View Full Version : Setting cold valve lash on a solid cam


Joe Prather
11-30-2009, 03:31:02 PM
Hi everyone, I just installed my new solid flat tappet Elgin cam today and now I'm ready to set the lash. The problem is, the only info I can find about the lash is to set the valves at .026 hot. I can't find anything for the cold setting. Should I set them at .026 anyway?
I made all of the precautions that are neccesary for a good break in. I just wanted to make sure I have my lash in the ballpark when I start it for the first time.

Thanks for your time,

Joe

High Country Z
11-30-2009, 04:48:55 PM
Someone else asked this same question last week, when setting lash cold the GM service manual recommended an extra .002 lash. After reaching operating temp. recheck and set at recommended hot settings.

Damon
11-30-2009, 05:56:39 PM
I always set it tighter on a cold engine. .002" tighter than spec with cast iron heads, .004" tighter than spec with aluminum heads.

scrapmetal
11-30-2009, 06:01:19 PM
I agree with Damon.After it gets warmed up check it to be sho!

Rick WI
11-30-2009, 07:17:41 PM
You set lash TIGHTER on cold lash.....end of story that is how it's done. Reduction in lash on cold adjustment is dependent on cylinder head and block material, all steel, less compensation, all aluminum more compensation...to the tight side.

Set at .022 - .024.

Joe Prather
12-01-2009, 05:39:16 AM
Thanks for the replies everyone. I'm going to set them at .024 later today.

Thanks again!

Joe

REARSPROCKET
12-01-2009, 12:51:34 PM
"When installing a new cam, the engine will be cold but the lash specifications are for a hot engine. What are you to do? There is a correction factor that can be used to get close. We mentioned that the alloy of the engine parts can be affected by thermal expansion in different ways, therefore the amount of correction factor to the lash setting depends on whether the cylinder heads and block are made out of cast iron or aluminum.

You can take the "hot" setting given to you in the catalog or cam specification card and alter it by the following amount to get a "cold" lash setting.

With iron block and iron heads, add .002"
With iron block and aluminum heads, subtract .006".
With both aluminum block and heads, subtract .012".
Remember this correction adjustment is approximate and is only meant to get you close for the initial start up of the engine. After the engine is warmed up to its proper operating temperature range, you must go back and reset all the valves to the proper "hot" valve lash settings."

This is from Crane Cams Website, so it all depends on if your heads are iron or aluminum? Enjoy :bowtie:

Battmann
12-01-2009, 01:22:20 PM
"When installing a new cam, the engine will be cold but the lash specifications are for a hot engine. What are you to do? There is a correction factor that can be used to get close. We mentioned that the alloy of the engine parts can be affected by thermal expansion in different ways, therefore the amount of correction factor to the lash setting depends on whether the cylinder heads and block are made out of cast iron or aluminum.

You can take the "hot" setting given to you in the catalog or cam specification card and alter it by the following amount to get a "cold" lash setting.

With iron block and iron heads, add .002"
With iron block and aluminum heads, subtract .006".
With both aluminum block and heads, subtract .012".
Remember this correction adjustment is approximate and is only meant to get you close for the initial start up of the engine. After the engine is warmed up to its proper operating temperature range, you must go back and reset all the valves to the proper "hot" valve lash settings."

This is from Crane Cams Website, so it all depends on if your heads are iron or aluminum? Enjoy :bowtie:
link to above reference website (i use it all the time):
http://cranecams.com/?show=techarticle&id=2

Joe Prather
12-01-2009, 02:47:27 PM
Thanks REARSPROCKET and Battmann, after reading the link it appears I should set my lash ay .028. My hot lash is .026, so I need to add .002 to that.

Thanks for the help guys!

Joe

GetMore
12-01-2009, 03:47:14 PM
Do us a favor and once you've got the engine up and running check the lash and tell us how it compares when hot. It would be interesting to see if the info Crane gives (posted above) matches what happens on your engine.

HULKZ28
12-01-2009, 09:20:38 PM
[QUOTE=Rick WI]You set lash TIGHTER on cold lash.....end of story that is how it's done. Reduction in lash on cold adjustment is dependent on cylinder head and block material, all steel, less compensation, all aluminum more compensation...to the tight side.

Thats what I did 1500 miles ago and never touched em since then..
I think it was .005 tighter for iron heads..

HULKZ28
12-01-2009, 09:42:59 PM
I always thought that as the head gets hot,and grows, the lash will become greater....The rocker stud will rise creating more lash,therefore set it on the tight side when cold..
good luck

Joe Prather
12-02-2009, 04:21:14 PM
I'm sure my lash isn't perfect right now. Once I get the cam broke in and my inner springs installed, I'll redo the lash.

Thanks again,

Joe

Doug Jaynes
12-03-2009, 12:15:16 AM
I set mine .016 cold and it ends up about .020 when hot. iron block alum Dart heads

mrdragster1970
12-03-2009, 12:11:39 PM
.

