solid lifter/edelbrock head guys?

[lewtot184]

anyone here ever do a cold vs hot valve lash check? i'm wondering what kind of differences your getting between hot and cold. my lash cold is all over the map, nothing consistent. trying to weed out "pilot" error vs thermal changes, thanks!

 

[dvw]

My Indy -1's are lashed cold. I feel it is more accurate do to the fact that hot lash the temp can vary greatly. I run .014"/.015" cold = .020" hot. I always check cold and use a sharpie to record any change with that rocker. Then next time I can see if the same rocker changes. In 200 passes I have yet to see more than .002" change in any rocker. Usually 1 or 2 are off .001" when checked. T&D paired rockers, comp 996 springs, .800" lift roller , 200 passes
Doug

 

[lewtot184]

dvw, i think your on to something. i set the lash hot a few weeks ago . cold i'm getting over .010" variance on the 1,3,5,7, side; just a few thousandths on the 2,4,6,8 side. do you notice the exhaust valve growing noticeably more than the intake went hot? thanks!

 

[IQ52]

The aluminum head is expanding and lifting the rocker shaft away from the cam and valve tips. On the aluminum heads it's pretty typical to be .006" loose hot, after setting the lash cold. If your lash is .020" hot, just set it .014" cold.

If you are going to set it hot, do one side, fire the engine back up and warm it up, then do the second side.

 

[lewtot184]

The aluminum head is expanding and lifting the rocker shaft away from the cam and valve tips. On the aluminum heads it's pretty typical to be .006" loose hot, after setting the lash cold. If your lash is .020" hot, just set it .014" cold.

If you are going to set it hot, do one side, fire the engine back up and warm it up, then do the second side.

i think your last sentence is my problem. i think going to a cold setting is going to be more consistent for me.

 

[Propwash]

I have the same issue with my eddy heads and solid lifter Comp Cam. Rechecking cold, there's no rhyme or reason. I stick with Comp's recommendation to set hot. PIA though.....get the car hot, pull the cover on one side, set as fast as possible without burning the crap out of myself, put the cover back on, start up the car again, get it hot and start all over again.

Come spring I may try the -.006 theory. Set them cold and see where they sit hot again. Thanks!

 

[dvw]

dvw, i think your on to something. i set the lash hot a few weeks ago . cold i'm getting over .010" variance on the 1,3,5,7, side; just a few thousandths on the 2,4,6,8 side. do you notice the exhaust valve growing noticeably more than the intake went hot? thanks!

That's why I set the exhaust .001" looser. For those of you that believ in hot setting. Set them cold, run it and get it hot. Pull the cover and check them all quickly and record the readings. Let it cool over night and recheck. calculate the difference. You won't have to set it hot again. Mine is .020" hot, .014/.015 cold on average. How hot is hot? check it warmed up and right after a pass. Then tell me what you see. I doubt they'll be the same. Get it in the ball park and adjust from there for best performance, just not to loose, It 's not valve train friendly.
Doug

 

[66Satellite47]

I'm with dvw, set them cold, don't burn yourself & check 'em again hot. The difference cold/hot should stay consistent over time. Good records are a help.

 

[lewtot184]

when i put this engine together i did the -.006" lash reduction. on start-up i had some low rpm running issues









i reduced lash .006" when i put the engine together with the intent of getting some run time on the new parts and then re-setting hot. apparently that's not going to work. there was .008"-.010" lash difference between the odd fire and even fire bank. the engine runs cool, especially in this weather, and i think the cool down was greater than i would have expected. i'll start a cold lash setting work-up and stick to it. thanks everyone!

 

[Canyon707]

I see big differences between hot and cold. I have a comp cam and al heads. I set cold allowing what comp recommends. I was told by other pro drag racers to set one hot then check it after the engine is completely cold and make the adjustments at that point .these valve covers make it easy to adjust hot with no mess.

 

[69 GTX]

Will how often do you have to set yours? Trying to decide between Hyd roller & solid roller.

 

[lewtot184]

Will how often do you have to set yours? Trying to decide between Hyd roller & solid roller.

what i've noticed is frequent adjustments are more due to the person doing the adjusting than due to parts wear. we usually create our own maintenance headaches. go solid. juice lifters may be a greater headache with a roller.



just got done re-adjusting the lash cold. will do a test drive shortly.

