delayed ignition timing
 

I bought a vacuum gauge and today was trying to tune up my 360 but the vacuum gauge needle always stays on "Delayed ignition timing" red section.

Can this be solved adjusting the initial timing advance or maybe I have vacuum leaks or timing chain problems?

https://moparforums.com/forums/attac...1&d=1397779291

You might not have it hooked to manifuld vacuum. Can you shoot a photo of where you have the gauge hooked?

I believe you must have a timing light and tachometer to do a proper and full engine timing diagnosis. Stop guessing and go back to the basics and be systematic confirming or eliminating each problem as you go.

To check your timing chain for stretch, move the crankshaft back and forth until you feel the valve train resistance. This can be done moving a non clutch fan having the belt turn crank or a socket wrench on the crank bolt. 5 degrees is acceptable, 10-15 degrees is not.

Can you tell us what distributor you have?

Here's where I hooked up the gauge vacuum line, the other vacuum lines are caps and the big one is booster vacuum line, I already tried unhooking all and putting new caps but the result is the same
https://moparforums.com/forums/attac...1&d=1397842072

I'm doing the tuning with vacuum gauge and tachometer, I tried with 550, 650 and 750 RPM at idle but the result is the same, at 750 RPM the vacuum signal is a bit better but the gauge stays at "Delayed ignition timing". I tried to move the crankshaft but only moves a bit and is very hard to move. This is my distributor

The description says nothing about mechanical advance, not knowing and adjusting without a timing light is guessing and possibly harmful to the engine.

When you say "tuning with vacuum gauge" are you twisting the distributor to see results or just setting idle mixture?

No I didn't touch distributor but when I install the new distributor I set it to 8 degrees of initial advance I'm only touching idle mixture screws and idle speed

You need a ported vacuum source from the carb for the gauge

My vacuum advance hose is hooked to the highlighted (red) carburetor vacuum port. Can I use the other vacuum port or which must be better?

https://moparforums.com/forums/attac...1&d=1397869018

Uh, wrong. You want the vacuum gauge hooked right where it is........to full manifold vacuum. Where do you believe ignition timing to be, and have you checked timing marks with a piston stop?

Ask the full complete question..........What lead up to this? What is going on? Do you believe the cam timing is off? This could be as simple as a frozen (stuck) mechanical advance

Vacuum gauge is good, distributor to ported vacuum.

You need to put a light on this and record timing at what RPM with vacuum advance disconnected and plugged.

Is the cam different than stock oem?

Camshaft and pistons are stock

The initial advance should be 8 Degrees, that was where I set it five months ago (I'm going to check it again).

The main reason of this tuning was that I felt the car out of tuning and start to shut off at WOT, I checked the spark plugs and all looked bad so I replaced them with a new set of champion 404 (I was using motojunk motorcraft). I hooked the vacuum gauge to start the tuning process and the gauge was showing only 12 ~ 13 vacuum, I started dealing with idle mixture screws and idle RPM until it started to show 15 ~ 16 vacuum but no cares what I do, it doesn't reaches 20 inches of vacuum.

Now at idling the engine feels a lot better but stills feeling a bit out of tune and shaking a bit. I'm going to check the timing advance and post the results

Can be safe to set the initial advance at 10 or 12 degrees?

Really want you want to do is to set the idle advance (initial advance) for best vacuum. But if this CHANGES dramatically, this would be an indication that something mechanically changed most likely the cam drive IE timing chain

Without knowing what mechanical advance is in the distributor raising initial could make your total too much. When you retime it see when mechanical starts and at what RPM total is.

I checked the initial advance and it was 7 degrees instead 8, I set it to 11 degrees and now I have a better vacuum signal, the engine stop shaking, idles a lot better and responsed better to throttle but the vacuum gauge still not reaches 20 vacuum signal. Here's a video, maybe this can help:

http://s1067.photobucket.com/user/jo...6220f.mp4.html


How can I check the total advance? someone said me to rev the engine with the timing light plugged and when the advance stops increasing that was the total advance. Is this a safe method or there's something better?

Must have been having a senior moment !

