Duraspark Distributor Problems

[wsa111]

I'm in the process of converting from a modified 68 distributor with a pertronix I.
Installed the duraspark unit with a MSD-6AL. When i first cranked it up it spit & backfired out the exhaust. Disconnected the vacuum advance unit set initial advance close to 14 degrees. I have 24 degrees centrifigul advance in the distributor for a total of 38 degrees. When you put vacuum advance to the can the engine jumps spits. I put in a new pickup coil & plate. I have run out of time tonight & will refire the engine tomorrow night with the new pick-up installed. I hope the lead in wiring to the pickup has an intermittent open. When running just centrifigul advance the engine sounds crisp & idles smoother. Just applying vacuum to the can just turns the engine to jumping, backfiring out the exhaust & a rough idle. Just moving the vacuum advance plate just makes the engine waco.
Any ideas or previous problems with this distributor would be appreciated..
When i light it off tomorrow night i will see what happens? William

 

[StraightSixer]

The vacuum diaphragm is probably junk. Run on centrifugal advance until it gets fixed, or you might want to see if there is any difference in performance/mileage on the duraspark dist. with centrifugal adv. only. I am curious myself. 8)

 

[wsa111]

Tonight i put in a new pick-up in the duraspark. With no vacuum advance the engine will run to perfection, hook up the vacuum advance to the carb or put vacuum to the can via a handheld pump the engine just goes spastic. Without the vacuum advance you can set the initial advance & the centrifigul advance is perfectly visable with a timing light on the crankshaft pulley.
The engine runs great on the centrifugal advance + the initial 14 degrees on the initial with 24 degres in the distributor for a total of 38 degrees.
hook up the vacuum can for this engine and the engine shakes, backfires out the exhaust & the timing mark just jumps all over the pulley when vacuum is either applied from the carb or a hand held vacuum pump to the can. Believe me the vacuum advance can is the proper one for this engine.
The msd is hooked via the magnitic pick up lead from msd to the duraspark using a msd adapter harness.
If i can't come up with a solution I will reinstall the 68 distributor with the pertronix I.
Any professional response is welcome. this SOB is a mystery??
Maybe someone with duraspark experience can help?? Thanks William

 

[xctasy]

Mark P said that aftermarket caps for some electronic igniton systems are incorrectly indexed. Up to 15 degrees on the cap. Even if its supposedly a Ford part. On a stocker, no problemo, just a shakey idle when warm, which can be tuned out some. On something on the cutting edge, like a cammed up and well tuned 200 cube jewel like yours, it could be the reall issue.

Mark P has a post for Fairmonters in the tech section, and I'd check everyone of his posts. There is also the yellow grommet connection which can forstall total advance under certain conditions when the existing EGR and emission fittings are used.

The answer will be small, and you'll be able to fix it with a factory blue printed component. As you'll be aware, optimising a stock component is the right idea with an ignition system. Even in the 70's, Ford were spending millions on them, and a few 'crook' parts which don't meet the FoMoCo spec could be the problem.

 

[Anonymous]

Bill,

I have some duraspark diagnostic info out in my shop. I'll take a look through it tommorrow and get back with you!

Later,

Doug

 

[wsa111]

I don't know which componet is at fault. right now i don't care. Tonight i ripped out the msd & the duraspark, put my modified 68 distributor back in and the engine runs great, just as it did before.
When i get time i will try the msd with the 68 distributor & pertronix to see if the msd is the problem. I will also get a junk yard duraspark module & test the distributor. Its a shame cause i invested a lot of money & time to custom tailor the advance curve to what i had in the 68 modified distributor.
So be it lets move on to the over oiling of the valve train with the yella terra rocker arms causing excessive oil consumption.
I'll keep you informed. William

 

[addo]

The over-oiling with Y/T rocker arms is common enough. The rough 'n' ready response is to stuff a wire into the pushrod, to restrict flow. Beyond that method, I'm not sure.

 

[wsa111]

Adam, I have heard of using pipe cleaners & sticking them in the pushrods in small block chevys. Looks like i will visit my local smoking store & get some pipe cleaners. I also plan to use small block chevy valve stem o'ring seal on each valve. I tried to see if it will fit & it seals to perfection, cause the groove cut in the 11/32 chevy valve stem is very close to 5/16 which is the diameter of the ford six valve.The fel-pro part # is SS 5112 intake & exhaust stem seal kit. Another would be to put a restrictor in the adjuster of the rocker arm.
I think i will find a duraspark module & try the duraspark distributor 1 more time.
I entered the MSD troubleshooting web site. They say you can't use a timing light with the adjustable control for checking total advance when using the msd unit. I'll keep the forum informed. William

 

[wsa111]

Doug, mustang geezer, how do you have your msd hooked up.? Have you used the direct magnetic pickup lead or did you use the white wire to trigger the msd?
If i get time tomorrow i will hook up the msd with the pertronix using the 68 stock distributor using the white trigger wire. If the engine runs ok i may try the white wire hookup to the duraspark, if not i will send the msd-6al back to msd to check out.
In the mean time i will also hook up a stock duraspark setup to try. This will get expensive but i will find the problem. William

 

[Anonymous]

Bill,

My white wire is cut so I must have wired it up the other way Did you get the MSD duraspark adapter wireing harness too??

