adjusting rocker arms/lifter help

[knightowl73]

ok, ive tried this 3x by the book and with you guys help, once running.

i loosened each one tick they started ticking, slowly turned them back n till they didnt, then went exactly a half turn more.

the truck runs a hell of alot better now, doesnt run hot with lil sprints down the street like it did, but it still clacks under hard accelaration. is there something i am missing or is there something else i need to be checkng. could this be a lifter's fualt? im stumped. this motor seems plenty strong, but sounds horrible when i wanna just drive it like i normally drive. ive been having to drive like normal people lately lol.

someone please help me out here.

[jared87350]

check your oil level.
check your oil pressure.
if your ajusting over and over there is somthing wrong.
sounds like you got some miles on the springs.try replacing them.
im sure that will help you in the end.
at the worst you might be losing the lobes on the cam.

[MR .T]

how many miles on engine? It could be a bad / sticky lifter or lobe.

[James McClure]

If it doesn't clatter when driven normally you probably have lash set properly, and in all likelyhood cam and lifters are OK as well. Here is a quick check to see if the cam has a lobe warn to a point where it will clatter. First you want to remove rocker covers and watch valve action at an idle. See if one isn't opening as far as the others. Next, throw it in gear,(manual trans just pull a hole shot) mash the brakes and floor it quickly, hold a few seconds and release. Does it pop back thru the carb? This will check the cam. It will not, however check springs, guides, pulled out studs or valves. Check oil pressure when it's doing whatever it does. Could be the oil pickup is bent or broken right off and hard acceleration moves it out of the oil and sucking air. You don't say if the eng is an older one (GM had a problem with soft cams back in the 80's and replaced them under a recall) Hope this helps, Jim

[knightowl73]

Originally Posted by jared87350

check your oil level.
check your oil pressure.
if your ajusting over and over there is somthing wrong.
sounds like you got some miles on the springs.try replacing them.
im sure that will help you in the end.
at the worst you might be losing the lobes on the cam.

well the motor is supposed to have a erson cam in it. i have no clue how many milkes or anything because it is a newer motor and was in the 73 truck that i bought. i found out through some reasearch that i couldnt really do it by the book like i had because of the fact of the aftermarket cam. but there is no tellin, my dad told me to just get the heads redone, but im not trying to be without transportation so i just wanted to fix it the cheapest way possible.

beginning to sound lke the i will have no choice but to tear down the top of the motor. i have to pull the heads to swap springs right? is there a way to check cam lobes in the motor or check lifters?

oil level and pressure are fine. havent been far the 2 months ive been driving it ive never left this lil town, but maybe need to change the oil again. thicker than 10w-30? thinner? maybe even pay for some good name brand oil, ive always used house brand, and some lucas ol treatment again, which is already n there.

i dd notice the bottom of the valve covers didnt look too good. pree=tty gummed up with oil. just actually thought about it, but the rockers werent shooting oil everywhere like i remember, when i go back in, cleaning the pushrods wouldnt hurt. makes me wonder about that cam too.

[knightowl73]

im not sure if it still pops back thru the carb, but it used to do that when i first got it, and now ive been concentratng on the clatter. my exhaust makes it hard to determine in the cab while driving, but the lil clattering im hearing when drivng it hard could be it still popping back thru the carb. sounds similar with exhaust noise in the mix

[73chevyman]

just like said above open 1 valve cover at a time check valves. sounds like a whipped cam to me but the way adjusted them was wrong one to check valve lash or adjust one you did it while your on top dead center of number one once you get there you can adjust both valves at the same time. then rotate the motor till the next in firing order are both down and so on so forth. to adjust valve lash one loosen the valve until the rocker is sloppy now slowly tighten up bolt untill you can't twist the push rod anymore at that point you give the bolt a half turn lash is set. do that to all and comeback and give us more info on what it is doing

[73chevyman]

heres a video of what i tried to explain to you

YouTube- Valve Lash Adjustment Video - Engine...

[leegrady]

You can change valve springs without pulling the heads. Pump compressed air into the cylinder via the spark plug hole. Not so high psi that it moves the piston down, but about 30-40 lbs. just to keep the valve from dropping. There is an inexpensive valve spring removal tool that is available at most parts stores that is made for this procedure. I'v done this many times to change valve seals. You can also use string to keep the valve from dropping, but I always use air.
However, if the springs are weak there would be valve float, probably not a clatter.

fyi: If a cam is worn out it will be shinny all the way across the lobe. On a new or good cam the lobe is angled so as to bump the lifter on only part of its flat so there will be this kind of wave mark of discoloration across the lobe. In this way the lifter will spin in its bore and wear evenly, lasting longer. Cam in block the intake manifold must be removed to do this visual inspection. But, I don't think at this point you have a bad cam.
I do, to some extent, suspect a bent push rod.

