I have heared different methods of setting the rockers on a 186 head and thought I'd ask for your prefered methods. Someone told me in the past that you pull rocker down until you can just turn pushrod and in the Holden book from memory tells you to set rocker to zero lash and turn down approx 1.5 turns while engine is running. Which one is right or are there other methods out there?
Over head tune for 6
Started by
_gtrtorana_
, Aug 27 2006 08:14 AM
13 replies to this topic
#2
rodomo
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Posted 27 August 2006 - 10:38 AM
The "just turn the push rod" method is for when you assemble a new egine. You adjust each pair to just turn on the firing stroke for that cylinder. (This gets them somewhere in the "ballpark" to start the engine) Then after you start the engine you back them off (one at a time) until they just start to rattle. Then slowly tighten backdown 1 1/2 - 1 3/4 turns. The engine will miss and fart as you tighten but come good after a few seconds. Go about 1/4 turn at a time as you tighten and wait for the motor to run properly before the next 1/4 turn.
#3
_Keithy's_UC_
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Posted 27 August 2006 - 11:44 AM
I do them with the motor off to save getting oil everywhere... You get a feel for them once you've done them once.
With roller rockers its a bit easier though... You simply tighten them until you can wiggle the rocker but it has no play up or down. I.E. When you wiggle them they dont move up or down at all, only left or right. Once you've fired it up you'll know if you have done it right.
If you want to do it with the motor running, as rodomo says, back them off til they rattle (do one at a time and have a keen ear), then slowly tighten them 1/4 turn at a time, when the motor starts to die on you and does not recover, back it off slightly until the motor is ok again.
With the motor off method make sure you have the motor in compression stroke for each set your doing.
Cheers
Keith
With roller rockers its a bit easier though... You simply tighten them until you can wiggle the rocker but it has no play up or down. I.E. When you wiggle them they dont move up or down at all, only left or right. Once you've fired it up you'll know if you have done it right.
If you want to do it with the motor running, as rodomo says, back them off til they rattle (do one at a time and have a keen ear), then slowly tighten them 1/4 turn at a time, when the motor starts to die on you and does not recover, back it off slightly until the motor is ok again.
With the motor off method make sure you have the motor in compression stroke for each set your doing.
Cheers
Keith
#4
_gtrtorana_
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Posted 27 August 2006 - 07:32 PM
NOT HAPPY 
I placed new roller rockers on and I now have 3 broken studs and one bent stud, (The rockers are the same ratio as std rockers). I have the original press in studs (3/8) on a Yella Terra Head so now the head is off to replace with screw in studs. I checked for spring bind at full lift and found all to be ok. I only set rockers so push rods just turn so I have not over adjusted rockers. From the ID marks, the adjustment screws have a rub mark on one side as though rocker has twisted while in operation. Was I supposed to use guide plates? The rockers are ST 2007 and claim they are a bolt on and go design. Any ideas?
I placed new roller rockers on and I now have 3 broken studs and one bent stud, (The rockers are the same ratio as std rockers). I have the original press in studs (3/8) on a Yella Terra Head so now the head is off to replace with screw in studs. I checked for spring bind at full lift and found all to be ok. I only set rockers so push rods just turn so I have not over adjusted rockers. From the ID marks, the adjustment screws have a rub mark on one side as though rocker has twisted while in operation. Was I supposed to use guide plates? The rockers are ST 2007 and claim they are a bolt on and go design. Any ideas?
#5
rodomo
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Posted 27 August 2006 - 11:50 PM
Does it have solid lifters?
#7
rodomo
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Posted 28 August 2006 - 04:53 PM
When you did your adjustment, the piston for each cylinder was at top dead centre on the firing stroke?
#8
_Keithy's_UC_
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Posted 28 August 2006 - 08:20 PM
What pushrods are you running? Has the head been shaved?
I'll tell you why i ask this:
202 pushrods are shorter than 186 pushrods. If your head has ever had a shave, it is now a smaller height than it used to be. As you would be (I am assuming) running 186 pushrods, you have now pushed your roller rockers into the studs causing them to bend, and some to snap. I had this happen to me (against the advice of others).
I maybe should have asked this before you asked for advice on tuning roller rockers.
Simple solution - get a set of 202 pushrods now before you keep snapping your studs.
Cheers
Keith
I'll tell you why i ask this:
202 pushrods are shorter than 186 pushrods. If your head has ever had a shave, it is now a smaller height than it used to be. As you would be (I am assuming) running 186 pushrods, you have now pushed your roller rockers into the studs causing them to bend, and some to snap. I had this happen to me (against the advice of others).
I maybe should have asked this before you asked for advice on tuning roller rockers.
Simple solution - get a set of 202 pushrods now before you keep snapping your studs.
Cheers
Keith
#9
barny_lx
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Posted 28 August 2006 - 09:11 PM
what clearance do people run with solid cams?
#10
rodomo
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Posted 29 August 2006 - 01:20 AM
.008" inlet, 012" exhaust or as recommended.
#11
_gtrtorana_
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Posted 30 August 2006 - 07:37 AM
That was it, need 202 rods. Off to pick a part tonight. Thats if they have any 202's anymore or just vn commodores.
#12
_Keithy's_UC_
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Posted 30 August 2006 - 07:44 AM
Crow Cams do them, repco do them, even supercheap can get them. Overnight freight is no problem with any of these companies, and you'll probably snag a set for around the $100 mark through repco...
Cheers
Keith
Cheers
Keith
#13
orangeLJ
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Posted 30 August 2006 - 11:09 AM
we've got an old rocker cover that we use when painting the block and head, but we cut the top out of it so when it comes time to adjust em, simply wack it on fire the car up and adjustaway , stops most of the oil goin everywhere... just the odd spray here and there. Cheers Chris
#14
_Keithy's_UC_
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Posted 30 August 2006 - 12:30 PM
Not if you've got a high volume oil pump... oil hits the walls the bonnet, everything... i had to cut my rocker cover top part into 6 sections and put hinges on it... open them up individually to stop oil getting everywhere...
Keith
Keith
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