Setting Valve Lash

tbauer03

tbauer03

TRBOBOX
OK i got comp promagnum 1.52 roller rockers with comp 850-12 hydrallic roller lifters comp 987-12 springs and a comp 422 cam. I am having to switch the poly lock nuts that came with the promagnum rockers bc of clearance issues with the valve covers and i am going to be installing cranecams nuts instead. The machine shop assembled the long block and i have never done this b4 and was hoping someone could someone walk me through this. It would be helpful.

From what i understand is i find TDC of the compression stroke on a cylinder so both valves are closed and then i put the new nuts on until they get seated and then just turn them 1/2 turn? a full turn? I have read different #'s from different sources.

Anyway if someone could help me by pointing to a link or replying with a nice walkthrough that would be very helpful.

Thanks
 
jwaller

jwaller

Evil Genius/SyTy Guru
simply bring the harmonic balancer up to TDC. and you will either be on tdc for #1 or #4. look at the rockers to see which pair are fully closed. then you can adjust all the rocker that are closed. turn the motor 1 turn and adjust all the ones you didnt just adjust.

from zero lash give those lifters you have 1 full turn.
 
dgoodhue

dgoodhue

BuSTeD 4.3
I just got finished adjusting mine for the 3rd time. The first time I did, the engine had been sitting for a while and the lifters bled down (had a bad idle). I readjusted them, again with the engine off, but something wasn't quite right (some slight stumbles between 1000-2000 rpm). I redid it with the engine running and now it run greats. I talk to myclone about his advice, I warmed the engine nice and good before taking off a valve cover and used a peice of cardboard to contian any oil splash, I only spilled a little oil from one of the rockers using this procedure. It was super easy I know its done right.
 
T

typhoon92

Donating Member
Re: Setting Valve Lash

Hey Ted,
Which way did you end up setting valve lash? I had the machine shop assemble the bottom end and i'm doing the rest.Everthing is pretty much done except setting the valve lash which I have never done before.So any help would be appreciated!!!
 
sytyguy

sytyguy

Moderated User
Re: Setting Valve Lash

On the 875-12 lifters, I go to zero lash and 3/8 turn. Comp says .010s preload (which is barely tightened), but I go a tad bit farther to keep 'em quiet. Nice and quiet for 4 years now in my Syclone.

Hood
 
sytyguy

sytyguy

Moderated User
Re: Setting Valve Lash

No torque spec on adjustable rockers. Just tighten the nuts to zero lash (no noise if running, no spin on base if not running) and then tighten the recommended amount (usually 1/4-1/2 turn) past zero lash.

Hood
 
T

typhoon92

Donating Member
Re: Setting Valve Lash

sytyguy said:
No torque spec on adjustable rockers. Just tighten the nuts to zero lash (no noise if running, no spin if not) and then go past the recommended amount (usually 1/4-1/2 turn).

Hood
Click to expand...

Alright sounds good!!! Thank you for your help!!!!
 
9

92Typhoon1679

Member
Re: Setting Valve Lash

Ive installed the same rockers on my engine they were hard at first dont read the books its not for these lifters.
first time too tight truck didnt run
second time after loosing still to tight
third time adjusted while engine running runs great.
but remember i looked at the book and searched online and no help. what i did

install rockers.
make hand tight
start engine with valve covers off. it makes a mess let engine get up to temp
loosen nut until rocker makes noise

slowly tighten with fingers not wrench you can get better feel with fingers and watch oil. if you use a wrench you can make it too tight if its too tight oil will not flow out of lifter and you will see it.

so just tighten with wrench a 1/4 turn after they feel tight with fingers and not making noise,and oil is flowing good and set the lock nut.

believe me it took me three times and this way worked for me. the lock nuts that come with them are good so they screw on the studs smoothly so you will feel when it gets tight.

I have no clearance problems with valve cover i the edlbrock aluminum valve covers which are the same size as stock.

have fun...
 
Last edited:
sytyguy

sytyguy

Moderated User
Re: Setting Valve Lash

PM me if you need any help, but the above length gives pretty good detail of how to adjust them.

Hood
 
T

typhoon92

Donating Member
Re: Setting Valve Lash

92Typhoon1679 said:
Ive installed the same rockers on my engine they were hard at first
first time too tight truck didnt run
second time after loosing still to tight
third time adjusted while engine running runs great.
but remember i looked at the book and searched online and no help. what i did

install rockers.
make hand tight
start engine with valve covers off. it makes a mess let engine get up to temp
loosen nut until rocker makes noise

slowly tighten with fingers not wrench you can get better feel with fingers and watch oil. if you use a wrench you can make it too tight if its too tight oil will not flow out of lifter and you will see it.

so just tighten with wrench a 1/4 turn after they feel tight with fingers and not making noise,and oil is flowing good and set the lock nut.

believe me it took me three times and this way worked for me. the lock nuts that come with them are good so they screw on the studs smoothly so you will feel when it gets tight.

have fun...
Click to expand...

Thanks for your input also!!
 
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