Top-End Problem
03-29-2014, 10:56 AM
#21
Moderator
Join Date: Dec 2005
Location: Hills of California
Posts: 5,208
You sure you counted good? Barnett is going to be pissed.
So if you are sure the order is right but its not firing like it ought to then Racer Dave makes a good point....we cant assume that plug #1 is correct
Can you see the timing marks on the damper wheel as shown in the drawing?
You'll have to roll the engine over by hand using a 15/16 socket, ratchet and 2 foot long cheater bar on the handle of the ratchet
Roll the engine over until the pointer (the pointer is probably the aluminum protrusion with a hash mark on it that comes off the timing chain cover) is aligned with the TDC mark on the damper wheel
The problem is we have 2 TDCs. TDC during exhaust stroke and TDC compression stroke. We need the engine to at the TOP of the compression stroke and the pointed aligned to the TDC mark.
How the hell do I know if its TDC compression you might ask???
A simple way is to feel for it. During compression stroke both the exhaust and intake valve are closed so no air can escape from that cylinder. Remove the spark plug from #1 cylinder and place you finger over the plug hole while a helper rotates the engine (turn it to the right) with the ratchet and cheater bar.
When the piston is moving up the bore you'll feel this air escaping past your thumb as you attempt to plug up the spark plug hole roll the engine over a few times until you get to know how it feels
Roll the engine over until you feel the air rush past your thumb this is compression stroke. NOW watch the damper wheel timing marks and continue to rotate the engine until the TDC mark is aligned with the pointer.
Now remove the distributor cap
Where is the metal part on the rotor pointing? That would be plug #1 regardless of the wires actual location...put a big sharpie mark on that one and try last nights process over again for firing order.
-Gun
So if you are sure the order is right but its not firing like it ought to then Racer Dave makes a good point....we cant assume that plug #1 is correct
Can you see the timing marks on the damper wheel as shown in the drawing?
You'll have to roll the engine over by hand using a 15/16 socket, ratchet and 2 foot long cheater bar on the handle of the ratchet
Roll the engine over until the pointer (the pointer is probably the aluminum protrusion with a hash mark on it that comes off the timing chain cover) is aligned with the TDC mark on the damper wheel
The problem is we have 2 TDCs. TDC during exhaust stroke and TDC compression stroke. We need the engine to at the TOP of the compression stroke and the pointed aligned to the TDC mark.
How the hell do I know if its TDC compression you might ask???
A simple way is to feel for it. During compression stroke both the exhaust and intake valve are closed so no air can escape from that cylinder. Remove the spark plug from #1 cylinder and place you finger over the plug hole while a helper rotates the engine (turn it to the right) with the ratchet and cheater bar.
When the piston is moving up the bore you'll feel this air escaping past your thumb as you attempt to plug up the spark plug hole roll the engine over a few times until you get to know how it feels
Roll the engine over until you feel the air rush past your thumb this is compression stroke. NOW watch the damper wheel timing marks and continue to rotate the engine until the TDC mark is aligned with the pointer.
Now remove the distributor cap
Where is the metal part on the rotor pointing? That would be plug #1 regardless of the wires actual location...put a big sharpie mark on that one and try last nights process over again for firing order.
-Gun
03-29-2014, 01:38 PM
#22
Thread Starter
Join Date: Mar 2014
Location: Georgia
Posts: 12
I pulled plug 1 and put one of my wife's cotton ***** gently in the hole. I spun the engine using the fan and pressure on the belt, which spun the engine and the distributor (I have the cap off). The cotton ball popped out when expected, and based on where the distributor was - at that moment - everything is "set up" the right way. Actually disappointing that this wasn't it. Does it suggest anything that it is every other cylinder out of the 8 that is appearing to not be firing? Two on each side of the engine. I will post some pictures of the wires to attempt to show they are correct.
Doug
Doug
03-29-2014, 02:33 PM
#23
Thread Starter
Join Date: Mar 2014
Location: Georgia
Posts: 12
Here are some pics showing the wire order. As above, it SEEMS to me that TDC is correct and 1 is, in fact, 1. Taking the implied suggestion from above, I pulled all four of the "not firing" wires at the same time (shocked my self twice - so no need for coffee today...) and the car ran ALMOST the same. When all 4 were off, I could detect some difference in the idling of the engine - so maybe its only 3 - but I tried to upload a video showing it running on four - note it is every other cylinder. I pulled both idle screws, and shot carb cleaner in the holes. I reinstalled and backed them out 1.5 turns and this was "ok" and when I backed them out a total of 3, it was a little smoother. I guess I am back (credit above) to something bad in the carb. Any final thoughts? I hate to keep bothering everyone when I am really shooting in the dark....
Doug
Doug
03-29-2014, 05:04 PM
#26
4th Gear Member
Join Date: Nov 2013
Location: arizona
Posts: 1,398
you are not bothering us with questions. the only think that bothers us is that you are too sissy to put your finger in the plug hole to feel for compression and you use your wifes cotton ***** instead.
ok your wires must have been wrong because i said they were, lol.
actually they still look wrong in the orig photo but they are correct for sure in the second photo.
i never would have told people that i used my wifes cotton ***** in the plug hole instead of being a man and having your neighbor stuff his finger in there and feel for compression.
i would do a compression test with the distributor wire disconnected and the throttle open.
does the bad carb screw now work?
does it run bad above idle?
in other words is it an idle related problem only?
have you driven it?
how does it run while driving?
what do you mean "the jets are weak"?
when did thid car last run good?
if the dist cap is not new install a new one.
