289: "Popping" from exhaust?
05-29-2018, 02:01 PM
#12
Banned
Join Date: Jan 2018
Location: Pennsylvania
Posts: 2,327
Those values WERE low, but consistent... Did you test with the engine warmed up for proper ring seating?
It may just be timing... The exhaust valve is partially open on ignition of the fuel. Have you tried
a timing advance?
It may just be timing... The exhaust valve is partially open on ignition of the fuel. Have you tried
a timing advance?
05-29-2018, 02:24 PM
#13
Gentleman's Relish
Join Date: Feb 2005
Location: AZ
Posts: 13,090
Dammit 08 you beat me too it 
Timing too advanced gives you pinging
Timing too retarded gives you a stumble/miss feeling.
10TDC I believe is the factory recommendation on these or after after a rebuild. Start it up and let it warm up. Check the timing with a light to see where it's at for now. Shut it down, Mark the dizzy's position with a line that goes from the dizzy to the intake, start it back up again, then loosen the dizzy nut just enough to get some rotation. Gently and slowly turn the dizzy to advance or retard the timing while listening. See when it sounds best, tighten it down and check it with a timing light see what the actual timing is.
If it's off by a degree or two, the timing chain and gears might just need replacing or if you are off by a lot, you need to realign your dizzy with TDC.
Timing too advanced gives you pinging
Timing too retarded gives you a stumble/miss feeling.
10TDC I believe is the factory recommendation on these or after after a rebuild. Start it up and let it warm up. Check the timing with a light to see where it's at for now. Shut it down, Mark the dizzy's position with a line that goes from the dizzy to the intake, start it back up again, then loosen the dizzy nut just enough to get some rotation. Gently and slowly turn the dizzy to advance or retard the timing while listening. See when it sounds best, tighten it down and check it with a timing light see what the actual timing is.
If it's off by a degree or two, the timing chain and gears might just need replacing or if you are off by a lot, you need to realign your dizzy with TDC.
Last edited by Derf00; 05-29-2018 at 02:26 PM.
05-29-2018, 02:42 PM
#14
Banned
Join Date: Jan 2018
Location: Pennsylvania
Posts: 2,327
Still think it's exhaust valves, not seating or partially open when the fuel
ignites. It can't be from a hot exhaust if it does it from cold.
The only other way, is if you get spark on the exhaust stroke too, and there
is unburned fuel in the chamber.
ignites. It can't be from a hot exhaust if it does it from cold.
The only other way, is if you get spark on the exhaust stroke too, and there
is unburned fuel in the chamber.
05-29-2018, 04:54 PM
#15
Moderator
Join Date: Dec 2005
Location: Hills of California
Posts: 5,208
I dont think it any of those thing
lol
This internet diagnosis is tough.
How did the plugs look? were they even in color or were some black and some white?
How long have you had this car?
When did this problem start occurring?
Did the car sound fine then sat for months and started doing this right when you started it back up?
lol
This internet diagnosis is tough.
How did the plugs look? were they even in color or were some black and some white?
How long have you had this car?
When did this problem start occurring?
Did the car sound fine then sat for months and started doing this right when you started it back up?
05-29-2018, 08:39 PM
#16
4th Gear Member
Join Date: Nov 2013
Location: arizona
Posts: 1,398
A 10 lb difference is not enough to definitively say it is a bad valve or bad rings etc.
05-30-2018, 05:17 AM
#17
Banned
Join Date: Jan 2018
Location: Pennsylvania
Posts: 2,327
Anything more than 15% over OE is not good. So, if all his are supposed to be 120? Well,
all those 95s are bad. 100s, that's 20%, so, it all depends on what it's supposed to be,
compared to what it is, for the percentage calculation. 20% and up, is bad, especially
when the engine is warmed up. You still have to listen to where the leak hissing occurs,
with each piston at TDC:
Oil Fill = Rings.
Intake = Valve(s).
Exhaust = Valve(s).
all those 95s are bad. 100s, that's 20%, so, it all depends on what it's supposed to be,
compared to what it is, for the percentage calculation. 20% and up, is bad, especially
when the engine is warmed up. You still have to listen to where the leak hissing occurs,
with each piston at TDC:
Oil Fill = Rings.
Intake = Valve(s).
Exhaust = Valve(s).
05-30-2018, 01:31 PM
#18
Gentleman's Relish
Join Date: Feb 2005
Location: AZ
Posts: 13,090
I dont think it any of those thing
lol
This internet diagnosis is tough.
How did the plugs look? were they even in color or were some black and some white?
How long have you had this car?
When did this problem start occurring?
Did the car sound fine then sat for months and started doing this right when you started it back up?
lol
This internet diagnosis is tough.
How did the plugs look? were they even in color or were some black and some white?
How long have you had this car?
When did this problem start occurring?
Did the car sound fine then sat for months and started doing this right when you started it back up?
A white coating on the plug can indicate a lean condition and/or a timing issue
But yeah, internet diagnosing by the seat of your pants, literally, is tough.
06-15-2018, 05:28 PM
#20
Join Date: Jun 2018
Location: Washington State
Posts: 12
put a vacuum gauge on a direct port of intake manifold. watch for needle movements. it will help with diagnosis. standard comp test is just a start. it will tell you if there's a problem, but not what. if all is well with vac test then do a compression leakdown test. It uses a different comp gauge. well worth the investment though. pops through exhaust could be a myriad of problems from minor to major.