timing Q...

[magnethead]

Ok, am I seeing things, or is my engine running 180 degrees out on timing? Just a forewarn, the images are big...The engine happened to stop at 6 degrees after TDC...the yellow dot on the dizzy base is #1 cylinder when cap is on.

I hooked the timing light up, and it was VERY erratic...I could see the line but it bounced between off the chart BTDC and off the chart ATDC..and pretty much every place in between.

I unhooked the vacuum advance and tried again, and i never saw the mark, at all. And I tried the shut the motor off with the vacuum advance off, and it kept running...it all but never tried to shut off..it wasn't the dieseling pinging like i have when it's warm with the advance connected, but a mellower (but still shakey) continuous run, as if the ignition was still on but with a misfire (it ran for 10 seconds before i clicked the ignition back on, no backfire, and used the P/S pump to kill the motor). What the...?

The plugs are 45 degrees apart on the cap...It looks about like the rotor is 135 degrees from the #1 plug. I can't think of any mathematical way that it could possibly be running the way it looks like it is?

*ok, my internet won't let me upload pics right now....so post if you can provide input until i get pics up*

[Billla]

OK, there are a couple of things here

First, timing is set with the vacuum advance removed at the distributor and plugged (I use a golf tee) so that we don't create a vacuum leak. Then, we ensure that the idle speed is set correctly, and if it's a points distributor set the dwell. Once all this is done we can check the timing. I would start there before you get too worried - if the timing was as far off as you think it wouldn't be running

Originally Posted by magnethead

Ok, am I seeing things, or is my engine running 180 degrees out on timing? Just a forewarn, the images are big...The engine happened to stop at 6 degrees after TDC...the yellow dot on the dizzy base is #1 cylinder when cap is on.

I hooked the timing light up, and it was VERY erratic...I could see the line but it bounced between off the chart BTDC and off the chart ATDC..and pretty much every place in between.

I unhooked the vacuum advance and tried again, and i never saw the mark, at all. And I tried the shut the motor off with the vacuum advance off, and it kept running...it all but never tried to shut off..it wasn't the dieseling pinging like i have when it's warm with the advance connected, but a mellower (but still shakey) continuous run, as if the ignition was still on but with a misfire (it ran for 10 seconds before i clicked the ignition back on, no backfire, and used the P/S pump to kill the motor). What the...?

The plugs are 45 degrees apart on the cap...It looks about like the rotor is 135 degrees from the #1 plug. I can't think of any mathematical way that it could possibly be running the way it looks like it is?

*ok, my internet won't let me upload pics right now....so post if you can provide input until i get pics up*

[magnethead]

ah, i forgot to plug it.
I went back and looked again with the cap back on it, everything is right except the timing itself. It's an HEI big block. I'm going to have my dad look at it when he gets home (i just have to bump it around with the starter so the balancer lines up to 8 BTDC).

But, i'm starting to wonder if my balancer is off? I pointed the dizzy rotor at the #1 plug, and the balancer mark was over pointing at the passenger side water pump connection. When i get the balancer lined up later, i'll look at the rotor again to make sure it agrees.

balancer at 6 degrees ATDC = rotor at cyl 5
rotor at #1 = balancer at ~~90 degrees BTDC

[piecesparts]

Pull #1 plug out and rotate the engine until you feel the air coming out of the hole (This should give you a compression stroke), then turn the motor unti the piston is at the top of the cylinder, you can look into the hole or have a small soft stick in the hole to feel the piston top out and then start back down. Tha should be at TDC or real close. Now look at the dizzy for the pointer and where it is at, as well as the harmonic balancer. If it i s not at the pointer than you have probably slipped the timing marks. Are you using the right timing pointer and marks? Different motors have marks in different places. Some are down the front of the motor past the timing chain cover and others are off to the driver's side ot the block. Know where the motor is timed at, first.

[Nolowrider]

I see two things that I disagree with.

