How much lash for a solid cam set cold?
Thread Starter
Melting Slicks
Joined: Jun 2002
Posts: 2,842
Likes: 99
From: Orrtanna Pa.
How much lash for a solid cam set cold?
I am getting the fever to tweak once again,and since the 406 now has a solid cam,decided to check my lash. I read somewhere if you had aluminum heads,and lashed the cam with the engine stone cold,(no burnt fingers),that you subtracted .006 from the cam spec lash requirements.
Mine calls for .016 lash hot,so I figure if I set it at .010 cold I'd be dead on. When I installed the cam,that's what I did,but I broke it in usng stock springs,and had a local machine shop swap the springs after break in.He lashed it to .016 cold,and told me the difference between hot and cold wasn't that much.
To be honest, when I lashed it at .010 cold,I was amazed at how quiet the solid sounded idlng.It was actually quieter than the hydraulic Comp XE-284 it replaced.
Any insight from solid cam users here?(This is a flat tappet solid Isky Z-35,running 1.60 roller rockers)
Mine calls for .016 lash hot,so I figure if I set it at .010 cold I'd be dead on. When I installed the cam,that's what I did,but I broke it in usng stock springs,and had a local machine shop swap the springs after break in.He lashed it to .016 cold,and told me the difference between hot and cold wasn't that much.
To be honest, when I lashed it at .010 cold,I was amazed at how quiet the solid sounded idlng.It was actually quieter than the hydraulic Comp XE-284 it replaced.
Any insight from solid cam users here?(This is a flat tappet solid Isky Z-35,running 1.60 roller rockers)
Drifting
Joined: Dec 2004
Posts: 1,345
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If you have iron heads there isn't much difference between hot and cold settings, perhaps .002". That is cold, set the valves .002" tighter. With aluminum heads (on small block) they should be set .005" tighter.
It is OK to set a solid cam as tighter to get more lift and duration as long as the valves are not allowed to loose all clearance. They can be set a little looser than spec but if too loose the cam can be damaged due to the cam being hammered by the lifters.
Some set the valves close to Zero Lash cold, so they get maxium lift and duration. The downside is that you need to readjust the valves more frequently so the valves never go without running lash to avoid burning the valves.
It is OK to set a solid cam as tighter to get more lift and duration as long as the valves are not allowed to loose all clearance. They can be set a little looser than spec but if too loose the cam can be damaged due to the cam being hammered by the lifters.
Some set the valves close to Zero Lash cold, so they get maxium lift and duration. The downside is that you need to readjust the valves more frequently so the valves never go without running lash to avoid burning the valves.
Race Director
Joined: Dec 1999
Posts: 19,610
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From: Forked River NJ
I just set mine for break in at the .016 they should be set at. While it was still warm I checked them after break in. They had .022 clearance. So they gained .006. I just put in the new springs, dual springs. Broke the cam in with a set of outer springs only. I am going to set it at .012 cold and see what happens.
Race Director
Joined: Apr 2000
Posts: 17,672
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
The reason it was so quiet is because you probably got it pretty close to zero lash by going -.006". I looked at the Crane cams website and it does not ring true for my setup with aluminum heads. I set hot one time and then let it completly cool down over night. They were -.002" when cold so that is what I set them at cold, instead of .018E/.016I I set them at .016E/.014I 
Pro
Joined: Jul 2002
Posts: 723
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From: North Port, FL
Your cold lash will certainly be less than the hot lash. The best thing to do is dicard the rule of thumb numbers and measure the difference between hot and cold lash for your particular engine, then use that difference to establish the cold lash for a hot lash of .016". You may have to iterate a couple of times. For my engine with aluminum block and heads I set lash at 70 degrees at .004 to get .016 hot.
Thread Starter
Melting Slicks
Joined: Jun 2002
Posts: 2,842
Likes: 99
From: Orrtanna Pa.
Gordon,
When I set mine I snugged it down with a .010" feeler and tried to fit a .012 feeler in after the lash was set.Not the most scientific method,but I know I was set for more than .010,but less than .012 cold. I never checked it hot.
I think it was the Crane site that recommended subtracting .006 for aluminum heads on an iron block,so if that's what you saw,I guess I'll use it.
BTW,If your 385 runs anything like my 406 did,you'll need a prybar to get the grin off your face when you get back from the first ride.
When I set mine I snugged it down with a .010" feeler and tried to fit a .012 feeler in after the lash was set.Not the most scientific method,but I know I was set for more than .010,but less than .012 cold. I never checked it hot.
I think it was the Crane site that recommended subtracting .006 for aluminum heads on an iron block,so if that's what you saw,I guess I'll use it.
BTW,If your 385 runs anything like my 406 did,you'll need a prybar to get the grin off your face when you get back from the first ride.
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
Originally Posted by ZL1powr
Your cold lash will certainly be less than the hot lash. The best thing to do is dicard the rule of thumb numbers and measure the difference between hot and cold lash for your particular engine, then use that difference to establish the cold lash for a hot lash of .016". You may have to iterate a couple of times. For my engine with aluminum block and heads I set lash at 70 degrees at .004 to get .016 hot.
best approach.
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Instructor
Joined: Feb 2006
Posts: 144
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I got a Erson Mechanical Roller cam, it was set 0.018 cold wich i think is too much, any difference in lash on Flattapped mechanical and roller mechanical?
I would love to get rid of at least a little of the valvetrain noice.
I would love to get rid of at least a little of the valvetrain noice.
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
Originally Posted by The Money Pit
Gordon,
When I set mine I snugged it down with a .010" feeler and tried to fit a .012 feeler in after the lash was set.Not the most scientific method,but I know I was set for more than .010,but less than .012 cold. I never checked it hot.
I think it was the Crane site that recommended subtracting .006 for aluminum heads on an iron block,so if that's what you saw,I guess I'll use it.
BTW,If your 385 runs anything like my 406 did,you'll need a prybar to get the grin off your face when you get back from the first ride.
When I set mine I snugged it down with a .010" feeler and tried to fit a .012 feeler in after the lash was set.Not the most scientific method,but I know I was set for more than .010,but less than .012 cold. I never checked it hot.
I think it was the Crane site that recommended subtracting .006 for aluminum heads on an iron block,so if that's what you saw,I guess I'll use it.
BTW,If your 385 runs anything like my 406 did,you'll need a prybar to get the grin off your face when you get back from the first ride.
Maybe this weekend I'll get it out and run it. Having company for the holiday though.