[73chevyman]

i've adjusted mine like the video and never had a problem with with my valves. but the way you did it above was right to a point the half turn should of never been in that only when motor is not running. you have to watch what ur doing cause you can mess up the lifter while its running and collapse the lifter. if thats your case then you will have to take the intake off and check all the lifters one at a time to see if it is lobed on the bottom and if the lfter collasped. if the lifter is lobed on the bottom your cam is done if none are lobed then change all the lifters in case you have a bad one. i hope all this nonsinse i'm trying to say helps lol

[leegrady]

Hydraulic lifters need time to pump up when your making an adjustment with the engine running. Loose to clatter, tighten until it stops, then make one full turn in 1/4 turn increments. You should hear the engine miss as you make these 1/4 turns, and then as the lifter catches up it will smooth out.
You want the end of the push rod in the middle of the lifter. One full turn. (Some may not agree with one full turn. But I first learned how to do this on my Monte in '78.)

I'll bet all of you know this already, but I just like talking shop. Hope maybe it might be of some help.


______________

81 GMC K2500 350/sm465/corp 14/dana 60 upft.

[knightowl73]

ok my first 3 tries at this was something very similar to the video. i did it exactly how the book stated where you only turn the crank two times. i can do this like on the videoo looking at the rocker arms assume. i really dont want to pull the ntake unless i have to.and i was so worried about it possibly running hot that i ran and checked the guage after i slowly got each one adjusted, im thinking that would be enuff time for them to pump huh?

as far as the half a turn, i did ths in 2 1/4 turns for each one. was i supposed to go 1 full turn when i did it running? i thought it was a 1/2-turn more? knda confused here.

but i will pull the covers and watch them to see whats going on.

[knightowl73]

when i did it runnng it seems so damn close. it runs well except for this and the junko carb. carb setting fuel mxture or anythng would not matter on this would it? also, any suggestons for listening while running? the exhaust is pretty loud and makes it hard to hear whats gong on, i had to turn the nuts really slow and really listen hard to tell when the noise was completely gone, then i went the half turn more after. was i supposed to do 1 full turn running?

[leegrady]

Use a scrap piece of garden hose, or heater hose as a stethoscope to hear the rocker clatter over your exhaust noise. Put one end right to your ear, and the other end to the rocker.

Cut the top of an old scrap pair of small block valve covers, and temporarily install them on the engine to perform a hydraulic valve adjustment while the engine is running. In this way you can relax, and take your time, not having to worry about oil leaking out all over the exhaust.

1) At normal operating temp', engine idling, loosen the rocker arm nut until you hear it clatter.

2) Now tighten the nut until just when the clatter stops.

3) Put the handle of your wrench at the 12 '0 clock position, and nice and easy make one quarter of a turn to the 3 '0 clock position. Stop. Wait. Pause for about 20-30 seconds. Wait for the lifter to pump up with oil. You may hear the engine rpm drop, but you may not. Doesn't matter, just pause for a few moments.

4) Continue to tighten the rocker arm nut another 1/4 turn to the 6 '0 clock position. Again wait for the lifter to catch up.

5) Repeat the process until you are back to the 12 '0 clock position. Pause at every 1/4 turn throughout the procedure until you've made one full turn.

Do this with all the valves. The thread pitch on those nuts has a slight interference fit so they feel tight. They are made like that so as to not come loose during service.
The procedure in the youtube video gets the valves adjusted enough to run the engine after assembly. Then this engine running adjustment is made to get them on the money.

Once this adjustment is made there is no longer any reason to adjust hydraulic valves. As the tappet gap increases due to wear of the valve train components more oil will pump into the lifer, and remove any slop.

If your truck is overheating it may cause detonation when you accelerate. This sounds like what your describing too. Also, top end performance will be poor, if the timing is set too far advanced for the octane rating of the gas you're burning.

There are seven(7) major fuel systems of a carburetor, technically called circuits:

1. Choke circuit.
2. Float bowl
3. Idle circuit
4. Accelerator pump circuit
5. Off idle
6. Power and/or mid range circuit
7. Wide open throttle circuit

The mixture screws only effect the idle circuit.

[68 TT]

Originally Posted by leegrady

If your truck is overheating it may cause detonation when you accelerate. This sounds like what your describing too. Also, top end performance will be poor, if the timing is set too far advanced for the octane rating of the gas you're burning.

Just what I was going to say. If it doesn't clatter at idle then the valve adjustment is not the problem. Bad detonation can sound like lifter clatter.

Check the timing with a light then back the base timing down a little.

Unless it has way too much compression you should be able to run it at 8 degrees advanced on 87-octane fuel without detonation.

Who knows how much compression the PO built this engine with.

