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  #151 (permalink)  
Old 02-10-2010, 02:34 PM
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lol, if it were not for guys like me, what woould ya be doing?
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  #152 (permalink)  
Old 02-10-2010, 04:10 PM
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I went ahead and tried to find TDC by myself and just couldn't do it. I installed a temp remote switch outside and removed #1 plug. I could get it close, between indicated TDC and 8 before TDC is where it typically landed on its own. The bad part is that the power steering fluid container, headman header and steering shaft prohibited me from holding a pencil and turning the crank at the same time by hand to confirm TDC. However, I doubt it is 10deg off. If any maybe 4deg but if all else said, I bet it is TDC on mark. However, I will check later when I can get some help and dry ground to work from! The wet muddy ground, even with a piece of cardboard to lay on, at 44deg temp doesn't help either....lol

Ya gotta love it!
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  #153 (permalink)  
Old 02-10-2010, 05:37 PM
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Quote:
Originally Posted by Blue84JeepCJ7
I went ahead and tried to find TDC by myself and just couldn't do it. I installed a temp remote switch outside and removed #1 plug. I could get it close, between indicated TDC and 8 before TDC is where it typically landed on its own. The bad part is that the power steering fluid container, headman header and steering shaft prohibited me from holding a pencil and turning the crank at the same time by hand to confirm TDC. However, I doubt it is 10deg off. If any maybe 4deg but if all else said, I bet it is TDC on mark. However, I will check later when I can get some help and dry ground to work from! The wet muddy ground, even with a piece of cardboard to lay on, at 44deg temp doesn't help either....lol

Ya gotta love it!
Pencil, what pencil?

You need to take as much of the ancillary equipment off the engine as you need to get a clear shot at the crankshaft. You attach a degree wheel to the crank, this is not a tape on the damper but a calibrated measured tool you can get them from any brick and mortar or web speed shop along with a positive piston stop. The positive piston stop is a steel gadget that looks like a sparkplug shell with a bolt in it. You'll need some sufficiently stiff wire, coat hanger works if your careful not to hit it when turning things.

Remove the pulleys, damper and timing case cover. Reinstall the damper then degree wheel and a washer, install the damper bolt and torque it to spec. Take a length of coat hanger make a tight loop on the end that will over hang the degree wheel. Take the other two ends and make a bolt loop on each. Select two good nearby bolts, usually a pair of the timing cover bolts. Remove the valve cover over the number six cylinder's rockers. Wrench the engine over in it's direction of normal rotation (clockwise when viewed from in front) till the crank is about 20 degrees before the TDC mark of the damper and number 6 is ready to fire, (both valves closed). Install the the positive stop in either #1 or #6 and adjust it till it contacts the piston, this is nearly TDC on firing for number 6 (you'll see why I choose 6 on a Chevy and not 1). Write the number from the degree wheel that the pointer is facing on a piece of paper. Rotate the crank backwards till it hits the positive stop again. Read that number and write it down. Half way between those numbers is true Top Dead Center. Remove the positive stop, rotate the degree wheel to the computed number turning the crankshaft in its normal direction of rotation. You can reinstall the positive stop and adjust it to the piston if you wish. The timing gear pip marks better damn well be pointing at each other with the crank pip at the 12 O'Clock and the cam gear pip at the 6 o clock position (easy to see, instead of both at noon as firing number 1) as this is TDC on number 6's power stroke. You can check distributor alignment from here as well.

With a dial indicator on a solid checking lifter (that to remove any hydraulic delay from a hydro lifter) and a cam timing card, you can use this set up to see if the lobes are actually synched with the crank.

The root possible problems are:

- That the timing gears and chain have worn or aren't installed correctly and the pip marks don't align.

- That the damper marks are off.

- That the cam's as ground position isn't aligned with the timing gear's installed position. This happens more than you might think.

- Certainly you'll see if the distributor's rotor aligns to the cap and whether its cam or pulse wheel aligns with the points or sensor.


Bogie
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  #154 (permalink)  
Old 02-10-2010, 06:05 PM
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The methods mentioned above are fine for degreeing a cam- if that's what is desired. However, a degree wheel isn't necessary for locating TDC. Nor is a timing tape- homemade or otherwise.

But if- after verifying TDC w/what ever method is chosen- a timing tape is attached to the damper and/or a mark is scribed onto the damper to match the tab or vice versa, TDC can be located for use as a reference for setting and checking the ignition timing- the reason for the suggestion in the first place.

Now, if the cam's thought to be out of phase after checking/verifying TDC and the ignition timing, by all means, invest in a degree wheel, dial indicator, etc. to properly check the cam and timing set for correct installation. You will want to have the cam card info on hand for this.
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  #155 (permalink)  
Old 02-10-2010, 07:19 PM
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Cobalt, I agree. I was simply checking to see if the timing mark was close, which it was.

