Hard start, backfiring, clop clop clop at engine

[keelue]

Blazer has pretty much just sat in the yard for the last few years since I've been wheeling and building the K30. Finally decided to get it back in running condition to do something with, not sure what yet. Anyway, changed the oil, plugs, wires, cap and rotor, fuel filter, even had the carb gone thru. Got it running but...

Getting it started is rough, it tries and sputters for a while, then finally catches, once warmed up it'll idle but I'm getting some loud exhaust backfiring from one side, the engine (on the same side) has a clop clop clop sound. It's more than a tick but not a knock. Maybe a stuck lifter?

Any suggestions?

 

[diesel4me]

Sounds like an exhaust valve got stuck open or a lifter may have collapsed..maybe a push rod bent if the valve was stuck shut and forcing it open bent it...

If it is sticky valves or collapsed lifter it "should" eventually clear itself up after you run it awhile,adding some Marvel Mystery Oil to the crank case (dont overfill) might free the valves up quicker...if the tapping stays the same it could mean a push rod got bent or some other valve train part got tweaked--seen rocker arms break in two before!..in that case you'll have to take off the valve cover(s) and look for something wrong..

 

[ChrisPerry]

Double check the firing order. If you mixed up two of the plug wires, it can cause all sorts of issues and sounds.

 

[paratrooper307]

Double check the firing order. If you mixed up two of the plug wires, it can cause all sorts of issues and sounds.

^This. Always go for the easy stuff first. Check timing, firing order, and plug wire connections. A lifter may stick after sitting around, but it's less likely a push rod just turns up bent.

 

[diesel4me]

Yeah,it could be two plug wires got crossed up...

I had a truck a friend called me to ask for help getting it to run right,after a long outdoor storage...it ran great when parked,but he let it sit 5+ years and never even spun it over once in a while...it didn't seize up,but when he tried to start it,it did start and run a few seconds,then stalled,and kept backfiring when he attempted to re-start it..

We eventually got it to run,but poorly..spitting back thru the carb,stalling,running rough and no power...we figured the carb expired,so we tried a known good one I had,no change...checked all the other things,and couldn't find anything to blame,like the cap & rotor,etc...

We were stumped,then another friend said "let me try something"--he moved all the wires on the cap over one hole,then turned the distributor as we cranked it--it fired up and ran better,but still not "right"...he said "It jumped time,it needs a timing chain"...

My friend took off the balancer,water pump and timing cover--sure enough,it had a nylon toothed cam gear with no nylon left on it,the sprocket had barely any teeth on it,and when we went to line the timing marks up,it was about 5 teeth "off"....surprised it even ran,period!...he put a new chain and gears in it,and it fired up and ran great again...evidently some valves were "tight" from sitting so long,and the added drag on the timing chain was enough to make it "slip" and jump time....
We came close to just swapping another engine he had into it!..

 

[paratrooper307]

Yeah,it could be two plug wires got crossed up...

I had a truck a friend called me to ask for help getting it to run right,after a long outdoor storage...it ran great when parked,but he let it sit 5+ years and never even spun it over once in a while...it didn't seize up,but when he tried to start it,it did start and run a few seconds,then stalled,and kept backfiring when he attempted to re-start it..

We eventually got it to run,but poorly..spitting back thru the carb,stalling,running rough and no power...we figured the carb expired,so we tried a known good one I had,no change...checked all the other things,and couldn't find anything to blame,like the cap & rotor,etc...

We were stumped,then another friend said "let me try something"--he moved all the wires on the cap over one hole,then turned the distributor as we cranked it--it fired up and ran better,but still not "right"...he said "It jumped time,it needs a timing chain"...

My friend took off the balancer,water pump and timing cover--sure enough,it had a nylon toothed cam gear with no nylon left on it,the sprocket had barely any teeth on it,and when we went to line the timing marks up,it was about 5 teeth "off"....surprised it even ran,period!...he put a new chain and gears in it,and it fired up and ran great again...evidently some valves were "tight" from sitting so long,and the added drag on the timing chain was enough to make it "slip" and jump time....
We came close to just swapping another engine he had into it!..

Nylon teeth are a crapshoot. Some last 200K, others are done at 70. Thanks to some bean counter or noise/vibration/harshness engineer, you have a part that is destined to fail. At least on the new SBCs they use steel gears now.

 

[keelue]

Well dangit, hate overlooking something simple but yep, had 3 and 4 crossed at the dist. Battery is too dead to fire, charging it now, try again tonight. Thanks!