mark IV 7.4 with B&M 174 roller rocker question???
 

Would adding roller rockers to my engine be worth it? Would I gain any HP or reliability?

Is yes which ones woudl fit and are cheap and decent? I keep seeing deals on roller rockers and though while my engine is apart i might add a set!

supposedly, you will pick up a couple of hp, but not any significant amount. If you change to a higher ratio (1.8:1 vs 1.7:1) then you will gain lift and the valves will open and close a smidge faster thus giving maybe a 5-to-10 hp benefit, depending on your current cam profiles.

You should, in theory, see an increase in valve guide life due to the lessened side loading of the valves. Some say the rollers spin oddly on top of the valve stem tips anyhow, and that the roller tips help nothing, but they surely can't hurt.

In instances where the valvesprings are mean and stiff, the roller tips, fulcrums, and roller lifters all work towards ridding the valvetrain of parasitic friction but at stock valvespring pressures the benefit is mostly peace of mind. Plus, they look really cool.

Interesting subject
 

Heres what I believe. The stamped steel stock rockers arms are just fine for applications up to .500 lift and they will last a long time with good oil. Roller rockers can and do fail, but I think they reduce oil temperature a little and can handle higher lift cams. How roller cams affect this I have no idea. I have seen a very expensive engine destroyed because a needle bearing in a roller rocker came apart. The needle ended up between a lifter and push rod which caused the valve to hit the piston and boom. I do use roller rockers. I also check the bearings in them every year.

I have 32 roller rockers, 32 roller lifters and some other parts that are now junk:eek: :eek: This is all because some idiot somewhere decided that 180# plus closed seat pressure was exceptable. Since the time my motors were built (1998) the spring design has been changed. Crane is helping a little but not as much as I thought they would.

Point of the story Be carefull with your choices needle bearings and broken lifters can do a lot of damage:rolleyes:

Just like it was said before, not much horspower gain, but helps with side loading on the valve. I did not want aluminum rockers so I went with the Steel Magnums from Competion Cams. Its a nice peice and so far, so good.