I might of missed it, but my 2 cents. Any new cam with solid or solid roller should be checked the 1st 3 heat cycles.
Then checked again every so often, to make sure it's staying where it needs to be. For a few minutes time & effort,
you can catch an unusual wear or damage early sometimes.

Also a raised runner monster head will grow more than a standard valve head, for anyone with a full race set up.

.

High Country Z
12-03-2009, 12:39:39 PM
In my own experience on a stock configuration engine, whenever lash increases, excepting poly lock loosening, it is usually a sign of lobe wear.

Joe Prather
12-04-2009, 05:21:32 AM
I broke in the cam today and I think all went well. I'm going to run it for another hour or so and then install my inner valve springs. I'll have to relash my valves again after that.

Do you guys lash them while the engine is running? I'm wondering how hard it will be to get the feeler gauge between the rocker and valve while they are moving.

Thanks for your time,
Joe

mrdragster1970
12-04-2009, 09:53:29 AM
.

Back in the day we did it running. Late '70's-early '80's.
Now we do everything off, but heat soaked.

.

Joe Prather
12-05-2009, 05:38:19 AM
.

Back in the day we did it running. Late '70's-early '80's.
Now we do everything off, but heat soaked.

.

Thanks for the reply.

I think I'll try it with the engine running. sometimes it's hard for me to tell when the valves are closed when the engine isn't running.

spicewood1
12-05-2009, 11:07:45 AM
Good luck, have plenty or rags handy. Trying not to offend but I never set my solid lash with the engine running. Why not get everything up to temp, shut it down, then take your time with the feeler gauges? With it running you have to hurry, plus it's hard to do. You do know just locking down the polylock set screw upsets the lash setting, so you have to plan for that and always recheck after locking down the set screw.

pdq67
12-06-2009, 05:18:22 PM
I still lash mine hot idling right along.

It's a feelie deal the older Mechanics taught me as a pup.

And once she's broken in good, you might want to run a lash-loop on her to see how well your cam match's your combination. Lash her tight like .004", run her, then loose like .004" from your base lash.

This will tell you if she pick's up tight, you can use a tad bigger cam and vice versa. Pick's up loose, a tad smaller cam..

pdq67

mrdragster1970
12-06-2009, 06:37:23 PM
.

DAMN, you are old!!

.

pdq67
12-06-2009, 07:40:48 PM
mr,

Did I offend you? I hope not?

That's how I learned how to do this stuff and it still does me good, imho.

pdq67

mrdragster1970
12-06-2009, 09:02:08 PM
.

Never, just teasing, we have not done it running since the 80's.

That's how I learned myself in the 70's. I had the stock valve covers with holes,
I had the clip on deflectors, I had some plastic deflector POS. Trust me, been there, done that.

Plus I turn it over by hand. My starter guy yells at me if I bump it over a million times.
So I don't use any of the things I was taught back then anymore.

.

pdq67
12-06-2009, 09:17:13 PM
No.

Idling right along is how the old Mechanic's taught me.

pdq67

stenny
03-08-2011, 06:58:13 PM
ok if i set it to .028 with the feeler tool where do i put he feeler tool? in between the rocker and spring? i am trying to figure out the correct way to adjust the valve lash on my rockers because i just put in a cam and lifters came last night and lifters today so i am about to put in the push rods now but need the know how to get the job done without messing anything up right now the timeing marks on timeing chain and gears dots are lined up and so what valves do i adjust ? in the easiest terms! i know what cylinder 1 is but forget where the others are

COPO
03-08-2011, 08:46:13 PM
I go by the GM service method.
For cold lash you ADD .002 for Iron Block/ Iron Heads. http://www.cranecams.com/pdf-tech-tips/mech-lift.pdf

http://www.nastyz28.com/~copo/images/doc_adjusting_solid_lifters.jpg

stenny
03-08-2011, 09:00:33 PM
i have flat tappet hydraulic lifters and regular rockers also what do i torque the rockers at?

stenny
09-28-2011, 08:40:46 PM
I had it idling I cut a set of old valve covers so I could adjust valve lash while engine was idling I loosened each valve until it started clicking then tightened a little bit at a time until they stop then turn 1/4 to 1/2 a turn to lock down and go to the next one until your done then run car for a half hour or so and your done

cmonson
09-29-2011, 04:06:13 PM
i have flat tappet hydraulic lifters and regular rockers also what do i torque the rockers at?

You can follow the same sequence as solids when the engine is off, but set the valves to zero lash +1/4 to 1/2 a turn in. I prefer 1/4.

bfmgoalie
09-29-2011, 06:47:46 PM
Education time for me. Maybe I'm misreading the posts. When material heats, it expands. So, if you set a lash at .020 cold, when you measure it after it warms up, wouldn't the lash get tighter, like .018? Believe me, I'm not questioning, just trying to learn.