I just wanted to let everyone know that Rhoads sells lifters for our cars. They are known to have a lifter design that makes you keep your low end torque even on bigger cams. Without loosing top end power and they won't calapse when using high lift cams and stiff springs.
Their site is www.rhoadslifters.com. They gave me a price of $195.00 for a set. Check um out.

 

195 for a set of roller lifters? That's cheaper than any of the good ones out. How does a lifter help keep low end torque? That's a function of cam overlap and efficiency, not really a lifter.

 

they acutally bleed down & reduce the effective cam duration at low rpm

 

They are annoying to listen to click & tick in most other motors. Seems like having the cams duration vary based on bleed down could making tuning harder. Sounds like a potential problem IMO and little else.

 

The lifter has time to bleed down at low rpm because of the oil control design effecting the duration and lift. As rpm increases the lifter stays pumped up giving you the full effect of the cam. These lifters are annoying as they make ticking sounds. But we have yet to see a LS1 with them so who knows.

 

if you have a 01+ LS1 raise your hand. If so you have Rhodes lifters in your motor stock on the exhauset lobe. whay do you think they click so much.

 

Interesting. Is that a rumor or a fact?

I used flat tappet Rhoads lifters before. They work as advertised. I used different weight oils to adjust pump up. It seemed to lose some mid range power until the lifters pumped up full. Using them on the exhaust side only was an experiment that I always wanted to do with them but was too lazy to try. That's why this post caught my eye.

 

These lifters sound like a great idea. At low engine speeds the valves dont open so much. Saving wear and tear on valve springs.

 

Wow I did a search on these and got almost no hits! Why aren't the Rhodes lifters more popular with the LS1 crowd? They seem like a great design and the factory spec'd them for the exhaust side on all '01 up cars.

 

Is it just me, I would be a little curious why you would use a lifter from one company for exhaust and a different company for the intake. It sounds like they cant make a good lifter for the opposite valve. I understand bleed rates, and stuff but think it would have been much easier to have the same company make both sides, I mean if your making a lifter for an application would it be that much harder to make a little different lifter for the intake as well?
Be interesting to see the difference if any these make, and the audible signature in a LS application.

 

If true, that's some compelling information. What is your source?

 

I've always heard that the factory lifters were designed for controlled bleed down...for years now.
but I hadn't heard they where Rhodes brand. And I didn't know the exhaust were different from the intake.

 

I've read the SAE paper GM published on the LS1 back in 1997, there's no mention of this. Not to say it isn't possible, but it needs a credible info source.

 

I'd like to see part numbers if that is true. I bet they are the same number otherwise they would have people watchin whitch lifter they put on each side of the cam none of the GM manuels I've seen have any kind of info to support this.

 

I cannot, at this point in time, say for sure you are correct or otherwise. That said, I DO know that Rhoads lifters are in business to make money, like everyone else. It seems to me that with the stock performance of this engine series being as stout as it is, if I was Rhoads, I'd be cashing in on this and pushing ads real hard in the affirmative, such as "Corvette LS6-405 HP stock, with a little help from Rhoads!! Alas, nothing from them about it at all, as yet. I know you said LS1's are so equipped, but this engine series does seem to share in the best pieces from either one (LS1 & LS6) being slowly integrated into the latest motors. It would therefore be a logical assumption that if they worked well in the LS1, they would be even better in the LS6, with its slightly hotter cam. I have been around these ECM/PCM controlled engines for awhile now, in their various incarnations such as the TPI motors, LT1 motors and the Gen III's as well, and they all do share one common denominator: Knock sensors, which are quick to pull back the timing when the slightest hint of detonation is detected. I would think that as a result of this, the factory would be very reluctant to use any engine component that would take power away as the competition out there is pretty fierce. And these engines are not known for being a real quiet engine, mechanically. Your statement is intriguing in that I wanted to install Rhoads lifters in a 383 small block I built 15 or so years ago (Gen 1) for an '85 IROC-Z I had. I bought the "Box" intake for it from LPE (Then John Lingenfelter Racing) as well as many other components from LPE as well. When this subject was broached to LPE, they adamantly opposed this idea, for the aforementioned reason(s). I'm not a genius, or trying to sound like a remote version of one, so maybe someone else who has more experience with this could verify your statement. If you are right, I am mad as hell I didn't try them in that ol' 383!!

 

Same here. Thus far we have a post from someone who can't spell "exhaust" and someone who always heard.

 

Excellent point. Thier website image does little to impress and doesn't give me a feel of an OEM-type supplier.


Another great point! With this information in hand I think I'll stick with the quiet aftermarket options (Comp) until someone else can show any advantage with the Rhodes.

 

Quick bleed down lifters like the Rhoads generally take the duration off of the closing side. When the valve is on the seat the lifter is pumped up persay but as it opens the valve the pressure is bled off taking timing mainly off of the closing. This is the reason why usually high bleed off rate lifters are only used on the exhaust side since it usually produces the best bang for the buck results. The main reason for lacking low end performance on a big cam is exhaust reversion into the intake. So you cut say 10* off of the closing side and you dont run into such a problem as the valve closes sooner and at any one point it isnt open as far. The reason youd want the exhaust valve and intake to be open at the same time for an NA motors is the high velocity of the exhaust leaving can create a strong enough vacuum to pull the intake charge into the cylinder. But until the engine reaches a sufficiently high enough rpm the exhaust leaving is to slow and doesnt empty the cylinder to atmospheric pressure (well whatever pressure is in the intake) before the intake valves opens. Since the chamber is still above intake manifold pressure the exhaust gas looks for any path it can take and goes back into the intake manifold diluting your intake charge and warming it up. So not only do you lose oxygen content in your intake charge you heat it up. This doesnt mean that adding them to the intake side cant help out. They just arent as beneficial. But to get the best results from a high bleed down lifter you need a cam with lobes designed for it. There are also many different bleed down rates depending on whos lifters you use. Rhoads did much of the pioneering in the development of high bleed down lifters but many others such as comp, crane, isky, etc all make high bleed down lifters and they have all been making them for a while now (Think early 90's and before). Though the Rhoads are generally a little faster then the rest.

Im thinking what 42NIGHTZ28 meant is that they use high bleed down lifters not necessarily rhoads specifically. Though I agree with others that Id find this odd since your manuals would need to reflect this as most mechanics wouldnt even notice any difference and youd end up with different lifters in different holes.

Josh

 

Did anybody ever verify that GM used this type of lifter in later year LS1s?

 

I'm looking at them right now.Look exactly the same to me