Flat tappet spring pressures.

EngineTech1 · Post by **EngineTech1** » Sat Jan 15, 2005 6:14 pm

I am working on a solid flat tappet combination for drag racing and am considering a slightly different spring set up than I usually would run. I think I have a pretty good system for breaking in the tappets and lobes but I was wondering what kind of spring pressures some of you have run with success as far as the upper limit of seat and open pressures. I have seen some combos run in the 130 to 145 range seat pressure but the springs I am considering using would set up a little more than that on the seat with about 390 to 400 over the nose pressure. I know the open pressure wouldn't be a problem because I have run more than that before with no problems but mainly concerned with the seat pressure and if it might cause any problems. This is a small block with steel valves 2.02 1.6 rules with fairly light valves but rpm will probably be low 7k range in rpm.

Racer7088 · Post by **Racer7088** » Sun Jan 16, 2005 2:16 pm

Danno, that's a Ford small block right? I have seen even 170 seat on the Fords with their bigger lifters and base circles with good break in and maybe the lifters with the oil holes. You know we have 145 on the circle trackers and 470 open and not one flat cam in 6 so far and now 7800 rpm and no float with all steel stuff and Ti retainers.

Guest · Post by **Guest** » Sun Jan 16, 2005 8:17 pm

Wouldn't the agressiveness of the lobes and the accuracy of the lifter bores make a big difference here?

Racer7088 · Post by **Racer7088** » Sun Jan 16, 2005 11:27 pm

The pressures I was talking about are on Comp FL lobes which are optimised for .875 lifters and are fairly fast.

EngineTech1 · Post by **EngineTech1** » Mon Jan 17, 2005 12:09 am

I remember the pressures on the N heads for Todd but I wasn't sure if I'd get away with something on the order of 165 to 170 seat. Was considering using that beehive spring I told you about but I don't think the open pressure will be enough. I may just use an Isky or Comp spring instead.

idunno · Post by **idunno** » Mon Jan 17, 2005 9:57 am

Talk to Vern @ Schumans ,he is presently running his new lifters thru testing to see what pressures will kill them. They are lighter than the std Standardyne & high lift style lifters.The lighter lifters will be a good factor in your case.Also Ferrea is testing their lifters at to see how a std core flat tappet cam will stand up to their new coated lightweight body.