ok guys... timing question

[maglinjosvinn]

got my vac issue solved. car fires right up, advance is clearly working and everything, but i got **** for power.

i figure its either the tappets, or a timing issue, but i got a car shop right next door that will do the timing for free, he just needs the 'how to' on it, so he has all the right numbers.


problem is at this point i don't have a resource for getting the timing right! lol. i mean, i know the points are .018, and they already are, the plug wire order is right (drove it here), i can see the dot moving on the flywheel and advancing when you rev, but i don't know the dwell settings, timing mark settings, and the conditions to get them all right.

so. from the very begining, i'm timing tuning and getting this engine right. what do i do, step by step?

[Anonymous D]

Complete Tune Up Guide, located under "June 2006" (in 2 Acrobat downloads), is here:

Engine

[maglinjosvinn]

ok. got my hands on it. but it doesnt' say spit about where to set the advance to at what rpm... or even a blurb on what RPM you should check the timing at even.

so, if i got the car running at 1100 rpms, how much advance should be on my timing? or if its running at the, what, 3500 rpms? it advances how much? but won't advance further?

i can't find solid information here or on the web about these questions.

[jvandyke]

From memory, block all vacuum lines to dist. Get idle to about 800/900 loosen dist. hold down bolt, point light at flywheel/ball behind exhaust manifold, twist dizzy until ball is in line with pointer, tighten, recheck. Done. Reattach vacuum lines. Drive (quick while it's warm in Michigan in Jan.!)

[maglinjosvinn]

whats the vac guage supposed to read and at what RPM?

[Anonymous D]

Factory specs are to set timing at zero degrees at #1 TDC. This means installing the distributor so that it's in the correct alignment (using the cam sprocket mark and flywheel ball mark as indicators), and using a timing light for more precise adjustments. An engine compression check of each cylinder, can also indicate if the engine is worn (or if a valve is mis-adjusted), which can be relevant as increased vacuum will assist the distributor vacuum advance unit too.

[maglinjosvinn]

Originally Posted by jvandyke From memory, block all vacuum lines to dist. Get idle to about 800/900 loosen dist. hold down bolt, point light at flywheel/ball behind exhaust manifold, twist dizzy until ball is in line with pointer, tighten, recheck. Done. Reattach vacuum lines. Drive (quick while it's warm in Michigan in Jan.!)

ok, so i reconnect the lines, obviously, the ball is going to move. how much? above or below the pointer?

[jvandyke]

If I understand it correctly, when you reattach the vacuum advance line it will advance the timing a bit during idle only (there's vacuum at idle) as soon as the carb starts to open that vacuum is gone and you're on mechanical advance. Do you suspect vacuum adv./mechanical adv. not functioning correctly? Set initial timing as above and go for a ride, see how she goes. You can watch the ball move as you rev the engine, timing will advance up until about 3500 rpm than that's it (I think). Total mech advance is 32 degrees or so, different per year, I don't know, I'm pulling this out of my head.

[namba209]

O.K. according to my Chilton's or Haynes, I can't tell, the dogs ate the covers, Idle RPM is 850-900 standard tranny, 800-850 auto tranny. Dwell angle is 50 +/- 2 degrees. Total advance is 43-55 degrees @ 2500 RPM. Centrifugal advance starts at 800-1100 RPM, 17-23 degrees @ 1500 RPM and 31-37 degrees @ 3200 RPM. Vacuum advance, starts at 800-1100 RPM and maximum is 31-37 @3200 RPM. It will be impossible to tell where the advance peaks at, because there are no advance indicators on the flywheel. The only way to tell for sure what the advance will be is to mark the flywheel as Jeff Denton has suggested in earlier threads, or put the distributor on a machine, that can check the mechanical advance curve. HTH.

[maglinjosvinn]

.. ok. face value looks good.

why is there a vac advance at all then? lol. sounds like the mechanical advance takes care of all the BS while ... hell ... almost all times.

and yeah. car idles like a dream. starts right up. vac lines all nice and sealed and new. sprayed every inch of them with carb cleaner and the gt never missed a beat.

i just don't have power when i rev it up, she acts like she's missing like crazy, and flat out dies when you down shift to an intersection. i'm getting tired of starting it so much (i've actually broken the keyway in the column about a week ago cause of the constant restarts.)

[jvandyke]

Where was the vacuum leak?
I think vacuum advance is there for a bit cleaner burning at idle.

[namba209]

Originally Posted by maglinjosvinn .. ok. face value looks good. why is there a vac advance at all then? lol. sounds like the mechanical advance takes care of all the BS while ... hell ... almost all times.