[knightowl73]

i am currently and have been for a while now, runiing at 8 degrees. i wasnt sure but 8 is factory and that was also where i had the most compresion.i checked and it s still there, i have tried higher octane, but doesnt do much besdes run smoother and use the gas alot faster. a while back i had bought a distributor advance kt, thinking i needed to do something with that because of the cam, but problems is i dont know nothing about the cam, but it def aint stock. will compression test tell me my CR? also have a accel super coil ive been scared to put on becauseit might make it worse, but will that possibly help?

[knightowl73]

by the way, yesterday i noticed the old quadrajet was leaking around the gaskets, was telling my buddy and he gave me a brand new 2bbl motorcraft carb he had bought for his old statonwagon project. well i bought the adapter and put it on and it actually responds alot better, runs alot better, just i havent got it to idle worth **** yet, and yes after driving it a bit, i do think it is predetonaton too. if i go back to 6 degress u think it will help. i remember it did not like above 8 for sure and 6 seemed to low, like i had less power. if it wont hurt tho, ill try it

[leegrady]

If it runs better with the two barrel it means the secondaries on the Q-Jet were coming on too soon.

There is an adjustment for the spring on the secondary plates that open, and raise the secondary metering rods. These are the butterfly plates right on the top of the carb. (not the throttle plates). Increase tension on the spring so your secondaries open later. The carb will act like a two barrel until higher in the rpm range, with much better response. Esp. if your Q-Jet came off some other vehicle.

Note: the primary metering rods on the Q-Jet are numbered, as are the jets. In this way they can be mixed and matched to dial the carb. in richer or leaner. I have no reason to believe you have any problem with this, just thought maybe it might interest some readers.

[73chevyman]

all that explains is that the gasket was bad on the 4 barrel. he was getting to much air beneath the carb.

[knightowl73]

was a brand spanking new gasket on the quadrajunk i took off. i even checked for vacuum leaks with the wd40 and couldnt fnd any. I am still gong to try and go back in and do it all over again and see if i can make it better. i tried the higher octane gas again today and no real difference. gonna try tommorrow setting my timing at 6 instead of 8 and see if that does anything. if that doesnnt work, i might try 3/4 turn instead of a half turn while running.

[knightowl73]

ok here's the update.

re-adjusted the rocker arms and they seem just fine now when the motor is cold. once it warms up, everythng is fne when you drive normal, but when you get on it a little, it still clatters and its not spitting thru the carb now, just the clatter. but also I am stumped now that my temp guage works properly because the temp raises almost all the way to hot if i try and go over 50mph. im thinking maybe the water pump is not the correct one and is spinning the rght direction, but the fins are backwards. its a 88-up motor and i bought the truck with this waterpump on it. i dont really have a way of checking this though, becuase i can see it flowing back in the radiator while running. i also have a new thermostat in it.

still i know the truck has a erson cam in it, and to stop the clatter on the top end i tried to advance it a bit. this seems to work, might need to go a little more, i had it at 8 and its about 9 right now, im thinking 10 should do fine, BUT it is getting hotter faster now.

WTF SHOULD I DO GUYS? I am truly stumped and still scared to leave the city. Please help. Would switching from 10w-40 oil to straight 30w help any? i have it full of water and antifreeze too, no water in oil either.

[knightowl73]

hei advance kit maybe help if it drops my total timing some so i can go back to 8 degrees o rmaybe even 6? figured that would make the clatter come back tho.

[68 TT]

The reverse rotation water pumps have a different pulley bolt pattern on them so you can't mix them up with the standard rotation parts. If your pulleys fit then the water pump turns the correct direction.

It shouldn't heat up that fast if everything is working right. It is possible you have a universal fit fan on there designed for the opposite direction of water pump rotation. This would greatly hinder airflow through the radiator. Look for a seven blade clutch fan on something at the wrecking yard that has the same belt setup as your truck.

Have you replaced the thermostat? Do you even have a thermostat? Some people mistakenly yank the thermostat out of vehicles when they are having cooling problems. You may not have one in there or it could be stuck shut. A 180 degree unit will work nicely year round.

What kind of oil pressure do you have? It may not have enough volume to run at the higher rpm and not starve the lifters for oil (causing the high rpm lifter clatter).

[knightowl73]

ok it s doing this still with a brand new flex fan and spacer, the fan is correct rotation, and oil pressure is about 30psi at idle, maybe 40psi when revved. brand new 180 degree thermostat too. so a 88-94 waterpump will not bolt up to the stock older pulley? i was hoping to be going in the right direction but i guess i can rule that out.

[knightowl73]

brand new temp sensor and guage too, so im sure its not a fualty reading. will idle just fne and drives good tll you try the highway or feeder road. i know the 4.10 rear isnt helping, but i dont thnk i should be having this problem. only have a 2-core rad, but its from my other truck i didnt have this problem with and is only 8 months old. should i be running bigger rad because of the gear ratio? im planning to change it to a 2.73 i have soon, so it shouldnt see these rpm's much longer, but would like to fix my temp problem first.