Valve lash

What feeler gauge should I go to on my 521(roush yates)with scj heads? Also is there a fix for slight oil breather smoke on the big end? 99% sure it's passenger side only

I talked to a few old racers and 24 was what they suggested.

What are they at now?

Try .018"-.019" Cold, that should work out to .024"-.025" Hot. Check and see were you and record were you are at for future reference.

Cam card came with recommended lash based on cam design. Set them to the cam card initially. That is a hot lash set. Then, let engine get cold, and check what the cold lash difference is. That variance, is the minimum lash you can get to, before the valves wont seat when cold. From there, the lash your combination likes, varies depending on how "real" head flow numbers where, what restrictions intake and exhaust tract place on the combination. Lash changes are small adjustments to cam events, opening or closing valves longer. One size doesn't fit all. If cam is a little small, adding (or tightening) the lash a bunch may net big gains. If cam is right on, changes of a few .010 might make things worse. Its a trial and error, to see what nets you the best results. Best place to play with it is on a dyno where back to back to back tests can be done, with little change of weather or track condition to prove results.

I have cam # but no card. I will be pulling valve cover today and see where it's at initially. There's no dyno close to me and a chassis dyno is 150+ miles away

If its a Roush/Yates crate engine, can't you get a cam spec or lash spec from them? Especially if you are the original buyer I'd think.

Post the cam # and make. The numbers I listed or recommended for the SVO 514/521. Like I said see were they are at now cold, and go from there, they may not be loose.

One was really loose. Lifters are svo (blue) and it rubbed it shiny metal on one side. Tightend 2 on passenger and 4 on drivers side with one on drivers real loose like .025 + loose!!

Mechanical roller cam M-6250-A514 and I bought this as a project car that i've slowly been working out all the major issues.
From research cam is made for above 3500 rpm lift is .640" intake and exhaust duration .050" 254 degrees intake 258 exhaust

Recomended was .026" hot.  For a start up check, .018 cold, get engine hot.  Check what you got.  Adjust.

  Then next morning double check cold set. Tight it down, thats your vsiance due to expansion.  Never take em tighter than that or it won't  cold  start.

Thanks

When you go to check them hot pull one valve cover and check/set them. Put valve cover back and restart engine to warm it back up. Then do other side.

Done will do cold tomorrow. Ended up loosening 3 on each side with it hot.

6jeff6 wrote:What feeler gauge should I go to on my 521(roush yates)with scj heads? Also is there a fix for slight oil breather smoke on the big end? 99% sure it's passenger side only

https://www.429-460.com/t23504-hooker-super-comp-slip-on-collectors-collector-evacs What are you running for an evac. system?

Nothing have manual brakes and manual steering no heat etc. My evaporation consists of a breather on each head(on valve cover) but the valve cover bolts were like a 1 inch pound tight so that could've been my big end slight smoke

Valves adjusted thanks everyone