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Discussion Starter #81
Take a look at this link https://www.youtube.com/watch?v=SWC-sl0id30
This is my buick 350 when I couldnt figure out why it was running so rough. After talking to the cam manufacturer he recommended I double check to make sure the cam was degreed properly. Easy to do, even with the heads on. Only need a dial indicator and I made a degree wheel out of cardboard and a printed degree wheel I glued to the cardboard. It was 100% good enough to give me consistent numbers.

Turns out the cam was ground 4 degrees retarted and installed straight up ( dot to dot) and that was my issue. Especially since the manufacturer says this cam is recommended to be installed 4 degrees advanced... i was 8 degrees away from where I should have been. In my case I did buy a 9 keyway sprocket, however, Ive been told that's not necessary. If you know what you're doing, you can simply advance the teeth on the chains, just have to double check your work when you're done to confirm you are where you need to be with your adjustment.

After this adjustment the idle smoothed right out. Still have some carb tuning to do, but boy did this make a night and day difference.

POI the cam was manufactured by TA performance
So did TA performance send you a cam card telling you it should be installed 4 degrees advanced or did they just figure you were a mind reader? Did you degree it when you installed it? S#%&s that we have to do somebody else's job. I used to work in a wood moulding company way back, and would have to stop the moulders if it was spitting it out more than 1/32 bigger that spec. Well I got my cam etc from spotts. Gonna drop in a rebuilt distributor replacing one that has 50 plus years on it. And new wires. cap and rotor with brass terminals, and a new coil and nos points. Also bought a dizzy spring kit, just in case. Runs pretty good but all the parts I am replacing are about 12/13 years old. Time for a upgrade. See what happens. RM
 

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TA sent a cam card recommending installation between 0 and 4 degrees advance, yet the cam was ground off and the engine builder I went to didnt bother to degree the cam, just installed it straight up.
 

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Discussion Starter #83
New rebuilt distributor will require you to find out what the centrifugal advance is on that one.

Since you are buying the curve kit, take off the two stiff springs that come with it and put on ONE medium silver spring from the kit.

Recheck your total advance, same way. My guess, it will be 32 or so centrifigal, where you have 17 now.

If so you will need to use the brass bushing in the curve kit and put it on the post, usually will take 2 to 8 degrees timing out of centrifigal.

Say it takes out 6, then you will have 26 inside, the only way to know is with a test. Taking off a spring just saves you from having to rev the engine up so high.....

You do lean the mixture at higher altitude to keep the gas in the correct AFR ratio”, if you adjust the carb or the fuel injection to keep the mixture correct, say 13.5 at cruise,...timing just interacts with the correct mixture, just like it would at sea level

But if your mixture is too lean advanced timing is better for firing a leaner mixture, but a too lean mixture is very bad for your engine, creates heat and can cause detonation, and the detonation will cause heat and you get in a circle.

Are you in Colorado? Take your distributor over to Lars he will set it up for you, he is the best there is. Email him @ [email protected]

You are very close to having a real good runner there and good luck!
Dropped in rebuilt distributor nw points dwell set to 32,new cap,rotor,wires and coil. All flamethrower brand. The springs that came with the distributor were heavy duty, so for now I installed the two black ones from the kit. I tried one silver spring but would not return the advance. So my initial timing is now 30* with the vacuum connected and 10* without. Why so much? Is this where the bushing comes in? How does that install? Thought I would get your opinions before I go any farther.Thanks
 

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It means your vacumn advance can is giving 20 degrees advance real common, some give more but no good......

Remind me was this an HEI?
 

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Ok, you need to change that vac can get a standard motor parts VC 181...Rock auto has em

O’Reilly has em under a borg Warner number BWD V375....same can....$15 or so

It pulls the lowest at 16 but that is still too much on today’s gas........

Email Lars, I gave you is email before and buy one of his vacumn correctors, about $14...he will mail it to you with instructions.

The vac can is easy to change, wait until you get both parts then put em in....another $30 bucks I know but the running difference is way better.

Get your Centrifugal the same way as before, one spring off vac plugged ,..run it til it stops advancing....subtract the base you had when you do this...

Then you will know if you need the bushing or not...it goes on a stem inside a slot under the center cam of the dist....

Don’t get too far ahead....find out your centrifugal advance number first....
 

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Discussion Starter #87
Ok, you need to change that vac can get a standard motor parts VC 181...Rock auto has em

O’Reilly has em under a borg Warner number BWD V375....same can....$15 or so

It pulls the lowest at 16 but that is still too much on today’s gas........

Email Lars, I gave you is email before and buy one of his vacumn correctors, about $14...he will mail it to you with instructions.

The vac can is easy to change, wait until you get both parts then put em in....another $30 bucks I know but the running difference is way better.

Get your Centrifugal the same way as before, one spring off vac plugged ,..run it til it stops advancing....subtract the base you had when you do this...

Then you will know if you need the bushing or not...it goes on a stem inside a slot under the center cam of the dist....

Don’t get too far ahead....find out your centrifugal advance number first....
Can I just put the one off my old distributor? I think it was pulling like 12 or 13. In a prior post
 

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Can I just put the one off my old distributor? I think it was pulling like 12 or 13. In a prior post
Should be able to, just compare them to make sure they are the same and will attach in the same manner. I'd give it a try and if it does not work, then go the other route.
 

