help me out with some diagnostic?

[johnny]

So i've been sort of rebuilding this 350 chevy truck i bought from an older lady who bought it new in 75. Well it's always ran good but i haven't been driving it for the last 4 months or so because i've been replacing all the front end parts. Anyways i got it tagged a few days ago and i went out and had to take the carb off to put the choke back on, then i put it back together, started it and it ran like crap. So i get out check all the vacuum hoses, the carb for tightness, the gaskets ok, so i check the vacuum, it's going wild. well i let it warm up a bit, it'll idle it's just spitting and spattering. well after it gets to about 140 or so i bring the idle up to about 2500 and hold it there for 15 seconds or so then let off and the choke releases so it idles down but it still sounds like crap. so i rev it again to about 25 for a few seconds then slowly up to like 3500 and then let it back down, well all the sudden it starts running normal so i'm like alright!! well i get out and go to the front and now there's an uneven tapping noise that seems to be coming from the lower end of the valve train or the combustion chambers themselves i'm not sure. i thought i possibly dropped something inside the intake when i pulled the carb off? and it got hung in a valve and then came loose. I also had a worn lobe, or possible stuck lifter because one of them barely moved, so it could be something from that. I'm not sure, and i don't want to tear anything down just yet until i get some more opinions. But i guess this probably means the heads are going to have to atleast come off sunday, and probably more. Thanks a lot for any help. johnny

[37 Terraplane#2]

Pull that lifter [I assume it's hydraulic } and see if it collapsed. Check the bottom for wear while you got it out. If it's worn best pull the cam and go from there.

[johnny]

alright thanks man, i've gotta go to work now but when i get home i'll pull it apart and see how it goes from there. I'm not too sure if it's hydraulic or not, it's the stock cam, i'll have to do somne research to find out

[Jon B]

This may sound dorky, but have you tried pouring one of those "miracle cure" oil treatments in a can, into your oil? (Or maybe you pour them into your carburetor, I'm not sure.) I'm wondering if something is sticking (a valve?). I was skeptical of this but back in the 70's a fellow with a fairly new Ford poured this stuff into his oil and the darned engine smoothed right out!

It's probably not the "right" way to fix the problem but from what you say, this problem comes and goes and that leads me to think it's not something that's "busted", but something that is momentarily not working. I always say, start your troubleshooting with something cheap & simple, THEN move up to the expensive stuff!

[Steve E.]

worn cam lobes were very common in those engines, so check your cam. The immediate problem does sound like a collapsed lifter. Have you added anything to the crankase? some times additives will thin out the oil too much and cause rather than fix problems. Good luck.

[johnny]

i'm kinda worried i started it up tonight when i got home and it almost sounded to be getting louder, it might be getting a little bit of the death rattle but it's hard to say for sure. no additives and 20 50 oil, so i dunno. I started pulling it apart tonight but i got home late so i only got the intake off but i'll take the rocker arm off and check out the lifter tomorrow

[37 Terraplane#2]

HI JOHNNY, no lift or little travel of the push rod has got to be--collapsed lifter,caused by wear ,gum build uo , or crud bolcking the oil passages in it. Or bad push rod ends ,worn cam lobe, etc. Lets HOPE just a bad lifter is the problem. Check the bottomof it. It MUST NOT be concave,, not even the least bit. It should be shiney all over with some BARELY noticeable circular patterns on it, this indicates it is rotateing as it should. If it is OK but collapsed you can take it apart if you can handle that and clean it, refill with oil and pump it up before you put it back in. Don't want to take it apart? Soak it good in some strong parts cleaner,carb cleaner,anything you got to cut the gum and crud and try to free it up.get it to pump up on the bench before putting it back. ANY, and I mean ANY abnormal wear on the bottom means you gotta check the cam as it likely has a bad lobe. Also, check the ends of your push rods for wear. On used parts I always like to put them back in exactly the same place they came from as they are "worn in" you might say. If you get lucky and have no wear and can get it to pump up on the bench, add some Marvel Mystery Oil to your crankcase. Good stuff for gummy lifters. Oh yeah, be sure you lube the bottom of lifter, maybe a little STP or heavy oil, before you drop it back in. If This don't work { bad lobe on cam or something } DO NOT mess around trying to get it to run "somehow". Only going to tear up more stuff. I and a whole lot of guys like that engine, easy to work on , all kinds of options at reasonable cost for parts. Hope things come out the best. BUD

[Oldcar_Mechanic]

I would be most concerned with the noise that you are having in the combustion chamber.

1) Did you drop something down the intake allowing it to become stuck in a valve and now working it's way into the combustion chamber?

