Rhoads lifters. Considering using these in a 390ci hydraulic roller LT4 build. The cam is 242/248 at .050 on a 110lsa. Should be pretty lopey at idle and I'd like to calm it down as much as possible. Sounds like these lifters would be ideal for a street motor---reducing duration down low by 10 or so degrees. However, I gather from searching CZ28/LS1tech that these things tick like solids. I cannot imagine why that would be unless they're set up to run a gap between the pushrod and the rocker arm. If this is the case, is there the additional wear & tear associated with a solid roller setup when using these lifters? Any other considerations (keeping in mind this is strictly a daily-driven street car I'd prefer to do nothing more than change the oil in)?

 

Frankly I think you should tame down the duration of the cam rather than try and bandaid things. No need for that much cam in a daily driver LT1, not even a stroker.

 

This type of lifter is very noisy. You could not use with a knock sensor. I am not sure, but believe that they are not intended for high mileage use.

Rich

 

I heard about the knock sensors. Correct me if I am mistaken, but with a large cam, aren't the knock sensors usually turned off in the tuning process anyway?

PS: I ran a cam not much smaller than this one in the motor when it was a 350ci. No problems.

 

What size was that cam? Isn't that a LOT of cam for a 350?

 

I don't think you want to fool with them for a DD.
Ran these back in the early days and pulled them out.

 

I agree they are junk.......25 year old technology.


Much better stuff out now that will outperform them in a hyd. roller

 

What, specifically? Assuming the object is to accomplish some kind of "variable" timing / improve idle quality.

 

I'm really not understanding your question.....


But a good lifter in a LT4 like a LS7 or morel will do just fine and make good power. You don't need the "variable timing" from the lifters b/c the lobe designs EFI/tuning etc. has all advanced light years since these lifters were designed.

What they "claim" to do......they really don't, I didn't even know they were still around. It was a great idea and I have a feeling alot has come from that style of thinking.....

 

I was looking to improve idle quality / make tuning easier for a relatively large cam by reducing effective duration at low RPM. This is what Rhoads lifters are advertised to do. Apparently, they're junk. I'm willing to believe that. I was just wondering if there is ANY brand of lifter that can do what I was looking for them to do?

 

The cam has alot to do with it but the tuning can smooth it out a whole lot. I have no idea how to do it

 

I already own a set of COMP lifters (presumably comparable to LS7s or Morels). I hadn't intended on using anything else until a friend of mine informed me of the Rhoads . . .

 

Comp markets a high bleed down rate flat tappet hydraulic lifter and even in their own words they are "not recommended for extended periods on the street". And they are trying to sell them! The noise is because at low speeds, there is slack in the valvetrain. This leads to excessive wear. I think a roller would like this even less than a flat tappet. A solid lifter cam has ramps designed to take up the slack created by any clearance remaining at operating temperatures. If you were committed to trying these, you should consider trying a solid roller type cam.

This is a clever idea that in the end works only for the very specific situation of a "vacuum rule" race class. Kind of like a very early attempt at variable valve timing.

Rich

 

You say there were "no problems" but how did it perform?

A lot of guys fail to realize the performance they are missing in getting combinations wrong.

See it at the track all the time, guy with a heads and cam Camaro was happy with his car's perfomance till my cam only Caprice matched his times, these days it is a stroker and slower than my heads and cam car. He doesn't have any "problems" either.

 

380rwhp / 335rwtq on a Mustang dyno. That was thru a Ford 9" with 4.11:1 gears and 17X11 ZR1's out back, and before I swapped in the new longtubes, electric water pump, LTCC and MSD Opti. Haven't had it to the track since.