Moparts
Mechanical advance too quick on Mopar Perf Dizzy?
Posted By: Chilort
Mechanical advance too quick on Mopar Perf Dizzy? - 05/20/10 02:42 PM
I've put a Mopar Performance dizzy in my 440 (.40 over, Eddy heads, around 9.2:1 compression, 60303 cam, 16* initial, 34* all in). I am getting a part throttle rattle at higher engine speeds (75mph with a 2.76:1 gear ... sorry, no tach). The engine builder seems to think it is detonation especially since it seems to get more sensitive as the engine warms up. It doesn't sound like any kind of ping or rattle I've hear heard. And it doesn't make the noise at or near full throttle.
I pulled the initial back from 18/36 this morning to the 16/34 I listed above. It still does it. And yes, I pulled the vacuum advance hose off and plugged it to make sure it wasn't the vacuum advance (I've also gone 2 turns CCW with the adjustment in the vacuum canister).
The engine builder gave me a bag full of springs to try out but they look to be for the older Mopar Performance Dizzy based upon what I can find here with the search function.
So, here's a picture of the springs that are in the dizzy now. What would you do?
Posted By: dave571
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/20/10 04:37 PM
You can see the heavier spring in the top, is slotted, so it doesn't do anything initially. two springs like the toher one would like help the problem.
You can probably get some thing that will work at a local speeed shop. just ignore the applications on the packages. I have found gm pre hei springs work well on these.
You could grind a little off the weights too if you like, but with the long slotted spring you have, it won't help. AND there isn't a lot to the weights in those anyway, so if take much off, it becomes hard to get springs that are light enough.
Posted By: Chilort
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/20/10 04:44 PM
I did see the long slot in the heavy spring and didn't even think about it not doing too much initially. I may have a heavy spring like that without a slot to try out. Or I could go with another like the smaller one too. Looks like some experimenting is in order.
Posted By: mr_340
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/20/10 05:14 PM
http://www.summitracing.com/parts/DCC-5153446You might want to buy one of these kits to dial in your distributor. I bought one of these, but they are for the newer MP distributors. It shows the advance curves for each spring combo in the sheet that comes in the kit.
Posted By: Chilort
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/20/10 09:40 PM
Looks nice, but for $40, I'll play with the hand full of springs I've got.
I've got one that looks like the big one but without the slot. I've got some blue ones. I've got some slightly heavier than the blue but smaller than the big one. And then I've got some really light ones. I think I'm going to put the one that is slightly heaver than the blue in the place of my one big one and see what happens.
Posted By: Chilort
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/20/10 09:58 PM
The slot in the spring with the slot in it is so large that it isn't even doing anything at full advance. So I'm going to put a somewhat light spring on.
Posted By: 68LAR
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/20/10 11:22 PM
Posted By: Chilort
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/21/10 01:17 AM
I've got some kind of noise and I don't think it is pre-ignition. Another friend thinks it is just the sound of the exhaust at that specific rpm because it goes away right away when I get into the throttle a bit more. The engine builder also suggested it could be the sound of the exhaust. I don't know though.
I swapped out for one range colder plug (the AutoLite version of the RC9YC4). That didn't make a bit of difference. I put the medium spring where the one with the slot used to be. Now my timing is all in by 3100 rpm (used to be 2400 IIRC) and it still makes the exact same sound at the exact same speed. I also tried backing the timing down again from 16/34 to 14/32 and it didn't make any difference other than the engine wanted to get a little warm in traffic.
Its gotta be something else. Right?
And I generally run 93 from Shell or something similar.
Posted By: dave571
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/21/10 02:12 AM
I've seen 9:1 alum motors ping when the dist is set up wrong. It's not uncommon at all
Carry on with your plan to bring in the advance slower, and see what happens.
Posted By: Chilort
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/21/10 02:28 AM
It is an auto with a bad setup for quench (pistons are .100 in the hole), which appears to be a great combo for detonation. Maybe I'll try the slightly stiffer spring tomorrow depending on rain.
Posted By: Viol8r
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/21/10 03:23 AM
A 9 plug is too cold for that set-up. I would think a 12 is closer. Keep in mind the winter gas is crap so be consersative and re-check early summer.
Sounds to me like you have something else wrong.
Posted By: RapidRobert
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/21/10 03:43 AM
unhook/plug the vac adv hose and see if it pings @ 16/32 or 18/34. If it stop pinging I'd go back to 18/34 (assuming the eng/cam likes 18 inital) and go more CCW on the vac can and probably need a can w a smaller #.
Holler back. Also what rpm is the mech all in at?