Later,

Doug

 

[mustang6]

MSD troubleshooting web site. They say you can't use a timing light with the adjustable control for checking total advance when using the msd unit.

Hmmm.... I use a Sears adjustable control timing light on two cars with MSD, one with a 6A and one with a 6AL, and I've never had any problem. Timing sets up just the same as it does on my Ranchero that is running a stock Duraspark module (until I get a MSD for it). In both cases, I use the MSD Duraspark/MSD adapter harness, I don't use the white pickup wire. Your scenario is a real stumper- I suppose there could be something defective in the MSD but in my experience they either work great or they are dead, never anything in between. I agree with the idea of trying a Duraspark module with the distributor in an attept to isolate the problem.

 

[wsa111]

Doug, the first hookup with the MSD was with a harness adapter right from the MSD to the distributor.
The results were disasterious. Just read my previous posts.
You line up the magnetic reluctor to the pick up coil & this thing would fire half way between the reluctor to pickup coil. I will give the msd 1 more shot & will try it with my pertronix on a modified 68 distributor. I will use the white wire as my trigger to the msd. If that fails i will send the unit back to msd & find out what the problem is.
I will also try the duraspark using a stock module & see if that works.
I hate to scrap the duraspark cause i have spent many hours tailoring the proper advance curve that i have done to my 68 distributor.
If that fails i will scrap both units & will stick with my modified 68 unit.
I am on this problem like a pitbull. I will find the answer. I am not a trainee or a novice in the business.
The same situation with the over oiling from the yella-terra full roller rocker arms. It seems like i have to do the R&D work for a professional company.
As Adam stated it is a known fact the yella-terra rocker arms over oil the valve train area.
For example the small block chevy push rod oil hole in the stock rocker arm only supplies oil during the closed position of the valve. The oil hole is not at the top of the pushrod cup but at a 30 degrees angle. Which results in less oil to the top end of the engine flooding the valve guide area. The yella-terra rocker arms have a hole triple the size it should be for proper oiling.
Any body looking for a rocker arm up grade should stick with the 1.6 or 1.5 rockers using the shaft oiling system till i find a way to fix this over oiling condition. William

 

[wsa111]

Scott, thanks for the reply. I just might have a defective MSD unit??
The true test will be using it with the perfect working pertronix system.William

 

[wsa111]

I hate to combine this problem of the msd with yella-terra oil consumption, but here goes.
If you use these chevy oil ring seals? Don't just put them on the valve stems & install the springs & retainers.
first install the valve in the guide, then install the valve spring, put the retainer on top of the valve spring, compress with a spring compressor, then slide the o'ring seal onto the valve stem below the keeper groove on the valve stem, install the keepers, then release the spring compressor.
This traps the seal at the bottom of the taper of the retainer between the keepers to stop oil from traveling down the valve stem to the valve guide or seal area.
Doing this will stop oil from traveling down the valve stem. If i could find a metal shield just like the older small bllock chevys had would be a way to prevent the spray of oil to the valve guide area.
In a race application no one cares about over oiling, but in a street engine valve guide oiling can be critical. William

 

[Anonymous]

Bill,

Which oil seals are you using?? I got my current set from Mike and my original set (for my 66 head) are sealed power GM units. My machinist had to machine the head to make them fit and he said it was impossible for them to leak no matter how much oil was pumped up there. (Unless you have bad valve guides to start with)

If you have these seals installed like I said I still think it has to be a pcv problem. There used to be a guy on the forum that had the same problem (Jimbo65) do a search on his problem

His (yella terra) rocker arms was tossing oil up on top of the valve cover baffle and then his pcv system was sucking it into the intake.

I designed a new pcv system based on my own problems for him but I dont know if he ever used it. If it is sucking oil into the engine you have to either get a factory Ford screw on oil cap or a aftermarket Dodge cap and install the pcv valve in it.

In extreme cases like my own I had to go back to the OEM valve cover because of the superior oil baffles than the aftermarket ones have.

If you pop off your pcv valve and look into the valve cover there should be no oil sitting in there. if there is I think you might have found your problem!

Later,

Doug

 

[Anonymous]

William,
I have my Pertronix hooked up on my Mustang using the white wire to the MSD box. I believe my Vette with no Petronix is has the points hooked up to the white wire also, but I have not run out there to lay an eyeball on it.

I have been timing with a dial back timing light and now I wonder why it has been working. I had forgotten about MSD's instructions on not using such a light. I did not have a dial back light when I put on the MSD boxes 6 years ago. I may have to hook up both types of timing lights and see if there is a difference.
Doug

 

[wsa111]

Doug, i will follow your advise on the pcv deal. That may be the problem. The stock rocker arm oiliing system does not spray oil all over the top of the valve cover. I may also put a baffle in the valve cover to divert oil to the rocker arm fulcrum. Thanks Bill