did an adjustment the other day. now the engine idles poorly, struggles a bit at low rpm, and is rougher than usual at high rpm. my guess is that i need to loosen the screws a bit rather than tighten, but i am not sure. this is my first time doing an adjustment, and i used the mid-range specs to check them (.008 intake, .010 exhaust with slight drag..maybe too much drag??). hayne's manual was followed thoroughly, though judging proper drag is the most difficult part.

thoughts and suggestions? are those symptoms generally those of tight adjustment or loose adjustment or both?? there is no clicking/tapping to indicate loose adjustment..

more importantly, how long does it take for the engine to be sufficiently cold to do the adjustment? what if i open the hood and take off the valve cover..about how long then? i know it is recommended to just leave the car overnight, but i dont wanna risk messing up the adjustment at 6 in the morning before work..

thanks in advance!!

 

Yes leave it to cool overnight, and your valves are to tight.

 

yea, sounds like the valves are not closing all the way so you are losing compression. Re-adjust with less lash.

 

alright, cool thanks guys. i will try this. i guess i will have to wake up birght and early

so just trying to understand how it works..how do u lose compression? with having more lash, the valves open more (lower) i guess, and do u lose some pressure from giving air more time to escape or something like it? i am a bit confused..

 

but wait, doesn't more lash mean more gap which means looser? and less lash would mean to tighten?? so wouldnt less lash open the valves more?

 

When you tighten the valves to much they stay open a very very tiny bit, when they should be closed tightly to not let any air escape when the piston is in compression/ignite cycle. Therefore your car will run rough and you will lose compression.

 

ah understood!! thanks again!! i will hopefully get this fixed tomorrow morning then..

 

exactly as littleblue stated. it would be better to have them not tight enough so they dont open enough than open so far that they dont close all the way. we have this problem with muscle cars sometimes when the pushrods are too long or the rockers are adjusted too tight. The valves dont close all the way and during the compression stroke all the air/fuel goes right out the intake/exhaust valves leaving nothing to burn during the power stroke. you can sometimes tell this by how fast the motor turns over during startup.

 

Righty tighty lefty losey. If you tighten, it will push the valve down.

 

alright, i'm running out of ideas here. i readjusted the valves 5 times, loosening a bit every time. it got to the point where i used .013 exhaust and .011 intake (tiny bit of drag when checking gap). at this lash, the engine still ran rough and was starting to get noisy.

i then tightened the valves a bit using .011 exhaust and .009 intake (which was about the lash that had my car running just about perfectly when cold but still sucked when warmed up) but it runs pretty horribly now. i am just wondering if there is something else that i may have messed up?? i used a new valve gasket and plug seals..i broke a cover bolt, but the cover stays on well and doesn't leak oil.

would a compression check identify if valves are too tight on a given cylinder? also, one of my plug wire rubber tips (seal? boot?) came off and is stuck around the plug (any suggestions on how to get it out would be awesome ). i did a compression test on the other 3 cylinders with the 4th plug still in the hole and got 170, 170, 180ish..thoughts?

 

Are you sure that you're rotating the engine correctly so the valves are in the fully closed position when adjusting the lash?

 

Well..I am rotating using the crank pulley counterclockwise. When the 'UP' mark is pointing up, i do cylinder 1. Then when it is facing the front, # 3. Then down, # 4. Then back, #2.

I honestly follow the proccess perfectly. I'm starting to wonder if i burnt a valve when i drove it for a bit with the valves too tight?

Did another adjustment. The middle specs (.008 in, .010 ex) fit with drag and the size bigger do not fit unless forced with some arm strength. From what i understand, that should be perfect. The car runs nearly perfectly when it's cold (i can't decide whether the slight bounciness every now and then is cold clutch or bad valve lash), but as soon as it starts warming up it gets bad.

The idle is really really rough once its been driven for a while. I just don't understand what could possibly be wrong??

Maybe, come to think of it, it isn't valves that's my problem. I do have a coolant leak somewhere and sweet smelling exhaust (no smoke, clean oil/coolant, not overheating). On the same day i did the 1st valve adjustment, i topped off the coolant in the rad and the reservoir, and it has diminished a bit i think. Maybe i got some air in the system or maybe coolant being burned is the culprit? But there's no way i couldve gotten much air in the system (if any) from topping it off..

 

bump

 

compression seems to be good if ur getting those numbers. check ur cap n rotor....

 

The way you do the valve adjustment is correct.

Having issues with IACV?

 

hmmm i did just replace the rotor and seal about a week before..the new cap had thicker ends so the screw used for the old cap wasn't long enough. i am still using the old cap.

what should i look for? corrosion? burning? is there a spec to how tight u tighten the rotor screw? it was making noise so i tightened it..wires are all in proper position (going cw from top right of cap: 1,3,4,2)

 

i cleaned the iacv about 2 weeks ago..was running fine until i messed with valves..

 

i lie. the reason why i cleaned the iacv is because the revs were going up and down at start up, then calming down at idle. i believe that the problems are seperate, but maybe that, coolant leak, and the recent running rough after the valve adjustment are related??