Posted By: Chilort
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/21/10 03:58 AM
It does the exact same thing at the exact same vehicle speed (like I said, no tach, I get rpm from the timing light when setup in the carport) with or without vacuum advance. I've tried several setups with the initial (18/36, 16/34, and 14/32) and get the exact same result at the exact same speed except that it likes to get warm with the low initial.
I think that it is something else at this point. I'm running Harland Sharp rockers and maybe I have too much side clearance on one pair (I tried setting them at 0.020 per set of rockers based on advice from a well respected individual here on Moparts), a bad lifter, or something like that. The sound to me is clearly from the passenger side of the engine (but I grew up on a farm around very loud equipment and have always liked loud engines and loud music and started losing some hearing a few years ago).
Posted By: dave571
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/21/10 05:41 AM
It could be that part of it is a mixture issue.
A quick look at the cam specs, if I was curving one for you, with that much gear, I wouldn't bring it all in till 3400.
You can do more initial, than where you are at. I think your starting at 18 was probably ok.
I think 18 initial, with 34 total(16 mechanical), all in by 3400 would be a good start.
Then do some plug reading, and see where you're at with your mixtures.
What converter are you using? that cam would seem to like around 3K or so.
Posted By: Dodgem
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/21/10 06:05 AM
tell us about the carb sounds like it me a lean knock???
Posted By: Chilort
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/21/10 02:57 PM
The carb is a Holley 750 (80508S). I don't remember what the stock jets were but I did go up a size or two.
Thanks for all the help. I may install a heavier spring in the dizzy this evening. But I likely won't get to test it out. I don't trust Atlanta drivers as it is and then add rain on top of that and it is a bad combo.
Here's a picture of a spark plug from when I pulled them out to replace them with the Autolites.
Of course, this is after driving it normally for a few miles while trying to test the effects of the things I've been doing and not a check after running it hard.
And the converter is a TurboAction - 17805S (10").
Posted By: dave571
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/21/10 05:32 PM
After a normal cruise, and that much cam, it should be a lot more brown than that.
Bump it two jets up on each end, after you do the timing mods, and look again.
Posted By: Chilort
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/21/10 05:45 PM
With that carb I can only change the primary (I think it is the primary) jets. It came with 70s and I put 72s in it. So I need to go with 74s?
Edit: I ran the picture of the plug by the engine builder and he likes the color. I've always heard it should be a little brown too but he says his "gas man" says the plug should be the same color as when it came out of the box.... my new Autolites are black, so, I don't think I want that.
(some things can be taken too literally).
Posted By: Chilort
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/22/10 04:03 PM
Changed out the spring I put in for the blue spring. Seems to come all in around 3500 now.
Now for the test drive.
Posted By: Chilort
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/22/10 04:45 PM
That is now very close. I can still barely hear it and it is much easier to make it go away with a touch more or a touch less throttle. I ordered a set of 74 jets and they should be here Monday morning (I thought O'Reilly kept jets in stock, guess not). Maybe the jetting will clear up that last little bit.
Posted By: CRE2004
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/22/10 09:16 PM
Quote:
It is an auto with a bad setup for quench (pistons are .100 in the hole), which appears to be a great combo for detonation. Maybe I'll try the slightly stiffer spring tomorrow depending on rain.
What made you decide to build it this way?
Posted By: Chilort
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/22/10 09:50 PM
Quote:
What made you decide to build it this way?
Pistons were in the block when I got it. The pistons were pert near new. I have no idea how long ago it was rebuilt but I've owned the block for over a decade before I tore into it. It looked like it had been run low on oil. We polished the crank, new bearings, new rings, pin fit the rods, and resized the big end and put it back together. I helped in the machine shop quite a bit to keep my bill down. I'm a student (though a rather old one). The goal was to keep the price as low as possible while also purchasing any long term parts that could be reused many times (i.e. rocker assembly, heads).
The next question is "why a 440 then?" or something along those lines. That is what was in the truck when I got it and was one of the reasons I got the truck. I got it about 3 years ago so my wife and I could work on our house without having to rent a truck or pay for delivery. I could have gotten something more reasonable but that wouldn't be any fun. When the crank broke in the truck in September I decided it was best to use the block I had in storage and save the one from the truck for later (still not quite sure what went wrong, I was following a Honda minivan on a ramp onto the interstate so you know I wasn't reaming the pi$$ out of it).
I use the truck frequently as a daily driver; use it to haul lumber, yard supplies, and occasionally new appliances; never use it on the strip; and some times use it to turn rice into rice crispies.
I also have a dog and cat.
Answering these kinds of questions really doesn't solve the issue or even help anyone really learn much. It is what it is man. But some people just gotta know I guess. 
