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  #31 (permalink)  
Old 07-12-2019, 10:25 AM
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you see the timing Mark moving or the distributor moving? the clamp doesn't have to be very tight to hold the distributor body in place.
if the timing Mark is moving then there are a whole new range of possibilities from inside the distributor to timing chain, cam gear, dist gear, etc.

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  #32 (permalink)  
Old 07-12-2019, 11:26 AM
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Quote:
Originally Posted by Onepieceatatime7 View Post
Ok so I grounded they heads to the block then to the frame on both side. Then I cranked it up and got the timing light out again. The dizzy is moving when I increase rpms. I can literally see it going from 10 to 0 as I increase rpms. I know I know...lock it down. The dist lock sux. It’s a chrome one and the metal is soft. I’ve bent the teeth on it once as it flattened out. The lock down bolt is not bottoming out. Any suggestions on helping the dizzy lock down?

Just seems like a cheap lock down...

Will take it out this weekend after fixing this and update.
If there is component damage already adding grounds will not fix that. If internals are not yet fried you should see an improvement but component life span may prove to be reduced.

If this unit is in warrantee MSD will repair it if it hasn't been opened up. if out of warrantee there are some shops like MSD Ignition Repair MSD Ignition Traction Control that can repair it, this is not assured repair depends on whether the condition of the circuit board(s). Or you can take a shot at home repair but unless your an electronics tech already this is a steep learning curve.

Bogie
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  #33 (permalink)  
Old 07-12-2019, 11:50 AM
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Quote:
Originally Posted by 55 Tony View Post

I do have a question that popped up and makes me really wonder. When you say the 6AL boxes can get worse over time, what type of components is it that is going bad?
This thing has several variations that change some of what you see inside across the years of manufacture. What you will usually find is burnt supressor diodes, resistor networks in the power transistor output section, and ancillary transistors in various supporting functions. Most all failures will evidence heat failure of some sort. I apply the old British joke about Lucas electricals and electronics. That in general says these type things operate using smoke, when the smoke leaks out, they stop working. You have to admit to the off handed logic of this. Generally if the circuit board isn't burnt these parts can be replaced, but do it yourself circuit board repair is not a place for the untrained. Usually the etched circuit has delaminated from the board and this is difficult to repair and keep it that way. If the circiut path has space to work in somtimes a wire jumper can be soldered in. But as I said unless your already an electronics technician the chances of success are pretty slim. With Radio Shack gone its a lot harder to find parts, not that theirs were all that great, but with one or more outlets in every town they were convienient.

MSD will cover this under warrantee if the unit has not been opened and in still in period. There are some shops out there that can fix these such as Tech West, I linked it an a different reply in this thread.

Bogie
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  #34 (permalink)  
Old 07-12-2019, 12:10 PM
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Quote:
Originally Posted by Onepieceatatime7 View Post
Ok so I grounded they heads to the block then to the frame on both side. Then I cranked it up and got the timing light out again. The dizzy is moving when I increase rpms. I can literally see it going from 10 to 0 as I increase rpms. I know I know...lock it down. The dist lock sux. Itís a chrome one and the metal is soft. Iíve bent the teeth on it once as it flattened out. The lock down bolt is not bottoming out. Any suggestions on helping the dizzy lock down?

Just seems like a cheap lock down...

Will take it out this weekend after fixing this and update.
You and we need to know if this is with vacuum advance connected or not?

Keep in mind that manifold vacuum curves differently between opening the throttle on a unloaded engine compared to when the has to get down to lifting weight. It takes very small throttle opening to get a lot of RPM when the motor isn't dragging the vehicle around. So in the case of not having to work hard, the manifold vacuum will be high for the RPM, if connected to the vacuum advance you can see the total of base , vacuum, and centrifugal all at once which would not occur on the street with the engine working to move a load.

This is not to say the distributor needs to be anchored, but also the forces on it shouldn't be so large that a chrome made in China clamp couldn't hold it, not that I cant be surprised, but I wouldn't expect this unless something else is wonky in this chain of parts.

Bogie
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  #35 (permalink)  
Old 07-12-2019, 12:18 PM
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As far as 6 AL box reliability goes you guys will note that real serious racers install multiple boxes and use a switch to activate the back up incase of failure of the prime operating box and or a switch back to conventional ignition without these boxes being involved.

Bogie
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  #36 (permalink)  
Old 07-12-2019, 01:07 PM
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Quote:
Originally Posted by BogiesAnnex1 View Post
You and we need to know if this is with vacuum advance connected or not?

Keep in mind that manifold vacuum curves differently between opening the throttle on a unloaded engine compared to when the has to get down to lifting weight. It takes very small throttle opening to get a lot of RPM when the motor isn't dragging the vehicle around. So in the case of not having to work hard, the manifold vacuum will be high for the RPM, if connected to the vacuum advance you can see the total of base , vacuum, and centrifugal all at once which would not occur on the street with the engine working to move a load.

This is not to say the distributor needs to be anchored, but also the forces on it shouldn't be so large that a chrome made in China clamp couldn't hold it, not that I cant be surprised, but I wouldn't expect this unless something else is wonky in this chain of parts.

