Engine running badly,played too hard help!

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???:whacked:

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...

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!!!!!!:LOL: :LOL:

Quote:

---

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

Like Dave says, check for the simple things first. Here is another handy hint, pull the cap off the distributor and check your centrifugal advance is operating smoothly. Just grab the rotor (with the ignition off ! of corse) and advance it, it should snab back, if there is any resistance, find out why. It's just one of those sneeky distributor problems that drives peolple bananas.Hope this helps.

Sounds like the timing chain jumped. Line up the timing marks, and see if the valves on no.1 (or no.6, depending) are right on split overlap, exhaust just closing and intake just opening. If not, its out a tooth . A new roller chain and sprockets will fix it.

OK, first off, thanks again to all. I think I have solved the problem. A few of you insisted on compression test. Did it today and all seven cylinders came up with about 124-128. The last cylinder on the passenger side closest to the firewall (of course) Was 0. Yes, 0. Pulled the valve covers again to check. Pulled the rod, rolled it on the table, and yes, there was an ever so slight almost hard to see bend. Still, I thought it cant be enough. Went back out, put it in, put the rocker on and started to tighten. I realized that soon, the nut was down further than the rest and the rocker still had play. Lo and be hold, the spring was busted, broke in three places. I've never seen that, or it's never happend to me anyway. Went to the store and got a hose to hold pressure on the vave, filled it to about 100 psi and removed the spring. Putting in a new set, and pushrods too.

Now here's the scary part. There does seem to be a few small or a couple small pieces missing. So, where are they? In my oil pan I hope? Am I ok?
Thanks, Phil.

By the way, thanks to "thesals". My neighbor also mentioned the possibility of the studs pulling out. He's seen it before. Thats what we actually thought was happening as I was tightening it back up until I noticed the busted spring! You pretty much hit the nail on the head. Phil...

Bent pushrods and broken valve springs, fairly common on high revving small blocks with stock springs and stock pushrods and a stout cam. :CRY:

Quote:

---

Originally Posted by DennyW

You mean the sixth post didn't hit the nail any at all. :LOL: :LOL: :LOL: I'm taking your hammer away for that one. :LOL: :LOL:

---

Sixth post, How about the 5th one? :LOL:

Glad you got it figured out, hopefully the missing pieces are in the oil pan. Might be worth investing in a magnetic oil pan plug.

Pat

Apologies to Denny & Stucool, when I look at all these posts, by the time I write the reply I forget the names! Cant read without glasses either anymore! At only 45 I thought these things didnt happen till 60!!!
But what about those broken pieces??? Is this a problem? Where are they???

Hey no offense taken nor apologies necessary. Was just a lucky guess on my part anyway. The stray pieces probably are in the pan. There is an oil return hole right at the back of the head there so that is a likely route for them to take. Probably a good idea to change your oil, and pick up one of those drain plugs with a magnet in it. That will catch any stray pieces left hanging around in there. The oil pick up has a screen and anything smaller than that the filter should pick up. While you were replacing the spring, did you work the valve up and down and spin it to make sure it was not bent? I would also suggest another compression test now that you have it all back together to make sure that valve is sealing.

Pat