Vacuum "advance" is a misnomer. It should actually be called vacuum retard. The purpose of the vacuum can is to retard the ignition timing as the vacuum is lost during open throttle applications to inhibit pinging caused by the mechanical and vacuum advance being too far advanced, such as going up a hill and as you slow down you give the car more gas. Without the vacuum retard the engine will ping if the ignition is too far advanced. Part of the "old school" timing procedure is to take the car up a hill, step on the gas an see if it will ping. If it does, retard the timing, repeat until it doesn't ping, or just starts to.

[Anonymous D]

If you don't want to do all the work to correctly verify that your timing set up is correct, then you can time it by ear (with the vacuum lines still attached). Idle the engine, then rotate the distributor (turn the vacuum unit away from the engine (CW)) to retard it. Do this so far that the engine starts to slow down, then rotate it back in the opposite direction just a nudge. This retard at idle setting, provides more power at higher rpm's on the road (presuming all other components, such as carb, valves, cam timing, etc., are adjusted correctly)

[maglinjosvinn]

Originally Posted by jvandyke Where was the vacuum leak? I think vacuum advance is there for a bit cleaner burning at idle.

valve cover to manifold.

[maglinjosvinn]

Originally Posted by Anonymous D If you don't want to do all the work to correctly verify that your timing set up is correct, then you can time it by ear (with the vacuum lines still attached). Idle the engine, then rotate the distributor (turn the vacuum unit away from the engine) to retard it. Do this so far that the engine starts to slow down, then rotate it back in the opposite direction just a nudge. This retard at idle setting, provides more power at higher rpm's on the road (presuming all other components, such as carb, valves, cam timing, etc., are adjusted correctly)

ok in quick review:

get car to idle at 800 - 900 rpms

remove vac lines from distributor.

plug vac lines

rotate dist until dot is at tip of needle

connect lines



to better power at higher speeds/rpms, retard the timing back a bit. would the same be in reverse for power at lower speeds? i mean city driving vs highway driving?

[maglinjosvinn]

Originally Posted by namba209 Vacuum "advance" is a misnomer. It should actually be called vacuum retard. The purpose of the vacuum can is to retard the ignition timing as the vacuum is lost during open throttle applications to inhibit pinging caused by the mechanical and vacuum advance being to far advanced, such as going up a hill and as you slow down you give the car more gas. Without the vacuum retard the engine will ping if the ignition is too far advanced. Part of the "old school" timing procedure is to take the car up a hill, step on the gas an see if it will ping. If it does, retard the timing, repeat until it doesn't ping, or just starts to.

ping?

[tomking]

Valve cover to manifold????????????????????
Ping.

[Anonymous D]

Advanced timing increases idle speed. That's why uninformed persons adjust their timing to where it "sounds best", but then lose high RPM power on the road.

Presuming all other settings are correct (again: you should verify cam sprocket mark, correct distributor installation for #1TDC, correct valve adjustments, and secure vacuum circuits, before doing final timing), retarding the distributor (just a notch above where the retard affects idle stability) will gain you smoother street operation and more power at higher rpm's.

[maglinjosvinn]

yeah, the valve cover has a small hole that is supposed to be connected via a hose to the lower nipple on the mainifold, just under the power booster and retard side of the dizzy nipple.

whats a ping. not ping. the guy said the engine will ping. haven't got a clue what that means.

[maglinjosvinn]

Originally Posted by Anonymous D Advanced timing increases idle speed. That's why uninformed persons adjust their timing to where it "sounds best", but then lose high RPM power on the road. Presuming all other settings are correct (again: you should verify cam sprocket mark, correct distributor installation for #1TDC, correct valve adjustments, and secure vacuum circuits, before doing final timing), retarding the distributor (just a notch above where the retard affects idle stability) will gain you smoother street operation and more power at higher rpm's.

ok.

here's a tidbit:

when you stand on the drivers side of the car, and look into the engine compartment, you can see the dizzy then the engine block


rightnow my wires are at:

2 --- 1
| |
| |
4 --- 3


but now that i'm looking at the pdf a bit closer, i see that i'm apparnetly rotated so that my plugs are all off by one quarter turn of the dist,.... 1 should be where 3 is, 3 where 4 is... so forth and so on... but i can also say that when you hook that timing light up to the 1 plug and shoot the window at the flywheel that mark is usually dead on... at least lower rpms


so i guess my question is wether or not i got this right. lol. i mean. ... how would it even run?


next question... imagine i can check the cam position w/ #4 tdc without taking the engine out? i know that this car has run absolutely beautifully in the past and i can assure you no one's played with any of the component positioning. lol.

[Anonymous D]

I would reinstall the distributor. Moving the wires back, is a quick-fix, for not doing it right in the first place. Also, it limits how much rotate it to fine-tune/advance.

[hrcollinsjr]

Line up the timing marks on the flywheel and check to see where the rotor button points. It should be pointing at a little line in the top of the housing to the dr. side fender of the vacuum unit. As Anon D said if it isn't you really should remove the distributor so you can adjust the timing properly. It probably can be done the way it is but you are really limiting the amount you can turn the distributor.

