Hey guys, I have searched the forums for help, but I still feel confused. I need to set the timing for my 1970 chevelle malibu, but I don't know at what degree to set it at or how to figure out how to set it. I 'm trying to do it my self if possible. Can anyone tell me how to set the timing, the procedures and steps? Here are the specs of my car: 350 engine, 350 automatic transmission, high performance cam, 760 holly carb, MSD ignition Kit with 6AL box and coil blaster, MSD wires and the rest is stock.
Any help and suggestions will be helpful and appreciated. thanks

Eddie

Ok, disconnect the vacuum advance from the distributor and plug it. Connect your timing light to the #1 plug (front plug-drivers side). Loosen the distributor set screw so that you can turn the distrubtor but no so loose as it spins easily. Start the car and set the idle to @750 RPM. Then using your light set the timing. Stock is 8-10 degrees but with a performance cam you can probably get 10-15degrees. I would start maybe around 12 degrees before top dead center. Basically you want to get the most advance timing you can without pinging. If you have a timing gun that has the advance dial on the back of the light then set it to 12 degrees and when you pull the trigger and point the light at the timing mark, you should set the distributor so that it appears to be at 0 degrees. Then turn the dial back to 0 and it reflect 12 degrees on the engine. Then tighten the distributor and check your settings again. Once you have the timing set, you want to check your idle again. If you have a vacuum guage then you can also set your carb so that you get the highest vacuum possible by turning your air screws 1/4 turn at a time then switching to the other screw.

Sorry if I am hijacking...

I'm in the same boat. i was wondering what you mean by pinging?

On acceleration you will here a kind of knocking or rattleing, You then retard the timing till you dont get this sound any more.

If you have a MSD box, from what I have read, you cant use most dial back timing lights. Just use a regular timing light and follow what they said. Also when they say to retard the timing if pinging, that means to go from 12 deg to 11 before top dead center untill the pinging stops.. Buy a Chiltons car book for your year-make car, at any auto parts store, it will help with all the basic stuff.

Pinging refers to the early ignition of the air/fuel mixture in the cylinder. By early I mean that on the compression stroke some of the mixture starts burning a bit early such that the piston is literally compressing a flaming (expanding)mixture before the spark plug fires the mixture. It can be caused by too much timing or a hot spot in the combustion chamber ( glowing carbon deposit for example.).

You hear it as a "pinging" noise from the engine under load and as soon as the load stops the noise stops.

Taken to extremes you will experience "detonation" which refers to the air/fuel mixture exploding instantaneously and inpacting the piston which is on its way to TDC. Detonation can break rings or even punch holes in the piston.

Pinging on the other hand will usually only cause the engine to run hotter than normal since the flame front is occuring early and therefore the cylinder walls are exposed to more heat than normal due to the early firing of the mixture.

Pinging and detonation are only different by the degree of damage they can cause per unit time. Neither are desirable conditions.

If you suspect that you are hearing pinging do what an earlier post said. retard your timing a degree or two at a time until the engine no longer pings.

My instructions on my new zz454 says 36 degrees total at 3,000 RPM. Will I follow the same procedure with my numbers?

Mike, disconnect vac advance, rev till the dizzy stops advacing (hopefully it be done advanceing by ~3000) set the timing to 36*, thats it. Hook up vaccuum advance.

Your initial should fall around 14-16*. You have no choice w/inital..it has to stay there if you want to run 36* total. If you want more initial with teh same total, the dizzy has to be modified.

by dizzy do you mean distributor?

by dizzy do you mean distributor?
There is no "Z" in distributor.
The abbreviation would be "dist." wouldn't it?
:D

Yeah it's a silly "word" for distribitor lately for people that don't want to spell it out or for people that don't know how to spell in some cases.
(not necessarily in this case maybe)

Good info here! On the topic of pinging, I noticed on my 1970 350 that I will get pinging on the freeway at higher speeds (70+), especially going uphill. But it doesn't do it at lower speeds, even if my foot is buried in it. My timing is about 10 degrees BTDC. Anything I should check?

Pozi,

At part throttle, you'll have both mechanical and some amount of vacuum advance. If you're pinging more than a little, you need to consider taking a look at things. You may be running too much initial timing, or have too much vacuum advance, need better gas, etc.