You want to set the timing THEN adjust your idle. You may have to bump it up some to get her to idle while setting the timing. But, timing first then drop your idle back down..

Why are you putting your balancer at 8*? Put the balancer on 0* then drop your dist in. Rotor points to the #1 lug on the dist, not the plug. They are close but they are a few degrees apart. If you set your balancer at 8*, then your are basically adding 8* mechanical advance. You can drop the dist in on the #1 compression stroke or the exhaust stroke, just drop the dist in accordingly. Meaning when #1 is at TDC drop the dist in pointing to the 1, if it is at BDC drop it in pointing to the #6 lug. That way you don't have to drop a nut rotating the motor, or keep bumping your starter. Both of which are not good. You can pull the valve cover and see what the valves are doing. That will tell you TDC or BDC.

A bouncy or really eratic timing mark is a good indication that the vacuum advance module or the mechanical advance is going bad in the dist.

[Billla]

I'll respectfully disagree right back Timing is specified at a set RPM; as you adjust the timing you should continually re-adjust the idle as req'd. It makes no sense to have a high idle with mechanical advance in and trying to set timing.

There's nothing wrong with dropping the distributor to establish initial timing; it's easy to set the engine at whatever you want for static timing and then point the rotor directly at #1. For example, I usually set my engines to 16 degrees BTDC and drop the distributor with the rotor pointing at #1 when starting for the first time - this works fine. If I misunderstood something in your post, my apologies.

Erratic timing can come from many sources and isn't limited to just the advance mechanism IMHO.

[Billla]

Originally Posted by piecesparts

Pull #1 plug out and rotate the engine until you feel the air coming out of the hole (This should give you a compression stroke), then turn the motor unti the piston is at the top of the cylinder, you can look into the hole or have a small soft stick in the hole to feel the piston top out and then start back down. Tha should be at TDC or real close. Now look at the dizzy for the pointer and where it is at, as well as the harmonic balancer. If it i s not at the pointer than you have probably slipped the timing marks. Are you using the right timing pointer and marks? Different motors have marks in different places. Some are down the front of the motor past the timing chain cover and others are off to the driver's side ot the block. Know where the motor is timed at, first.

I think you have too many variables here. Make sure you've got the balancer on TDC compression #1 and then back off to your advanced timing setting and drop the distributor pointing at the #1 tower. I wouldn't stick anything other than a piston stop in the hole IMHO - it would suck to have a piece of soft stick in the bore

http://store.summitracing.com/partde...5&autoview=sku

[Nolowrider]

Originally Posted by Billla

I'll respectfully disagree right back Timing is specified at a set RPM; as you adjust the timing you should continually re-adjust the idle as req'd. It makes no sense to have a high idle with mechanical advance in and trying to set timing.

There's nothing wrong with dropping the distributor to establish initial timing; it's easy to set the engine at whatever you want for static timing and then point the rotor directly at #1. For example, I usually set my engines to 16 degrees BTDC and drop the distributor with the rotor pointing at #1 when starting for the first time - this works fine. If I misunderstood something in your post, my apologies.

Erratic timing can come from many sources and isn't limited to just the advance mechanism IMHO.

Billa- I am not saying that you are wrong, we just do it different ways. What I am saying is that it is better to set your TOTAL timing and let the iniatial fall where ever it lands. Then adjust the idle.

When you set the balancer off of TDC you are really advancing the cam 6*-8 * not the timing. And with most aftermarket cams they are already ground 4*, so now you are looking at anywhere from 10*-12*. Either way the end result is the same. Either 16* mechanical advance and the narks will be on xero, or line them up on zero and marks show 16*. Same thing.

Vacuum leaks will also lead to eratic timing. Just from wha he posted he didn't elude to any engine problems other than timing. That is why I only that the mech/vacuum advance could be bad.

The engine will run 180* out, just adjust your dist to #6 instead of #1.

