running rough!!

[Rootie524]

so bent intake valve or one that doesn't close all the way? and yeah, i get no smoke out the tailpipe at all. and when i did my cam 2 head studs broke off in the head so i got a head from the junk yard and put that on. i put my valves in it and put my springs on it and i think i put new valve stem seals on it but i forget if i did that to this head or another set of heads i had before. so if i didnt change them on this head..a junk yard head that has been weather for a while and unused im sure the seals would be shot which could explain the oil, and would explain why its cyl 4 because thats on the head that came from the junkyard. the head was examined and cleaned though and i didnt see any cracks or anything like that. so maybe a bad guide that was overlooked, or seals, or seats.

i thought nothing of it because this just seemed like a spark or gas problem..but now its starting to look like so much more.

[86FieroSEv6]

Hey, look on the bright side. At least it's the front head (cyl 4) and just doing a single head off on this motor really isn't that bad a job.

[Rootie524]

yeah ture. i've had this car apart enough that i can tackle a removing/replacing a head pretty easily. and like u said it's only the front...

so are we in agreement that gas is getting in my oil from a misfire possibly caused by a bad head (seals, guides, seats, whatever) and while its off ill be cleaning and testing my fuel injectors like no other just to be able to completely cancel that as the source of the problem.

only thing i find odd is it's only sometimes..and lately when i first start it, it's fine..but after its running for awhile it gets worse...its very odd.

[86FieroSEv6]

Sure, after first firing up, there isn't as much oil up on top to get sucked into the guide. Also, when hot, the oil flows more freely and there is more of it up in the head getting splashed around. A hard acceleration run probably blows out the cylinder and it gets "hot" enough to run on for a while till it cools back down and misfires again. Of course, these are merely my suspicions but Occam's razor states that the simplest explanation is most often the correct one. Alternatively, you could use some 100% cotton rope stuffed in the cylinder, then push the piston up against it, to support the valve while you jump out the keepers, lift off the retainer and spring to actually see the seal before committing to a tear-down.

note: Any fibers left behind by the cotton rope are harmless to the engine. Do not use synthetic rope.

[Rootie524]

so i understand what you saying but im having trouble understanding how it causes a misfire.. oil is getting in my cylinder possibly by going down the valve through the seal. and it causes it to run rough..the PCM try to compensate by giving it more gas, which causes it to run rich..hence the smell, gas in oil, rough running, and poor fuel economy?

its definitely not a spark issue..thats off the table.. so is my understanding correct or am i missing something? i think we are finally onto something though. ill probably just replace the heads and get new seals, have them milled, and guide inspected and stuff (i already have a set laying around)

[86FieroSEv6]

Based on the discussion so far, in my mind anyway, it's kinda the only thing that fits all of the observable events together.

[Rootie524]

same, that's what I'm thinking too. but i mean is my explanation explained above whats causing everything or am i missing something?

im just trying to get an understanding of how oil can do this. and i think how i explained it is correct. i mean i kind of want to strip everything down to the block and put milled heads on for better head to gasket contact, with new seals, lap the valves, put water in each runner to check for leaks, and put everything back together very slowly. everything i should have done the first time. ill admit, when i did my cam shaft i just wanted to get the car back together, i didnt care how at that point. i was pissed cuz somehow pushrods were swapped. so instead of it taking 2 days..it took a week. so because i was sick and tired of that project and all its problems i probably didnt take necessary precautions which is possibly why my head is screwed up.

so now i have a reason to redo it all and make sure every little detail is perfect. ill clean the injectors while they are out too. but like u said and other people..it cant really be a piston/ring problem or a crank or anything bottom end. the problem rests somewhere heads-up.

[Rootie524]

is it possible its a lifter problem? i just thought of that today. but im not sure.

[bszopi]

Do you have a multi-meter? If so, a different thread led me to think of something easy to check. Check the resistance of the spark plug wires, and report back. I know you said you replaced them, and that you are getting spark, but if you have a high resistance plug wire, the spark may not be strong enough.

[Rootie524]

so check resistance at the end of the wire boot that goes on the plug?

itll be a day or two till im back home and have access to my meter but ill check it out then.

[robertisaar]

for reference: normal delco or replacement wires have 30,000 ohms or less resistance, depending on length...

my spiro-pros all totalled together have less than the resistance of the shortest delco wire however.

[Rootie524]

damn those are good wires.

[robertisaar]

i'd like to think they are as excessive as you can go before causing interference with the PCM's sensors...

the rear 3 came out to an average of ~600 ohms, while the front 3 were roughly ~800...

which comes out to roughly 4200 combined... i believe the shortest stocker i had was between 4500-5000...

[Rootie524]

ok got my spare set of heads back from the machine shop. the guy there is awesome, he's my new best friend. he can do everything i need for my build and he is unbelievably reasonable with prices. but thats another topic for another day..

so first off, apparently the heads i gave him were warped so he had to take 10 off to completely flatten it. I'm assuming thats so little an amount im still good running stock autozone head gaskets and wont have to worry about valve to piston clearance?

right now i have my car ripped down to heads and have already removed the front one. so far i haven't noticed anything out of the ordinary which is kinda pissing me off. i was expecting to see something obvious and be like wooo hooo! but no. although i can not there was alot of oil in my intake. in my cai tube near the TB and after the MAF, at the TB, in the plenum, and in the LIM..all up in there...normal? UIM gasket was fine, LIM gasket was fine, Head gaskets were fine, poured water in intake and exhaust ports of the front head (the one supposedly with a problem) and none came out around the vavles. so good valve seating.

i need to get a valve spring compressor (my friend lost the one i had...) and ill see if the seals are f-ed or not. also..im thinking it might be a lifter. granted it will still lift the valve..but if its collapsed it wont lift it enough and would cause the problems im having....right?

idk..ill continue the investigation tomorrow. in the process of finding a shop that can inspect and clean fuel injectors just for added precaution.

[Azrael]

The oil in the intake tube is from the breather from the rear valve cover. Some is normal as the OEM plastic tube isn't made to drain any accumulated vapours back to the valve cover. I replaced mine with some hose that makes a gradual upwards path and haven't seen anymore oil before the TB since. Oil vapours also come in through the PCV valve. Using a pneumatic air/water separator is a cheap way to make an oil catch-can to stop this.