Ok, disconnect the vacuum advance from the distributor and plug it. Connect your timing light to the #1 plug (front plug-drivers side). Loosen the distributor set screw so that you can turn the distrubtor but no so loose as it spins easily. Start the car and set the idle to @750 RPM. Then using your light set the timing. Stock is 8-10 degrees but with a performance cam you can probably get 10-15degrees. I would start maybe around 12 degrees before top dead center. Basically you want to get the most advance timing you can without pinging. If you have a timing gun that has the advance dial on the back of the light then set it to 12 degrees and when you pull the trigger and point the light at the timing mark, you should set the distributor so that it appears to be at 0 degrees. Then turn the dial back to 0 and it reflect 12 degrees on the engine. Then tighten the distributor and check your settings again. Once you have the timing set, you want to check your idle again. If you have a vacuum guage then you can also set your carb so that you get the highest vacuum possible by turning your air screws 1/4 turn at a time then switching to the other screw.:thumbsup: MINT!

Thanks for that info 69-CHVL. You always seem to pop up with the right answers when I need them. I love this site!:thumbsup:

Ok, disconnect the vacuum advance from the distributor and plug it. Connect your timing light to the #1 plug (front plug-drivers side). Loosen the distributor set screw so that you can turn the distrubtor but no so loose as it spins easily. Start the car and set the idle to @750 RPM. Then using your light set the timing. Stock is 8-10 degrees but with a performance cam you can probably get 10-15degrees. I would start maybe around 12 degrees before top dead center. Basically you want to get the most advance timing you can without pinging. If you have a timing gun that has the advance dial on the back of the light then set it to 12 degrees and when you pull the trigger and point the light at the timing mark, you should set the distributor so that it appears to be at 0 degrees. Then turn the dial back to 0 and it reflect 12 degrees on the engine. Then tighten the distributor and check your settings again. Once you have the timing set, you want to check your idle again. If you have a vacuum guage then you can also set your carb so that you get the highest vacuum possible by turning your air screws 1/4 turn at a time then switching to the other screw.

So if he sets his timing to 10-12 initial, he will end up with 30-32. Being that most SBC's like 36, he's going to loose power that way.

Again, the right way to set timing is to set the total where you want it, and live with wherever the initial falls (with vacuum disconnected of course).

STICKY TIME!!!!!

There is no "Z" in distributor.
The abbreviation would be "dist." wouldn't it?
:D

Yeah it's a silly "word" for distribitor lately for people that don't want to spell it out or for people that don't know how to spell in some cases.
(not necessarily in this case maybe)


YO DEAN!!!

Its true actually...:rolleyes:

69-CHVL, what do you mean by "rev till the dizzy stops advancing?" Am I suppose to rev by accelerating to 3000 and then move the dizzy until the 36 degree mark line up?

Percisely.

Some advances arent in till like 5000rpm. You want to make sure that when you set the timing that your not in the advance curve, b/c you may end up w/more timing than 36*.

Just rev till you see it stop advacing, then set to 36* . For best performance, its good to see that the full advance curve is in by ~3000. Can be a little higher or lower. Make sense?

Thanks again 69CHVL.

So 36 (deg) ATDC is the magic number you want to set your timing at if you have a SB? I thought certain factors effected this number. Like cam size, engine size possible stall number and rear end gear ratio. There is a lot of info on this site that contradicts itself so just trying to get the right info. But the more threads I read, the more I see 36 come up as the magic number.

Jim - yes, most combos seem to like that #. The newer style heads though seem to like 34*.

The problem is though, most mechanical advances give you like 20-22* of advance. So if you run 36* total, you initial will fall to 14-16*. That should be OK, but alot of these cammed-up motors like 16-20* initial for crispy throttle response and bottom end. If you merely set the inital to 20*, your total will be 40-42*...too much in most cases. SO you have to live with whatever initial you get. UNLESS...you get a distributor w/adjustable mechanical advance, or modify what you have to have less mchanical advance.

For the record, my distrib. has 22* mechanical. I run 36* total timing. That only gives me 14* - not enough for me. I like running 18-20*. So I modified my dizzy (Hi Dean :p) to give me 20* initial, 36* total - a 16* mechanical curve. Works like a charm.

Jim - yes, most combos seem to like that #. The newer style heads though seem to like 34*.

