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Discussion Starter · #1 ·
1996 LT1, stock motor, internals ect. I just installed comp cams 1.6rr, and 918 beehives. I set the lash as per the FSM, car ran for about a minute but I had to feather the throttle to keep it going. I reset the lash and now engine will not start. Spins freely as if there were no plugs in it. Fuel pressure is good, spark is good, swapped out with a good PCM, checked with compression gauge getting zero psi. WTF? ANy ideas or info as to what is going on? Cylinder wash down? 16 bent valves? Any help would be great.
 

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Discussion Starter · #3 · (Edited)
Damm. I didnt think of that. I wasted so much time trouble shooting, checking wires, fuses and stuff.. The car sat for about a week while I was waiting on a retainer to come in, so the lifters bleeding down is a very good posibility. Thank you.

I'm on my way to work now so I'll have to wait untill tomorrow to try agian.
 

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I suggest you look at your lash method......sounds like you went past zero pre-load before lash.....and/or did not lash in proper sequence
 

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doh~!
 

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Remember when using the 1 and 6 cyl method of adjusting (adjusting half the arms when cyl one is TDC and half when 6 is TDC) the piston needs to be at the highest point in the bore on the COMPRESSION stroke. I have actually had two friends call me up with problems with valve lash adjustment and when I went over to check it out, I find out that they didn't have #1 or #6 at TDC on compression stroke so valves were open while adjusting them.


Also be warned, while I have had no problems with the 'spinning' the pushrod method, the engine builder at my job warned me that many times an oiled engine (meaning an engine that was previously run, not just being assembled) will provide less friction due to oil and you won't always be able to get an accurate feel for zero lash. Never had this problem with doing them myself, but I like to spin and also do some up and down movements just to be sure. Obviously if the up and down movement is long gone before you feel any friction while spinning, you know there is a problem.

HOw tight did you make them past zero lash anyway? Don't tell us 3 turns or that you torqued them to 25ft lbs :p
 

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ive always used the spin theory as well with no issues. You talk to 10 different engine builders you'll get 9 different ways to find zero lash and adjust.

another good way to make sure the lifters are on base circle of the cam during adjustment is going by the firing order (18436572). with 1 at top dead center compression both lifters are on base and can adjust #1, then turn the motor over 90* go to #8, then another 90* and then #4 etc. every 90* is the next cylinder firing. done correctly the last 90* turn should put you back on #1
 

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with the intake off or even a flash light..
rotate the engine watching for just one lifter to hit and stay at the bottom of travel as it mate / partner is up/ lifted
then adjust just that rocker
that will get a good in the ball park rocker adjustment fast.

when your done fire it up and redo it...running:D
 

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Discussion Starter · #9 ·
ive always used the spin theory as well with no issues. You talk to 10 different engine builders you'll get 9 different ways to find zero lash and adjust.

another good way to make sure the lifters are on base circle of the cam during adjustment is going by the firing order (18436572). with 1 at top dead center compression both lifters are on base and can adjust #1, then turn the motor over 90* go to #8, then another 90* and then #4 etc. every 90* is the next cylinder firing. done correctly the last 90* turn should put you back on #1
What would be the best way to find TDC?

I turn the engine over and watch the arrow on the hub/balancer as it approaches 12o'clock if the valves on cyl 1 do not move as its about to hit 12o'clock, I've been assuming I'm at cyl 1 TDC.

I'll try the way you suggested to rotate the engine 90* and do each cylinder.
 

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Discussion Starter · #10 ·
with the intake off or even a flash light..
rotate the engine watching for just one lifter to hit and stay at the bottom of travel as it mate / partner is up/ lifted
then adjust just that rocker
that will get a good in the ball park rocker adjustment fast.

when your done fire it up and redo it...running:D
I assume you mean to adjust the rocker with its corresponding lifter at it's lowest point in the bore or am I miss reading.
 

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Do yourself a big favor, use the EOIC method. It's fool proof, and depending on your cam it's the safest way to do it.

Simply bump the engine to rotate the cam, and do as follows:
  • As the exhaust valve just starts to open - Adjust the Intake.
  • As the intake valve starts to close - adjust the Exhaust.
Repeat this for each cylinder.

