(I think) Timing chain issue... might explain dyno/starting/timing issues..

SadbutTrue · Apr 16, 2009

where can i find a tdc checker? summit?

A_Code_Kiwi · Apr 16, 2009

Yep, summits got them for under $12 I think. They just screw into the spark plug hole. I saw them on there when I was trolling around their site

Capt Dan · Apr 16, 2009

Find TDC and mark your balancer at your current timing pointer and go on.
You can get tape to remark it cheap.

Summit SUM-163594 - Summit® Timing Tape

View attachment 261654

SadbutTrue · Apr 29, 2009

Update.

Used the Summit Piston stop (and timing tape) and determined... my timing marks are right on the money. Verified twice, using two different methods. Definitely right on.

Also physically watched all the rockers open the valves, so there shouldn't be an issue of a collapsed lifter or worn cam lobe (didn't think any cam lobes were worn, since we didn't see any metal shards in the oil... but figured a lifter might have collapsed... guess not).

Finally... checked my floats as per the Holley instructions. While I did this after I had taken out the radiator/valve covers (and hence couldn't start the car as recommended)... the float levels were dead on for the primaries, right on the bottom of the clear sight thingy.

The secondaries are tougher to gauge (the Holley manual warns of this.. particualry if you haven't started it recently and actually opened the secondaries), but since we're just talking about idle tuning here the secondaries don't matter too much. For what its worth, the manual also predicted they'd be low and they were.

So floats appear to be fine.

So.. at this point... I guess its maybe just the most epic vacuum leak in history? What could possibly make an engine run at such high initial timing readings (now that we know those timing marks are not false)?

Rusty67 · Apr 30, 2009

Start spraying the carb cleaner.

mrmustangman357 · Apr 30, 2009

those floats need to be set with the motor running at idle dude.

rhyno9 · Apr 30, 2009

mrmustangman357 said:
those floats need to be set with the motor running at idle dude.

+1

I am curious as to what the holley manual says. How else can you check the floats?

During a rebuild you set them (ballpark only) when the bowls are off but I am guessing that isn't what happened in this case since he mentions clear sight plugs.

Unless I am missing something you still haven't verified that the float isn't stuck. We know that the bowl is low........that's because what was in it leaked onto the intake manifold and left all the yellow junk.

CraigMBA · Apr 30, 2009

I think you need to call MSD. This is an ignition problem. The carb floats have nothing to do with the engine jumping from 0 degrees advance to 25-45 degrees at idle.

rhyno9 · Apr 30, 2009

CraigMBA said:
The carb floats have nothing to do with the engine jumping from 0 degrees advance to 25-45 degrees at idle.

That is correct. He already tried a different dizzy and had the same results. Maybe it is the msd box?

Fuel, Air, Spark. If you don't have enough or too much of any of those you have a problem. The fact is the floats are still a problem. He is leaking gas on the intake and the heads and has fouled plugs. These are all classic signs of too much gas.

The fact is the float is a simple 5 minute fix. Fix the simple stuff first and then move on.

Once he gets that resolved then he can isolate the next issue.

jcode68 · Apr 30, 2009

A few things come to mid regarding your timing problem:

1)Are you certain you are using the #1 cylinder plug wire?
2)Are you sure your timing gun is working properly?
3)What type of plug wires are you using? MSD specifically states that you need to use helically wound wires and not solid core or interference will occur. Not sure what type of interference, but covering the basics.

Not sure what else could be causing the timing to be reading so far off. Have you double checked all your wiring for the MSD box to ensure it's wired properly? Haven't seen a problem go this long unresolved on Stangnet in quite a while...

SadbutTrue · Apr 30, 2009

rhyno9 said:
+1

I am curious as to what the holley manual says. How else can you check the floats?

During a rebuild you set them (ballpark only) when the bowls are off but I am guessing that isn't what happened in this case since he mentions clear sight plugs.

Unless I am missing something you still haven't verified that the float isn't stuck. We know that the bowl is low........that's because what was in it leaked onto the intake manifold and left all the yellow junk.

As I said (i know i'm verbose but i swear if you read my whole post i cover most the details ), the Holley manual DID say to check it with the engine running. My engine was apart, so for the moment thats impossible. I did not know how much difference it'd make. I will check it again when its back together.

How do I verify the float isn't physically stuck?

Craig - I used two different MSDs though (my original 6A, which had worked perfectly on my old engine for 6 years... and a brand new 6AL, no difference).. how could they both possibly have the same issue?! Especially with all MSD ignition components at this point (coil, distributor, etc).