That is the best way for you to check total with vacuum advanced disconnected and plugged.

Have you turned crank back and forth to check chain slack?

You might want to confirm your TDC mark before doing total just to be sure.

How did you set it for 11 deg ????? You NEED A timing light !!!!

One of the HEI dist.. ported goes to the vacuum advance

I'm using a timing light, I unhooked the vacuum advance, connected the light source to cylinder #1 and set it a bit before the 10 degree mark

Yes I used a torque wrench but the crankshaft only moves a bit, is this te right way to check or must I remove all the accesories belts?

Can all this be part of the problem that I showed on the video that the engine dies on hard acceleration?

The crankshaft and pistons will move clockwise and counterclockwise easily without any valve springs, they are the resistance you will come up against. If you moved it both ways up to the resistance with few crank degrees the chain is not too slack and the belts should not change how it feels.

I think what I would do knowing I have low vacuum and it stops at WOT is do a hot compression test and a cylinder air pressure test. I`m thinking there is more going on then what timing can solve.

That sounds like some went wrong with the engine rebuild :(:(

is there a way to do the compression test with the vacuum gauge?
Can you explain me what is an air pressure test?

Here's more information, maybe can help with the problem diagnosis

1. I think the engine oil pressure is low, some time ago while idling a bit fast (maybe 800 RPM) the oil pressure was 55 ~ 60 PSI right now idling at 550 ~ 600 RPM is 25 ~ 30 PSI
2. I don't know if is normal but there's a bit water steam on the valve covers, when I remove the oil cap after being idling 10 minutes I can see water steam coming out the valve cover and some waterdrops on the oil cap. I checked the engine oil and is over the full mark but isn't milky and checked the radiator coolant and seems to be fine.

Compression test will need an actual compression testing gauge.

The air test uses a spark plug adapter to pressurize the cylinder with the piston at tdc, watch that the engine dosn't turn quickly as the pressure may push the piston down.

Air heard at carb is leaky intake valve, at exhaust pipe is leaky exhaust valve, at valve cover is rings and any bubbles at radiator is bad.

The steam on the valve cover could be a small leak at the front of the manifold.

The droplets under the fill cap can be considered normal and could go away after a long hot drive but I would check to see if my PCV system is operating correctly.

I just now looked at your video and noticed the PCV fitting at the carb is plugged.

I would start right with the basics here. I have learned over the years to ASSUME NOTHING

1.....Do not assume that the timing marks are correct. The balancer is a two piece deal with a rubber in between and can sometimes move. In addition, "different engines" over the years have different timing marks. Early / late small blocks are a good example. USE A PISTON STOP to verify timing marks. This is marked "1" for good reason. This is the VERY FIRST STEP

2.....Next is to determine cam timing. If you have a "stocker" cam, you can do this simply by verifying cam timing events. You can even do this by estimating valve timing. For example, refer to the shop manual, you can download some here:

http://www.forabodiesonly.com/mopar/...p?p=1970088617

and here

http://www.mymopar.com/index.php?pid=31

and there are procedures in there to estimate cam drive wear. However, this assumes WEAR from a PROPERLY installed FACTORY timing chain/ sprocket set. This is not geared toward performance cams, nor IMproperly installed or performance cams

But if you can get the valve timing specs on your cam, and you SHOULD be able to, you can estimate this. The intake valve will open something in the 20* range BTC, which is easy to measure. You can easily see this and that can be easily checked without special tools.

Otherwise, "rig" a degree wheel, indicator, and actually measure the thing.

3.....Ignition timing. Basics apply. The mechanical advance must be free and working. I NEVER apply vacuum advance when troubleshooting a problem such as this until I figure out what is going on, then leave that "for last." So leave the vacuum unhooked until you get this figured out. If you have one of those fancy "dial up" timing lights, suspect it as part of the problem until you get it figured out.