Bogie

no vacuum advance.

https://www.holley.com/products/igni...et/parts/85551

I have the blue springs in it, which are on the softer side and 21 degree stop bushing. pretty sure now that it's the distributor moving.

It would seem natural for the timing to want to retard/push back on a high compression engine with a mild cam (268H) would it not?

hypothetically, if the dizzy was left completely loose would it not eventually retard even on a mild engine.

if not, whats the use in even having a lock down. just rambling
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  #37 (permalink)  
Old 07-12-2019, 01:34 PM
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Quote:
Originally Posted by 55 Tony View Post
I would love to see some directions from msd that mention separate grounds and grounds from the head to the intake. And where in the world do you get the idea that "a high energy square wave pulse that is hard to absorb through these unintentional connections."? I've seen you write it many times and just wonder what your electronics background is? Have you watched the square wave signal on a scope? Have you EVER worked on equipment using a scope to check a square wave pulse? Has anyone here ever benefited from running extra grounds like you always suggest? Not that I've seen. Can you please show me one set of instructions warning you of "sneaky" electrical pulses?
Think of electricity like fluid pressure. When you're pumping a fluid through an orifice and the pressure gets to be too great to force it through as fast as the pump wants to, where does it go? Same way with a turbocharger when you let off the throttle and you get that fluttering sound, that's air pressure building up and forcing its way back through the "pump" in this case the turbocharger. Its the same concept for electricity, just on a sub atomic scale

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  #38 (permalink)  
Old 07-12-2019, 03:25 PM
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Quote:
Originally Posted by Onepieceatatime7 View Post
no vacuum advance.

https://www.holley.com/products/igni...et/parts/85551

I have the blue springs in it, which are on the softer side and 21 degree stop bushing. pretty sure now that it's the distributor moving.

It would seem natural for the timing to want to retard/push back on a high compression engine with a mild cam (268H) would it not?

hypothetically, if the dizzy was left completely loose would it not eventually retard even on a mild engine.

if not, whats the use in even having a lock down. just rambling



The 268H and its near relative the XE268H are right at the edge separating the world of quite hot but street-able cams from the world of truly hot cams. Both of these worlds are intolerant of little set up errors, obviously getting worse the further up the scale you go. In my view the 268's are not "mild" cams. With these it takes very little effort to get into the range of 400 to 420 hp and similar amounts of torque from a 350 and that on only about 9.5:1 SCR. So what this means is all the players at the table need to bring their 'A' game.


This can is not so insane that it can't support vacuum advance. There are a lot of people who just say through this or that out vacuum advance and timed vacuum advance seeming to be leaders on that list. I'm more the experimental type that hunts for best integrations from the available tools, I don't just toss options I test and test and retest again and again.



If I remember accurately you are running a points ignition. Points ignitions put more of the shaft rotation forces into the distributor body by way of having to lift the contactor block, so yes these need to be securely restrained especially compared to a Hall Effect HEI distributor. One of the mechanical things this does is to speed wear on distributor bushings and bearings which allows the shaft to orbit with its rotation which results in unpredictable changes in gap thus dwell angle. This would affect the timing as a result of the variable shaft movement. To this end any off centered movement of the plate to which the points mount would have similar effects.


As usual the Devil is somewhere in the details.




Bogie
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  #39 (permalink)  
Old 07-13-2019, 08:45 AM
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Quote:
Originally Posted by BogiesAnnex1 View Post
The 268H and its near relative the XE268H are right at the edge separating the world of quite hot but street-able cams from the world of truly hot cams. Both of these worlds are intolerant of little set up errors, obviously getting worse the further up the scale you go. In my view the 268's are not "mild" cams. With these it takes very little effort to get into the range of 400 to 420 hp and similar amounts of torque from a 350 and that on only about 9.5:1 SCR. So what this means is all the players at the table need to bring their 'A' game.


This can is not so insane that it can't support vacuum advance. There are a lot of people who just say through this or that out vacuum advance and timed vacuum advance seeming to be leaders on that list. I'm more the experimental type that hunts for best integrations from the available tools, I don't just toss options I test and test and retest again and again.



If I remember accurately you are running a points ignition. Points ignitions put more of the shaft rotation forces into the distributor body by way of having to lift the contactor block, so yes these need to be securely restrained especially compared to a Hall Effect HEI distributor. One of the mechanical things this does is to speed wear on distributor bushings and bearings which allows the shaft to orbit with its rotation which results in unpredictable changes in gap thus dwell angle. This would affect the timing as a result of the variable shaft movement. To this end any off centered movement of the plate to which the points mount would have similar effects.


As usual the Devil is somewhere in the details.




Bogie

So, just curious what kind of HP you would ballpark on my setup as my goal is 400+

Balanced shortblock .40 over zero deck
Edelbrock E street heads
Roller rockers
MSD Box , coil and dizzy
Shorty headers
Weiand single plane intake
Holley 650 DP
268H cam
10.5:1 scr

I had to use the Weiand and shorty headers for clearance.....

