Ignition timing - odd behavior
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=43159
Printed Date: April-29-2024 at 12:32am
Topic: Ignition timing - odd behavior
Posted By: garykocis
Subject: Ignition timing - odd behavior
Date Posted: July-15-2018 at 5:22pm
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I been working through a series of issues with my 1978 Mustang 17 (Ford 302), and had some postings last year. At this time, I'm working to get engine running after having it re-built (2017 winter) and re-assembled (within the last few weeks). I'm a novice, so I'm doing the best I can with information that I can find. I believe that the engine and most components are in reasonably good shape. Engine will run, but it is behaving strangely. Recently, I have done the following: [a] attempted to get distributor in proper alignment by having engine at TDC with rotor pointing at spark plug #1 (and I have checked/double-checked firing order, spark plug wiring). I'll call this position A. At position A, I can't get the engine to start, not even close! The only way I can get engine to start is to rotate distributor clock-wise about 1/2 the distance to the next spark plug post in the distributor cap. I'll call this position B. At position B, the engine will start consistently, but it idles fast as ~1600 RPM (carb idle adjustment will not reduce idle speed). And, when I try to get timing reading I find that it is off the scale completely. So, then I adjust distributor in counter clockwise rotation and when I get back to position A I find that: (a) I can get idle around 1000 RPM, and (b) I can get a timing reading, (c) and I can fine-tune positioning to get a good reading at 12 degrees. In other words, everything seems fine (as best I can tell) at Position A. But, engine WILL NOT start at this position. Does this indicate some issue that I need to fix? I'm thinking it is something obvious to folks who know engines... I am looking for a local mechanic that can set my timing as I expect an experienced mechanic will understand what I happening (I don't). |
Replies:
Posted By: Gary S
Date Posted: July-15-2018 at 5:33pm
We have no idea where you are  ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
garykocis wrote:Posted By: 8122pbrainard
Date Posted: July-15-2018 at 5:34pm
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Gary, Is the mechanical advance free to move in the distributor? They will rust up. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: 8122pbrainard
Date Posted: July-15-2018 at 5:37pm
Gary, I found Gary's location in a previous post.
Gary, What's up with Backyard Boats? Too "backyard" ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: garykocis
Date Posted: July-15-2018 at 6:17pm
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[a] forgot to mention... I'm in northern VA (outside of Washington DC). "mechanical advance free to move in the distributor": I don't know. I'll need to check that, but I'll first need to find the mechanical advance. I think I found you-tube video that will help... Gary |
Posted By: garykocis
Date Posted: July-15-2018 at 6:35pm
| I checked the following for starts since it was fairly easy. Removed dist cap, and checked movement in the rotor. It will rotate/pivot a small amount (about 1/2 the distance between two adjacent contacts in dist cap), and is spring loaded to return to original position. So, I'm guessing that this is related to mechanical advance and indicates that it is not frozen. Unless, I need to do more, partially disassemble distributor to access mechanical advance ... ? |
Posted By: 8122pbrainard
Date Posted: July-15-2018 at 6:56pm
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Gary, Since the rotor does move, it indicates the advance isn't locked up but, you don't know if the advance moves all the way. To check and lubricate, the point plate needs to come out since the mechanical is below it. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: garykocis
Date Posted: July-15-2018 at 7:06pm
| right, I figured I might need to remove that plate to get the complete story. guessing it is worthwhile to spend the time to look into this further. Will look at this Monday (tomorrow). |
Posted By: garykocis
Date Posted: July-15-2018 at 9:18pm
| I checked the movement of the mechanical advance. They are not frozen/bound, and I did lubricate lightly. But I did noticed that the two springs are not a matching pair. One on right is light (almost as light weight as you would find in an old pen) and is engaged/tight. The one on the left is much heavier, and quite loose. Not sure it this is as it should be, or if it is a potential issue.... Attaching picture: |
Posted By: 8122pbrainard
