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Discussion Starter #1
I am replacing the centrifugal weights on my dizzy with a Mr. Gasket kit. The instructions call for pressing supplied plastic bushings into the centrifugal weights before installing the weights on to the pins. When I do that it makes the weights fit SUPER tight on the pins hence the weights do not move side to side freely/easily around the pins. My old weights did not have any plastic bushings and almost flopped around the pins hence side to side movement was not an issue. Instructions don’t say anything about how tight these should fit.

Should the weights move freely around the pins or be super tight or does it really matter?

Please see pic. (BTW, bottom pic does not have the weight pressed on all the way just yet…affraid to press it on as it's going to a #$%& to get off)



 

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They should probably be as loose as possible without wobbling around. Maybe use a little emery cloth and wd-40 to cleanup the rusty pins -maybe that'll free them up. if not, maybe its just not quite the right size and try a different curve kit.
 

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Discussion Starter #3
That's what I thought too....the real issue is that the pin hole on the weights is way too tight for the darn bushings, squeezing the bushing really tight around the pin. Why would the do that? Starting to have doubts about this kit. I guess I could always drill out the pin holes bigger in the weights making the bushing fit nice a loose
 

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Clean up and surface rust....rust has a greater volume than steel and will cuase binding
Without springs on, turning the dizzy on its side, the weights should fall away..be fee, at the most , a tintest of shakes, and they move
And no slop in the bushings...
I have had issues over the yrs with 'new' weights being tight, which the bushings are designed to prevent....So now just clean up old weights out of the Dizzy junk box...work every time
 

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Matt,

The kit should have come with two sets of bushings. How does the other set fit? Most of the instructions say to pick the one that fits snugly on the pins but they don't mean "press fit" snug. With my cheap set the ones that fit on the pins were a press fit into the weight and were just a little loose on the pin. The old set that came off was that way as well.

If you dress those pins with some emory cloth it will probably clean them up, and a dab of white lithium grease in the right place probably wouldn't hurt. I believe that the weight and bushing should rotate around the pin, not the weight rotating around the bushing.
 

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Discussion Starter #6
Thanks guys. The other set of bushings in the kit are even tighter. The ones I have on there now fit snugly on the pin until I put the weight on which crushes it around the pin and makes it too tight. I will clean up the pins and see how much difference that makes. Now that I am convicted that they should move freely with no slop around the pin, I will get them to work one way or another.

One other question regarding the advance mechanism overall. Using my hand, should I be able to manually move the advance mechanism back and forth throughout its full designed travel? Specifically if I was to grab the middle piece that the weights wrap around, should it move back and forth? It certainly does NOT now.
 

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I believe that the weight and bushing should rotate around the pin, not the weight rotating around the bushing.
Correct.

Using my hand, should I be able to manually move the advance mechanism back and forth throughout its full designed travel?
Yes in the same manner as I described for the weights above
ANY tightness in the adv mech or the weights will severly effect/consistancy how the curve (springs) respond

Another question, have you also replaced the shaft bushes? I hope you did not reem to size....these require a special tool to install, they a sintered bushes descinded to hold lubicant...reeming closes off the surface of the bush preventing lubication
 

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Discussion Starter #8
Correct.


Yes in the same manner as I described for the weights above
ANY tightness in the adv mech or the weights will severly effect/consistancy how the curve (springs) respond

Another question, have you also replaced the shaft bushes? I hope you did not reem to size....these require a special tool to install, they a sintered bushes descinded to hold lubicant...reeming closes off the surface of the bush preventing lubication
Understood and I did not replace the shaft bushings.

The advance mechanism was literally froze up. I got it all loose, lubed and working again. I will be dialing in the advance/timing over the weekend. This of course means I had no advance. That would explain the crappy gas mileage I've been seeing, the overheating (which I masked by 700 HP cooling system) and stubble/loading up issue I was seeing. Can't wait to get the car dialed in this weekend. My cooling system should laugh at my motor now instead of work very hard to keep it cool, gas mileage should go way up and the overall power band should drastically improve. I’ll post results (and maybe a few more questions). Thanks again. :beers:
 

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Do not lube, everything good clean and dry and a faint surface smear of light oil on a rag.
In the AC /Delco electrical servive manual of the time, there are 100s of dizzys, and a page of VA units all with different curve specs...and vary also as to how many degrees in the Dizzy considerably...
One cant just take a dizzy, change the weights and dial in.
One the other hand with a bit if fiddling it is not hard to make it fully adjustable.
Pionts and HEI.
 

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Discussion Starter #10
OK, so here are the initial results with one potential ?why?

Initial timing @idle (without vac adv can) is set at 10*
Initial timing @idle (with vac adv can) jumps to 38*
Mechanical advance (without vac adv can) kicks in when RPMs got up but I can only get around 12-15* out of it @2500-3000. I have tried all the spring combos I can still only get 12-15*. Of course when I drop way down in the springs, the timing starts advancing at idle or too soon but still only 15*. So having said that, I can only end up with around 25* or so of total mechanical advance (10* + 15*,no vac can) when mashing the throttle down . I was hoping to end up around 32-36* of total with mechanical advance (no vac can).

