Paulos
Active Member
- Joined
- May 7, 2018
- Messages
- 479
- Reaction score
- 210
- Points
- 43
- Location
- North Carolina
- Vehicle Year
- 1987 STX
- Make / Model
- Ranger
- Engine Type
- 2.9 V6
- Transmission
- Manual
- 2WD / 4WD
- 4WD
@Dirtman,WHAT!?!?!
If you were referring to my comment on valve stem heights (which will affect valve spring height and valve train geometry) and old (weak) valve springs, I wouldn't care if I was slapping together an old 2.9 in an old Ranger beater. But that's not the case. Sinking the valves or excessively grinding them increases valve stem height, which in turn increases valve spring height. If you compensate by grinding the valve stem tips and install shims under the springs, it's not a problem. But most shops don't take the time to do this. Randomly sinking or excessively grinding the valves will give you an unequal (unbalanced) combustion chamber volume. I'm spending a lot of money rebuilding this 2.9, so I'm going to do it right. An uneven combustion chamber volume (compression), floating valves at high RPM due to weak or improperly compressed valve springs, and uneven valve train geometry due to excessive tolerances of valve stem heights, is not something I want from the start in a new build. Yeah, I'm not building a dragster (hmm... a 2.9 in a dragster; I'll have to run this by PetroleumJunkie412), but why not do it right before the engine is assembled? The peace of mind of spending a few dollars for new springs, valves, and retainers is worth it to me.