Weird ignition timing problem

Page 1 of 2  
I'm working on my 1977 dodge 360-3 engine. At first it was running OK. then I needed to pull the distributor to replace the oil pressure transmitter. I
put the distributor back (aligned with old marks and now I get some really back backfiring; flames shooting up from the carburator. I checked that #1 piston is at top of travel and timing mark is at zero and rotor is pointing at #21 plug wire. ???????
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
do you mean cyl number 2? I'm assuming you have adjusted the timing with a timing light?
firing during the intake stroke is what causes flames shooting out the carb. majorly out of time. make sure its on the compression stroke and distributor is in time.
how many miles on the engine? what kind of condition is the distributor in ?

then
I
pointing
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
No; I mean cylinder #1, (NOT 21) and I did check that piston is full up with timing mark at zero. I know of no other way to determine that it is the compression stroke.
And yes, it does seem like it's firing on the intake stroke but that doesn't make any sense based on the above.
Milage is about 34,000, and distributor is in good condition.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

then
I
pointing
Your probably 180 degrees off, just because the number one piston is up doesn't mean it is on the compression stroke, you have to know where the camshaft is. Its been a long time since I worked on these but that is what I could suggest. If it worked before you took it out and now it doesn't I would back track
Glenn Beasley Chrysler Tech
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
It sure sounds like it is 180 out but why do I have a timing mark at zero??
Also found that spark is very weak, will look into that but can't see why that would give me the problem I'm having.
Thanks for the input
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
The crank turns 360 degrees for every 180 deg of distributor / cam rotation so the timing mark (and piston) come to the top twice for every revolution of the cam and therefore distributor. yes if your 180 out it's firing number one at the top just at the top of intake stroke not power stroke! 4 strokes 1 power mixture fires driving piston down 180 deg cam goes 90 2 exhaust is released / forced out through open exhaust valve 180 to top cam moves 90 deg 3 intake stroke, mixture is drawn in through open intake valve. engine moves 180 deg cam and distributor turn 90 deg 4. Compression mixture is compressed as piston goes from bottom to top 180 deg cam and distributor go 90 deg. full cycle through the four strokes has crank turning 720 degrees and cam and distributor 360. Distributor only fires every other revolution, cam only has events happen every other revolution.
Cam gears are 2 to 1 ratio cam gear has twice as many teeth as the crank gear so it takes two full revolutions to turn cam and distributor once. moving the distributor 180 degrees you are moving it 360 crank degree's! Hope that helped. Dodgem
Now a two stroke fires at the top of every revolution has no cam and poor power especially at lower rpms.
Issy wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
It's a four cycle engine. It takes two revolutions of the crankshaft to make the four cycles. From zero, cylinder 1 piston will travel downward on the intake stroke, then back up for the compression stroke. When the piston is at the top of the cylinder, your timing mark will be on zero. Then the power stroke occurs, the piston travels downward again, then back up on the exhaust stroke, where the timing mark will be on zero, again. Quick way to find the top of the compression stroke, remove the spark plug for cylinder 1, stick your finger in the spark plug hole and have someone MANUALLY turn the engine until your finger is forced out of the hole.
Larry Behold Beware Believe
| It sure sounds like it is 180 out but why do I have a timing mark at | zero?? | | Also found that spark is very weak, will look into that but can't see why | that would give me the problem I'm having. | | Thanks for the input | |
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I understand the piston travel during intake, compression, firing and exhaust. I more or less did what you suggested(used screw driver instead of finger). With piston full up the rotor points at #1 plug wire and the timing mark is at zero.
I had a weak sapark (about 1/4 inch) out of the coil and practically noting at the plug wire end. I replaced the coil and now have about 3/4 inch spark out of the coil but only about 1/4 at the plug wire end.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
But if it's firing 180 degrees out (360 crankcase deg)it will still set the carb on fire. great thing about an old Dodge they are either in right or 180 out no teeth on the distributor just the slot! Barry A. Lee
Issy wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
In article

From what you write below, apparently you do NOT understand.
Your timing mark will line up under two circumstances; 1) when #1 cylinder is at top dead center. 2) when #6 cylinder is at top dead center. Your screwdriver will NOT allow you to know which is the case.
Do as Max said and FEEL for when there is compression in the cylinder! Or; save yourself the grief and re-index the rotor 180 degrees.

Now rotate the crankshaft exactly 360 degrees, the rotor will be pointing at the #6 cap terminal. IOWs, the rotor is 180 degrees off as evidenced by the flames barfing out of the carburetor.

Weak spark doesn't usually cause backfiring. You're grasping for a solution and ignoring the correct advice that you've been given.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I think these distribs are same as big block with the drove shaft having a slot in it rather than a gear so maybe trying taking it out and putting it in 180 degrees

transmitter.
really
#1
I
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

that
what
Good idea
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
You are missing a basic point with removing the #1 plug and using that to find #1 TDC.
Sticking a screwdriver in the #1 plug hole will only tell you when it is at the top of its stroke. It could still be 180 off.
Put your finger over the hole and having someone manually turn the engine in its proper direction, then when air forces itself past your finger you are comming up on the compression/ firing stroke. Align your timing mark on the balancer to where it needs to be and align the distributor so it is pointing on #1 wire and you should have it.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Theres a lot of truth I the old saying that there is no fool like an old fool. I was positive that I did not rotate that shaft 180 and it was hard for me to take your advice. But eventually I did what I should have done and rotated it 180 and, as you well know, it solved my problem.
Thanks for you help and patience.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
We know cause we have all been there more than once ourselves! Dodgem
Issy wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

old
hard
And I thought I was the only one!!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

Not a chance, buddy. Don't believe there is a mechanic alive that's worked on those older engines that hasn't done it at least once.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@sny.der.on.ca wrote:

The Slant Six can be trickier. You can get it off by any number of gear teeth, not just 180 degrees. And if somehow you get the distributor cap cocked so the rotor catches on it (some of the older aftermarket caps were just a teensie bit off-spec and could go on crooked if you weren't careful), the camshaft will strip the plastic distributor drive gear as soon as you crank the engine.
Better the plastic distributor gear than the camshaft!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

done
Ok Ok so you caught me, I did it twice
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I found the solution to the slant six problem. ONLY remove the distributor with the rotor pointing straight up. Don't know why, but as long as you don't turn the engine over with the dist out, you can drop it back in perfectly every time. ANY other position you'll do it AT LEAST twice.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.