Thread: Engine running badly,played too hard help!

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Got on it a little to hard over the weekend. Have a 283, 4bbl edlbrock. Heard a loud pop, then sounds and feels like Im runnin on 7cyls. No smoke, engine starts cold, hot etc. Will run, but not like before. Have spark at all 8, changed plugs last night. Pulled drivers side v. cover, all ok. Harder to get rt side off but I will if I have too. Does not appear to have any vac leaks. At the rear, it sounds like im runnin a radical cam. Like I said, its like Im runnin on 7. All help on what to check is appreciated! Thanks...Phil.

Take a compresson check ,you might have a piston that went south.

I thought that too, however, I just set timing and test drove again. Getting lots of little sputters and pops on harder acceleration. If I drove it on backroads, feels like I could drive it forever. Could it be my HEI coil? or my carb? Would a piston cause these symtoms and run fine w/no smoke or bad sound in engine at all?

A piston with a hole in it could do just that- lost the top of a piston once and all I had was a miss with just a whimper of smoke.

Valve spring? Have you pulled off that other rocker cover yet? The compression test is still a good idea. If there is something in pieces in there, the more you run it, the more damge you will do. Something made that "POP".

Pat

Just pulled off the other valve cover. with both off, clean as a whistle, all moving ok w/no noise at all. oil looks super clean. The pop i'm reffering to could have been backfire or bad pop through the carb.

Car idles much lower than before. Was at about 900 rpms in drive, now 400-500. Really cant figure this one out. Could I have damaged my carb? It seems I have no top end?

What condition is your timing chain in? If its orignal it could have slipped on the plastic? There has to be a reason for it running bad. Did you lose a plug on a vac. line??
Good luck

If you have automatic maybe the vac line is off at the trans???

It does have fresh fuel right?

Appreciate all the help. Cffisher, I too thought vac of trans, plugged the line at the manifold and its fine, also climbed under to check. Still think it might be vac and not ruling it out. I Still think I could have back popped badly out the carb and done some internal damage, maybe even a vac leak there. Going to go all around the manifold and carb with a propane torch (not lit of course) as if there is a leak, the propane will smooth out the idle instantly. Crowbie, if teeth on timing chain, woulnd't timing be off? I checked it right when problem occured and it was right where I generally have it set. Generally there would be some noise there. The old screwdriver handle to the ear check says it sounds pretty good in there. Not sure I wana rip it out yet.
Gonna check compression over the weekend to rule that out. Still thinking that GM HEI coil went bad. Although it was pretty new, 2000miles, I know these things crap out and leak at higher rpms. Also, my cap is really close to firewall as you chevy guys may know. Under harder torque, I suppose it could hit. Going to buy a new one for kicks. Any other ideas are appreciated. One final thought on vaccuum, if I pull the PCV valve and hold my thumb over it, should I feel vac there? Because there is plenty. Thanks to all...

Oh, and NTFDAY, alomst forgot, I did check pushrods and they appear fine. Would I see the bend with covers removed and running? Or would I have to pull them? My neighbor also thought a lifter wasn't seating all the way. Thanks...

Originally Posted by fiftee6

Oh, and NTFDAY, alomst forgot, I did check pushrods and they appear fine. Would I see the bend with covers removed and running? Or would I have to pull them? My neighbor also thought a lifter wasn't seating all the way. Thanks...

Probably would see a bend until you pull them out and roll them on a flat surface.IMO Timing gear and chain would be the first thing to check out ,and compression test.

Dave:That reminds me of a problem I had with my engine.Spark was jumping to the wrong cylinder from a bad distributer cap.I spent about 200 dollars on ignition parts until I looked inside the cap and could see where it was jumpin to another cylinder.

heres a simple thing to quickly rule out cylinder damage.... goto your local parts store, rent a cylinder leakage tester..... bring each cylinder to TDC one at a time, take plug out, hook up too, fill with compressed air..... it'll fill the cylinder up and let you know if theres seapage, then you start checking for seapage, the main spots are crank case, exhaust pipes, radiator, intake, and neighboring cylinders.... if you hear air leaking at any of those points, you can tell whats bad, crank case is generally rings or possibly head gasket, intake/carb is intake valve, exhaust is exhaust valve, radiator bubbles means headgasket, and neighboring cylinder means your shit out of luck...... if you want to quickly rule out a head gasket you can also use a block tester to check for carbon monoxide in your coolant.... first get a compression tester and test all your cylinders though..... i want to see numbers on each cylinder posted here so we know your not skipping it... if you pass the compression test you can skip block tester and cylinder leakage test...... that does sound like a valve problem to me, pull your pushrods, and put them on a flat surface one by one and roll them while watching very carefully and closely..... that'll rule them out.... once they're ruled then you'll have to put them back and readjust your valves.... but after adjusting the valves.... see how she runs.... it could even be as simple as a rocker getting loose.. i've also had problems with high lift cams and stock rocker setups where the rocker studs start to pull out.... causes a very similar problem.... the only way to fix that is to have all studs removed, have them tapped for screw in studs and upgrade to roller rockers hope some of this info was useful to you and didn't bore you

Don't overlook the simple things, check the obvious, the distributor could have rotated a bit and changed the timing, cracked rotor, plugged fuel filter. A leak down test will determine a lot more on engine condition than just a compression test.

Classic story. Couple years back started the car and headed for the staging lanes, puffing black smoke running like crap...... Thought about all kinds of terrible things that could have happened..... Then opened the hood and removed the shop rag that was covering the carb!!!!!!