The problem is though, most mechanical advances give you like 20-22* of advance. So if you run 36* total, you initial will fall to 14-16*. That should be OK, but alot of these cammed-up motors like 16-20* initial for crispy throttle response and bottom end. If you merely set the inital to 20*, your total will be 40-42*...too much in most cases. SO you have to live with whatever initial you get. UNLESS...you get a distributor w/adjustable mechanical advance, or modify what you have to have less mchanical advance.

For the record, my distrib. has 22* mechanical. I run 36* total timing. That only gives me 14* - not enough for me. I like running 18-20*. So I modified my dizzy (Hi Dean :p) to give me 20* initial, 36* total - a 16* mechanical curve. Works like a charm.

Voooom - over my head :-)

I think my distributor has an adjustable mechanical advance. It is a MSD Pro Billet (Ready to Run) 8360

Other stats are:

mild small block 350 with only a couple thousand miles

Edelbrock Performer RPM cam (duration @ .050" intake/exhaust 234 degrees and 244 degrees. Lift .488" and .510"), with the matching intake manifold

Edelbrock gear drive (quiet).

Comp Cam roller tip rockers.

Holley 600

BM turbo 350 transmission with the deep sump fluid pan

3,000 stall converter

stock ten bold with 373 gear non posi

The heads were rebuilt with he engine. And they are the double hump 1.94 intake and 1.60 exhaust

upgraded valve springs

Jim, that dizzy that you have is adjustable, its a nice unit. If you put the largest bushing in there, (the black one I think), that gives you a mechanical advance of 18*. With that bushing in place, you can run 18* initial, 36* total..about perfect for your combo, especially with that cam of yours.
And change out one of the heavy springs for a blue spring - that will get the curve in around ~3200.

Jim, that dizzy that you have is adjustable, its a nice unit. If you put the largest bushing in there, (the black one I think), that gives you a mechanical advance of 18*. With that bushing in place, you can run 18* initial, 36* total..about perfect for your combo, especially with that cam of yours.
And change out one of the heavy springs for a blue spring - that will get the curve in around ~3200.


It came with the car, so i will have to go find these parts you speak of.

Ok so if that is the case, I guess I don't actually have to find the initial, I just need to set the total at 36 then (by twisting the distributor).

All I need now is to get a piston stop so i can find TDC.

Yes...do it running, no need for piston stop.

Unless you have no timing tab?

Here's the instructions for you dizzy. Just check the timing - it may be OK as is:

http://www.msdignition.com/pdf/8360_frm%2023793.pdf

I have a timing tab. Just don't trust the guy before me.

Pinging refers to the early ignition of the air/fuel mixture in the cylinder. By early I mean that on the compression stroke some of the mixture starts burning a bit early such that the piston is literally compressing a flaming (expanding)mixture before the spark plug fires the mixture. It can be caused by too much timing or a hot spot in the combustion chamber ( glowing carbon deposit for example.).

You hear it as a "pinging" noise from the engine under load and as soon as the load stops the noise stops.

Taken to extremes you will experience "detonation" which refers to the air/fuel mixture exploding instantaneously and inpacting the piston which is on its way to TDC. Detonation can break rings or even punch holes in the piston.

Pinging on the other hand will usually only cause the engine to run hotter than normal since the flame front is occuring early and therefore the cylinder walls are exposed to more heat than normal due to the early firing of the mixture.

Pinging and detonation are only different by the degree of damage they can cause per unit time. Neither are desirable conditions.

If you suspect that you are hearing pinging do what an earlier post said. retard your timing a degree or two at a time until the engine no longer pings.


Mr. Mobley has advised me that, while I have the right idea with my definition of pinging and detonation, he feels that I reversed the phenomenon. I am thinking that we have a confusion of terms here. "Detonation" is the instantaneous uncontrolled explosion of the fuel/air mixture in the cylinder with out regard to timing or piston position at the instant of the explosion.

If the piston if before TDC then it will attempt to compress that explosion with disasterous results to the piston and rings. We are talking massive brute hammering on the piston/rings.

Pinging on the other hand is the early ignition of the fuel/mixture prior to the properly tuned ignition event. The difference is that with pinging you still have a controlled burn so the effect on the piston/ring assembly is less destructive. The ping is the sound the piston makes when it compresses this early burn. There is still a machanical hit on the piston but it is significantly less destructive.

