I have a xr 280 r solid roller. What do I set the lash at cold to get me in the ball park for when it's hot. Hot specs are .016 intake and .018 exaust. I'll adjust it again when hot, just don't want it too tight for initial start.
Thanks,
Eddie

 

I adjust my solids .004 tighter when cold. I know that mine "grow" .004 when hot just from a lot of prior trial and error. Even if you set it at your hot specs it will not harm anything it will just be a little loose when they are hot. Measure them cold then hot and see how much they grow and use this for future valve adjusting.

 

You just worry to much! It's not an exacting science. I go out and get the motor hot and come home and pull the valve covers off and let it sit for 20 minutes. Just so stuff won't burn you when you touch it.

If i adjust the valves and you check my adjustments. What i call right and what you call right might have a few thousants variation. Not a big deal. To tight or two loose is more like being .008 or greater off the suggested .018 -.020

You have a pretty healthy cam there. Do you have good RR - retainer clearance and is your roller tip really centered on the valve stem for for 720 or more degrees of rotation of the motor?

I'm running some .200 longer pushrods to get my geometry right with the one step lower SR cam and Dart Pro 1 heads.

 

I'm running that cam in my 383 also. EDDIEJ82, have you dyno'ed that combo yet?

 

Great street cam, I ran it in my big block.

 

What are your heads and intake? How does it run for you in a 383? I have the 280's smaller Ex s-roller brother the 274. I'm thinking about down sizing on head size to my AFR 210. As is, with 227cc heads my sub 2000 rpm is really lacking with my 5 speed tranny.

 

George, I know I worry too much But I've built this one Extremly tight on all my clearances. Much more than usual.

Yes, I have plenty of retainer clearance with my RR's, checked that. My pushrods are .185 over if I remember right. That puts my witness mark starting about a 1/3 from the top of the stem and ending about a 1/3 from the bottom of the stem. So I think I'm OK there. I did have to grind a bit on my connecting rod bolts to get me about .030 clearance from the cam,(the tape trick worked) but not so much that I think it will be a problem. I know I should have went with 3D rods but it wasn't in the budget this go around.

I went this large because I wanted more RPM's, My last cam fell off about 6300. Not too worried about the lower end, It was actually pulling too hard on the low end as it was, couldn't keep the tires planted. Well that and 17#' in my ET's, I'm too chicken sh** to go any lower for fear of a solid dead hook and leaving rear end peices all over the track I let it spin about 10' out of the hole to help relieve some of the shock.

 

Heads (215cc) and intake are Vic' Jr's. I had the next size up cam, but I felt it was too big. More bottom end with the 242/248.

 

Go to the Crane cams website....the difference between "hot" and "cold" depends on the material of your block and heads, cast iron vs. aluminum..... ...redvetracr

 

I need to borrow a good digital video camera and do an in car of how my 383 runs with 5 speed and 4.11 rear and go for 4 shifts right at 7500 rpm with the speedo and tach in the screen.