Date Posted: July-15-2018 at 9:25pm
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Gary, The springs are normal. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: SNobsessed
Date Posted: July-15-2018 at 11:45pm
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Gary - Your timing light issue may be because of spark plug wire position. TDC mark on harmonic balancer comes around twice, so maybe it was not on correct part of cycle. Also, are you calling #1 as the front starboard plug? Sorry if this info is too basic. Hope you get it figured out soon! ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: garykocis
Date Posted: July-16-2018 at 12:03am
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Not too basic, and I appreciate all comments/ideas that I get. Yes, I am considering front starboard plug as #1. I should have mentioned that I have not confirmed that I have the correct cycle. My machinist said he delivered the engine at TDC. I've been meaning to check this as well. I'm planning on using the wood dowel method. |
Posted By: gt40KS
Date Posted: July-16-2018 at 12:07am
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OR the thumb over the #1 plug hole method ... which ever works best for you ------------- JCCI 1995 Ski Nautique GT40 |
Posted By: SNobsessed
Date Posted: July-16-2018 at 10:09am
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Just keep in mind that the wood dowel won't tell you when both valves are closed. The thumb method would be positive on that. ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: garykocis
Date Posted: July-16-2018 at 4:16pm
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Ok, didn't realize that - thanks! So, if I do have the true TDC and spark plug #1.... then I'm still lost in terms of what I'm seeing when starting/running this engine.... Anyone else ever run into this situation? |
Posted By: KENO
Date Posted: July-16-2018 at 4:50pm
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What is your firing order?, you mention that you've double checked it but never have said what it is. Are you saying the rotor is pointing at the terminal you're using for #1 plug wire or that it's pointing at the #1 spark plug? The rotor can point anywhere and as long as it's pointing at a terminal in the cap that terminal becomes #1 If the rotor is in between terminals, rotate the body of the distributor either way till the rotor is pointing at a terminal and that's your #1 and then you install your wires going CCW from there following the correct firing order.. The rotor doesn't have to point at #1 plug on the engine like some instructions will tell you. It's one of those things that's harder to try to explain that it is to do for the first time. |
Posted By: garykocis
Date Posted: July-16-2018 at 6:02pm
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ok, my firing order is: 18456273 (per plate mounted on engine). right, in what I called Position A: rotor is pointing to distr cap terminal for spark plug #1. I have it pointing directly at #1 with engine at TDC (I still need to do the check to make sure I'm not off by 180 degrees). Engine refuses to start in this position, and only starts if I rotate it CW to be about 1/2 way to the next spark plug terminal. But at that position (my Position B) the engine doesn't run correctly (idle speed, timing, etc.). |
Posted By: KENO
Date Posted: July-16-2018 at 9:55pm
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It all sounds good. It's the right firing order for a 78 ish 302, if by some chance you ended up with an early 302 cam during the rebuild you'd have running issues but not these wacked out timing indications.. When # 1 is at TDC on the compression stroke is the timing pointer pointing at 0 on the harmonic balancer? |
Posted By: garykocis
Date Posted: July-16-2018 at 11:39pm
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So you've hit the right question. Following the earlier suggestion I did the 'thumb' test to find compression stroke on #1, and I am WELL away from 0 degrees. As best I could estimate, I am 1/3 of a rotation from 0 degree mark. In other words, if my 0 degree mark is at 12 o'clock, the compression stroke would have been at 4 o'clock on the harmonic balancer. How does this happen, what does it mean, and what can I do about it? I suspect it means the guy who re-built my engine did something wrong! Feeling nervous here... I'll admit this was the first time I tried to find compression stroke with thumb over spark plug #1 opening. It was a fairly subtle amount of pressure, but I repeated it a few times to be confident that I was doing it correctly.... |
Posted By: garykocis
Date Posted: July-17-2018 at 1:18am