Like Red said, if it ain't broke.....!
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  #156 (permalink)  
Old 02-11-2010, 06:26 AM
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lol,
you "did" remember to disconnect the vac adv hose when trying the new light right???
(those are the kind of "dumb sh##" mistakes that make great stories to tell,,we all do them ,,,totally focused on one thing and blank out everything else)
a favorite for "me":
I hand made a complicated dash radio bezel,,,,carefully installed it for dead center and level,,,,sat back and said "wow that really does look good",,,,,looked again and saw (dumb sh##!!!!) I had mounted the radio up side down!!!!

clarification?:
use a long breaker bar and socket to "hand" turn the crank watching for the mark/pointer alignment at TDC
wooden pencil= (use it as a dial indicator if you can't do both at once),,,make marks on the pencil nudging the crank forward starting btdc thru atdc,,,only one mark will be the shortest location on the pencil length=TDC to then look at the pointer/damper alignment....

Darn easy to mis-interpete instructions (ex: is it a setting for 4 cylinders or for 4 cycle on the light?)(they keep adding capabilities to IC chips devices faster than anyone can keep up with or even likely want!!!!)
so,,,
stop by the garage and compare readings before checking the pointer,,,(you can confirm the pointer is dead on correct when ya do the cam swap)

just a comment:
buy a long block from a high volume elcheapo rebuilder,,,DO check the pointer/damper mark/TDC before install

Old Bogie's post can/will apply when the new cam goes in!!!!!

cobalt,
lol, using a tape to correct for the pointer is cheating!!!
ya gotta' spend a whole afternoon making a new correct custom "pretty" pointer from scratch!!!
or spend days reseaching to find what damper is marked correct for that mounted pointer...

blue,
LOL,,
I think you now hold the record on this board for the most whacko/weird/impossible readings values in a single thread.....
(you now have more than that 312 Ford dist thread from awhile back)

I post to excercise my brain,,,you sure are giving me a work out!!!
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  #157 (permalink)  
Old 02-11-2010, 06:57 AM
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Quote:
Originally Posted by Blue84JeepCJ7
lol, if it were not for guys like me, what woould ya be doing?
We're all here, because we're not 'all there'!
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  #158 (permalink)  
Old 02-11-2010, 04:17 PM
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lol, you guys crake me as much as I do you I'm sure!!!


Well, the light works fine and the vac adv has been discoed and pluged for now. This new light is great with the RPM reading and timing buttons on hand!!!

Ok, back to where I started. I set the initial to 16 and got 40 something at 3,000rpm I just cant remember now. Anyhow......

I reset the total at 3,000 rpm to 39deg and got 11.9 for idle initial. Problem is that it don't run good like that. It hesitates when I accelerate from a stop to about 25mph. Hard to explain that one.

Put it back to 16 and it runs like a dream but now the total is way back up there again. I put it on 13deg initial and will see what it does in the morning.

My brain hurts!
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  #159 (permalink)  
Old 02-11-2010, 05:13 PM
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Quote:
Originally Posted by Blue84JeepCJ7
lol, you guys crake me as much as I do you I'm sure!!!


Well, the light works fine and the vac adv has been discoed and pluged for now. This new light is great with the RPM reading and timing buttons on hand!!!

Ok, back to where I started. I set the initial to 16 and got 40 something at 3,000rpm I just cant remember now. Anyhow......

I reset the total at 3,000 rpm to 39deg and got 11.9 for idle initial. Problem is that it don't run good like that. It hesitates when I accelerate from a stop to about 25mph. Hard to explain that one.

Put it back to 16 and it runs like a dream but now the total is way back up there again. I put it on 13deg initial and will see what it does in the morning.

My brain hurts!
Don't over think this thing. I think you're nearly there!-

Just remember: The initial can go where the heck it "wants" to be- 16 degrees, 18 degrees, whatever. You are fine that way! Just as long as you compensate for the initial by backing off the TOTAL (less vacuum advance, as always) to keep it around 36 degrees total, to avoid detonation at WOT.
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  #160 (permalink)  
Old 02-11-2010, 05:31 PM
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Oh, is it ok to use 3,000 as WOT? Everything should be in by then right?
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  #161 (permalink)  
Old 02-12-2010, 06:20 AM
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cobalt,
thanks for the hearty chuckle....
I will remember your "George Carlin" comment above forever!!!!

blue has 24*c total in that dist right now,,,he's posting just mech so 16b+24c=40t all in

blue,
we have proven six ways from Sunday that you do have a relatively big cam and they do have to have more initial base timing....
(go waaaaay back to around post 5? and read the tuning article link I posted)
my guess, your cam probably want's 18b to be really "perky" driving normal...
(but you are at 40t already!!!!)