Posted By: Pacnorthcuda
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/22/10 09:52 PM
Quote:
Pistons were in the block when I got it. The pistons were pert near new. I have no idea how long ago it was rebuilt but I've owned the block for over a decade before I tore into it. It looked like it had been run low on oil. We polished the crank, new bearings, new rings, pin fit the rods, and resized the big end and put it back together. I helped in the machine shop quite a bit to keep my bill down. I'm a student (though a rather old one). The goal was to keep the price as low as possible while also purchasing any long term parts that could be reused many times (i.e. rocker assembly, heads).
The next question is "why a 440 then?" or something along those lines. That is what was in the truck when I got it and was one of the reasons I got the truck. I got it about 3 years ago so my wife and I could work on our house without having to rent a truck or pay for delivery. I could have gotten something more reasonable but that wouldn't be any fun. When the crank broke in the truck in September I decided it was best to use the block I had in storage and save the one from the truck for later (still not quite sure what went wrong, I was following a Honda minivan on a ramp onto the interstate so you know I wasn't reaming the pi$$ out of it).
I use the truck frequently as a daily driver; use it to haul lumber, yard supplies, and occasionally new appliances; never use it on the strip; and some times use it to turn rice into rice crispies.
I also have a dog and cat.
Answering these kinds of questions really doesn't solve the issue or even help anyone really learn much. But some people just gotta know I guess.
What are names of the dog and cat? 
Posted By: macmic87
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/23/10 02:23 AM
i would put a vacuum gauge on the carb and go for a ride and see at what vacuum you get the knock and compare that reading to the value of the power valve you are using. maybe you just need to change the power valve to match your setup.
Posted By: Chilort
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/23/10 03:52 PM
I looked up some more detailed info on the carb and it has a 21 metering plate and that works out to a 75 jet for the secondary. Additionally, the power valve is 65 and that is very close to what I would get if I were to follow Holley's instructions for sizing a power valve (halve the idle vacuum then multiply by 10). A 55 would be close too but am I that far off with the 65 to cause this issue?
Posted By: Pacnorthcuda
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/23/10 03:55 PM
Quote:
I looked up some more detailed info on the carb and it has a 21 metering plate and that works out to a 75 jet for the secondary. Additionally, the power valve is 65 and that is very close to what I would get if I were to follow Holley's instructions for sizing a power valve (halve the idle vacuum then multiply by 10). A 55 would be close too but am I that far off with the 65 to cause this issue?
No. The difference in throttle between 5.5 and 6.5 inches of vacuum is VERY slight--look elsewhere.
Posted By: Wedgeman
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/23/10 04:21 PM
More infos for you..
I'm running in a 408 stroker 180 lbs cylinder pressure with RHS Iron heads .......not a sound.
Iridium plugs from NGK
Dan
Posted By: Chilort
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/24/10 06:23 PM
I went up to 74 jets today. Still has the same sound at 75mph with light application of throttle over what it takes to maintain speed on flat land. I checked the vacuum at which it wants to knock and it is 15inhg. The butt dyno has liked all of the changes so far and the 74 jets feel nice. Looking forward to checking the plugs.
Posted By: RapidRobert
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/24/10 06:36 PM
Quote:
Still has the same sound at 75mph with light application of throttle over what it takes to maintain speed on flat land. I checked the vacuum at which it wants to
Stick a 3/32" allen wrench in the vac can & turn it 3 turns CCW and retry it.
Posted By: Chilort
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/24/10 07:42 PM
Been testing all of this without the vacuum advance hooked up.
Posted By: Chilort
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/25/10 03:23 PM
Could this be a phasing issue? I've heard a lot about it but never really checked much into it.
Posted By: Chilort
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/28/10 01:06 AM
So I've got a few hundred miles on the colder plug with the increased jetting and it still doesn't look right to me.
I've got the total timing pulled all the way back to 32* and I've still got the same issue.
Thoughts?
Posted By: ireland383
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/28/10 01:15 AM
I'd say by the look of those the plugs you're getting oil in the chambers. Possibly via valley pan.
Posted By: Chilort
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/28/10 01:21 AM
No oil. Must be the photo. Additionally, It is a black plug and I use anti-seize when I install plugs.
Posted By: RapidRobert
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/28/10 02:16 PM
Quote:
Could this be a phasing issue?
Drill a 1/2" hole in the top flat of the cap 2/3 of the way between the center and the #1 terminals and freeze the rotor at idle w your light & see if it is way off and the rotor phasing at idle will be at it's maximum CW location (big block) from the high vacuum and less vacumm will shift it more CCW from there.
Posted By: Chilort
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/29/10 07:06 PM
Phasing looks to be dead on.
Edit: Never mind. Winner is ireland383. Sucking oil.