| just thinking through this process.... IF something is not aligned as it normally would be, then can I find which spark plug is on compression cycle when HB is at 0 degrees, and align the rotor to point at the corresponding contact in the distributor cap? or, is it more complicated than this....? then, set timing using that spark plug wire (instead of #1). |
Posted By: MourningWood
Date Posted: July-17-2018 at 1:31am
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Here's another thing you can do to double check...remove the starboard side valve cover, and watch the cylinder #1 valves as you manually rotate the engine (the correct direction). When you see the intake valve close, the next time the piston is at the top of cylinder (firing position). you're at TDC #1 firing position. some folks then make a mark on the damper at the timing pointer. (which hopefully indicates "TDC" or "O". on the damper). ------------- 1994 Ski Nautique "Riot" 1964 Dunphy X-55 "One 'N Dun" 'I measured twice, cut three times, and it's still too short!" |
Posted By: KENO
Date Posted: July-17-2018 at 8:23am
I may have hit on nothing with that question. Don't feel nervous yet. Using the thumb over the hole method, you feel slight air escaping on the whole compression stroke and if you had air escaping for the last 1/3 of rotation sounds right. Using the thumb method all it really tells you is that with the air escaping you're on the compression stroke and you stop turning the engine when the pointer is at 0 on the balancer. In other words your thumb tells you that you're on the compression stroke, and in no way can you use your thumb to know you're at TDC without looking at the timing marks, or the valves like mentioned a post or 2 back or the distributor rotor. This assumes everything is correct, like the timing chain was put on correctly.with the timing marks on the cam gear and camshaft gear properly lined up. If you mark the distributor housing where your #1 terminal is on the cap, and do the thumb test with the cap off, you should see the rotor pointing to that mark when your pointer is aimed at 0 on the balancer. How about a picture of the pointer/balancer? I seem to remember reading that you have an electronic conversion, what kind is it? If it's a Pertronix is it the Ignitor (black module) or Ignitor 2 (red module)? |
Posted By: TRBenj
Date Posted: July-17-2018 at 9:06am
I would pull on this thread a bit more. Ford used a few different pointer locations so if the balancer was replaced during the rebuild with one that mismatched your zero timing mark with your pointer location, that would have the effect you describe. Confirming the actual location of TDC with a piston stop would be a good idea. You aren’t 180 off if you have the correct firing order and the engine starts, FYI. |
Posted By: KENO
Date Posted: July-17-2018 at 9:37am
| The best picture would be with #1 at TDC then you take the picture of the pointer/balancer |
Posted By: garykocis
Date Posted: July-17-2018 at 8:35pm
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Thanks for all the useful comments/ideas. Yes, I have a Pert Ignitor (black). I will upload some pictures this evening (if my rain stops here). Harmonic balancer and pointer are original (at least, I know they weren't changed in the recent re-build). I will pull the valve cover and find position where plug #1 valves are closed. I also have a dial caliper with a depth measurement so I should be able to accurately find the top of piston cycle (if I need to be precise).. I'm going to assume that this (with the thumb/air pressure) will let me find TDC. I'll take pictures, and mark this position on harmonic balancer. |
Posted By: garykocis
Date Posted: July-17-2018 at 9:53pm
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First I'll add some comments, then two pictures. When engine is at 0 degree mark: I get a measurement of ~ 1.25 inches to the #1 piston. If I rotate 180 degrees, I measure 5.75 inches. I believe this is as expected. When I rotate crank shaft CCW, I get air pressure about 2/3 of a rotation before 0 degree mark. I can feel air pressure/leakage over a range of 45 degrees (I think). Depth to #1 piston is 4.75 inches. First picture is HB scale when at 0 degree mark. I recently made the silver marks. The one yellow mark has always been there (since I owned the boat) at 12 degrees BTDC. In the second picture, I rotated a bit to show a piece of masking tape (near bottom of HB) which is where I get air pressure on plug #1. As you can see, it is ~1/3 rotation after 0 degrees or 2/3 rotation before. I'm working on valve covers next, might be difficult to get to this evening... Comments? |
Posted By: garykocis
Date Posted: July-17-2018 at 9:57pm
Pictures.... 