[Billla]

Originally Posted by Nolowrider

What I am saying is that it is better to set your TOTAL timing and let the iniatial fall where ever it lands. Then adjust the idle.

Agreed...but that's very different from what I saw you suggesting. Getting to 34-36 degrees total timing requires a degreed balancer or adjustable timing light, and you need increase RPM until all the mechanical is in and then adjust to have it all in by 3000 RPM or so. That's a performance tune...and a bit beyond where we're at in this troubleshooting process IMHO

[Nolowrider]

Originally Posted by Billla

Agreed...but that's very different from what I saw you suggesting. Getting to 34-36 degrees total timing requires a degreed balancer or adjustable timing light, and you need increase RPM until all the mechanical is in and then adjust to have it all in by 3000 RPM or so. That's a performance tune...and a bit beyond where we're at in this troubleshooting process IMHO

Yeah, maybe I was a little too far ahead of the cart. I agree with ya Billa.

[piecesparts]

WOW, a lot of different ideas and the basic is the reality.. Put the #1 at TDC and drop the distributor in with the rotor pointing at that #1 spot on the distributor cap. Install the plugs and wires and start the motor. You will have to turn the dizzy slightly in the advance direction, to get the motor to startand run. The idle should be set up slightly, BUT no more than is actually needed to set the timing. Once the timing is set, then adjust the idle to the RPM you normally keep for a vehicle in neutral or Park, I personally use about 900 RPM, which gives me 700 RPM i n the "DRIVE" popsition on the tranny. Now would be a good time to recheck the timing and ensure that it is set to where it is desired. I never did set timing at 8 degrees with my trucks. I used to set it at 10 to 12 degrees and then worked from there. I now finish my timing with a performance advance timing tune to get the TOTAL advance timiing of 36 degrees. However before you can run you must walk, so set the timing at the initial numbers that you like and then work from there.

Everyone has a different way of dropping a dizzy, but the most prevelent is to find TDC,using the #1 cylinder with the timing marks at "0", then set the distributor to feed from there. That way you will not go wrong or get confused.

[MylilBowTie]

One other thing is getting looked over also, thats the firing order.

Did you get the firing order back in order? With a piston stop you can also check to see if the harmonic balancer has slipped.

[Billla]

Originally Posted by piecesparts

Everyone has a different way of dropping a dizzy, but the most prevelent is to find TDC,using the #1 cylinder with the timing marks at "0", then set the distributor to feed from there. That way you will not go wrong or get confused.

An engine has a hard time starting with NO advance, IMHO - but agreed there are different ways to do it. Why start with a bad timing setting and then change it when it's so easy to just set 8-16 degrees initial when you drop it in?

Try it sometime

[piecesparts]

Yep drop it at "0" and then turn it about a 1/16th and we are running. And all I have to stick in there is something like a tie wrap to check the piston is at the top, I don't leave it in there. Been doing it for years, it works and works well. Yep dropping the dizzy at the timing mark setting will work, I have seen it done. There are some cases as to what angle the vacuum pot will set and what clearances you have, most times not. Both will work....

[magnethead]

we worked on it today. Turns out even though it's the origional block, it has a late 80's balancer designed for a passenger side timing guide. So today we replaced all the plugs, wires, rotor and dizzy cap, then used a coat hanger to find TDC and a pry bar, balpeen, and yellow model paint to mark where TDC is on the balancer.

It's now at ABOUT 12 degrees advance, with total (vacuum and all) at 44 degrees advance at 3000ish RPM.

also, we hooked a gauge up, compression ranged from 140 to 152 across the board, i had 1 140, a pile of 145's, pair of 150's and a 152.

[MylilBowTie]

It should be running a little better I take it? Engine still seems to be doing well.

[piecesparts]

Most of those 80s model motors had a timing mark that aligned with the pointer just behind the water pump. You had to look at it from the top.

