Does my distributor advance...at all?

[Peter Coomaraswamy]

Somewhere I thought I read that you could test the distributor advance by attaching some vacuum hose and sucking on the advance side and checking for movement (in the proper direction of course). I venture to say that Heide Fleiss -or Charlie Sheen for that matter- could not have budged my distributor using that method. I tried pushing the arm forward and it was very difficult. Is this indicative of a non functioning advance or when that thing starts spinning at 1-2K RPM's will the centrifugal force move it and overcome the resistance?

thanks-sorry

 

[Stevehose]

you should be able to twist the rotor a couple degrees clockwise and it should then spring back. If it wont move or is sluggish it's time for a cleaning at best or a rebuild or a 123ignition. Also the vacuum cannister mechanism might also be stuck/leaking which is why the ahem..suck test...isnt working.

 

[Ohmess]

Charlie Sheen! EEEEEW.

 

[MMercury]

Somewhere I thought I read that you could test the distributor advance by attaching some vacuum hose and sucking on the advance side and checking for movement (in the proper direction of course).

I think you have confused two types of ignition timing controls.

Depending upon the model, your distributor is equipped with two means of altering ignition advance and retard: (1) vacuum and (2) centrifugal. They are separate and distinct from each other although they work in tandem to obtain desired spark-ignition at certain engine speeds and loads. Yes, some distributors only have vacuum advance (e.g., Ford Load-O-Matic) and some have only centrifugal advance (e.g., early 02tii). The Ford Model Ts did not have traditional distributors and ignition timing was controlled manually from the steering column.

You mentioned vacuum. Ported vacuum from either the manifold or a carburettor typically pulls on the diaphragm attached to the side of your distributor. In turn, the vacuum pot is mechanically connected to the plate upon which your ignition points are attached. As vacuum is increased, linkage from the diaphragm causes the points plate to rotate, necessarily changing the ignition timing. If the vacuum diaphragm leaks or the pot does not hold vacuum, your vacuum advance will not function. Hence the vacuum test. If you apply vacuum to the vacuum pot and it doesn't leak, your distributor points plate may be restricted or the linkage is disengaged. Examine the points plate and you will notice it his tensioned with a ball bearing. The clamp that retains the bearing is adjustable and the entire assembly should be lightly greased and exhibit free movement. Same with other retention points, including the sistered distributor plate (See diagrams) If not, you need to investigate further. Too much movement is not good either as it is apt to permit irregular, rather than steady, ignition timing.

The second type of ignition timing control is centrifugal and consists of rotating weights and springs. It is, in effect, a rotating governor and should, like its vacuum advance cousin, be free moving, albeit with tension from the springs.

Since both types of ignition advance are mechanical, they are subject to wear and occasionally need attention. This includes checking for free movement and lubrication, including things as simple as oiling the wick at the top of the distributor shaft (under the rotor). As suggested by other responses, if your engine is running well, it is unlikely that you have a distributor advance issue. Pulling the vacuum tube at a high vacuum condition (while the engine is running) could be part throttle or even at idle depending upon the vacuum source, should provide a decent indication if the vacuum advance (and/or retard) is/are functioning. The
"twist" test mentioned by Steve is a fair tale of the centrifugal advance's health but using a timing light would be far more accurate. (See e.g., http://catalog.makewavesinstrumentcorp.com/ins/ins016.pdf )

Excellent illustrated distributor R&R courtesy of deQuincey >>>>> :wink:: http://e9coupe.com/forum/showthread.php?t=7653

More fun reading of various (dated but useful) test equipment: http://books.google.com/books?id=-d...test distributor using a timing light&f=false
Hth

 

[Peter Coomaraswamy]

MM superior information- thanks for putting this together- it will be used over and over by me and many others I'm sure!

 

[jmackro]

Peter:

How does you car run? If the distributor wasn't advancing at all - neither from vacuum nor mechanical - then the engine wouldn't run very well above idle speeds. Many cars were designed to just have mechanical advance, and work quite well that way. But it seems that e9's were intended to a three, rather than two dimensional advance map.

 

[Peter Coomaraswamy]

J, just having trouble getting her to run "powerfully" I know that means very little technically, but I have new carbs, balanced correctly- I think, timing set correctly, Petronics installed, balance tube connected, proper air filters, I just think it should have more "punch". I'm not expecting Shelby-esque power but something a little more than a VW bug would be nice. Once she's up to speed she purrs along really well though throttle response is just "power challenged". No specific issues, no hesitation, popping, runs smooth- maybe I'm just expecting too much.

On Friday I'm getting my second e9 from Mario which is completely stock. It's a 2800 so I think I'll be able to do a fair comparison- I hope. I know, this is not really useful information, but I'll post my "feelings" (I know, I sound like Barbara Streisand)

Has anyone noticed a power drop when using Petronics vs the old points system?

Thx

 

[jmackro]

You can test your advance using a timing light. Is it reaching the max advance mark at 3,500 rpm? Does it start easily (suggesting that the advance drops back at lower rpm's)?

Perceived power should be identical between Pertronix and points. A sensitive dyno might show a few more hp with the Pertronix, since it gives a "hotter" spark and more consistent timing.