Also, the lifter is at ZERO lash the moment you feel the slightest bit of drag as you spin the pushrod between your thumb and finger.
 

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The rocker arms should be tightened in this order, loosened until lash is felt, tightened to zero lash, and then tightening rocker nut one additional turn (360 degrees) per 1995 FSM instructions:

With engine at cylinder 1 TDC: Exhaust 1, 3, 4, 8 Intake 1, 2, 5, 7

With engine at cylinder 6 TDC: Exhaust 2, 5, 6, 7 Intake 3, 4, 6, 8
 

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The rocker arms should be tightened in this order, loosened until lash is felt, tightened to zero lash, and then tightening rocker nut one additional turn (360 degrees) per 1995 FSM instructions:

With engine at cylinder 1 TDC: Exhaust 1, 3, 4, 8 Intake 1, 2, 5, 7

With engine at cylinder 6 TDC: Exhaust 2, 5, 6, 7 Intake 3, 4, 6, 8
Oh you prob just confused him lol. I just posted in another thread but are the rockers installed correctly? The pivot in center has a flat and a rolled side .
 

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Discussion Starter · #14 · (Edited)
Oh you prob just confused him lol. I just posted in another thread but are the rockers installed correctly? The pivot in center has a flat and a rolled side .
Thanks. I know the rockers are mounted correctly, flat side up for the nut. I was positive i was a TDC on cyl 1 and followed what was called for in my FSM. I have been leaning towards what juicedimpss said about the lifters being bled down. I'll mess with it tomorrow and adjust each cylinder individually via 90* crank rotations. Finding zero lash by turning the pushrod, I have been going 1/2 turn past zero lash, I'll try doing 1/4 turn and see what that does.
 

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1/4 turn may be too noisy when then engine is warmed up. I wouldnt do any less than half. I typically go between 1/2 and 3/4. I have adjusted roller lifter up to 1 full turn without problems but i wouldnt go that much unless you had a noise issue
 

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Discussion Starter · #16 ·
Problem solved

Alright I got it running and lashed. I'm pretty sure the cause of my issue was the lifters bleeding down and making everything too tight when oiled back up. I loosened all the rockers till the locks were finger tight, then fired the engine up. It started right up. With the engine running I set the rockers at 1/4 turn extra when the "noise" stopped. It's running fine now. I'll drive it for a few days and maybe readjust if needed.

Thank you juicedimpss for your insight.
 

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My method. It is more time consuming than most but. I have never had to redo it.
Remove all spark plugs
Remove valve cover
Loosen all rocker arm nuts
Holding your thumb on the rocker end by the push rod turn the engine over untill the lifter is fully down in the bore. then turn engine 1/4 turn.
while spinning the push rod with fingers tighten rocker nut until you just feel friction. Remove socket from nut and spin again. If friction goes away try again.
Once friction is good ( very light) crank the nut down 1/4 to 1/2 turn. ( I use 1/4).

Your done with that rocker. Repeat 15 more times.

Like I said it is time consuming but, if you follow instructions it will come out right
 

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The rocker arms should be tightened in this order, loosened until lash is felt, tightened to zero lash, and then tightening rocker nut one additional turn (360 degrees) per 1995 FSM instructions:

With engine at cylinder 1 TDC: Exhaust 1, 3, 4, 8 Intake 1, 2, 5, 7

With engine at cylinder 6 TDC: Exhaust 2, 5, 6, 7 Intake 3, 4, 6, 8

That's pretty rich since 1 and 6 are TDC at the same time :)
 

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Removing the spark plugs at the same time has one benefit, you only need to use 1 socket for the spark plugs and the rocker arms nuts as both are 5/8" hex headed so can just use the spark plug socket for both plugs and rocker arm nuts :). - Peter
 

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Yes and no. The pistons are synchronized in their movements, but due to the cam spinning at half the speed of the crank the valves are 180 degrees off. Hence the firing order of 1-8-4-3-6-5-7-2 with 1 and 6 being 360 crank degrees off from each order, or 180 cam degrees off from each other. - Peter

That's pretty rich since 1 and 6 are TDC at the same time :)
 
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