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Discussion Starter #90
Yes sure 12 or thirteen is good, do that, then check your centrifugal.....
I swapped them and no change. Makes me question myself if I got them swapped.:banghead:Is it possible it has something to do with the distributor itself? If not I will stick my old dizzy with new? vacuum advance.
 

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Well you may have your weights moving at idle speed adding some advance. Usually to weak springs do that or a very high idle speed.

Normal idle has range, but lots of these cars are 750 850 with stroked motors, factory idle 500, 600, 700..

But you said that you had strong springs, weights could be hanging up and adding timing. Read the number on your new vac can does it say 20? Often they are stamped with an advance number in crank degrees.

If the can reads 20 and adds 20....it is operating correctly but the wrong can to use.

Your old can and dizzy may be and sound like to me they are a mess,....I would stick with the rebuilt and use the can and corrector I suggested....you cannot make a car run better for that $30 spent anywhere

But remember the first thing is to find out your centrifigal advance in the rebuilt unit.....

Once you know it you will be able to tell if any centrifigal timing is coming in at idle.....and if your idle is way too high you have to turn it down
 

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Discussion Starter #92 (Edited)
Well you may have your weights moving at idle speed adding some advance. Usually to weak springs do that or a very high idle speed.

Normal idle has range, but lots of these cars are 750 850 with stroked motors, factory idle 500, 600, 700..

But you said that you had strong springs, weights could be hanging up and adding timing. Read the number on your new vac can does it say 20? Often they are stamped with an advance number in crank degrees.

If the can reads 20 and adds 20....it is operating correctly but the wrong can to use.

Your old can and dizzy may be and sound like to me they are a mess,....I would stick with the rebuilt and use the can and corrector I suggested....you cannot make a car run better for that $30 spent anywhere

But remember the first thing is to find out your centrifigal advance in the rebuilt unit.....

Once you know it you will be able to tell if any centrifigal timing is coming in at idle.....and if your idle is way too high you have to turn it down[/QUOTE the Ok, so I swapped vacuum advance again :confused and wa la... 10* with vacuum disconnected and plugged, 20* when its connected.:crazy:mad: 750 rpm
 

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OK, so now you are where you should be with the can swap. 10 degrees at idle with no vacuum, 20 degrees at idle with vacuum connected. Means the vacuum can gives you 10 degrees.

750 idle can be fine. You can tell by sound. An HP cam may need more idle than a stock cam.

Now check for total mechanical advance (vacuum disconnected) and at what RPM.
 

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Discussion Starter #95
Remind me again. Should I turn my timing light to let's say 45* and see at what degree it's all in, and at what rpm?
 

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You will be testing for TOTAL centrifugal timing....forget RPM’s that where everyone gets confused

Rememmber to remove one spring so you reach mechanical limit quickly.......

The weights will only go so far...they stop, .....Steel hits steel....once they fully deploy.....if you just checked it to a certain RPM you will be way off as more timing will still be in there most likely......

Set your light up to a high number...say 40 so you are in range and zero it on the mark when it STOPS advancing

What you are looking for is when the strobe STOPS advancing....no matter if you rev more it won’t go more....you can read on the tape or the light.....

Forget RPM’s here.....

When you get that number subtract the base you had....like 10 for the centrifugal advance number.

Only now will RPM’s matter as you set springs for when that mechanical limit is reached...

By just reving it to 3000 is no good as your springs may not bring it all in until 4800...
 

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Discussion Starter #97 (Edited)
You will be testing for TOTAL centrifugal timing....forget RPM’s that where everyone gets confused

Rememmber to remove one spring so you reach mechanical limit quickly.......

The weights will only go so far...they stop, .....Steel hits steel....once they fully deploy.....if you just checked it to a certain RPM you will be way off as more timing will still be in there most likely......

Set your light up to a high number...say 40 so you are in range and zero it on the mark when it STOPS advancing

What you are looking for is when the strobe STOPS advancing....no matter if you rev more it won’t go more....you can read on the tape or the light.....

Forget RPM’s here.....

When you get that number subtract the base you had....like 10 for the centrifugal advance number.

Only now will RPM’s matter as you set springs for when that mechanical limit is reached...

By just reving it to 3000 is no good as your springs may not bring it all in until 4800...
So I took off one spring vacuum plugged. And at 20* on the timing light it was at 0 on the timing cover.
 

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When you remove one spring, it should idle at 10 degrees base......then watching with your light rev it up until the STOBE stops advancing..

Forget the RPM’s here it makes no difference.....

Rev it a few times and make sure you know where the advance STOPS.....turn it off, subtract your base 10 from that number and you will have your centrifugal advance number....

Then you can see what is next......that number is the “sine qua non”.....the essential element...
 

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Use one or the other the tape reading advance or the light reading advance not both...

If you are idling at zero turn the distributor to 10 degrees advance....by the tape..your timing light set at 0......

That is 10 degrees advance now rev it with one spring and how high it goes on the tape...where does it stop going any further...

You should have no retarded timing below zero everything you are dealing with is Before TDC
 

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Was your base set at 10 degrees advance when you began? If it was something is wrong if it was set at zero still seems low.....

Set your timing light to zero,..and just read the advance off the tape, set base at 10 on tape both springs on.

Now shut off car remove one spring, the only thing you want to see now is when it stops advancing,...rev it up until that happens a couple of times...a helper is good here , and parking brake and chock the wheels..

You have to aggressively rev the car up, but the particular RPM is not important here....try again and double check, you are close....
 
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