TEST
1. put your timing lite on every plug wire, if it does not flash on a wire that wire or plug is bad.
2. remove number 1 plug.
remove dist cap.
stick a long thin screwdriver in the plug hole.
have someone rotate your eng slowly until the piston comes up and then starts to go down again.
mark the flywheel at the timing mark on timing cover.
while closely watching the dist rotor, rotate engine counter clockwise until it just barely moves.
mark the flywheel again.
measurte the distance between the two marks on yhe flywheel.
if they are more than around 1/2" apart, your timing chain should be replaced.
if they are around 1" apart or more it will likely not run properly until the chain is replaced, however tgis is only part of your prob.
now continue turning counterclockwise until the piston feels like it stops moving.
look at the timing mark. if it is more than around 1" off your timing chain has likely jumped a tooth. if it is the original chain it likely disenterrated because they have plastic teeth and that is what they do, yup brilliant huh?
VIDEO - Load it to youtube.com then post a link here.
ok your wires must have been wrong because i said they were, lol.
actually they still look wrong in the orig photo but they are correct for sure in the second photo.
i never would have told people that i used my wifes cotton ***** in the plug hole instead of being a man and having your neighbor stuff his finger in there and feel for compression.
i would do a compression test with the distributor wire disconnected and the throttle open.
does the bad carb screw now work?
does it run bad above idle?
in other words is it an idle related problem only?
have you driven it?
how does it run while driving?
what do you mean "the jets are weak"?
when did thid car last run good?
if the dist cap is not new install a new one.
TEST
1. put your timing lite on every plug wire, if it does not flash on a wire that wire or plug is bad.
2. remove number 1 plug.
remove dist cap.
stick a long thin screwdriver in the plug hole.
have someone rotate your eng slowly until the piston comes up and then starts to go down again.
mark the flywheel at the timing mark on timing cover.
while closely watching the dist rotor, rotate engine counter clockwise until it just barely moves.
mark the flywheel again.
measurte the distance between the two marks on yhe flywheel.
if they are more than around 1/2" apart, your timing chain should be replaced.
if they are around 1" apart or more it will likely not run properly until the chain is replaced, however tgis is only part of your prob.
now continue turning counterclockwise until the piston feels like it stops moving.
look at the timing mark. if it is more than around 1" off your timing chain has likely jumped a tooth. if it is the original chain it likely disenterrated because they have plastic teeth and that is what they do, yup brilliant huh?
VIDEO - Load it to youtube.com then post a link here.
Last edited by barnett468; 03-29-2014 at 05:34 PM.
03-29-2014, 07:16 PM
#27
Moderator
Join Date: Dec 2005
Location: Hills of California
Posts: 5,208
Assuming plug wire 1 lines up with the rotor point at TDC compression I also now agree your firing order is correct.
I suggest using the timing light method to verify spark on each wire before doing anything else.
I am surprised it ran at all on only 4 cylinders
I suggest using the timing light method to verify spark on each wire before doing anything else.
I am surprised it ran at all on only 4 cylinders
03-29-2014, 09:09 PM
#28
3rd Gear Member
Join Date: Aug 2009
Location: Michigan
Posts: 516
To be fair, I'd rather use my wife's cotton ***** vs my own...
I think we need to back up a bit. We're looking at the induction because of the way the thread started. I'd go back a few steps...
1- Use the timing light to check spark on each wire, as that will rule out that issue. I'd do this first because it's easy
2- After the engine has been running drop some water on the headers to look for the cold ones. this is next easiest to check.
3- Compression check on all the cylinders. I think a bad pushrod/valve leaking might be part of this issue. The odd pattern of cylinders not firing I think rules out carb issue.
However, the odd pattern of not firing does make me wonder... Do we know if the cam/crank are stock? A long time ago(80's) we used to build a ford stroker motor that ended up with the firing order NOT matching what was on the intake. I don't remember the particulars, but I remember the engine getting claimed and the new owner tore it apart. He found out we weren't cheating, but when he put it back together it never ran right. We bought it back for $200 and put the firing order for the crank/cam that was in it vs what was stamped in the intake and it picked right back up. Could we have the same thing here? different cam/crank in older block so the firing order doesn't match?
I think we need to back up a bit. We're looking at the induction because of the way the thread started. I'd go back a few steps...
1- Use the timing light to check spark on each wire, as that will rule out that issue. I'd do this first because it's easy
2- After the engine has been running drop some water on the headers to look for the cold ones. this is next easiest to check.
3- Compression check on all the cylinders. I think a bad pushrod/valve leaking might be part of this issue. The odd pattern of cylinders not firing I think rules out carb issue.
However, the odd pattern of not firing does make me wonder... Do we know if the cam/crank are stock? A long time ago(80's) we used to build a ford stroker motor that ended up with the firing order NOT matching what was on the intake. I don't remember the particulars, but I remember the engine getting claimed and the new owner tore it apart. He found out we weren't cheating, but when he put it back together it never ran right. We bought it back for $200 and put the firing order for the crank/cam that was in it vs what was stamped in the intake and it picked right back up. Could we have the same thing here? different cam/crank in older block so the firing order doesn't match?
03-29-2014, 09:34 PM
#29
4th Gear Member
Join Date: Nov 2013
Location: arizona
Posts: 1,398
1-3-7-2-6-5-4-8
03-30-2014, 10:34 AM
#30
Thread Starter
Join Date: Mar 2014
Location: Georgia
Posts: 12