Popping carb

[Il Brutto]

Its raining, truck ran fine this morning. Took off from a stop sign and just started popping out of the carb, what the hell? 83 ranger 2.0 single barrel carb, over 1000 miles on a carb rebuild. This is my daily driver, I need help, thanks.

 

[RonD]

How new is the timing belt?
If tensioner is loose or belt has stretched it throws off the Cam/Crank timing so valve timing is off.
Compression would be low if belt is loose.

Too lean a mixture will cause fuel to ignite when it enters a hot cylinder, so pop is heard, does it pop when first started or just after it has warmed up?
Vacuum leak will cause a lean mix.

See if distributor is loose.
Make sure spark plug wires are separated and insulation is good, spark can jump wires if they are cracked or melted, causing a spark in a cylinder on it's intake stroke...pop.

 

[Il Brutto]

timing belt is new, plug wires are new, i need a timing light to check the timing. pop is under acceleration

 

[Il Brutto]

Could this be a bad valve or something?

 

[Andy D]

I would be looking for a vacuum leak, or something hosed with the accelerator pump on the carb.

 

[Mark_88]

It does sound like timing is out a touch and as RonD mentioned check that the distributor is tight (and hasn't moved since you set it). Could also be vac advance on the distributor is either off or leaking.

I guess it does depend a bit on how much it is popping and how often. If it is not drivable in acceleration mode due to the popping then it would be a bit different than just an occasional popping like backfire once in a while.

B/F through the carb indicates a lean mixture usually...so also check your fuel filter on the carb if you have one or in front of the fuel pump...if you have one...or have a good look at the vacuum setup as Andy mentioned...

 

[Il Brutto]

Oh, that explains it...

Well, I took off the valve cover and here is what I found. I touched nothing but the valve cover. Turns out I need a new cam and some other things, obviously.

 

[Mark_88]

Hmmmmm....yep, that might cause a bit of popping...

 

[RonD]

Yes, exhaust valve not opening would cause the pressure to be sent out the intake valve/carb, next time it opened.

Cam doesn't look marked up
Could be a broken spring on that valve, causing rocker to be floating and be pushed off.

If it is a broken spring you can change that without pulling the head.
Process is referred to as "the rope trick", very old school, lol
If you try to replace valve springs or seals with the head on the problem is that the valve will fall into the cylinder, ruining your whole day
So you need something in the cylinder to hold the valve in place while you do the work.

Rope will work, put the cylinder you will be working on at it's approx. TDC, then rotate crank a 1/4 turn either way, so piston is down about 1/2 way, feed a rope down the spark plug hole, it will coil up in the cylinder, feed enough to fill the cylinder.
Now rotate crank back towards it's TDC to force rope coil up to the top of the cylinder, valves are now held in place.

 

[19bonestock88]

Do a compression test on it with all the plugs out. This will tell you for sure what the issue is. If you have good compression like i did, then all you need is a cam and follower set and either new or rebuilt lash adjusters. I am currently trying to recover from the same issue, but it happened to me on cyl 3... Probably caused by a collapsed lash adjuster, but if it has been ticking any that cam and those followers are now trashed...

 

[Il Brutto]

The other side of that cam lobe is pretty tore up, I posted that pic before I really got to looking around. Both the rocker and the cam are pretty worn, the lobe and rocker look like they have been filed. What sucks is that all that metal that is gone...is now inside the motor.

 

[19bonestock88]

I would say that it would either be in the filter by now, or maybe in the bottom of the pan... (Magnetic drain plug?) if i am any example to go by, my engine is fine. I needed to move the truck about 40 feet and i couldnt push it, so i took off the other follower on cyl 3, sat my VC back on, and fired it up... No ominous noises, other than only running on three cylinders, lol... Your truck should be okay once you get the new cam in it... Either that or we will both break down again in 6 months this time with a ruined block, lol

 

[Il Brutto]

Thanks, Bones. I got another problem now. I got a new cam kit, came with rockers and hydraulic lash adjusters. Got the new cam in along with a new seal (yes I used plenty of assembly lube and I was careful not to nick anything), no problems there. I put my new lash adjusters in some oil to soak overnight and got to pulling out the old ones. Everything I have seen on this makes it sound like a very easy thing to do, all the instructions ever say is "take out hydraulic lash adjusters." I pissed around for 4 hours gettting 7 of them out (Yes there is probably an easier way to do this but its my first time and I don't care it gets me out of the house into beer drinking territory.) Now on to the problem at hand, #8 lash adjuster is stuck and the real pisser is that it has also come apart. How can I get this out? I thought about pulling the head but where the hells that going to get me, those things bottom out, its not like with the head off I can just push them out, so the head stays on. I thought about compressed air to blow into that oil hole under the lash adjusters but I don't have a compressor. I got a few of them out by blowing oil into those holes out of my little squeeze can but those turned. This one is STUCK. Any suggestions, would be greatly appreciated. Thanks