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Posted By: KENO
Date Posted: July-17-2018 at 10:19pm
When you took this picture was #1 piston at TDC? Was the rotor pointing at the #1 plug wire terminal in the distributor cap? |
Posted By: garykocis
Date Posted: July-17-2018 at 11:17pm
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Yes, #1 piston is at TDC...depth to piston through spark plug hole is 1+1/4 inches, and that is as close to top as I could measure. Darn, I got busy with valve cover, forgot to check rotor. I'll check that tomorrow (too tired, too dark). After removing valve cover... got what I guess I expected. Intake valve #1 is closed when pointer mark is on the masking tape which is 1/3 rotation past 0 degree mark. You can see masking tape mark in picture #2. |
Posted By: garykocis
Date Posted: July-17-2018 at 11:35pm
| wait a second... don't I have a big problem if both valves are not closed when #1 piston is at TDC??? |
Posted By: garykocis
Date Posted: July-17-2018 at 11:45pm
| Never mind.... I'm twisted up on valve being open/close. I need to look at it fresh tomorrow and check the rotor position as well.... |
Posted By: KENO
Date Posted: July-17-2018 at 11:47pm
Sounds like a plan |
Posted By: garykocis
Date Posted: July-18-2018 at 12:44pm
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I'm loosing my mind. After compression cycle starts (per thumb test), I rotate CCW until 0-degree mark. At this point, my rotor is points AWAY from #1 plug contact on distr cap. So, seems like I am 180 degrees off??? #1 piston is at top of it's cycle. Is there a full-proof way to know what is happening with valves (open/close)? At this position (TDC), I see that #3 intake valve is stiff and #4 exhaust valve is stiff (stiff as in locked in a position). Both of the #1 valves are not stiff (I can wiggle the rocker arm). I believe that both of #1 valves should be closed at TDC - right? |
Posted By: Gary S
Date Posted: July-18-2018 at 12:57pm
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I think your over thinking this.... What you could do pull all your wires off the cap. then where your rotor is pointing to is where the number one sparkplug wires goes to. Then follow your firing order and connect up the rest of the wires. Or the possibly more difficult way would be to pull the distributor out turn the rotor shaft to where you want it and drop it back in. Then again where the rotor points to is where number one cylinder plugwire connects Problem here for the inexperienced is sometimes the oil pump drive shaft,which seats into the bottom of the distributor shaft,does not line up easily and fights you as you try to seat the distributor into place. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: GottaSki
Date Posted: July-18-2018 at 1:50pm
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Have we yet determined that Gary has not misconstrued the #1 cyllinder on a Ford, like some others have? ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: Gary S
Date Posted: July-18-2018 at 2:41pm
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No your right just assumed 😳 and you know how that goes. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: KENO
Date Posted: July-18-2018 at 2:59pm
A quote from Gary K earlier in the thread
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Posted By: SNobsessed
Date Posted: July-18-2018 at 5:25pm
No cam/lifter pressure on pushrod means valves are closed. Sounds like you just need to reset you plug wires & you should be good to go. I think it is a miracle it ran at all, with plug wires 180 off! ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: KENO
Date Posted: July-18-2018 at 5:40pm
It would take more than a miracle to make it run timed 180 out There have to be some missing items in his timeline, such as when he took the distributor partially apart, did he take off the advance plate? If he did it's easy to put it back on 180 out and then your timing is ..................180 out. I'm not sure he's tried to start it since then Then again there is the TRBenj half miracle that we won't mention here, yet anyways |
Posted By: garykocis
Date Posted: July-18-2018 at 10:23pm