[magnethead]

Originally Posted by MylilBowTie

It should be running a little better I take it? Engine still seems to be doing well.

We'll find out next time i get to drive it to my friends house down the road.

now if I could replace the 2.25 stock pipes with 3" pipes to match the headers, then we'd really know the story, now that i put an air cleaner on it that's CLEAN and a tad taller. Problem is, no job, no money. My dad paid the $100 bill today for the parts. Hopefully i'll have a job before too long and I can get exhaust on it and get to the dragway before the end of the year.

[84slopwaggin]

Don't worry much about the 2.25 pipes. They are adequate for stock applications. Probably the only difference you'll notice is the sound of the exhaust. It could hurt low speed torque. 2.5 would be adequate for mild big blocks.

[68GMC454]

timing is the one thing i never figured out, and after this discusion,,i will still have to have somebody else do it..next tiem i wil make sure friend is sober first..

[piecesparts]

Originally Posted by 84slopwaggin

Don't worry much about the 2.25 pipes. They are adequate for stock applications. Probably the only difference you'll notice is the sound of the exhaust. It could hurt low speed torque. 2.5 would be adequate for mild big blocks.

I think that the 3" pipes will be too much, also. For a modified SBC motor (such as a 383 stroker) and a stock BBC 2 1/2 pipes are the border line. Anything past that will hurt low end performance, unless the motor has been worked over. If you want to upgrade, then look at putting on a 2 1/2" set at the most, but concentrate on things like style of mufflers, "X" cross-over, and mandrel pipe bends instead of standard muffler shop bends. All of this will upgrade you by giving you the best flow possible.

[magnethead]

Thanks for the input, didn't think of that. Just thought the 2.25 were restricting considering there's no reducer connector on the headers, we have the factory pipes bolted straight to the headers so 3/8" of the flange all the way around impedes flow right there between the pipes.

[piecesparts]

Originally Posted by magnethead

Thanks for the input, didn't think of that. Just thought the 2.25 were restricting considering there's no reducer connector on the headers, we have the factory pipes bolted straight to the headers so 3/8" of the flange all the way around impedes flow right there between the pipes.

SUGGESTION HERE: Go to Summit Racing and search for "header reducers". Look at the "HOOKER" brand reducers. They have many different selections. Pick the one that fits your desire the best and get something like that. These reducers are solid and NOT a mounting ring with a piece of flimsy pipe in them, that way they last along time and don't leak. Also look at getting a good gasket to fit your headers, I use FELPRO brand gaskets and coat them with COPPERCOAT gasket sealer. I have yet to have a gasket leak and I have run headers for years. There are also good aluminum and copper gaskets available. Mount the header reducers and then weld your pipes to them, that way there is no stress in the pipes to the headers.

[magnethead]

The Headers are made by Hedman. Here's the only ones that physically fit- 3" in, 2.25" out (note: OD measurement), no sensor, 3 bolt flange

Summit
SUM-G4751
SUM-G4751ID
SUM-G4750SS
HED-21100
HED-16010

[piecesparts]

Originally Posted by magnethead

The Headers are made by Hedman. Here's the only ones that physically fit- 3" in, 2.25" out (note: OD measurement), no sensor, 3 bolt flange

Summit
SUM-G4751
SUM-G4751ID
SUM-G4750SS
HED-21100
HED-16010

HUH?????? The Hooker outlets are made to fit many different header combos. They do not have to have the seperate pieces like the ones that Summit lists. If you purchase the adapters and they are just a s little smaller than the pipe you are welding them to, then go to a muffler shop and have the pipe swedged to fit, or cut them to fit. I have done it on my truck ---I am running 2 1/2" pipe and used the Hooker adapters to connect to my Cyclone header 3" collectors. I woud not ever use the flanged pipe and collector rings like the SUM-G4751 design is, again. There is to much chance for a leak on them. Take a look at the Summit pages and look at part number HOK-11040HKR and see if that will work.