The most likely effect of prolonged pinging is an artificial unintended rise in the engine temperature because the flame front, having ignited earlier will expose more of its heat to the cylinder wall during the power stroke. Additionally continued pinging will eventually erode the piston top due to this excess heat.

Tom pointed out that Diesels operate by "detonation" however even diesels fire their mixture in a controlled manner and they also run cooler than gasoline engines do so the heat issue is less important there.

I hope I am clearer in what I was trying to get across. Thanks to Tom Mobley for pointing out my error.

Jim, that dizzy that you have is adjustable, its a nice unit. If you put the largest bushing in there, (the black one I think), that gives you a mechanical advance of 18*. With that bushing in place, you can run 18* initial, 36* total..about perfect for your combo, especially with that cam of yours.
And change out one of the heavy springs for a blue spring - that will get the curve in around ~3200.

So I will check inside the dizzy as you say, and see what color bushing is in there. Hopefully it is the black one. if not, I will need to locate one.

Now I will also have to locate the blue spring as well.

Do I have that right?

Then I just have to find TDC.

Then as it is running, I take the tube off of the vaccum advance and plug the hose coming from the carb not the vaccuum on the dizzy.

Then i rev it to around 3000RPMs.

Then I twist the distributor and advance it to 18.

Then I plug the hose back into the distributor and lock down the distributor.

The timing is now done.

Then I will have a mechanical of 18 degrees and a initial of 18 degrees as well. This will give me a total advance of 36 degrees. And a curve of 3200.

I do not need to lock the vaccuum advance and do not have to turn the mechanism 180 degrees

Do I have all that right? The process and the logic. And with my cam, motor, and the whole shebang, I should be sitting pretty?

Thanks.

All sounds good, but as your reving the motor, turn the dizzy to give you 36 total, dont go by initial (which would probably work anyway...just set total to be sure). Rev motor till you see the advance stop advancing - then set it. If the advance is in around 3000, you dont even have to change the spring.

All sounds good, but as your reving the motor, turn the dizzy to give you 36 total, dont go by initial (which would probably work anyway...just set total to be sure). Rev motor till you see the advance stop advancing - then set it. If the advance is in around 3000, you dont even have to change the spring.

Sorry to bug you. I have read this before a few times, but don't quite get it. How will you know when the advance stops advancing?

Also, if I need to go to 36 total, I guess I will be needing some timing tape. I called Kragen and AutoZone and they claim to have never heard of it. Any ideas where I could pick some up. For the record I measured my balancer and from end to end it is under 8" and 1.8" wide if that means anything.

[quote=datapusher;1075433]Sorry to bug you. I have read this before a few times, but don't quite get it. How will you know when the advance stops advancing?

Keep reving the motor w/the timing light on the balancer..you will see the timing a mark stop moving at some point...hopefull that will be not later than 3000rpms.

Timing tapes are nice...go to a speed shop.

OR

put your balaner on 0, then mark the balancer where the 12 is. Take that mark you made on the 12 and line that up w/the 0. Mark the balancer at the 12 again, and again rotate the balancer to 0, mark the balaner at the 12 for the finial time.

Now, you have 3 marks evenly spaced on your balancer.

1st mark = 12°
2nd mark = 24°
3rd mark = 36°

Heck, make a 4th mark so you can check you vac advance.

Looking at the front of the motor, your lines will be to the right on the factory TDC mark on the balancer.

Well I took the distributor cap off and the red thing above the mechanism. I don't think I have any bushing in there. Not red, silver blue or black.

But wait, after looking at the pics I took, there looks to be a black bushing in there that I could not see before at my angle. I must go back out to investigate. I am hesitant to take the distributor apart because it looks to be a much more intricate device than I am used to.

Out I go...

Bummer. Although it looks black in the following pictures:
http://datapusher.org/chevelle/bushing1.jpg
http://datapusher.org/chevelle/bushing2.jpg
http://datapusher.org/chevelle/bushing3.jpg

As you can see in this picture, it looks to be silver and not black after all:
http://datapusher.org/chevelle/bushing4.jpg

Here's a pic of the springs I think you were talking about. Mine seem to be silver.
http://datapusher.org/chevelle/bushing5.jpg

So where would I go about getting a black bushing? I could call AutoZone, but the majority of the answers I get from them is huh? i am hoping it is not a special order sit and wait around thing.

