PDA

View Full Version : Per Request - HEI Advance Timing Weights



David O
02-26-2004, 08:57 AM
These are the weights and cam that come in the Moroso HEI Advance Curve Kit. See Photo
These are the instruction that come with the kit. See photo

Assuming the weights in my distributor are installed correctly then following the instruction would be simple but if one want to verify the correct installation of the weights, the instructions are of no use.
My question is, does anyone know of or have a diagram or know for a fact how to install these properly in a standard rotation Chev 350 HEI distributor?
The instructions say you can flip the cam for a counterclockwise rotation. Flip it from what, I wonder?
I have shown 4 different combinations of arranging the weights.
Another question was from looking at the spring info in the instructions what spring would one want to use and why?
Next question was, the instructions say to unhook the vacuum line while setting the timing. Well I don't have one. Is one needed and if so why and what does the vacuum do for you?
David O
Please do not reply using my e-mail address or private messaging.

MOP
02-26-2004, 09:15 AM
Boy you must be busy it took you long enough to post this stuff, one of the young Lions will get it straight for you :lightning

Rootsy
02-26-2004, 09:16 AM
David,

with the current setup installed and the cap off... turn the motor over and note direction of rotor rotation. grab the rotor and see which way it moves. this is the advance working. it should advance in the same direction as rotor rotation. when you install the new cam and weights it should actuate in the same direction as the rotor turns with the engine turning over. by flipping the cam stop plate, etc it allows the advance to go the other direction, for a reverse rotation motor causes the rotor to rotate in the opposite direction. see what i am saying?

as far as the advance... i'd start bringing it in about 1200 rpm (unless you are running some big bumpstick that requires a rather high idle).. have full advance by no later than 3500 if possible (whatever spring combo this is). run as much initial advance as you can and then adjust the mechanical advance in the distributor to achieve your total advance. which will very likely be 36 degrees or less.

as far as the vacuum advance... this is often used on automobiles. the engine vacuum pulls on a diaphram in the distributor housing which actuates the mechanical advance.. .this is commonly referred to as vacuum advance... it comes into play when cruiseing in your car for after you accelerate and unload the motor after achieving cruising speed... since the motor is under much less load at cruise (steady state - say crusiing speed- speed in a car doesn't require a whole lotta hp to maintain)... the vacuum climbs and actuates teh advance to improve cruise economy... on a boat it doesn't really have an effect since for each given rpm the vacuum declines in kind of a linear fashion until WOT when if you have no intake restriction the vacuum should be at or near zero... the vacuum will be highest at idle.. therefore your vacuum advance really isn't doing a whole lot for ya...

does that help any?

Jamie

David O
02-26-2004, 09:28 AM
with the current setup installed and the cap off... turn the motor over and note direction of rotor rotation. grab the rotor and see which way it moves. this is the advance working. it should advance in the same direction as rotor rotation. when you install the new cam and weights it should actuate in the same direction as the rotor turns with the engine turning over. by flipping the cam stop plate, etc it allows the advance to go the other direction, for a reverse rotation motor causes the rotor to rotate in the opposite direction. see what i am saying?

I think I will as soon as I do all the above.


does that help any?

YES YES YES
Thanks Jamie

David

MOP
02-26-2004, 09:41 AM
Damn Jamie though we don't use them anymore you have 6 stars in my book! I got him as far as I could with my dusty old brain shooed him off to the board for the tech stuff. I have not done cures, ground weights etc in a very long time, looks like I will be having to get refreshed for the 22.

Thanks Guy!

Phil / MOP

Greg K
02-26-2004, 11:35 AM
Assuming you have a Chevy motor you're working on, the distributor is going to rotate clockwise in this firing order, 18736542.
The bottom right configuration in your photo is correct. As shown in the figure I have attached.
Plan on some trial and error in getting your initial and total advance timing set.
Initial Timing:
The general rule is to run as much intial advance as you can, (without making starting impossible), and make full throttle runs with various spring rates, (you can mix springs without hurting anything and actually advance the curve in steps). This should be done with no vacuum advance hooked up at all. 12-14 degrees should be a good starting point.
Overall Timing:
Don't set your timing with initial advance only. This tells you nothing about the total advance which is near or where the advance is while the engine is running at speed. For some reason a lot of people seem concerned about initial timing. It has virtually nothing to do with performance. The measurement you should focus on is total timing advance and the advance curve. You want as much advance as you can get, coming in at the lowest RPM possible without detonation. Total advance ought to be between 32° to 36° for most any performance engine. You can start off with the light springs and see what the total advance comes up to. I also would run the motor 4000-5000 rpms as well to make sure it's not advancing anymore as another check.
Also, making sure the distributor is installed so that the rotor is pointing to the number one cylinder once you have the motor at TDC for cylinder #1. Might take a few stabs to get it close, once you do you can rotate it slightly to get it right on.

David O
02-26-2004, 05:38 PM
Greg
Copied below is all my correspondence with Moroso and their replies. They were no help as you will see. I had to send them a copy of their own instructions and I sent a photo of how I thought maybe the weights should be positioned. They agreed the positioning in the photo was correct. I have been trying to get the photo I sent to attach with this post and I can't get it to happen. Since posted originally The photo I sent them showed the weights positioned as is in the top left of the photos with the first post of this thread. totaly different from what you or the diagram shows. I can tell based on the shape of the center cam, it would be very important to have it correct.
The diagram you sent and the positioning in the photo with my original post that you make reference too as being the correct one, is not the same as the one I sent them and they said was correct.
As you will see they were of no help.

SOME HOW I TRUST YOU AND NOT THEM.
Headed to the house to see how it is in the distributor.
THANKS BIG TIME

COPY OF
What I wrote to Moroso asking for help.

