Because of a real vacuum problem from excessive overlap, I am considering trying a set of these lifters. Does anybody have any experience, good or bad with them, and do they actually help raise the vacuum a bit?

Steve

 

Rhodes lifters used to be in vogue in the 70's and 80's. They essentially are bleed down lifters which allowed the lifters to partially collapse at idle essentially decreasing valve overlap to mimic the characteristics of a smaller cam. At higher rpms, they would "pump up" and become more like normal lifters. Different variables would give different results; oil pump pressure, volume, temperature, oil viscosity, so if was hard to determine what the results were going to be when using the lifters. What worked for one motor did not work for another. I am surprised to hear they are still being sold.

 

I used them in every corvette that I built in the 70's and 80's.

Back when comp cams selection was limited . I would use the Comp 280 with Rhodes lifters and I was able to run Automatics and A/C with no problems.

 

Rhoads lifters is making a new lifter for the lt1 motor.I called them awhile back to ask about them as I have a gm 847 cam I had in my 9c1 caprice I wanted to put in my 93 corvette. They have been out for a couple of years and are not their old lifter type from the 70's or 80's they are roller lifters. Kind of high priced though that's the reason I didn't buy them. Good Luck Tim

 

I should say if you don't have a lt1 motor and use the older type in a older motor they work but expect some noise as they make a slight ticking noise at idle. Some don't like it, I didn't mind it in my old Mopar as that and the special vacume bottle was the only thing giving me brakes at all.

 

I ran a set right after they hit the market and they performed as advertised. Idle smoothed out, vacuum increased and, yes, they do talk to you with light tapping sounds. I've never tried the new one or their roller versions.

I wrote a long letter to the company complimenting them on how well they worked and Rhodes printed it in one of the mags.

Jake

 

Excellent product imo also,used them a lot in the 80s and 90s also would really tame a healthy cam and make it more driveable esp. With an auto. Havent tried the rollers but would do it in a heartbeat if the opportunity was there. Comp had come out with some that seemed similar way back i pulled them out after a week....They flat out work, worth the money imo.

Make sure and read the instructions...if I recall they dont use preload like a typical lifter if you do the valves hang open and it wont start ask me how I know lol

Think it was 0 oe .001/.003 lash something like that. Its been,awhile

 

Good good good! anyone else have a comment? I'm hanging on the fence about changing the lifters, but I've got to solve this vacuum shortage problem from the cam. the LSA is 108 and at idle or going real slow, the brakes are pretty feeble. I have already added a vacuum canister, and frankly, I wasted the $$$ as I don't feel or see an iota of difference from before I installed it.
Otherwise, the car runs great. Especially with my foot on the floor! :smiledrool:

Steve

 

they are noisy. I tried and tried to clean up the clatter, but finally, I took them out and lived with the "true" cam, and enjoyed the piece of mind a quiet engine produces.
They worked as advertised, but I was always thinking my lifters were failing.

1. check around for vacuum leaks.

2. Why don't you just buy an electric vacuum pump from Summit??
Takes way less time to install, and you can always take it out without disassembling the engine

 

I forgot to mention this, but the tapping can be reduced by playing with oil viscosity. Heavier weight oil quiets them down noticably.

More that just 108 LSA, what are the duration specs on your cam? I installed a 109 in my son's 96 LT1 last years and he's not having a brake (vacuum) issue. His engine is pulling just short of 14" of vacuum. Idle speed re-programmed to 850 rpm.

I'm wondering if there's something else contributing or causing your issue.

Jake

 

If you are going to buy Rhodes roller lifters to cure your vacuum problem, you will probably be better off getting the correct camshaft for your needs. A new cam will probably cost less than the lifters and you can pick one that will work better. Why are you running a 108 cam? Are you carburated? What intake and what gears are you running?

 

Run a vacuum pump, around 2001 some chevy pickup had a nice and compact vacuum pump that plugged into the brake booster and if the vacuum was too low (High) it turned on automatically and increased the vacuum. The pump only had two wires and it was all self contained. If you are happy with the cars performance and only need better brakes this is an easy and cheap trick.

 

Several was to skin this cat. Aftermarket vacuum reservoir kits work well too. May be cheaper and easier to do than changing cams or lifters.

Jake

 

ABSOLUTELY. I have a set in my car. I got an extra 5" of vacuum which is alot! The other benefits are that you get crisper throttle response and a little beter gas mileage around town. What are your cam specs? Im running the comp cam XFI 280

 

The Rhoads ROLLER lifters do not make noise. I have them and they sound just like the stock lifters when cold.

 

I have ran several sets of Rhoads Lifters and they do work and I have had different levels of very mild ticking which is barely audible with hood closed.

 

My cam is 230/230 - 480/480 LSA 108. Since I went from 1.5 to 1.6 roller rockers I am sure I picked up a bit more lift and duration. My problem is basically at idle or under 1000 rpm's as I almost have to stand on the brakes at a light. It was a real problem the other evening when I had a woman in front of me stopped and waiting for traffic to clear before pulling out into the road. She started out and being right behind her, I started to roll forward too. Well, you know what happened next... She decided to stop, for some reason known only to her, and there I was already on a roll. I jammed on the brakes but still rolled forward enough to just lightly touch the rear bumper of her MERCEDES!!!! It scared the bejesus out of me but luckily didn't do any damage. This was the second time I have had that type of incident happen, and I don't want to deal with it anymore.
I like the idea of the electric vacuum pump. That's certainly simpler and an easy fix. I already have a vacuum canister installed, but frankly, it doesn't seem to help the problem.
I put up a WTB on this forum for a vacuum pump to see if anyone has one laying around. I'm hoping to find one used or addaptable from another model car as a new one is pretty pricey.
Thanks again for all the help and advice.

Steve

 

Hmmm, with that cam, you should have enough vacuum to run your brakes. Something else is amiss. What is your idle speed? BTW, with the rhoads lifters, I was able to reliably reduce my idle by 100rpms. (750)

 

230 degree duration at .50 is at the top of the range I use for flat tappet motors. In fact I never used one that reached 230, usually below a few degrees.



I don't know if a roller cams makes a difference.

 

I have never run the roller versions, but the flat tappet versions DID work. Basicly, reduced the effective duration by 8-10 degrees, letting you run 1 step toward the bottom of the page. I have run them in several engines with good results, no failures. Noisy if you have a non-adjustable valvetrain. Critics have said they lose power and revs on the top end, but i proved they didnt ao a back to back dyno test. I will try them with a turbo spec roller LS1 when I rebuild to help spool the turbos.