2) Did you possibly knock a piece of carbon lose and it was lodged in the valve and now into the combustion chamber?

Years ago we used to have a practice of dribbling water down the carb. Doing this would help clean the carbon in the cylinders. One problem with that was that sometimes it would dislodge a large piece of carbon and it would rattle around the combustion chamber and sounded like a rod had gone. Pouring more water down the carb would most likely break the carbon down and it would pass through the engine ( like a kidney stone lol).

If you can isolate the cylinder to which the noise is coming that may save you some work.

Keep us posted as to what you do and find.
Ron

[johnny]

ok so i pulled the lifter out and cleaned around it lots of sludge, it was barely moving now it moves freely so that got the lifter moving better, it still doesn't go as far as the others though? possibly from being stuck so long i'm not sure. It is still making this same noise though, and i thought it might be a piece of carbon like you were saying so i let it warm up then revved it up a few times well now it's gotten a lot louder, i hate to say it but i think she's dying :S i don't want to give up quite yet but i don't know what else to do. someone said find where it's coming from and pull that plug wire or something, but i'm scared to run it, is it going to like blow out the side or something? any more help is greatly appreciated

[johnny]

also i'm curious about the carbon thing because my uncle declared it as the death rattle instantly, but he couldn't explain to me why it ran so horribly before this noise and then all the sudden started running good, as if something was lodged, which i could see as me possibly dropping something inside but it's not likely, i covered the manifold then looked inside with a light before i put the carb back on so i took all possible precations. to me it seems logical that something got stuck in the valve and as i revved the engine a few times cam unlodged well now it's bouncing in the engine. this engine was drivin by an older lady who bought it brand new so it's in good shape, also only 82 thousand miles and no burning oil. but i'm not sure. should i just go ahead and pull a head off and look inside? or is there an easy way to diagnose it?

[37 Terraplane#2]

Johnny, not sure what you mean by how far it's moveing. If you mean the lifter parts , Remember it must pump up so it feels to you like solid on the bench, Has to be able to handle the pressure of the valve spring when installed. Doin't really like to see you run it either till you elinate the problem. But try this at an idle tighten the adjustment untill you can not feel any looseness/clearance when you put your finger on the rocker. If it's a weak lifter the noise will decrease and eventually stop as you thighten it down. If then the push rod and rocker don't move as far as the others you have a bad cam for sure. Then you gotta tear it down. Pull the cam /heads, clean out all the carbon and junk, new or good cam and ALL the lifters. Lotsa sludge says the old gal did'nt change the oil too often and you need to boil the heads out to clean the oil passages while you have them off.

[Oldcar_Mechanic]

If you have a lifter that is not moving as much as the others, I would guess that you have a lobe on the camshaft going flat.

Sounds like it's time to dig deeper.
Ron

[johnny]

ok so i work during the week so i haven't had much time to mess with it, but last night i ran it for a little while, and my uncle was here, he was saying that it was a knock, but it kind of comes and goes and goes at different speed, he agreed this was awkward, so i pulled the plug wires one by one and started it, i read in a magazine that you can figure out which rod is knocking this way, but it didn't seem to make a difference, i also pulled a couple of plugs to check for damage of something that possibly fell inside? i pulled four and didn't find anything but i've yet to pull the others. So i guess that's still a possibility. isn't there an easy way to diagnose for sure if it's knocking or what, i've only had one vehicle that started to knock and it was much different than this. thanks guys, i'll pull the other plugs tonight possibly, i'm not sure i just got home

[37 Terraplane#2]

HI JOhnny, the comes and goes thing and the sludge you mentioned sure sounds like cruddy lifters and oil passages to me. If you have a rod out bad enough to knock I would'nt worry about doing more damage as it all ready has had the big lick,crank bad and the whole bit. Differant ways to get the sludge out--engine oil flush additives the easyest but not neccessarily the most effective.Yanking the heads aned cleaning them and all lifters the best if you get it pinned down to lifters. Might try the heater hose stethescope trick to locate where the noise comes from . Top side / pan/ side of block/all over. Seen a few other crazy things in the past like cracks around the hub area of the fan/loose torgue converter on the tranny that cause hard to find knocks. If you try the flush treatment I'd run it the recommended time of what you use then let it set and soak 24 hrs to help dissolve crud / run it enough to warm up good then drain. Did you get the travel thing all the same ? this is a must be and may not be able to get done without getting ALL the crud out. You can clean a lifter,put it back and pressure will just clog it again. And of course dropin the pan and checking for rod looseness with your hand should show up one bad enough to knock. BUD

[Oldcar_Mechanic]

Dosconnecting the plug wires one at a time while the car is running will take the load off of that cylinder and the noise will be less if it is a rod.