----- Original Message -----
From: David Owsley
To: techhelp@moroso.com
Sent: Tuesday, February 24, 2004 3:56 PM
Subject: advance curve kit

I bought a 72300 HEI curve kit today and need to see how it all goes together for a clockwise verses a counter clock rotation distributer.
I do not trust the one I am replacing to be installed correctly therefore following your instructions to put the new one in the same way the old one comes out may only repeat something that is incorrect already.
Could you please tell me where I may view a diagram of the kit installed correctly in the HEI 140003 distributor I have?

David Owsley
850-438-0050
850-432-8631 fax

THEIR REPLY

-----Original Message-----
From: Moroso Tech Service [mailto:techhelp@moroso.com]
Sent: Tuesday, February 24, 2004 3:08 PM
To: david@sdace.com
Subject: Re: advance curve kit

We do not offer a picture of the kit installed. The kit will not work on a reverse rotation engine.

MY REPLY

"We do not offer a picture of the kit installed. The kit will not work on a reverse rotation engine."

Interesting comment since your instructions say you can reverse it for counterclockwise distributors. See attach photo "Kit instructions.jpg"

Also attached is a photo of your kit. See attached photo "advance kit.jpg" and tell me if I have the center plate and weights laid out correctly for a standard rotation chev 350.
Thanks again

Now you have a photo of what it should be installed like if I did it correctly.

David Owsley
850-438-0050
850-432-8631 fax

THEIR REPLY
-----Original Message-----
From: Moroso Tech Service [mailto:techhelp@moroso.com]
Sent: Tuesday, February 24, 2004 3:35 PM
To: david@sdace.com
Subject: Re: advance curve kit

The instructions are incorrect we have not made the change yet. Your orientation is correct

David O
03-01-2004, 08:15 AM
Greg the new ones are in per your instructions. If it worked I have attached two photos showing how the old one were compared to the new install.
I hope I did it right.
THANKS
David

BUIZILLA
03-01-2004, 08:46 AM
Did you install any of the limit bushings? When you flip the center shaft against the gear play, do the weights clear the center pivot arm? or do they hit when expanding?

J

David O
03-01-2004, 09:08 AM
Did you install any of the limit bushings? When you flip the center shaft against the gear play, do the weights clear the center pivot arm? or do they hit when expanding?

J

Lost me on those questions!!
In the kit there were the blue bushings and the black ones. I could not find anywhere to put the black ones so I assumed they were for different makes of HEI distributors. The Blue ones fit perfectly in the weights and around the pivot shaft. As you can see from the instruction, they are not much help.
Now where and what bushings and shaft are you talking about?
David

Rootsy
03-01-2004, 09:46 AM
David,

the stop bushings dictate how much mechanical advance the distributor has. The blue ones and the black ones allow different amounts. If the blue does not provide enough or provides too much you remove and put the black ones in. without knowing what each gives you in DEGREES it is ahrd to tell which you need.

the whole advance thing goes like this

INITIAL ADVANCE + MECHANICAL ADVANCE = TOTAL ADVANCE.

Initial is what you set with the timing light at idle

mechanical is what the distributor provides with the stop bushings - the rate of advance is dictated by the springs you have installed

total advance is the two added together.

here is MSD's tutorial on their HEI distributor... they make reference to blue and black bushings and springs and what not but don't trust that for your kit is from someone else... this is just for reference

http://www.msdignition.com/pdf/pn8365.pdf

Greg K
03-01-2004, 10:09 AM
Just a note, David doesn't have a MSD HEI distributor. MSD is the only one who uses those types of bushings. Stock type HEI's do not have this type of arrangement.

Rootsy
03-01-2004, 10:45 AM
ahem,

notice the last sentence or two of my post...

;)

BUIZILLA
03-01-2004, 10:50 AM
Okay, i'm lost. If MSD is the only one with those bushings, then why does David have to use bushings on a stock HEI, like a see in the picture, that he in fact did use? Some of the HEI's had a stepped pin on the weight guide, some did not... apparently his new weights are for a stepped pin HEI so he used the weight bushings.

Now, did he, or didn't he, use a new limit bushing was my original question?? Judging from the new vs. old weights used in the picture, he is going to end up with a TON more advance than he wants, going by the design of the full travel weight stop ears. In fact, if you blow up the pic (I did) and study the relationship of the center guide to the locked advance plate, you will see that the static base timing already is already visually different due to the design of the new weights. He may end up with 45*-50* of full advance.

J

why is there saran wrap on my Sun machine...

Greg K
03-01-2004, 11:16 AM
Okay, i'm lost. If MSD is the only one with those bushings, then why does David have to use bushings on a stock HEI, like a see in the picture, that he in fact did use? Some of the HEI's had a stepped pin on the weight guide, some did not... apparently his new weights are for a stepped pin HEI so he used the weight bushings.
Bushings in his kit were for the weights to fit the pins.



Now, did he, or didn't he, use a new limit bushing was my original question?? Judging from the new vs. old weights used in the picture, he is going to end up with a TON more advance than he wants, going by the design of the full travel weight stop ears. In fact, if you blow up the pic (I did) and study the relationship of the center guide to the locked advance plate, you will see that the static base timing already is already visually different due to the design of the new weights. He may end up with 45*-50* of full advance.

He'll definitely have different timing with the new advance kit and will have to reset it. From my experience with most advance kits for stock HEI's, the most advance you can get is 22-24 degrees (not including MSD's) plus intial without a stop. It's possible though, that's why I will check all the way up to 4500+ rpm to make sure what I'm getting.