Thanks

Local speed shop or summit:

http://store.summitracing.com/partdetail.asp?part=MSD%2D8464&N=700+400122+4294845373+115&autoview=sku

Those are the heavy "coil springs"..they are the slowest. You have to rev up the motor up a bit till the advance is all in. I suggest leave them alone for now...you have enough going on.

Ok so the springs can wait then. I found this from MSD, seams to be what I need:

Advance Kit, All MSD Distributors PN 8464
http://www.msdignition.com/dist_69.htm

Guess I'll just call around till I find someone that has it.

Thanks

Thats the kit.

As your distributor is, with the silver bushing and heavy springs, the total curve is not in till about 4800rpms!

But, when you get the black bushing in there, the curve speeds up, so you can leave those heavy springs in there, as your timing will be by 3500. If you live dangerously, you can put one med weight spring (blue colored) on instead of one heavy and your curve will be in by 3200 - good enough.

I encourge you to read up on your dizzy:
http://www.msdignition.com/pdf/8360_frm%2023793.pdf

This shows all the curves available w/that kit on page 3.

Thats the kit.

As your distributor is, with the silver bushing and heavy springs, the total curve is not in till about 4800rpms!

But, when you get the black bushing in there, the curve speeds up, so you can leave those heavy springs in there, as your timing will be by 3500. If you live dangerously, you can put one med weight spring (blue colored) on instead of one heavy and your curve will be in by 3200 - good enough.

I encourge you to read up on your dizzy:
http://www.msdignition.com/pdf/8360_frm%2023793.pdf

This shows all the curves available w/that kit on page 3.

I've read it a couple times. means nothing to me. They assume a prior bit of knowledge on the end users part when they make those sheets. I am unfortunately jumping into a whole lot at once.

Hell, i don't even know whay 3200 or 3500rpms is better than 4800.

I am trying to locate this part. Looks like I may have to wait till Tuesday to get it.

So 36 (deg) ATDC is the magic number you want to set your timing at if you have a SB? I thought certain factors effected this number. Like cam size, engine size possible stall number and rear end gear ratio. There is a lot of info on this site that contradicts itself so just trying to get the right info. But the more threads I read, the more I see 36 come up as the magic number.


Sorry but its not ATDC its BTDC. ATDC would be horrendously retarded.

I've read it a couple times. means nothing to me. They assume a prior bit of knowledge on the end users part when they make those sheets. I am unfortunately jumping into a whole lot at once.

Hell, i don't even know whay 3200 or 3500rpms is better than 4800.

I am trying to locate this part. Looks like I may have to wait till Tuesday to get it.

When full advance comes in at this point is all you need to know if you want to set it up right now. Basically, where the springs are set now, max timing only comes in when your really starting to hammer on the engine, near 5000 rpm..

The problem is, you have to rev the engine up to at least 4800 rpm to set your max timing (34 or 36 degress or whatever your going with). It's not really a problem, just having someone help you makes it easier to see the tach, rev the engine, turn the dist and see the timing mark all while this small block is starting to scream at 5000 rpms in your face.:D

Or wait, get the bushings and springs kit. You don't need to pull the dist to replace the springs, just a good pair of needlenose (and a extend-a-magnet to chase the spring if/when you slip putting it in:waving: ). The springs determine how fast the max advance comes in (right now it reaches max near 4800 rpms). The bushings determine how much advance it will add (different color bushings allow different amounts of mechanical advance). A silver bushing adds 25 degrees. So if you set your idle timing near 10 BTDC, your total timing (without vacuum advance) would be 35 degrees when your engine is near 4800 rpms.

Ok finally got a ride out and picked up the bushings spring package.

Just some minor clarification.

Then I am going to replace the silver bushing for the black one.

However, it looks like you wanted to have me change the silver springs out for the blue ones to get a curve of around 3200. But unless I am misreading the chart, if I put in the two blue springs, I will have a curve of about 2400.

Now keep in mind these charts arew Greek to me, but wouldn't I want to do 1 Silver (Heavy) and One Blue spring to achieve 3200?