Bud has the right idea. Listen at different points to try to establish where the noise is coming from. Whithout listening to the engine, it's difficult to determine what the knock might be, lifter, rod, carbon in the cylinder a belt or even a fuel pump push rod.

If you think it may be something in the cylinder, you can always pull all the plugs out of the car and crank the engine. Maybe something will pop out.

If all else fails and the engine is very sludged up, it's then time to bite the bullet and disassemble it.

Ron

[johnny]

ok, so i forgot the other night that was one thing i did too, i got a long thin stick and tried to determine where it was coming from. it seemed to be coming from the front left side of the engine, but i couldn't determine which cylinder, i did the wire test on both and pulled the plugs on both but found nothing. the rocker arm that barely moves is the intake i believe on number 5 cylinder so it's not the same as where the noise is coming from. so i guess my only next step is to pull the head? i mean i can pull the pan easier, buut i don't think if it is a knock which i'm pretty sure it is, that it's bad enough, but i dunno maybe i can tell? opinions please lol thanks, johnny


PS: disconnecting while it's running? let's just say you got bigger weivos than i do, i hate the shock of the hei i killed it and restarted it each time, maybe that's why i didn't notice a difference?

[37 Terraplane#2]

HI JOHNNY, If that lifter does not move as far as it should you have a bad cam. No need to even think about anything else untill you resolve that. Take the rocker off, dissable the ignition and useing the push rod to push the lifter backdown as you turn the engine check the travel. If not enough the cam is bad, if it then moves as it should the lifter is bad. The noise from left front side can also be caused by a worn fuel pump lobe on the cam. Sounds to me as tho if you want an engine worth haveing it's time to bite bullet and tear it down for overhaul or yank the whole thing and replace with one known to be good. We try hard but long disstance diagnostics is pretty catchy. Once again , solve the travel thing ,with out that your ready for a complete tear down as there are going to a number of worn out parts due to lack of proper maintainance. No need to bang your head on a brick wall BUD

[johnny]

ok so i'll try testing the cam lobe tomorrow night, i don't have anything else to do, then i'll go from there
hmm, ok so i guess i could pull the fuel pump and check for wear? I'm not afraid to tear it down and replace some stuff and clean, the problem is if it is a rod or a sleave, i don't want to waste all that time, i'd rather just use it as a trade in and get a rebuilt engine

[37 Terraplane#2]

HI JOHNNY, back to the lifter travel, check it as I suggested, if it do'nt move far enough any other checks are not needed. It's a dead horse. And unless you want to build your own useing it for a trade in core is the way to go. BUD

[johnny]

ok sorry guys, it was cold tonight, so no progress, i just came inside and sat by the heater vent. When i do go i'll try what you said about taking the rocker off and the ignition wire, and turning it over. I didn't quite understand what you guys were saying about the lifter i didn't even try to pump it up, i only remover it from the block and cleaned that and the area around the lifter, sorry i'm still new to this stuff and i'm learning how everything works. sucks i pulled all that and didn't even do the right thing, whatever, that's how you learn. this thing about pulling the valve cover and rocker sounds a lot better though.

[37 Terraplane#2]

HEY JOHNNY , We've all been there,beleive me ,hearten up a bit. One rule I allways follow is most probable cause/problem first and stay on track. Don't jump from one to another,eliminate one at a time. BUD

[johnny]

well more dissapointment, i went out to start it and let it warm up so i could check out the lifter, and th ebattery was dead. My mom is gone in the car at the moment, so i'm out of luck. I'll give it another try when she gets here

[37 Terraplane#2]

No need to warm it up Johnny, just get it as high as it will go,take a measurement,then as low as it goes and measure again. Do the same with another one to compare. If you pull all your spark plugs you can likely turn it by hand to be more accurate. If the proper travel is'nt there it's tear down or replace time. BUD

[johnny]

ok guys, i didn't actually measure but i pulled the valve cover off today and had my uncle hold the push rod as i turned it over, and we compared, huge difference, i can see it just by watching. so i've been looking at heads, i guess i'm just going to buy a short block also because i pulled the rest of the plugs to nothing banged up so the noise must be a rod or something. so you guys got any suggestions on heads? i just got my income tax so i can spend about 600 i'm looking at some 202 160 75 cc reman'd heads on ebay for about 500 any opinions?