Would there be a reason why I can only get a max of 15* and not more from the mechanical advance?

Not sure if I am good or not as I thinking that the vac advance can will supplement the mechanical adv at normal driving so I will be around the 35-38* which I believe is good and desirable. Appears the car is running around 10 degrees cooler and the fans on the BeCool are kicking in much less frequently. Haven’t checked the mileage yet.
 

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Sounds like it is binding and the weights aren't spinning out all the way. The vacuum can won't add in any advance when you go full throttle so it will feel sluggish.
 

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Discussion Starter #12
Sounds like it is binding and the weights aren't spinning out all the way. The vacuum can won't add in any advance when you go full throttle so it will feel sluggish.
I can easily rotate the dizzy rotor by hand or take the rotor off and rotate the overall mechanism. The weights appear to fall back into place and fall apart when I move it back and forth. One thing I did notice is that the new weights appear to be a little lighter than the old ones. I am wondering if they are simply not heavy enough to move the advance all they way out.
 

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I can easily rotate the dizzy rotor by hand or take the rotor off and rotate the overall mechanism. The weights appear to fall back into place and fall apart when I move it back and forth. One thing I did notice is that the new weights appear to be a little lighter than the old ones. I am wondering if they are simply not heavy enough to move the advance all they way out.
Could be. Was there a chart on the weight pack that showed total advance and advance timing with the different springs? Also there may be an advance stop in your distributor. I've got a cheap set (Spectre) and it has a graph showing the total advance (20 degrees in my case which is pretty much stock) and the RPM curves for each spring set. I think most generic HEI weight kits are 20 degree sets for stock unless they are specifically labeled as different.

Also, what is your idle RPM when you're setting it? If it is above 800 RPM, the centrifugal advance may already be coming in so you might not be getting a true number for setting your initial. You can always spin up the RPM's with vacuum advance plugged and adjust your distributor to full advance of 32 (or whatever you want). Then lock the distributor down and release the throttle to see what your initial is like that and adjust your idle.
 

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No chart included with the kit. I thinking about cleaning up my old weights and putting them on just to see...

Was editing while you were posting. :) Check out the rest.
 

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I have tried all the spring combos I can still only get 12-15*.
I mentioned before there are a lot nof dizzy configs...
Then total cent in the dizzy is not determined by the springs..
The sptings ONLY determine the rate at what they swing out at...
To be in the ball park, you should have them START to advance 300 to 800 rpms above the idle speed.
The AMOUNT of degrees in the dizzy is dtermined by the shape of the tail of the weight AND the shape of the 'anvail' they work on...
Again I strongly suggest to used orginal GM weights and bushes...
By very cearfully filling, rounding off .5 to 1mm on the tail you will get more advance in the cent adv...be careful because this is very easy over done.

Then if u do go over, tapping out one of those holes next to where the rotor screws on, getting a grub screw, rounding the head into a cam shape, you can then adjust how far out the weights stop..
Also, if u take off too much on the weight tail, the weights can fall off those little round 'plates 'they move on, jambing open over the edge....
If this is still a problem after making the 'cam' grub screw...those round plates can be pulled out, get a scrape of that fiber material, cut a thin sliver, make lager diameter so the rotor clears it and epoxy into place

DONOT setup 2 things at once..ie the cent and advance....get the cent setup
THEN start on the VA...otherwise you will get your self in a big mess, totally screwe by science, and when the Cent is right the VA will be screing things up any way...
 

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Thanks for all the ideas
m8 they are not ideas..I have been modding GM points and HEI dizzys for 20yrs adapting to dedicated LPG engines.
The limitations is a idle of 500 rpm @ 8 degs in gear, curve coming off at 650 rpms all in @ 2800 rpms with about 28 degs in the dizzy (thats total of 36 on the engine)
 

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Discussion Starter #20
Well got the old weights cleaned up and back on the dizzy. I am getting the full advance for sure now. Wow! :hurray: The car drives so much better. The punches throw you back a whole lot more then before. I still need to do some fine tuning as I am getting a little too much advance initially. With the can/vac at idle I am around 39-40. When you gradually bring up the RPM's I am seeing well over 40 as the mechanical is kicking in top of the still holding vac. Once the RPM’s come up high enough to where the vac drops, I am right around 36. I have the adjustable can so I need to play with it to see if I can bring the overall advance back to mid 30's or come up with some advance stop on the can. Also, maybe try stiffer springs to delay the mechanical advance just a bit. I haven't clocked the mechanical advance against RPM's yet to see when it comes on and when it's fully deployed. Didn't have a helper tonight to watch the RPM gage and I don't own a RPM module of some sort just yet. May pick one up tomorrow though...
 
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