 

[lewtot184]

like frankenstein; it's alive, it's alive! kinda funny for as much as i loosened some of the lash up it didn't make much difference in the way it drove.

 

[383man]

The aluminum head is expanding and lifting the rocker shaft away from the cam and valve tips. On the aluminum heads it's pretty typical to be .006" loose hot, after setting the lash cold. If your lash is .020" hot, just set it .014" cold.

If you are going to set it hot, do one side, fire the engine back up and warm it up, then do the second side.

Thats what I do. Mine calls for .020 hot and I set them at .014 cold. I drive my car alot on the street but I only adjust the valves once a year and they are always right on or very close. Ron

 

[dvw]

what i've noticed is frequent adjustments are more due to the person doing the adjusting than due to parts wear. we usually create our own maintenance headaches.

You are correct. It takes finesse to learn how to do it correctly. Make sure you set them on the same spot on the backside of the lobe. If you're unsure about your "feel" try .001" larger and .001" smaller feeler gauges after setting the lash. Once a year lash is plenty on street car once everything is broken in. My race car I check around every 25 passes. I'm looking for changes that could lead to disaster as it runs .800" lift. I have yet to see any significant lash changes after 2 years and 200 passes.
Doug

 

[Canyon707]

Thats what I do. Mine calls for .020 hot and I set them at .014 cold. I drive my car alot on the street but I only adjust the valves once a year and they are always right on or very close. Ron

I think that's the best.

- - - Updated - - -

what i've noticed is frequent adjustments are more due to the person doing the adjusting than due to parts wear. we usually create our own maintenance headaches.

I was told by some race guys that they seem to settle down after awhile and not to much adjusting is required

You are correct. It takes finesse to learn how to do it correctly. Make sure you set them on the same spot on the backside of the lobe. If you're unsure about your "feel" try .001" larger and .001" smaller feeler gauges after setting the lash. Once a year lash is plenty on street car once everything is broken in. My race car I check around every 25 passes. I'm looking for changes that could lead to disaster as it runs .800" lift. I have yet to see any significant lash changes after 2 years and 200 passes.
Doug

 

[Bigal75]

Ok I'm going to set my cold too - solid lifter and the recommendation is 0.016 - I have aluminum heads as well - where should I set them at?

 

[lewtot184]

what i've noticed is frequent adjustments are more due to the person doing the adjusting than due to parts wear. we usually create our own maintenance headaches.

You are correct. It takes finesse to learn how to do it correctly. Make sure you set them on the same spot on the backside of the lobe. If you're unsure about your "feel" try .001" larger and .001" smaller feeler gauges after setting the lash. Once a year lash is plenty on street car once everything is broken in. My race car I check around every 25 passes. I'm looking for changes that could lead to disaster as it runs .800" lift. I have yet to see any significant lash changes after 2 years and 200 passes.
Doug

thats pretty much what i do. i have the feelers for the setting i want but also some larger and smaller layed out for double checking. roller stuff i always double check!

- - - Updated - - -

Ok I'm going to set my cold too - solid lifter and the recommendation is 0.016 - I have aluminum heads as well - where should I set them at?

the .016" is a hot setting that would give you .010"-.011" running clearance at the lobe. i'm a little **** here and get a little freaky when the tappet to lobe running clearance dips below .010", which will happen if you set the lash at .010" cold with an alum head. i would treat .016" running lash at the valve as the minimum, not necessarily as the ideal. i'm going to guess your using a comp cam,...? something to keep in mind that lash isn't about clearance at the rocker/valve tip but about establishing a running clearance at the tappet/lobe. it isn't practical or possible to set that clearance with all the parts bolted on, so working at the rocker/valve tip makes sense. always keep in mind that rocker ratio changes require lash changes to maintain running clearance at the tappet/lobe.

 

[Bigal75]

No its a Bullet cam. Yeah, that seems kind of tight huh.

 

[lewtot184]

No its a Bullet cam. Yeah, that seems kind of tight huh.

call bullet and see if there's someone there that can talk to you about tappet/lobe clearance minimums. there has to be a minimum running clearance on the ramps. i'm not a comp cams fan but they do have some tight clearance profiles too; but i'd be afraid of getting one of their clearasil junkies on the phone if i was needing hard core info.