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ok, so I was also having difficulty believing I was 180 out. I repeated the exercise with an assistant (yes, my wife) and I pulled all the plugs to make life easier. I think I was confusing a suction with a positive air pressure. So, with a helper we definitively found the compression cycle. once I had that, continued to 0-degree mark and I'm confident this is the correct TDC position. Checked rotor... it is pointing to distr cap contact for #1 plug. So, after a bunch of diagnostic work - I am back to exactly where I was at the start. I haven't changed the distributor position at all. I'm convinced that I had correct initial timing position from the beginning. Don't have time to try it tonight, but I have no reason to believe anything is different from what I had initial posting a few days back. ??? |
Posted By: garykocis
Date Posted: July-19-2018 at 10:59am
Resistor picture as is: |
Posted By: garykocis
Date Posted: July-19-2018 at 8:36pm
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I wanted to check the firing rotation which plugs were out. So, starting from TDC (where piston #1 is at TDC), I rotated the crank shaft 1/4 turn (8 times) and checked to see which piston was at TDC. I got the following: 0/4: 1 and 6 1/4 : 2 and 8 2/4: 4 and 7 3/4: 3 and 5 So, I conclude that this is aligned with the engine firing order, by working top to bottom and alternating left and right: 1 - 8 - 4 - 5 - 6 - 2 - 7 - 3 Eliminates the possibility of having the wrong cam shaft (I think).... |
Posted By: SNobsessed
Date Posted: July-19-2018 at 8:45pm
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Going back to original post, did you have a shop assemble the engine? If so why not have them figure this out? Wouldn't it be worth a hundie? ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: garykocis
Date Posted: July-19-2018 at 10:34pm
| That is a wise and logical idea. The one guy I could find to rebuild the engine would only work with the long block. I tore it down to that point, and got it to his shop. He said he only does the machinist work. And, I regret having this guy work on it at all (difficult to work with, communication, etc.). I have attempted to get some info from him, but unsuccessful. I'm open to have a trainer pro help, but it won't be that person. |
Posted By: MechGaT
Date Posted: July-20-2018 at 7:50am
The engine will run at the correct timing, but it won’t start there. It will start with more advance and idles fast. Maybe you said and I missed it, but what’s the condition of your carburetor? When was it last rebuilt? We have been pretty far down the timing route, maybe it is like Ken frequently says “when you think it is ignition, look at the fuel.”  ------------- '92 Sport Nautique |
Posted By: KENO
Date Posted: July-20-2018 at 8:49am
Funny that you mention that. I had a conversation with Gary and that's something that came up, it was rebuilt a couple years ago, but that doesn't mean much, a lot can happen in a couple years of sitting or use.. He gonna look at the rest of the ignition system first like the coil and also bypass his ballast resistor since it's got electronic. ignition It does seem that he's done a very good job of verifying things as far as the timing. One of those little voices keeps saying vacuum leak vacuum leak (like a carburetor base gasket) and the higher rpm,s from the advanced timing let it start and run He'll know his engine pretty well when this is over |
Posted By: KENO
Date Posted: July-20-2018 at 9:13am
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If you get to checking for a vacuum leak Gary, here's a thread with a picture of a likely spot . http://correctcraftfan.com/forum/forum_posts.asp?TID=42091&title=fuel-system-issues-help-please" rel="nofollow - link |
Posted By: garykocis
Date Posted: July-20-2018 at 10:20pm
| Well, too early to crack open the champagne... but - pulled my carb to take a look and found some fuel in places it should be! so, if gas is leaking out I'm sure there was air getting in. going to try a gasket tomorrow, depends on what I can get locally (or I'll order from natique parts and be patient for a few days... |
Posted By: KENO
Date Posted: July-26-2018 at 8:21am
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Just to update this thread, Gary found a vacuum leak at one of the base gaskets http://correctcraftfan.com/forum/forum_posts.asp?TID=43240&title=vacuum-leak-vacuum-leak-thanks-ken-brent" rel="nofollow - link |