Or should i jsut leave in the two Silver heavies and keepo it at 3500.

See this stuff just doesn't click at all.

So what combo springs should I use with the black bushing to keep my machine running good with my specsa listed on the other page.

And does it matter which post you put which spring on?

Sorry for being so clueless on this.

When you read the chart, 2 blue springs with a black bushing will bring total advance in around 2500 or so RPMS (see top chart on the right side). Follow the black bushing dashed line over to intersect with the rising line of the 2 blue springs advance rate. You will see it would connect near 2500 rpms.

Well, since I was told I needed 3200 earlier, I put in one blue and left one heavy silver.

I put in the black bushing. Man getting the washer and locknut on there took forever. I ended up using superglue to glue the washer and locknut together.

Anyways, I hvae 1 blue and 1 heavy silver in there with a black bushing.

So that is just where I need to be no?

Now to find TDC.

I have a forum member coming over tommorow with a piston stop to help me find TDC.

Just to clear a few things up. From end to end, the balancer looks to be under 8" but longer than 7.5"... Which timing tape should I use, the one for 8" or 7.5"?

1- Also, when I am doing my timing, since I set my mechanical advance to 18 with the black bushing, my total should be 36deg BTDC correct?

2- And to advance my total timing 36 deg BTDC, I will rotate my distributor Counter Clockwise. Correct?

3- I put the tape on the balancer with the 0 on the balancer line, but which direction does it go. Sorry for the newb questions. If I am looking at the timing line from the front of the car and the top of the engine, my timing tape should go the line to the right. So 0 will be at the top and 36 would be off toards the driver side.

Thanks for handling the newb questions

Anyone?

yes, the 36* mark will be clockwise from the zero mark on the damper.

Thanks, and the rest of my comments were right. Especially about rotating the distributor counter clockwise?

the distributor rotates clockwise, so rotating the body CCW causes things to happen sooner, advancing the timing.

Sorry but its not ATDC its BTDC. ATDC would be horrendously retarded.

Thanks for catching that BTW, glad someone did.

datapusher-

I'm just curious, how did it go? I'm getting ready to do the same thing myself and this thread has answered a lot of questions for me so far.

I also thought I'd share some really good fundamental info I found.
http://www.centuryperformance.com/timing.asp

datapusher-

I'm just curious, how did it go? I'm getting ready to do the same thing myself and this thread has answered a lot of questions for me so far.

Sorry for the delay... It didn't go well, read this thread for the detailed account. The short of it is the balancer may have slipped.

http://www.chevelles.com/forums/showthread.php?t=147371

Thanks for the link, I'll give it a read.

So if he sets his timing to 10-12 initial, he will end up with 30-32. Being that most SBC's like 36, he's going to loose power that way.

Again, the right way to set timing is to set the total where you want it, and live with wherever the initial falls (with vacuum disconnected of course).

STICKY TIME!!!!!
yeah but if u read the post he said "START" at 12 degrees...

Yeah but if you looked at the posts you will see that this thread died a while ago...

Yeah, it never got resolved. I tried everything and even consulted the MSD boards. For some reason my mechanical is just not what it should be. I still need to fix the timing so i can move onto other things.

Plus with the vacuum advance disconnected and the timing off, I get about 2 miles to the gallon. if I really try hard, I can squeeze out about 7.7mpg. On the 18gallon tank I average 50miles -90miles. If I really atch myeslf and do a lot of non city driving, I can get a little over 130 miles to an 18gallon tank.

Need to fix timing, so thanks for reminding me I need to get on this.

Yeah, it never got resolved. I tried everything and even consulted the MSD boards. For some reason my mechanical is just not what it should be. I still need to fix the timing so i can move onto other things.

Plus with the vacuum advance disconnected and the timing off, I get about 2 miles to the gallon. if I really try hard, I can squeeze out about 7.7mpg. On the 18gallon tank I average 50miles -90miles. If I really atch myeslf and do a lot of non city driving, I can get a little over 130 miles to an 18gallon tank.

Need to fix timing, so thanks for reminding me I need to get on this.


HOLY S$&T! that's horrible. i feel bad for you dude. something needs to be done here.

What exactly is the problem other than horrible mileage?

Backfires, irradic idle in gear, etc etc etc.

Whats the timing setup look like?