Harold

[dcm013]

Originally Posted by maglinjosvinn ok. here's a tidbit: when you stand on the drivers side of the car, and look into the engine compartment, you can see the dizzy then the engine block rightnow my wires are at: 2 --- 1 | | | | 4 --- 3 but now that i'm looking at the pdf a bit closer, i see that i'm apparnetly rotated so that my plugs are all off by one quarter turn of the dist,.... 1 should be where 3 is, 3 where 4 is... so forth and so on... but i can also say that when you hook that timing light up to the 1 plug and shoot the window at the flywheel that mark is usually dead on... at least lower rpms so i guess my question is wether or not i got this right. lol. i mean. ... how would it even run? next question... imagine i can check the cam position w/ #4 tdc without taking the engine out? i know that this car has run absolutely beautifully in the past and i can assure you no one's played with any of the component positioning. lol.

Certainly confuses me. You say the car previously ran fine.

going back to your earlier post for help:
"begging for help.

this is the story to date:

i'm using a solex on my 1.9L engine. this weekend, i took that solex off, dipped the parts in a bucket of cleaning agent, put everything back togehter with the new bits, and start the engine. its beautiful. fires right up after a couple presses of the pedal and idles at 1000 rpm, no questions.

i fiddle with the idle air and mixture screw according to the rebuild kit's direction. i got my timing (with vacuum lines off) so that the dot on the flywheel is deadnuts on the pointer arm."

It appears the only thing you did was mess with the carb, so why would you head off in the direction of a timing problem? Obviously you had vacuum leaks you've since corrected so why shouldn't the car run the same as it did before?

Did you readjust the timing since rebuilding the carb? If so why, and how much did you move it? If you didn't touch it and it ran OK before the carb rebuild leave it alone. Or put it back where it was when the car was previously running OK. I do agree that IF your distributor is mis-indexed you should re-install it correctly but you can do this later, assuming it was in this position when the car ran.

If your timing's on the mark at an 800 RPM idle with the distributor a quarter turn off your timing is wrong. With the # 1 plug wire in the correct orientation the timing should be on the mark at idle with the vacuum lines plugged, as you are aware. If the timing ball moves out of view as you rev the engine your advance is probably OK - it ran OK before, right?

When you "dipped the parts in a bucket of cleaning agent" did you have the carb completely disassembled? Did you take care to make sure everything was clean? Did you blow all the passages out etc? You could have some dirt blocking flow.

You say you used a rebuild kit and replaced some of the parts. Were they installed correctly and were they correct for your model Solex (did they look exactly like what you took out)? Was the accelerator pump diaphragm replaced? All the jets back in the positions they came from? How much fiddling have you done to the idle adjustment? Go back to the nominal setting in the FSM.

You dont still have the cardboard you were experimenting with blocking the air intake, do you?

It's really hard to remotely diagnose what went wrong, particularly if you haven't given all the facts on what was done between when the car ran OK and when it didn't.

When you work on a car that was running fine before and it doesn't run right when you're done, the first thing you should assume is that the work was done incorrectly. This was apparent in the fact that you distorted the heat shield and left off the valve cover vacuum hose. It may be tempting to head off in multiple directions looking for something else that's wrong but it's very, very unlikely that some other problem mysteriously cropped up on a part or system you didn't touch.

The key to solving a problem like this is to stop and think about what you have done to the car and how that work may have gone wrong. Don't start tearing into other things looking for the answer. Think more, work less!

If you were closer to Troy or if the car ran well enough to get here I'd be willing to look it over with you.

Don

[tekenaar]

Originally Posted by jvandyke Where was the vacuum leak? I think vacuum advance is there for a bit cleaner burning at idle.

Not quite, grasshopper, all GT CIH engines came with "dual chamber, single canister" distributors, i.e. vacuum advance AND retard provided from a single, at least that's what it looks like, canister. If you'll look very closely at the cannister, you'll see two nipples for vacuum hoses, the larger line at the canister "front/top" is hooked to the carburetor above the throttle plates, has ZERO VACUUM at idle and is the distributor vacuum "ADVANCE"!

The small port very close to the distributor at the "back/bottom" side of the canister is hooked directly to manifold vacuum, has MAXIMUM VACUUM at idle and is the distributor "vacuum RETARD"! This is the one that's there to lower pollutants and operational only at idle and deceleration when the engine produces higher levels.

[Anonymous D]

"...all GT CIH engines came with "dual chamber, single canister" distributors, i.e. vacuum advance AND retard provided from a single, at least that's what it looks like, canister"

Beware "absolute" type statements (that are not prefaced as an "opinion"), young impressionable grasshopper.

Then know that 1968-69 Opel GT CIH 1.9 engines, used a dual-cannister vacuum setup, with separate mount locations and separate functions of advance and retard.