your choice:
(my $.02)
Chebbie's can handle 16b+24c= 40t WOT but wise to burn premium due to the tall gears and tall tires = huge load on the motor....
(basically just don't constantly beat the sh## out of the motor till the cam gets swapped and it will be fine)
for light-medium throttle driving 16-24-40 is totally totally fine....

or,,,

you can re-configure/change the centrifugal advance plate in the dist to be in the max 20*c added locating holes?/pins?/stops?** position...
(**damn CRS=I can't recall what I did read in your instructions sheet for how to change cent,,,find that link please)
in order to have more "peace of mind" at 16b +20c = 36t WOT till the cam does get swapped which will then use less base (about 12 for a RV duration cam)

re:vac adv
big cams need all the help they can get for normal driving and IDLE Hg!!!
it's only <5 minutes to adjust the new vac unit hex screw to add 6-8* to the base...
rephrase for the post way back?:
timing light hooked up/base at 16/plug in the new unit to manifold vac and read the new timing total to see where was it adjusted to at the factory (probably 10 so idle base now reads 26)/turn it one full turn counter clockwise and if it only adds say 4 to the 16,,,turn it clockwise a 1/2 turn = done = "plenty good enough/close enough" till the cam gets swapped...

LOL,,,you WILL get to adjust those idle mix screws again and rpms linkage screw that you "love" to play with by adding vac adv...

(it is possible, with help from the vac adv you may be able to back off the base a couple of degrees for 36-38t and still have very good performance,,,only a test drive can tell)

PS
I WOULD use the vac adv with the big cam right now because it does have a "stabilizing" control influence on all the cent parts movement...
(helps control any slack due to worn dist body parts and adds/subtracts movement resistance as cent goes up and down )

PPS yup, all in at 3k is fine (because your cruise rpms are so low)

just a comment:
agree,,,,on a strip only race motor you don't care where the base falls,,,you only need to know best high rpms timing....
cams do have a recommended base timing range (based on duration) to work best below the TQ peak rpms which is the normal street driving rpms range...

Last edited by red65mustang; 02-12-2010 at 07:00 AM.
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  #162 (permalink)  
Old 02-12-2010, 08:38 AM
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Quote:
Originally Posted by Blue84JeepCJ7

Well, the light works fine and the vac adv has been discoed and pluged for now. This new light is great with the RPM reading and timing buttons on hand!!!

Ok, back to where I started. I set the initial to 16 and got 40 something at 3,000rpm I just cant remember now. Anyhow......

I reset the total at 3,000 rpm to 39deg and got 11.9 for idle initial. Problem is that it don't run good like that. It hesitates when I accelerate from a stop to about 25mph. Hard to explain that one.

Put it back to 16 and it runs like a dream but now the total is way back up there again.
I wasn't going to jump in here because you have gotten very good suggestions already. However, you are over complicating your timing situation and this is shown by the results you have so far.

The "all in" RPM for the timing can be adjusted by swapping out the advance return springs. The "all in" RPM will be best if kept between 2500-3000 RPM. I have found that using one light and one medium spring will yield the "all in" RPM close to the 2500 figure.

The maximum timing with NO vacuum advance added should be around 38 degrees. I don't remember if you are running Vortec heads, but if you are, then the maximum should be around 34 degrees. You can control this by limiting the available travel of the advance plate. This is done sometimes with inserts and sometimes by welding up a small portion of the slots.

Because of the cam you are running, the initial timing should be around 16-18 degrees. I suggest the 18 degree setting.

You should also be using FULL manifold vacuum advance. Adjust it so that you limit the amount of added vacuum advance to 10 degrees.

The hesitation you are getting could be because the timing is off OR because you need additional pump shot. Set your timing first. With the engine at "normal" operating temps, perform an acceleration test from a stop. If you experience any hesitation, I suggest that you go up two sizes on the squirters (Holley, Demon or similar carb) or adjust the accelerator pump linkage for an Edelbrock style carb.

Your initial timing should be checked at or below 800 RPM to insure that no centrifugal advance is being introduced.

The timing should always be set with the vacuum advance dis-connected from the vacuum cannister and plugged off. Checking as to where the timing is with the vacuum advance connected is for reference only. This is because there is '0' vacuum when going to WOT and other than when at idle or cruise RPM the amount of vacuum will vary.

After the timing has been set, re-connect the vacuum advance hose. The timing will advance and the idle RPM will also increase. Lower the idle RPM so that it is at or below 800 RPM in DRIVE if an automatic or in Neutral if a standard shift. If you have an automatic trans, be sure to have the parking brake engaged, the wheels blocked, and even have an assistant with their foot firmly applied to the brake pedal when checking the idle RPM in gear. Do NOT rev the engine when checking/adjusting the idle RPM while in gear.

