Hey guys i have a buddy who just got some new springs but needs some help on what retainers to buy wonderin like what is the size of a stock vavle stem on the lt1 meaning where the vavle stem goes in retainer what size does he need to get is it 11/32 or 3/8 someone plz help us thanxs

 

LT1 valves have a stem that is 11/32" in diameter.

 

does that mean that i buy retainers that are 11/32

 

YES - See the link below from crane for multi fit retainers but most are for a specific valve stem size.

http://www.cranecams.com/index.php?s...lvl=3&prt=2134

 

The outside diameter of the valve spring is nominally 1.25 inches. The diameter of the valve stem is 11/32. The Summit catalog has several listing for steel retainers that will fit. Look at Comp Cams #CCA-742-16 or Crane #CRN-99915-16 for examples that fit those dimensions. If the motor is for street use the steel retainers and 7 degree locks will work fine.

 

iight but see he has aftermarket 918's can he still by the standard locks or does he have to get +.050 or the -.050

 

I make a determination of the valve lock configuration as a function of the valve spring installed height:desired spring pressure ratio. Set up an intake and an exhaust valve using the stock 7 degree lock with the after-market retainer, then measure the installed height of each spring between the spring pocket in the head and the bottom of the retainer. Compress the new spring to that installed height and record the seat pressure. Then, subtract the camshaft lift spec from the installed height, compress the spring to that dimension and record that number as the open pressure. If the seat and open pressures are within a range of acceptability, add or subtract shims to adjust the pressure more precisely. If the pressures are too high without shims, you can use a +.050" lock to increase the installed height and reduce the pressure. If an inordinately thick stack of shims is required to achieve the desired pressure, a -.050" lock will reduce the installed height and shims can be removed. This is essentially a trial and error process. A few basic tools are required to complete this process but it's a choice between accepting spring manufacturers spec on the box or making sure by doing it yourself.

 

For most manufacturers, the retainers fit all their locks regardless of the valve stem diameter. The locks are what vary. So, don't assume you can mix and match brands. Buy the retainers and locks together. Just pick the correct locks for the valve stem diameter and be sure the retainers fit your springs.

Rich

 

im so confused lol

 

hey guys one more ? and thanxs for all the help lol but ya uhm i have 987's not 918's ya are they single or double or triple springs last ? i promise lol

 

Reference:
http://www.compperformancegroupstore.../merchant.mvc?

 

May i ask does anyone have 987 and what would they recommend .050+ or .050- or standard