And yeah that lock down is a POS. Broke pretty easy last night when I tried to bend the forks.
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Old 07-13-2019, 12:43 PM
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I noticed that the spark plug gap was 0.40Ē. I assume that is because you have a MSD ignition. Try closing the gap up to .035Ē or use Denso spark plugs with the platinum tips. They are preset at .035Ē.

Avoid ACDelco plugs at all cost. They are now made by various offshore producers. Those spark plugs have not been a GM product since 1992, following the GM bankruptcy.

Or get rid of the MSD ignition system. A PerTronix system is hard to beat.
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Old 07-13-2019, 01:30 PM
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So quick update. Iím ready to throw this msd box in the can. I got the dizzy clamp and thatís secure. Take it for a ride and itís just off.....like sputtering but not the complete fall off a cliff it was doing. I make a couple miles, come back and adjust the timing..little better but now I hear kind of a rattling sound, maybe detonation........then itís running strange so I stumble himoe and it dies when I get in the driveway. Coill is bad. No spar etc. change the coil and it runs again, but go for a ride and itís off....like sputtering. I didnít even leave they neighborhood as I knew it was off. The 5 and 7 plug wires were close to each other and the msd wiring is bundled....and reading through the web and msd they say thatís a no no as spark can jump etc.

I am at a loss. Next move is to pull the plugs and valve covers to check for any damage and wire it w/o the msd 6al. Any links for that would be appreciated and I hope I have no internal damage.

Idles fine, sounds good, revs in park, but go to drive it and itís ****.

I have to run the msd billet dizzy for clearance issues. Just an FYI.
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  #42 (permalink)  
Old 07-13-2019, 02:37 PM
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Quote:
Originally Posted by Onepieceatatime7 View Post
So, just curious what kind of HP you would ballpark on my setup as my goal is 400+

Balanced shortblock .40 over zero deck
Edelbrock E street heads
Roller rockers
MSD Box , coil and dizzy
Shorty headers
Weiand single plane intake
Holley 650 DP
268H cam
10.5:1 scr

I had to use the Weiand and shorty headers for clearance.....

And yeah that lock down is a POS. Broke pretty easy last night when I tried to bend the forks.
10.5 static is probably too high for E Street heads. The chamber design is a bit too much like the old double quench and not quite up to the Vortec. The differences are subtle but significant. At this SCR it is likely that this is detonating which can display as missfires and smoothness oddities before it is so violent you can hear it.

The single plane intake is probably not your friend either, these can be quite hard to workout cylinder to cylinder balance in terms of mass port flow and of mixture ratio when not runnng at competition RPM and even then you can knaw your knuckles raw trying to get cylinder feeding balanced. When you start getting into racing parts you leave the arena of bolt on and go behind. Getting this stuff to play together can take a lot of time.


Bogie

Last edited by BogiesAnnex1; 07-13-2019 at 02:46 PM.
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  #43 (permalink)  
Old 07-13-2019, 03:14 PM
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My 1963 Pontiac with a 455 CI engine had a 268H camshaft. The engine had 12:1 SCR . The only complaint about the Comp Cams 268H camshaft was the Comp Cams lifters. I could never set them with polylocks where the lifter noise was gone.

After about three hundred miles in the engine, I switched to Melling JB951R (now discontinued) limited travel lifters and set the preload at .002”. Comp Cams and most other aftermarket camshaft grinders started offering limited travel lifters after the Melling limited travel lifters were discontinued.

The Melling limited travel lifters eliminated all the lifter noise but the roller rocker arm clicking was still there. . Comp Cams camshafts have fast cam lobe ramps and lifter noise with standard travel lifters is impossible to eliminate. Mose people with aftermarket performance camshafts are not bothered by lifter noise especially when using a loud exhaust system..
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  #44 (permalink)  
Old 07-13-2019, 03:36 PM
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I can't agree with Bogie on detonation at 10.5:1 compression and aluminum heads, the E-street chamber looks decent enough to not pose any problem in this regard. and you've got a nice quench situation.

Same with the old Weiand single plane(X-cellerator I'm assuming?), it'll hurt potential power but won't just cause the miss and stumble issue as described.....I've run it, so I know it worked enough to put a 3700 lb car with a short rod 388 stroker and ported 2.02" valve'd smogger heads into the low 13 range 1/4 mile..

My thought is there is something going on in the ignition.
The distributor you have cannot be wired to run without an ignition box, as it has no provision for an ignition module.

Maybe buy a $60 small cap self contained magnetic trigger distributor unit off Ebay and keep it around for a spare/test unit. Just an example, Bunch of different vendors selling them.
https://www.ebay.com/itm/Distributor...4AAOSw1hJb0s4m

Your parts combination ought to make at least 390 HP, if it doesn't make 420 HP it is the fault of the intake and shorty headers.
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  #45 (permalink)  
Old 07-13-2019, 05:07 PM
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About the 5-7 plug wires, just keep them from running touching and parallel to each other. They can cross, but try to make it at something approaching a 90* angle and there will be no problem.
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