for proper clamping, and in the good old days everything came
together easily due to the fact that everything involved was designed/manufactured in SAE 'standard' dimensions.

However, the new PMGR starters that everyone is upgrading to are a metric design, and the holes that the 2
starter bolts go through will have excess clearance if English bolts (that thread directly into the block)
are utilized. In other words, the starter can twist or misalign unless you use the exact right conversion bolts.

Here's a couple of threads where a good description of all this has happened:

(Big and little starters + special metric shank/english thread bolt details)

and

(Schurkey shares starter & conversion bolt photos & details)

****

Don't know if you have already extracted the snapped off part of that starter bolt.
If you haven't, I've actually found these affordable left-handed drill bits at the local
Harbor Freight to work much better than their price would lead you to believe.
(See attached.)

Here in the rust belt plenty of bolts snap off despite all the normal efforts to ease
this stuff apart. Once I started using these, after stepping up in size a few times,
often the drill bit will catch, and instead of trying to send the remnant further down
the hole, when the left-handed bit spinning CCW it catches and threads it out for
you as neat as you please. (!)

I buy these kits 2 at a time, always have a fresh kit in the traveling SNAFU bag, give
them to my motorhead buddies at Christmas, etc. It's become an essential lifestyle
thing in the old car/truck hobby. :0)

As always, the trick is to to get that first hole started as close to the center of the
bolt/stud as possible. If you are lucky, within 2 or 3 drill size steps it spins out.
Other times I'm pretty close to the threads themselves before the drilling function
relaxes everything enough for it to come out. (We used to have a small 'wailing wall'
in the shop, and some of our prized items on display were snapped off bolts that
looked like heli-coils because this is how we got them out. This wall often gave us
inspiration/reassurance by showing us that removing snapped off bolts *is* possible. :0)

Hope this is helpful. Getting these starters really right & factory reliable *is* possible,
and is well worth the extra effort.

Best of luck --

Im suspecting it's due to that. I've went out and got dorman starter bolts that were longer like the stock bolts. the old starter used to kick and i had the cmp crankshaft code (still do lol) mess of stuff, probably a perfect storm of **** but now it's starting and has 0 issues catching, no back firing like i did prior.

Interesting that you mentioned that....we had a problem with Burb when we first got it, that the starter would sometimes not catch, and you'd have to bump the key to get it past the bad spot. Flexplate had some damaged teeth, and the truck ate several starters over about two years. I think it started with the notorious Vortec cap crossover firing, because after a new starter, flexplate and cap and rotor, and new appropriate starter bolts, problem is fixed!

If there's really crossfire im gonna invest in the distributor cap with brass posts. Because i just threw a new distributor cap and rotor in there. Annoying. But as long as it doesn't break another bolt I'll be happy. this new starter sounds different as well, despite being same model. both were remanufactured so maybe something happened there. I don't know the exact thing that caused it but car is driveable and the starts are nice and smooth, smoother than it's ever been. I'm starting to think timing set might be the biggest culprit, local old timer told me that's what he thought and he's been around a lot of 350s. I don't know. But that grinding will haunt my dreams for a while.

 

[Road Trip]

I'm starting to think timing set might be the biggest culprit, local old timer told me that's what he thought and he's been around a lot of 350s. I don't know.

Elsewhere in the forum we kicked around this CKP/CMP synchronization (aka: Cam Retard) issue
until it made sense, especially from the rotor vs spark tower terminal alignment perspective.
(See attached.)

And the reason why Schurkey emphasizes that you aren't adjusting the spark timing when you
are clocking the Vortec distributor housing is because it's possible to have correct ignition timing while
at the same time allowing the mechanic to get the rotor/proper cylinder terminal so misaligned that
the rotor is actually closer to the wrong cylinder spark terminal when the spark is triggered. (!)

Since electricity will take the path of least resistance, having the wrong cylinder's terminal closer
than the right one is bad juju.

And this can seem intermittent, because the normal spark advance/retard operation can either cover
up or exacerbate the issue, resulting in really rough running, or no problemo, depending upon how
all the variables (including driver demand) stack up.

Anyway, do yourself a favor and get that CMP/CKP sync set as close to 0° at 1100 rpm as possible.

And if for some reason you can't nail this then let us know what you do get, and we're talk you in the rest
of the way. (I could get into the whole 13-tooth/180° out thing, but let's not dive down that rabbit hole
unless it's really necessary in order for you to be able to hit the dizzy & crank sensor sync bullseye.)

In English, you should be able to hit the 0° and enjoy easy starting and smooth running.

Best of luck. Let us know what you discover.

 

[JalopiedAllOver]

Elsewhere in the forum we kicked around this CKP/CMP synchronization (aka: Cam Retard) issue
until it made sense, especially from the rotor vs spark tower terminal alignment perspective.
(See attached.)

And the reason why Schurkey emphasizes that you aren't adjusting the spark timing when you
are clocking the distributor housing is because it's possible to have correct spark plug timing while
at the same time allowing the mechanic to get the rotor/proper cylinder terminal so misaligned that
the rotor is actually closer to the wrong cylinder spark terminal. (!)

And this can seem intermittent, because the normal spark advance/retard can either cover up or exacerbate
the issue, resulting in really rough running, or no problemo, depending upon how all the variables (including
driver demand) stack up.

Anyway, do yourself a favor and get that CMP/CKP sync set as close to 0° at 1100 rpm as possible.
And if for some reason you can't nail this then let us know what you do get, and we're talk you
in the rest of the way. (I could get into the whole 13-tooth/180° out thing, but let's not dive down
that rabbit hole unless it's really necessary for you to hit the dizzy & crank sensor sync bullseye.)

In English, you should be able to hit the 0° and enjoy easy starting and smooth running.

Best of luck. Let us know what you discover.

Visualizing it like makes sense. I bet it was significantly advanced prior and now retarded by a smaller margin since i moved it. Gonna get it dialed to 0, appreciate the help.