4......Vacuum leaks and other ilk. Don't discount anything. Could be a cracked vacuum line, leak(s) at the carb, booster line or ruptured booster, most anything. Squirt water around suspect areas and listed for changes in idle. Do the carb idle screws "evenly" affect idle quality? They should be pretty much evenly "unscrewed"

5......Unforseen. There's always a chance the vacuum gauge itself is out of calibration or just plain defective. Don't forget, it's nothing but a pressure gauge.

well. I know the "air pressure test" like "Leak down test" :)

I did the compression test, these are the results on dry:

Cylinder # Pressure PSI
1: 105 PSI
2: 110 PSI
3: 100 PSI
4: 105 PSI
5: 105 PSI
6: 102 PSI
7: 95 PSI
8: 108 PSI


should I repeat the test using a putting some oil on each cilinder?
I think the compression is a lot low, I was expecting something like 125 PSI

I didn't the leak down test because I don't have the necessary gauge. Should I get one and do the test or with this results is enough?

1. Now that you mentioned that, when the mechanic was rebuilding the engine he told me that he can't find the timing mark on the damper and next he told me that the damper was moved but him placed it correctly again, but now I have doubts about how correctly it is. I didn't find the mark "1" but I know which is the number 1 cylinder, I put it on TDC but don't see anything on damper (I known it was on TDC because I put a little sheet of paper on spark plug hole and when the compressed air blew it out the hole, I used a screw driver to feel when the piston was on top)

2. I'm going to download some of that manuals and try to understand how to calculate the valve timing. I think that manual should be fine because my camshaft, timing and sproket timing are factory specs, I don't have any high performance part installed.

3. I tried unhooking the vacuum advance but nothing happened.

4. I found vacuum leaks on some hose caps, I think they're already fixed but the vacuum signal doesn't changed also I think will be better to replace all the homemade hose caps. Is there a good online shop to buy them?

5. mmm well that could be a good point because the engine now feels a lot better. How can I be sure that the gauge is not the problem?


There's other point and I think maybe is related to this problem: When I removed the spark plugs to do the compression test I notice that most of them (maybe five or six) are black like a symptom of a too rich fuel mixture and the spark plugs have been only for 3 days on the engine and I have not driven the car, just did some tests on garage. I think this can be related to this problem because the low vacuum signal is not enough to move the carburetor needles so the mixture isn't correct. Is my theory fine or maybe this is a symptom of a carburetor or big vacuum leak problem

I hope you did your compression test with engine warm, all plugs out and carb fully open.

The plug colour should be looked at. When you screw in both idle mixture screws does the rpm drop to a point where the engine will stop when screwed in all the way?
If it does not then you have a problem, possibly fuel bowl level.

Yes, the engine was working for 10 minutes after the compression test and carburetor fully open but not all the plugs out, only the cylinder that I was testing. Most of the plugs was black colored, only two or three of them was brown colored.

Now you talk about the idle mixture screws I have this problem: When the engine is working without the air cleaner I can hear the normal carburetor whistle but If I close all the left mixture screw that whistle dissapear and engine turns unstable but not stops, If I only manipulate the right mixture screw the whistle doesn't change but If I close it the engine stops. is this normal?

Do you think is necessary to repeat the dry compression test and try with a wet compression test?

If you follow up your warm compression test with a wet one it will show if rings are worn.

Try turning them both in 1/4 turn then both in another 1/4 until it stops. If it stops that is good and they are working and you have control of your idle circuit.

Count the number of turns, they should be the same within 1/4 turn of each other and 1 1/2 - 2 turns out.

Yes, the engine usually responds at the same turns of each idle mixture screw, the problem is that for example If I turn the right mixture screw 2 turns the engine stops but if the left mixture screws turns 2 times the engine doesn't stop but turns very unstable.

Tomorrow I'll do again the compression test

I just did again the compression test but the results are very similar. I removed all the spark plugs, throttle body full opened, let the engine warm for ~12 minutes and used SAE 10 hydraulic liquid for wet test

Cylinder # Pressure PSI Dry / Wet
1: 125 / 120 PSI
2: 115 / 110 PSI
3: 105 / 110 PSI
4: 110 / 110 PSI
5: 105 / 105 PSI
6: 105 / 105 PSI
7: 95 / 100 PSI
8: 105 / 105 PSI

Good work. Now it's time to get your best idle and find your total advance at what RPM.