Quote:
Originally Posted by Cliff R
Just a note on using Rhoads lifters and noise.
We used to adjust them down from zero lash which leaves a LOT of plunger travel. When the engine gets fully warmed up and heat soaked and the oil thins out, you'll get some "clackers" in the bunch, but even then, it's not hurting anything.
I ran them for quite a few years in my first 455, first with iron heads then with KRE heads. I started out with standard lifters and swapped in the Rhoads on the dyno to see if they made any difference. We even loaded the engine down pretty low with the brake and saw nothing at all in power production.
We did see a solid 2" improvement in vacuum at idle speed, and noticeably improved throttle response right off idle. When I returned the engine to the car, I saw LESS RPM drop placing the trans in gear, and improved throttle response and power in the "normal" driving range. The engine was clearing working better right off idle and below about 2500rpm's, past that as the dyno told us same as standard lifters. As for noise it was noticeable but nothing, you'd concern yourself with and they shut right up by 2000rpm's or so.
When I finally removed that cam/lifters and went to an HR cam the cam showed no wear nor did the lifters and they ended up in a 400 RAIV build a few years later.
Lessons learned years later is to tight lash them to control the noise and how much bleed-off is available. So, the builder/tuner cam simply bottom out the plungers with a .020", or .030" if you want more bleed-down available and they will be more consistent and you control how much clattering is going to happen when the oil thins out. They still work as advertised and they even make a version where they recommend setting them in that manner, the V-Max. I took V-Max lifters apart and they are identical to standard Rhoads lifters aside from having a stainless-steel shim in them to reduce plunger travel slightly.
For those worried about noise, I'd for sure set them at .020". You can still enjoy the improvements in vacuum production with a "hefty" cam and some improved low speed power, but they will not be any louder than a flat solid cam lashed about the same......FWIW.....
https://www.rhoadslifters.com/Pages/Installation.html |
Mike said:
I just got done reading about the Rhoads lifter info. , Do you think that they will solve this Reverb problem or noise that I experienced?
Read this please:
This is a picture I drew of the Pontiac cooling Mod. that I found on this forum, I have drawn it in the pink marker, I am seriously thinking of incorporating this modification as I have the Heads remanufactured. My roommate and I are Leary about doing any other work than sealing off the exhaust crossovers at this time and we need to degree wheel the cam. Since I don't have the crossover exhaust "X" and the vehicle always ran without it tells me that I don't have to add one if I just go back the way it was.
It is noted that the 80 degrees of overlap with these "041" cams is a lot of OL. However, I can always buy a set of Roads Lifters and 1.6:1 Rockers later, again this car ran with the Johnson lifters in the past. We think that the 80 degrees OL, having the Intake and Exhaust Valves open for that duration, coupled with holes in the exhaust crossovers in the Head, plus, lack of proper mufflers and having the 2-1/2" Exhaust Pipes running some 10' to the Diffuser, plus the 3 degrees advanced at the distributor that we added, could cause this noise, that I never had, except on several recent test and tunes.
We are willing to take our chances, as we always have, to do what we think will work, the worst-case scenario is that we have to go back into this motor. At this time, I feel that the Pistons being reversed did not cause this issue, so why would I touch them at this time? This motor is strong at the bottom and if it is not broken don't fix it. Someone knew what they were doing when they modified this motor. Although the factory does things for a reason, so do the racers. Since no one has explained to me why the crossovers "X" is installed, after the collectors makes it hard for me to make my decision. " Why do people use an "X" type crossover abaft of the collectors"? Note: this vehicle has been running less that 10 k miles since I got it running, with the Exhaust system going from the Headers to the collectors and Streight out to the diffuser, with no problem ever. I have very few miles on this "041" Cam and I had installed it with the advanced timing just prior to the Transmission accident, thus this Cam could have something to do with the current noise issue?
Because I had the vehicle off the road for 2 years building the Trans. So, People who are telling me that I must use the Roads Lifters, I ask is this current noise the product of 80 degrees overlap, because if that is what you mean by saying, get Roads Lifters than I have to agree with you people. Please bear with me as I learn something, this is out of my league. Believe me, for those of you who are steering me toward the piston change that won't solve the current issue, duly noted. After I squeeze the life out of the bottom end of the motor, then I will rebuild this motor, as stock using new Rings and all new Bearings. This engine already has had all the other replaceable parts installed, then sell it to someone that needs a Pontiac YK code 428 HO with Tri-powers and I will buy a modern Engine like one of those 1AII with Aluminum Heads and all the goodies.
Questions is this: If I install the Rhoads Lifters, block off the exhaust plugs at the heads, Rebuild the Heads and put it back together, Will the noise have disappeared as quick as it came?