To check your timing marks as to TDC. Remove all the sparkplugs. Install a piston stop in the #1 cylinder. Rotate the engine by hand in a clockwise direction until you feel it contact the stop. Make a temporary mark on the damper where the pointer shows '0'. Now rotate the engine counterclockwise until you feel contact with the stop. Make a second temporary mark on the damper where the pointer shows '0'. Remove the piston stop. Halfway between the two temporary marks will be TDC. Make a permanent mark at that point. When that point is lined up with the '0' mark on the pointer your engine will be at TDC.

After the timing has been adjusted you can adjust the carb for the air/idle adjustment. Hook up a vacuum gauge to FULL manifold vacuum source. Slowly (1/8th turn at a time)adjust the air/idle screws to achieve the highest vacuum reading you can get at idle. The air/idle screws should end up being very close in their respective adjustment to each other.

Best of all, ENJOY!!!
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  #163 (permalink)  
Old 02-12-2010, 09:06 AM
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Frisco thanks for that added info.

Just a reminder to all, here is what I have

350 casting #10066036
Head castings #33417369
Stock stamped rockers
Reported mild cam and lifters
Edlebrock 2701 manifold
Headman (in frame for CJ-7) Headers
Edelbrock 1406 carb
Accel 71100E distributor (24c)
MSD #8202 coil
Be Cool radiator

Unknown pistons, cam chain etc.

Adjusting the vac adv the other day with the hex screw, all I could get was 2 degrees advance. Suppose to be able to get 10deg. So for now I have it plugged until I get a good setting for now. In the future I can make major changes, ie cam, or gears etc, maybe later on in the year.
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  #164 (permalink)  
Old 02-12-2010, 10:49 AM
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Quote:
Originally Posted by Blue84JeepCJ7
Oh, is it ok to use 3,000 as WOT? Everything should be in by then right?
My reference to WOT is just that the timing must be no more than about 36 degrees total- this will avoid detonation at WOT, regardless of any other ignition timing settings.

As for the centrifugal timing being all in by 2500-3000 RPM- that is what you should aim for. Conditions may vary, however. This could be as soon as 2200 RPM, or as late as 3400 RPM, depending (these figures are arbitrary, BTW).

Quote:
blue has 24*c total in that dist right now,,,he's posting just mech so 16b+24c=40t all in
I understand that.

He has got to remove some of the centrifugal advance from the distributor. 40 degrees total is too much advance- I know of no OEM SBC heads- even the worst smog-era heads- that require 40 degrees. Even if it's not pinging like crazy, the power is very likely to suffer. 36 degrees will be much more forgiving as far as pinging under load, as well.

Remember your too much of a good thing, thing? Well, this is just such a case, IMHO.

Quote:
Adjusting the vac adv the other day with the hex screw, all I could get was 2 degrees advance. Suppose to be able to get 10deg.
As for why the vacuum can is not supplying more advance, it would seem that it is either defective or there's binding taking place in the plate or linkage.

If you were to remove the vac. can and apply vacuum to it, does it retract the linkage and hold vacuum if it's plugged? If yes on both, there's a problem in the alignment, linkage or plate causing it to not be able to add advance as it should.

As for Frisco's post- I agree w/it in its entirety, for what that's worth. And thanks for putting it all together, too. Good job, that.

Edit- I did not intend to belittle Red Mustang's extensive contributions w/the above observation- I apologize if it came across that way...

Good job on it all!

Last edited by cobalt327; 02-12-2010 at 11:08 AM.
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  #165 (permalink)  
Old 02-12-2010, 11:18 AM
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Frisco,
thanks!!!

blue,
Frisco pointed out something important that I never mentioned you must always do....
(thread is now so long I have forgotten about everything I have posted)

you can either
set the base with the motor at the lowest rpms where it will still run (ignore the very rough idle it doesn't hurt anything) by backing off the idle linkage rpms screw then turn the rpms back up with the linkage screw once it is set
or
set the base at your normal idle rpms and then back off the idle rpms linkage screw to the lowest rpms possible till it barely runs (ignore the idle) and check to confirm with your light that it is still the same base setting
(to confirm there is no cent added at idle rpms)

PS: give the whole cent advance parts a shot of WD40 and double check that the wire leads have enough slack for full cent travel...

edit:
cobalt, no question 40 is to much,,,but with premium gas and his low CR it will "survive" till the cam change,,,(I have been preaching use 36 same as you all the way thru this thread)
LOL,,,I have a "belittled brain" so why not belittle it

Last edited by red65mustang; 02-12-2010 at 11:44 AM.
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