 

[Stevehose]

You have Weber 32/36 downdrafts, yes? If so that's one possibility it lacks punch.

Pertronics will not drop your peformance, but it's not really a hotter spark either because it's just an electronic vs a mechanical switch (points). It's more consistent and doesn't degrade over time like a mechanical switch does. It also won't "bounce" open and closed like points can at higher rpm.

Like Jay says, check your advance at idle, at 1700 rpm, and 3500 rpm to see if it advancing.

J, just having trouble getting her to run "powerfully" I know that means very little technically, but I have new carbs, balanced correctly- I think, timing set correctly, Petronics installed, balance tube connected, proper air filters, I just think it should have more "punch". I'm not expecting Shelby-esque power but something a little more than a VW bug would be nice. Once she's up to speed she purrs along really well though throttle response is just "power challenged". No specific issues, no hesitation, popping, runs smooth- maybe I'm just expecting too much.

On Friday I'm getting my second e9 from Mario which is completely stock. It's a 2800 so I think I'll be able to do a fair comparison- I hope. I know, this is not really useful information, but I'll post my "feelings" (I know, I sound like Barbara Streisand)

Has anyone noticed a power drop when using Petronics vs the old points system?

Thx

 

[brian c]

I've been fighting with this issue too. Sucking on the advance tubing should budge the points plate a bit. As others have said, the centrifugal weights advance the rotor, the vacuum advances by turning the points mounting plate slightly. I gave up on my distributor and got a 123ignition unit at the recommendation of Steve. Seems like a great unit but have yet to get it set up as my carbs are still off the car. My distributor would just not advance correctly too. If I set the timing to 22 at 1700rpm, it would just not advance more than a few degrees up to 3500. If I advanced the timing to get it to above 30 at 3500rpm it was too advanced at idle and 1700rpm. I lubed, disassembled everything. Nothing seemed out of order, rechecked, reassembled....same problem. Without the proper advance you will get flat on power at the higher revs. Get yourself a good timing light with advance capability so you can really tell how much it is advancing or not advancing and go from there to decide if it is ignition or carbs. With the price of new distributors or the cost of a good rebuild, the 123igniton.com unit seems pretty slick.

 

[MMercury]

A properly functioning distributor is essential for a properly functioning engine. It is not surprising that a 40+ y/o distributor can have problems. Shafts and distributor bushes wear, centrifugal advance springs fatigue, associated bushings can deteriorate. If performance lags, a timing light is the probably the first order of business to empirically confirm a distributor malfunction. Even better, might be a distributor machine, with a large supply of different springs and weights for obtaining a desired timing advance curve. (For obvious reasons, these machines are becoming less and less common, as are the individuals who know how to use them.)

Assuming the distributor is within acceptable specs, and fuel delivery appears to function, the so-called butt dyno is hardly the most accurate measure of power or torque production.

How many times has someone claimed that their engine runs better after their car has been washed and waxed, or the oil has been changed, or when the exhaust is louder (due to a muffler's new hole). :???: Conversely, for some strange reason, a fast/powerful car often seems less powerful after you have driven it for several hours without a pit stop.

If I have a car that seems "sluggish" I might check for any obvious drag e.g., low tire pressure, dragging brakes (including parking brake), restricted exhaust, restricted air filters, slipping clutch, dragging auto transmission, contaminated/old fuel, contaminated oil, weather changes, fuel linkage (are throttle plates fully opening) or zombies clinging to the undercarriage. Next up, the same system checks mentioned in other posts and possibly a minor tuneup, including examining each plug and its gap and valve adjustment.

If the underpowered "malaise" persists, more general diagnostics, e.g., compression test, leak down, exhaust gas analyzer, etc.

Plan B: Drive a severely underpowered car or moped before driving subject vehicle.

Plan C: R&R engine, install colder plugs followed by addition of forced induction.

Plan D: visit Witch Doctor for talisman, placebos and/or removal of bad spell.

Plan E: Hide vehicle in vine-covered climate-controlled barn, drain fuel and coolant, cover with tarp. Leave for discovery by unborn relative. Pay cable and electric bill. Consume pizza and beer with reckless abandon.

Two "seemingly" identical cars can feel and perform differently. An engine with a lighter flywheel may seem more "lively" than the same engine with a heavier flywheel. Larger, wider and/or stickier tires can make a difference too, as can tire pressures (rolling resistance). Same with transmission ratios and - rear axle ratios. Even sitting lower to the ground can seem to make a difference.





According to the forever-lost shop manual, red cars tend to be faster than green . . silver faster than black (except at night) . . . turkis faster than ceylon . . . and sahara faster than fjord. Left hand drive is usually faster than right hand drive. Cars with Kph speedometers faster than mph. E9s with current Victoria Secret runway models tend to be faster than E9s occupied by former AARP models. There are of course many exceptions to these maxims as outlined in the aftermarket shop manual chapter entitled: "Sie wollen schneller gehen?" :lol:


Peter: Good luck with the new ride!

 

[Ohmess]

Great thread. I had forgotten to check for clinging zombies.