Do quick-bleed lifters provide any advantages in an EFI set up (like the LT1)? or are these typically used by carb guys to make cam profiles more driveable at low RPMs?

I understand that they, in theory, should work to run big cams on LT1's, but I've never heard of anyone doing this.

Are ignition/fuel delivery capabilities of EFI enough to compensate for a cam, making Rhodes style lifters unnessesary? Or does the loss in lift at low rpm's mess with the PCM too much? (I'm thinking in the sense of a crank-shaft position sensor, seeing how cam profiles keep changing overlap and peak lift points over low rpms)

Or am I just blind and LT1's have been running these for years without issues?

Just asking because I dig the idea of getting a larger cam with decent low-rpm qualities, and can't figure out why more people don't use these.

 

I had these on a previous project & liked the results. They were a little noisy, but seemed to work well.

With roller cams gaining in popularity, the overlap has been reduced a fair amount on street cams improving drivability by increasing the valve opening/closing rates for a given duration.

Rhodes website announces roller lifters to be available soon.

My only complaint was that these lifters were oil viscosity sensitive. The lifters bled down less when oil was cold changing the idle substantially. 10w40 also idled better than 20w50. With a carb, it always idled differently. Synthetic oil seemed to have more stable results. Fuel injection will compensate for this so it may not be an issue.

Unless you are running a big cam, 230 plus duration, it may not be required.

If anyone else has some input. Iwould like to hear it as well. I've been anxious to try another set in something myself.

 

link?

 

SAUSAGE! Oh, sorry. Thought we were playing "word association."

http://www.rhoadsproducts.com/

 

many thanks oh unstable one!

 

What Lonnie said makes sense to me. The purpose of the Rhodes lifters is to allow acceptable idle/low speed operation of cars with big flat tappet cams. But you can run a really big hydraulic roller cam on an EFI setup and still get acceptable idle/low speed operation. This would make the Rhodes lifters unnecessary.

However, if your cam choice is big enough to cause problems with vacuum at idle, etc. a lifter of that type might help. OTOH, if you are running a HR cam big enough to cause these problems you probably ought to have a SR cam anyway.

Rich Krause

 

I think what aome are hoping is to get a cam like the GM #847 or CC306 to pass emissions

 

lol... no comment.


oh ok... yeah, that's what prompted the look at varible-lift lifters, although I was having problems finding ANYONE who had done this on an LT1.

A big nasty SR cam sounds like fun, but I'm sticking to the stock PCM anyway, so there's no motivation to break 7000 RPMs, although that is pretty agressive for hydralic rollers. Compound the issue of registration in WA (I have 17 years of emmission testing left... ), and I'm left looking for a way to keep idle and low rpms clean enough to pass.

WA emmissions testing is probably similar to other states. First stage is an idle-speed stationary test (HC/CO/N2O) then a "cruise mode" test at ~2000rpms while the vehicle is on the rollers. I drove my own ride last time, although I hear the "procedure" is supposed to require the test-station operator to press the throttle.

This is the reason I'm considering a 396 for my engine build instead of the 383 that's currently the front runner... more cubes means more power, at better emmissions. I know it sounds dumb... by I'll be damned if the state is gonna limit my cam selection to sacrifice hp. With the 396 I can eat a bigger cam and pull more vacume... and hopefully less emmissions.

variable rocker arm ratios seems like a difficult (read: costly) proposition, so I've been looking for other ways to run a big cam without sacrising idle... looks like I may have found it, if I can find someone that has used them... preferably in the F*rd 0.474" sizing.

 

I had the Rhoads lifters way long time ago in a 427 Vette that I owned. All I'll say is I hope they figured out how to make them quieter as they were some noisey buggers.

 

Yeah, I keep hearing that and I'm not sure why the design is so noisey. I know most of them (up until recently) were just flat-tappet designs, although there are supposed to be roller versions now... just can't find em


Here's a review in SportTruck mag using the fast-bleed, flat-tappets in a pre-EFI 350 (in a Holley engine build kit): (this is also the review that shows JBA shorties outperforming LT's accross the board ):
http://www.sporttruck.com/howto/1482/index3.html

Here's what Crane has to say about their fast-bleed lifters:
- from: http://www.cranecams.com/master/lift...aulic%20Roller

So... are these really a viable option for emmissions control and daily driving? (assuming I can even find roller versions...)

 

Going straight down the list…

The biggest reason why people haven't been using them is that in most cases it would be a step backward from the stock, roller cams. I can't help wondering if the ticking would drive the knock sensor crazy.

WRT to passing emissions with something like the 306… well it's been done, both idle and treadmill tests, with a good program it's really not that big a deal.

If you want to run something 306 sized or larger on the street I'd recommend a street solid roller which will idle better then a comparably sized HR cam anyway (a safe estimate is like a HR with 10* or more less duration at .050").

More displacement is just a short term answer, I here that testing of actual quantities is coming down the pike, and they are trying to institute CO2 limits as part of the testing… a bigger engine will output more, even if it's running clean, and if California has it's way you'll get nailed for that (and we know who the epa follows).

I haven't seen a variable rocker setup that I would trust for street use.

The Crane variable duration lifters are quiet but do not have nearly the effect of the Rhodes version.

A parting thought, I don’t see the point on the newer GM engines that already have fairly high compressions. Running something like a Rhodes lifter will shorten the valve opening enough that you will have problems keeping the engine from detonating. Maybe on a blower motor that is running a really low compression and big cam to help low end/off boost response

 

i currently have rhodes lifters in my 81 camaro. im running 355, 296 with .510 lift, 9.8:1 comp, 202 heads, edelbrock performer rpm intake and the lifters work incredible for me. I screwed up and found out that my cam is a bit much for what ive got going on so i put in the lifters to try and help it out and what a difference they made. I have a much noticed improvement in bottom end power. The reason i used the lifters is cuz im running a TH 350 tranny with 3.23 gears and a 2500 stall and the cam was a bit much for that combination. I was very impressed with what they did for me and i would recommend them to other people. And YES, theyre definetely noisy.

 

Actually, a few years back, there was a product called "Hot Rockers" that featured a hollow-trunnion rocker arm which could pivot through different ratios. You could have a 1:1 ratio at low engine speed, a 1.5:1 ratio at mid-range and a 1.7:1 ratio on the top end. The system used a hydraulically-actuated pivot-shaft which ran thru the trunnion of the rocker arms to vary the ratio. Looked a little spindly, but in theory it should work.

Haven't heard anything lately of this system, other than Comp had shown some interest. Google turned-up nada.

 

BMW's Valvetronic variable intake lift system uses an eccentric "second rocker arm" between the cam and the rocker to effectively change the rocker ratio and therefore valvelift. On the 7-series variable intake lift is used to control engine speed: there are no butterflies in the intake.

This idea can help power a lot especially when VVT is also used. Not a retrofittable thing, but BMW seems to be headed for it across the board.

http://www.canadiandriver.com/articles/jk/020213.htm


http://www.bmwgroup.com/e/nav/index....onic.shtml?7_3


I wonder if GM's Displacement on Demand (DOD) will help cut emissions on a test with half of the cylinders shut down? Gen IV engines will have it in some models. So maybe our wilder cams might still pass tests.

 

That's what I was just thinking. Just what we need, more noise in the engine resulting in knock retard problems.