SadbutTrue · Apr 30, 2009

jcode68 said:
A few things come to mid regarding your timing problem:

1)Are you certain you are using the #1 cylinder plug wire?
2)Are you sure your timing gun is working properly?
3)What type of plug wires are you using? MSD specifically states that you need to use helically wound wires and not solid core or interference will occur. Not sure what type of interference, but covering the basics.

Not sure what else could be causing the timing to be reading so far off. Have you double checked all your wiring for the MSD box to ensure it's wired properly? Haven't seen a problem go this long unresolved on Stangnet in quite a while...

I'm using the Ford Racing 9mm wires at the moment. I had been using some 8.5mm Pertronix ones earlier when I first had issues, but they were about the first thing I changed out (there was some corrosion on them so they were one of the more obvious potential issues).

I know for a fact the Pertronix wires were helically wound. The Ford Racing ones...

Ford Racing M-12259-M301 - Ford Racing Spark Plug Wire Sets

They're 'spiral wound suppression wires'. Sounds okay to me but if someone knows otherwise, feel free to chime in. FWIW, I got them because of recommendations from this site though

zookeeper · Apr 30, 2009

I would think after 4 months of frustrating and pointless troubleshooting, I would ash-can the whole MSD ignition system and borrow or buy a stock, non MSD known working unit and substitute it for testing purposes. Carbs have nothing to do with timing.

SadbutTrue · Apr 30, 2009

zookeeper said:
I would think after 4 months of frustrating and pointless troubleshooting, I would ash-can the whole MSD ignition system and borrow or buy a stock, non MSD known working unit and substitute it for testing purposes. Carbs have nothing to do with timing.

Pointless? Um... k.

My MSD worked fine previously for ~6 years and I was very happy with it. Unless there's some fundamental reason the MSD is causing this problem, I don't see any reason to get rid of it.

I have called MSD, for what its worth. They were about as stumped as I was.

SadbutTrue · Apr 30, 2009

jcode68 said:
A few things come to mid regarding your timing problem:

1)Are you certain you are using the #1 cylinder plug wire?
2)Are you sure your timing gun is working properly?

I am sure we're using the #1 cylinder plug wire.

The timing light could be off I suppose. Guess we could buy another one and see if it works.

jcode68 · Apr 30, 2009

Is your distributors advance locked out?

There is a procedure documented in the MSD distributor manual on page 4 regarding locking out the centrifugal advance. I believe this is done for race applications where they are using a computer to control the advance. Did you ever perform this procedure as it would explain a lot about your situation - hard starting, timing 38 - 45 degrees advanced etc.

Also, here is a long thread on the MSD forum about a 68 Camaro chasing timing fluctuations where he would advance 16 degrees. It just so happens he intentionally has his advance locked out as well. Some good reading and lots of troubleshooting & isolation steps that might come into play for you. Double check the advance is NOT locked out though.

zookeeper · Apr 30, 2009

SadbutTrue said:
Pointless? Um... k.

My MSD worked fine previously for ~6 years and I was very happy with it. Unless there's some fundamental reason the MSD is causing this problem, I don't see any reason to get rid of it.

I have called MSD, for what its worth. They were about as stumped as I was.

I can tell by the tone of your reply you think I'm an idiot, but think about it for a second: you've torn the motor down to inspect the timing chain, you've checked and rechecked the timing marker, replaced the plug wires, you've felt the carb floats may be the problem, but found nothing at all to back this up. Yet through the past several months, you seem to be married to the MSD system. At this point you have nothing to lose by finding another ignition system. What's the very worst that could happen? You'll either (A) find nothing wrong in which case I am an idiot or (B) find it now works in which case you now have a great running car. If the timing is randomly moving, it ain't the carbs, regardless of what MSD says, it IS an ignition problem.

Rusty67 · Apr 30, 2009

You ever bolt on that spare carb I loaned you ?

CraigMBA · Apr 30, 2009

It's not the carb. I think the guy on the MSD forum figured it out:

After changing everything in the Ignition system to include the magnetic pickup trigger wires and powering everything seperate from the car I was convienced that it wasn't the ignition components. I then took a 9/16" wrench, placed it between the electric water pump and timing chain cover and pryed back on it... low and behold the timing moved back to 38 degrees and as soon as I took pressure off the wrench it creeped back to 54 degrees! I'm still in shock! The motor does have a limit botton on the cam. However, the timing chain cover is flexing and allowing this to happen! I loaded the car back onto my trailer and brought it home where I have been working non stop to pull the motor back out for the millionth time!

How do you check for cam walk in a SBF?

CraigMBA · Apr 30, 2009

SadbutTrue said:
I am sure we're using the #1 cylinder plug wire.

The timing light could be off I suppose. Guess we could buy another one and see if it works.

Just go try your timing light on a known good car.

(I think) Timing chain issue... might explain dyno/starting/timing issues..

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