[37 Terraplane#2]

Johnny heads won't fix it,waste of money, cam is SHOT and likely about everything else. For $600 you should be able to get a decent complete engine , Shop around, BE SURE YOU CAN TRUST THE SELLER, An auto salvage yard may give you some sort of warranty. Good luck BUD

[johnny]

ya i know, a long block stock is about 650, but i'm just plannign on building a new engine i'm not going to reuse the block, and i want to upgrade a bit now, since it will be cheaper than if i do it down the road

[johnny]

ok got some new news, i started taking everything off today to pull the engine, well i don't have the cherrypicker yet (no one to pick it up for me :S) so after i had everything ready to pull i decided to pull off the head that the noise seemed to be coming from just out of curiosity. guess what i found...bits of some sort of metal in the number 5 cylinder......i must have dropped something inside i guess, i'm not sure if there's anything that could of came loose. it sort of looks like aluminum, but it's tiny bits now so i dunno. it didn't scratch the cylinder walls too bad but i figure i should get a new block anyway cause it burns oil a bit already let alone after something like that happened....also any opinions on the heads? should i keep the old ones, they didn't get beat up on that cylinder. should i have them rebuilt? should i get new ones, or just buy a long block? help please!! :P
Thanks, johnny

[Oldcar_Mechanic]

If you're going to buy a long block, maybe you should just keep your old engine, read up on engines real good and when you find some time you could rebuild yours.

It's a great learning experience.

Ron

[johnny]

it's interesting that you say that, because i want to like drive the vehicle now, and i've got about 800 dollars, well i checked around with some motor dealers, the cheapest is 655 for a long block which includes oil pump rockers push rods timing chain, so you just need the covers.also it has a one year warranty on parts but not labor. or i checked with some of my dealers through work and they can get me one the same for 750 with no core charge and it has a three year warranty. so i was actually thinking exactly what you said. and i'm really good friends with my boss so i could keep it there in the shop.. but i'm still not sure, though that is probably what i do. I worry though, when i was pulling everything yesterday, i draned my tranny flued, well somehow the filter has fallen off, and there was a lot of silver in the bottom of the pan, so like i said i'm worried, that's probably soon to follow. though it migh thave to come from the junkyard.point being thanks for the imput man, i'm having a hard time deciding

[johnny]

it's interesting that you say that, because i want to like drive the vehicle now, and i've got about 800 dollars, well i checked around with some motor dealers, the cheapest is 655 for a long block which includes oil pump rockers push rods timing chain, so you just need the covers.also it has a one year warranty on parts but not labor. or i checked with some of my dealers through work and they can get me one the same for 750 with no core charge and it has a three year warranty. so i was actually thinking exactly what you said. and i'm really good friends with my boss so i could keep it there in the shop.. but i'm still not sure, though that is probably what i do. I worry though, when i was pulling everything yesterday, i draned my tranny flued, well somehow the filter has fallen off, and there was a lot of silver in the bottom of the pan, so like i said i'm worried, that's probably soon to follow. though it migh thave to come from the junkyard.point being thanks for the imput man, i'm having a hard time deciding

ps: i turned the engine over with it taken apart and the lifter that was messed up moves about a quarter inch or something

[Oldcar_Mechanic]

Sounds like that 750 with a three year warrantee is the way to go. You never know on transmissions. I've seen them like that and changed the fluid and watched them run for many more miles problem free. Then again....... you never know. Clean all of the fluid out of the trans and converter and start from the beginning.

I hope that it all turns out good for you in whatever way you go.
Ron

[johnny]

do you think i should take the tranny apart and clean it? or i have a flush machine i could use at work to actually flush it, the pressure stays pretty low though. i have changed the fluid in it once, cause the pan was leaking, aparently i didn't tighten the screws on the filter tight enough :S but i've never had any problems with it, i just don't want to flush it and like blow it up wiuth a little extra pressure or something, on the other hand it shouldn't be more pressure than harsh conditions like revving or being hot.

[Oldcar_Mechanic]

Personally, I would just drain everything, put it back together and drive to see what happens.

Ron

[johnny]

well i guess that's what i'll do then. i don't know if yall care but i got a camera the other day and i'm gonna take some pictures of the process. i think mostly because i want to try the camera but anyway. I'm still waiting on the cherrypicker to be brought to me. so i can pull the engine out and start cleaning and painting stuff. any reccomendations on painting? my uncle said he sanding, primered, clearcoated all under the hood on his and it's gone now... i'm not quite sure if it was the paint job or maybe because it wasn't garage kept? sorry i'm just rambling here. i know i'm anxious to get it running and drive it though.

[johnny]

myspace.com/_johnnym check out in the pictures for a couple pics of changing the engine if you guys want. I'll take more as it goes, right now i'm cleaning and painting. The new engine is supposed to be here friday, and i may try to put it in sunday.