Post about my GMC "making it"

[irishman999]

I may have found the problem, I pulled the cap off to check out the vacuum advance and noticed the button that touches the top of the rotor was all melted together and covered in molten plastic. Oriley gave me a full refund with no problems and i baught the high quality unit from Autozone, new cap and rotor look alot more quality, thicker everything and better looking material.

[irishman999]

New parts are in, same problems... I drove around town trying to get a timing light and nobody had one. I decided to advance the timing a few degree's and the truck runs way better, The backfiring out of the carb has stopped. Now it just has a dead cylinder, I think its plug wires.

I got the cheap set from autozone and for some reason they fit horribly, the number 8 plug should be the shortest and the one they gave me was so damn short it rides against the manifold shroud. I got a wire holder for my new plugs but it was missing pieces and i couldn't use it. Im going to try a plug wire set from orileys in the morning and see if it cures my dead cylinder.

[cableguy0]

At least your making good progress. If you put wires on it I would throw a set of plugs in it while your at it. With the fuel issues you had its possible one or more is fouled.

[psuedopimp]

glad to hear you got it back, and there isn't a bum living in it.

[irishman999]

Originally Posted by psuedopimp

glad to hear you got it back, and there isn't a bum living in it.

Yea man it was on braham exit right off the highway, no one lives out there.

[QUOTE=At least your making good progress. If you put wires on it I would throw a set of plugs in it while your at it. With the fuel issues you had its possible one or more is fouled.[/QUOTE]

I didnt have a gaping tool when i put the new plugs in so i just threw them in, when i do the plug wires i will make sure to check out the plugs and gap them. If i get this dead cylinder taken care of i think it will run nice, its revs quick again but backfires a little bit when you let off, out of the exhaust not the carb.

[irishman999]

Update: I dont think anyones reading this anymore, I got a new plug wire set to rule out a burnt plug wire and some moroso wire holders. Still has a dead cylinder, Im going to pull the plugs and see wich cylinder is not firing, gap the plugs since i didnt do it the first time and eventually pull the valve covers to see if they are moving correctly, as soon as this effin rain stops!

[irishman999]

Ok pulled plugs, plug 1,3,5,7,8 all firing correctly. Plug 2,4,6 were fouled. Pulled valve cover to find 3 bent pushrods!

[bigguy69]

ugh. hope it you get it running

[irishman999]

Got the new pushrods in, did a quick valve adjustment and fired it up for a few seconds, 3 more bent pushrods. Im guessing the valves are still stuck shut, im open to suggestions on how to get them moving freely again.

[cableguy0]

If you smack the top of the valves with a brass hammer you can see if they will move.Are you sure the cam isnt wiped out??

[irishman999]

Originally Posted by cableguy0

If you smack the top of the valves with a brass hammer you can see if they will move.Are you sure the cam isnt wiped out??

I considered the cam being trashed but i think its still got plenty of lobe, the push rods just are not strong enough to open the valves it seems. The first push rods i pulled out were bent horribly so im assuming the lifters have just been riding along the cam with no tension on them. I am thinking this is from the old sticky gas since all the exhaust valves are working right and all the intake valves are sticking. I put a socket under the rocker arm and ran the nut down, the valve opened. I really dont want to pull the head off.

[cableguy0]

One tank of old gas isnt going to make valves stick closed. You would have to have bad valves guides or a bent valve. If the valve opened by tightening the rocker down I would look elsewhere for a problem. Are your studs pulling out of the heads? Pull a lifter out and see what the bottom of it looks like.

[irishman999]

Originally Posted by cableguy0

One tank of old gas isnt going to make valves stick closed. You would have to have bad valves guides or a bent valve. If the valve opened by tightening the rocker down I would look elsewhere for a problem. Are your studs pulling out of the heads? Pull a lifter out and see what the bottom of it looks like.

I tapped on the valves with a hammer, No. 2 intake went down and wont come back up. No. 4 will not move and 6 i haven't messed with yet. The studs are not pulling out of the heads. Are these "interference motors"? When you say bent valve do you mean a piston smacked the valve?

I was not thinking and ran it out of gas a while ago, the entire intake and carb was coated in this super sticky varnish, it was so bad the butterflies on my carb wouldnt open, this sucks... any suggestions to try before i pull the heads?

[79gmcc15]

yes they are interference motors. have you tried running some seafoam through it and see if it will un-stick the valves?

[cableguy0]

If the engine is that gummed up and trashed inside it needs to be torn down and hot tanked or at least completely disassembled and cleaned. I would be extremely suspect of the valve guides being torn up anyhow.

[irishman999]

Originally Posted by 79gmcc15

yes they are interference motors. have you tried running some seafoam through it and see if it will un-stick the valves?

Dude im a seafoam fanatic, its in my oil right now as well as gasoline. Im not sure how i can apply seafoam to this application. Even if i start it with the valves closed it wont get any on the stem. I've been just soaking the piss out of the valves and springs with wd-40, it seems like im just going to have to pull the head off.

[BigBlocksRule]

No amount of varnish is gonna hold a valve open against a spring. You either have terrible carbon build-up, clearance or oiling issues.
Get a dang timing light, who knows what you're running now? Sounds like you might have a cam going south...

[irishman999]

Do the intake valves get carbon deposits as well? I have been spraying pb blaster on the tops of the holders and the base of the spring, i tap the valve with a hammer and they are moving, One popped loose so far.

[irishman999]

I cant believe it, after soaking the valves in pb blaster and tapping with a hammer the valves have been free'd.

[WigglesTheHoly]

If I were having troubles like this I think I would have gone back through the motor one more time to see what all is damaged. It would probably be quicker.

[irishman999]

Originally Posted by WigglesTheHoly

If I were having troubles like this I think I would have gone back through the motor one more time to see what all is damaged. It would probably be quicker.

I agree completely, i wish i had enough time and money to go through everything. Im trying it right now turning the motor with a breaker bar and my wifes help, so far so good. As far as things being damaged i confirmed 3 pushrods are bent and 3 valves were stuck closed. Im suspecting the cam is okay since it had plenty of lift to bend the living hell out of the pushrods. Im hoping carbon or caked on oil deposits cause this, in that case it may work, if the valve guides are screwed up its going to bend the valves and ruin the pushrods again im sure, either way worse case scenario i pull the head off, i've planned on this anyways but if this fixed it that works too.

[irishman999]

UPDATE: After turning it over by hand with my wife watching for loose rockers i decided it should be okay. I just started it and it runs perfectly, better than i have ever herd it run, perfect idle even. Im going to change the oil and seafoam the living hell out of this thing and drive it around a while.

[SBTork]

Originally Posted by irishman999

UPDATE: After turning it over by hand with my wife watching for loose rockers i decided it should be okay. I just started it and it runs perfectly, better than i have ever herd it run, perfect idle even. Im going to change the oil and seafoam the living hell out of this thing and drive it around a while.

well thats good news, hopefully all works out and you don't need to tear things apart.

[irishman999]

I still can not believe it worked, i changed the oil and put a new valve cover gasket on it and drove it around a while, as soon as im done eating im going to give it one hell of a test drive up a mountain close by. This thing is running like a top.

[Chionos GMs]

Thats good to hear!