Posted By: Chilort
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/30/10 01:17 AM
Reinstalled intake with new gaskets and it still clatters under the same old conditions. I didn't pull any plugs yet. Too frustrated.
Posted By: RapidRobert
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/30/10 12:13 PM
Might hook a small gas can in the eng compartment w several gallons of race gas to the pump inlet & take her out to confirm/deny that the noise is pinging or something else. Good luck bro
Posted By: ireland383
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/30/10 12:33 PM
Could your clatter be valvetrain noise? At certain RPM'S I get a clatter. Just from the fast ramp of the cam.
Posted By: Chilort
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/30/10 03:28 PM
Quote:
Could your clatter be valvetrain noise? At certain RPM'S I get a clatter. Just from the fast ramp of the cam.
That's what I'm kind of thinking. Even though it is a hydraulic setup could I have put too much preload on the lifters? I think I may check the preload today or tomorrow. But I'd really like to eliminate the possibility of detonation before I give up.
I don't know where to get race gas or I'd do it today. I'll have to call the engine builder because he'll know where to get some locally. I'm not running an hour north of Atlanta to the "Atlanta" Dragway to get race gas.
I've got one more thing I'm thinking of but I don't know how it could be it. When I mated the engine and trans together the torque converter had just slightly more than 1/8" play, something like .150 IIRC. I called Paul Forte and he said all would be okay as long as the flex plate bolts weren't hitting the torque converter. It was really close. Maybe I'm getting just enough flex in something that its touching... seems far fetched though. Either way, I picked up some washers this morning and found a matched set of four to try out.
Of course my wife wants to go to an art's festival today so I'll have to suffer through that before I can try this out. 
Posted By: Chilort
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/30/10 11:30 PM
Well, it wasn't the torque converter spacing though I am now much happier with that even though Paul said it would be fine.
I guess now it is time to start into the valve train. I was told to run 20 thousandths clearance per set of rockers on the Harland Sharps for a street engine. And that's how I set it up. But I've also seen others say 15 thousandths. I think tomorrow I'll try to adjust the preload and the side clearance.
Posted By: Chilort
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 05/31/10 09:26 PM
I re-adjusted the side clearance and the preload on the valve train and it didn't fix the problem. I don't know where to get race gas in Atlanta so I bought some Lucas octane boost ... yeah, I know. And it didn't make the problem go away either.
I need someone with a lot more experience than what I have who wants to go for a ride.
Posted By: Chilort
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 01/23/11 12:25 AM
Okay, I finally got around to messing with this again (new job slowed me down). I bought the Mopar advance kit. It is really geared toward making things faster, not slower, and is essentially useless when you have less than 16* or so of total advance (the heavy secondary springs don't even kick in until 16* or so because they are slotted).
I tried the two heaviest primary springs in the kit and that made it come in faster than what I already had with some stuff sitting around.
So I went back to a heavy spring that I had and the heaviest black spring. That has it all in by about 3000 rpm. So the ping is just hardly there but it is still there. I've even bent the spring perches out a little bit.
I'm wondering if I can actually take one of the heavier secondary springs with the slot, trim the ends down, and bend it in like a primary spring or if the spring metal will let me even do that.
Also, after getting the initial setup, I'm running about 22* initial with this cam (used the intake manifold vacuum up to highest point then back down by 1 inhg). So I really don't have much timing to play with.
Thoughts?
Posted By: RapidRobert
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 01/23/11 12:40 AM
Quote:
Thoughts?
Lets get some race gas in it & see if it IS ping or not (I think it is ). We gotta narrow the prob down
Posted By: Chilort
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 01/23/11 12:51 AM
I think it is too for sure. I drove it around with the pair of black springs (just because) and the ping was much worse in terms of how much easier it was to make it ping.
I've yet to find race gas local.
Posted By: @#$%&*!
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 01/25/11 06:54 AM
Quote:
I think it is too for sure. I drove it around with the pair of black springs (just because) and the ping was much worse in terms of how much easier it was to make it ping.
I've yet to find race gas local.
Is there a chance your timing marks are off and all your numbers are off? I 'fixed' a 360 recently that had slipped almost 30 degrees 
Posted By: Chilort
Re: Mechanical advance too quick on Mopar Perf Dizzy? - 01/25/11 02:56 PM
It is possible. I did not confirm that the #1 piston was exactly at TD zero after I installed the damper.
But, I do know that the dizzy only has 15* of mechanical in it for sure because 1) it is just a difference between initial and total, and 2) I verified it with the little checking tool that comes with the dizzy kit.
The engine runs well with anywhere from 16*-23* initial. It seems to run best from 19*-22*. Those numbers are in the correct ball park for the cam.
Good suggestion though since it is an original damper.
