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???

had pretty much the exact problem last summer with a 350... tried EVERYTHING before ripping it apart to find that the timing chain was badly stretched...

You might also want to check the pushrods, they will bend at high rpm's.

Well from what it sounds like, if you're idling lower than usual your timing could be way off, could have jumped a few teeth that is if your 283 is ALL ORIGINAL.. and if thats the case.. your camshaft timing gear has a few teeth missing by now. Why?

Well my friend bought my 283 off me. We tore it down. And guess what? GM decided to use a NYLON TOOTHED gear on the camshaft. Guess how many teeth were missing after 40 years? 11.
11 Teeth were missing. (See for yourself as to why I jumped timing!)

If thats the case, then you definately have jumped timing by alot; if the timing has jumped, then yes you could be experiencing the backfire through the carb due to being way off time. As for a hole in your piston? Smell your oil. See if you smell GAS. Gas has got to somewhere right?

I'd check my timing gear and chain first.

What about your Distributor Gear? I've never experienced a broken gear but.. maybe a tooth on it POPPED?
These are just some ideas and things to look into if the case is that your motor is original and untouched.

Untouched 283? Rebuild that sucker! It's a GREAT motor, it's very durable, reliable, and has thick cylinder walls, a stock build is relatively cheap and worth every penny.

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...