86 fiero se v6 5 speed. i just did head gaskets on my fiero like a month ago and when i put it back together i forgot to set the valve lash. so i took it all apart and adjusted them. it ran fine after that. hen yesterday i tried starting it and it was very hard to start and there was a faint knocking sound when it did run. if shut off like 2 munutes after running. now i got it apart after the mysterious knocking noise and the valve lash is off again. not jus one....all of them. i followed what it said in chiltons and somehow they came loose. can anyone help with this????

You need to set the lash with the hydaulic valve lifters primed. (full of oil). If you put the lifters back in and did not prime the oil galleries before you set the lash, it will be out very quickly.

PITA but doing it again should cure it.

Arn

Did the adjustment NUTS "back off" ? After 1-2 times re adjustment, they loose their "Grip" & you need new adjuster nuts.
Are you SURE you adjusted them "Correctly" ? I mean, you didn't adjust them "too tight" with the lifters "empty", then, when they pumped up, the valves hit the pistons ? (Knocking) ?

i took the valve covers off and they were all loose. i did the 1 1/2 turns and all that stuff like 2 weeks ago. it just started doing this yesterday. i didnt drive it for about 3 days before yesterday and when i did try starting it yesterday it was hard to start but when it did start it had a very faint knock. it wasnt like a very loud one but it was there. i did the 1 1/2 turns added on because they were loose about 2 hours ago and it still wont run. now it appears to be cranking fast.

Cranking fast? Sounds like they are too tight and holding the valves open all the time.

Did you use the "spinning" method to find zero lash? (cuz this has never worked for me)

[This message has been edited by Hudini (edited 01-23-2012).]

yes i did use the spinning method. but the firsttime i did t it seemed to work but i guess not if they were loose again. but i dont know how they could be too tight if they were still loose when i pulled the valve covers off. i just put it on tdc and did what it said in the book. but since they were already loose i just tightened them more until the lash was gone. that could be the reason why it is cranking fast. omg i think i figured it out. okay here it goes. after i did the heads all the oil came out of the lifters and thr pushrods, so when i put it back together the spinning method worked cause there was friction on the lifters. now that there is oil on them there is little friction so they can spin easily. so i tightened them down more and now they are tii tight causing it to crank fast. haha sound right?

[This message has been edited by fiero17 (edited 01-23-2012).]

Agreed, the spinning method doesn't work very well.

Since I've been there too, couple of ocassions, stringing multiple bad words togeather and throwing tools at the wall, i looked up my notes I posted on the forum in the past, perhaps this will be of some assistance.

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How I've adjusted my valves:

First of all let me give credit to where it is due. JazzMan and a couple of other PFF members actually wrote a good portion of this, I cut, pasted, wrote and edited this so that my non-mechanical brain could easily follow it. That said, let’s get busy adjusting some valves.

The idea is to get the lifter poppet part way down into its bore, about 1/4-1/2 of its travel. If you don't use up some of its travel, then your valve(s) will get loose as normal wear on valve-train parts causes the poppet to reach the top of it's travel. It will also requires more oil to remain (at pressure) in the lifter's plunger cylinder. The more volume to fill, the more chance that the plunger can be compressed, causing a ticking noise or at high revs a bent pushrod.


Make sure that the lifter being adjusted is on the base circle of the cam, this will be TDC on that piston with both valves closed. TDC #1 is where both #1 valves are closed and main fat timing mark on harmonic balancer is at zero on timing tab and distributor rotor is pointing at the number one plug wire terminal.

Set your intake and exhaust valve lash on #1. Rotate the harmonic balancer clockwise 120* to the next timing mark and you know that you are at #2 TDC. Set your intake and exhaust valve lash on #2. The next timing mark after that is #3 TDC and so forth. Remember that the GM/Fiero engines have three timing marks (0*, 120* and 240*) on the harmonic balancer, which makes this much easier than the Chiltons manual method.

The lifter plunger centering adjustment is 1&1/2 turns. Most people think is too much. It is not. The 1&1/2 turns (as specified in the FSM) will center the lifter plunger on an OEM valve train (with the standard rocker ratio). The reason most think that 1&1/2 turns is too much is because they don't properly identify the zero lash point.

If you are twirling the pushrod you won't be able feel the zero lash point unless your hands are 100 times (give or take) more sensitive than the average human. Anyway, while approaching the zero lash point, you should be gently rocking the pushrod up & down between the lifter and the rocker arm. That way you can feel the play diminish down to zero.

Wiggle the pushrod back and forth as you tighten the rocker nut, you will feel the pushrod end "clicking" as it moves around. The amount of movement will decrease as the nut is tightened until suddenly it stops. This is the point where the lash is out with the poppet at the top of it's bore. Now, you need to move the poppet down its bore, so you continue to tighten the rocker nut.

How much you ask? Well, the rocker stud has a 1.5mm pitch, so one full turn moves the rocker ball down 1.5mm. The rocker arm ratio (stock) is 1.5:1, so moving the rocker ball down 1.5mm moves the pushrod down 1.67x1.5mm, or 2.5mm plus or minus a very tiny bit. The lifter poppet travel is 6-8mm, so 1.5 turns on the rocker nut (factory spec) is 3.8mm at the lifter poppet, or about half-way. That's how much I tightened mine, and it worked just fine. Any less and the valves will need readjustment sooner due to wear.

I had mechanics using the Chilton’s manual mess up the lash, I tried the twirl and ¾ turn method and it was noisy as marbles. Jazzman gave me the pitch and rocker ratio measurements above and I went with timing marks on the balancer and the 1-1/2 turns on rocker arms. My engine is smooth now. Lots of power. Most important to me is that I wont have to go through the work to tear the upper half of the engine out to get the lash adjusted for a very long time. Some people have had success with other methods, all the power to you. If there is an easier way, count me in! Good luck with setting your lash and I hope you are using the rubber valve cover gaskets, they are sweet and don’t leak.

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There you go, hope this helps.

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jetman
Silver 86 SE 2M6 4-speed, with "check wallet light"
Now fortified with 8 essential slices of bacon goodness

Okay i will try this tomorow. i was busy all day today and didnt have the time to do so. But yea the chiltons is good for some things but not all. this is one of them. Ive come a long way in 6 months with this car. but maybe when i get it running again im gonna sell if. so if you know anyone that wants to buy a fiero for cheap tell them to come to me.

Wow okay this is a new one ive never seen before. i got them all adjusted and it was running and it sounds perfect but theres a problem. it idled fine and when i gave it gas it was a little slow response but i wasnt paying attention untill i looked at the motor and the exhaust manifolds were glowing orange. like not a dark orange like 2000 degrees orange. so i immediately shut it off. what is the cause of this?

Good Job!!!

You got the valves set right!

now re-do the timing. I think the fuel is not burned when the exhaust valves open up.

[This message has been edited by Gall757 (edited 01-25-2012).]

Okay so that is a timing problem?

you need to 'advance' the spark.....so the fuel has more time to burn.

Okay ill try that tomorow. ive come a long way with this caar in the 6 months ive had it. i put a clutch in it, head gaskets, and a ton of problems along the way and i finally hope that it is right

okay it was the timing but it wont go below 2000 rpms without shutting off. i pulled the intake snorkle off to check for vaccum leaks by blocking iac. it sounds like its stuck open cause it is sucking in a whole lot of air. it sounds like it is wide open.

Did you short the ALDL (a & b) connectors before doing the timing?

Make sure the O2 sensor is plugged in & working ! if disconnected, it will do just what you are experiencing.

you have to short the computer connections to set the timing???

[This message has been edited by Gall757 (edited 01-28-2012).]