Adjusting valves cold ?

[bowtie4542001]

Hey guys,

I remember there was a discussion on this subject before but I can't find it. When you are adjusting valves on a roller cam with the engine cold, do you adjust it a little tighter or looser than your supposed to. I appreciate yall's help. :D :D

[thetanman101]

A tad looser to allow for the parts expanding when they come up to temp. I generally lash at 0.022 cold, 0.020 hot for my cam.
-Tanner

[bowtie4542001]

Thanks Tanner,

Thats what I did, just wanted to make sure.

[dcarr511]

Hey guys,

I remember there was a discussion on this subject before but I can't find it. When you are adjusting valves on a roller cam with the engine cold, do you adjust it a little tighter or looser than your supposed to. I appreciate yall's help. :D :D

Adjust them hot as you normally would and then let it sit over night and check where they are at to get YOUR cold settings

[margaritaman]

OK now I'm confused. I too used to think you would adjust them looser because things would expand and tighten up, then I swear I heard the because the block and heads actually grow that the tolerances actually increase.

The only reason this even started to make sense was beacuse how much my block grows when warm as evidenced by my blower belt getting tighter.

Too many margaritas?

FWIW I always adjust mine hot and have burns to show for it.

[margaritaman]

With iron block and iron heads, add .002"
With iron block and aluminum heads, subtract .006".
With both aluminum block and heads, subtract .012

I knew it was somewhere. This is what I used on initial startup to get close.

[zipper06]

margaritaman, is very close on his startup,

Having been in the machining trade almost 50 yrs. there are growth differences in how metals grow and contract.

example: STEEL grows approx (.0001) per 10 degrees temperature change.

example: ALUM grows approx (.0007) per 10 degrees temperature change.

But other factors come into play, such as copper head gaskets, alum rockets, steel blks, alum heads etc.

Most solid cams set between .020 and .030, so the best method is too always set them loose, maybe .030 warm the car up to running temperature and reset them correctly and never run a car on the initial setting.

margaritaman is right about the blower belt tightening up and nothing will eat an idler pulley bearing or break a blower belt quicker than a overtight belt.

just my .02 cents

Zip.

[billhendren]

Rocker ratio plays an important part as well.with an aluminum block and heads on our SB2.2 engines using 1.9 int ratio and 1.85 ex.the int set at .018 hot will be .002 negative cold, the in valve is actually open. aluminum expands at .001 per inch of length for each hundred deg. steel expands at roughly .005 per inch per hundred.Bill

[bowtie4542001]

Thanks Guys,

What is the best way to set valves. I thought I was going down the right path but this weekend proved I was wrong. Also is there a different way to adjust valves if you are running a stud gridle? Thanks

[billhendren]

When using a stud girdle you just loosen it enough so you can turn the adjuster nut.studs on most heads aren't dead on as far as alignment so if you loosen the stud girdle all the way,set the valve and tighten it the valve lash changes.Bill

[bjuice]

Cris...all the information you are getting is GREAT information...but the things you need to see and feel for yourself is stuff like the feel of the friction on the feeler gauges between the rocker and the valve and stuff like that so you know how it feels ion the future..so if you get some time come this way and i will help you...we can do this at some exit off the interstate somewhere.......i always teach beginners to focus on 1 cylinder at a time and use your intake valve as the indicater.
example:...start with cylinder #1..watch the intake valve as it starts down or (opens up)..once it starts up or (closes) ...stop right there and adjust the exhaust valve....on the same #1 cylinder..then watch the exhaust valve...one it goes all the way down or ( open)...just right at the bottom RIGHT BEFORE it starts to come up or (close) adjust your intake....have a marker on hand and place a mark on your stud girdles on both valves ...letting you know these are done..so you do not get confused where you left off.....

when you get good you can skip around...keying on the intake valve..but until you get some experience...go right down the line..with 1,3,5,7..then go to other side 2,4,6,8......get you a bumper switch to hook to you seleniod switch...igintion off.....

before you do this...let the car heat up to at least 170 degree's...


any questions give me PM...

Brian