EFI and Rhoads lifters ?

[Jim Nilsen]

With the Accel DFI are Rhoads lifters going to make it more difficult to tune? I have been told that the programs that are written that get plug and played in are set for a specific cam profile and the lifters will change the needs and make it difficult to tune for.
I can understand that the lifters may make the premade program not exact but I would think I could tune around it a lot easier since I would have more vacuum where needed.

The cam is more than big enough and could use a bit of help for more vacuum and a smoother idle. I really like a more mild sounding car and the Rhoads lifters will give it to me but it sounded like it may make tuning a bit trickier.

Do any of you know anything about this being a problem?

Thanks

[Jim Nilsen]

I put the lifters in and have more vacuum and the idle is much better. The tuners will have to live with it and make it work,lol.

We will see if it really does the trick when the tires roll .

[Samckitt]

How do rhoads lifters make a difference on vacuum?

[Twentyover]

High bleed down softens the idle and increases idle vacuum. As the rpm increase, the oil feed rate exceeds the bleed down, emulating a conventional hydraulic lifter

[Samckitt]

Ah grasshopper.

[86Cutlass383SR]

I've used Rhoads lifters on a Gen 1 SBC with flat tappets. Did seem to make a bit of differance but never got any numbers to compare.

From the reading I've done on them, there is a small channel machined in the piston of the lifter which creates a controlled internal leak. At lower rpm's and oil pressure, there is enough time for the oil to go thru this channel creating less lift and duration. Part of the time this normally rising piston is traveling upwards with the lifter body, it's actually compressing due to the *leak*. At higher rpm and oil pressure, the time for this bypassing to occur is reduced, thus restoring all normal lift and duration.

Since differant rpms have to be programmed differantly I don't think it would be much differant to tune for this. This is based on the lifters doing the exact same thing at the same rpm *every* time. Tune for idle, tune for cruise, and tune for WOT. I'm just getting ready to start learning tuning for my GM OBD 1 setup, I may be way off-base on this assumption though.

[Samckitt]

So high volume or high pressure oil pumps would through off how they work.

[wiedemab]

Dumb questions, but wouldn't this make the valvetrain loose and rattly at idle - for lack of a better description.

[Jim Nilsen]

Dumb questions, but wouldn't this make the valvetrain loose and rattly at idle - for lack of a better description.

You might say that. The noise is like a solid lifter cam and unless you don't mind it you will like it if you want a super quiet engine they are not for you.

If you had heard the niose of the lifters that were in my engine compared to the Rhoads now you would be hard pressed to say if they make more or less noise because it is a different kind of noise.

On a cam with much less lift and duration the noise isn't as much and the engine I had that ran them before, you could hardly tell until the hood was open. Every once in a while someone would say my lifters were ticking a bit and I would just tell them that was the way it was suppoed to be.

When you need them you need them and when you don't you can still use them for mileage gains so they are worth it.

Another side to it is the new X series that has come out that has even more adjustability. I seriously considered some zero lash hydraulics but if my cam was actually a solid lifter cam and not a hydraulic cam they wouldn't have been able to be adjusted right. the Rhoads will work with either and can be adjusted for them both if needed. So when I had to find something to make lifer easier to adapt they are the only lifter manufacture that offered something that would work no mater what. Now I can actually adjust them to give me more power or more drivability and it is just a valve cover removal away, and on my car that is about 5 min. for both of them.

So far everything is much better and I can hardly wait to put some pavement under the tires. I have almost burned up a tank of gas on jack stands and have gone a few miles spinning in air.

Maybe this weekend if the front end assembly goes smoother today, yesterday I didn't get as far as I wished because of a headlight bucket alignment problem that will take some bending into submission to get it right.

[EFI69Cam]

If the lifters are noisy they won't work with a knock sensor if you don't have one that is not a concern.

As for the tunability, the gen 7 is tuned like a OEM LS1 computer, you get the VE table right, then tune the fuel ratio table for the desired ratio at each rpm/map point.

The VE table will take the changes in the cam profile due to the lifters into account, so as long as the tuner knows how to tune a Gen 7, the lifters won't matter.

[Jim Nilsen]

If the lifters are noisy they won't work with a knock sensor if you don't have one that is not a concern.

As for the tunability, the gen 7 is tuned like a OEM LS1 computer, you get the VE table right, then tune the fuel ratio table for the desired ratio at each rpm/map point.

The VE table will take the changes in the cam profile due to the lifters into account, so as long as the tuner knows how to tune a Gen 7, the lifters won't matter.

Thanks for the tuning advice. I was talking to someone just the other day and told them that all I should have to do is work with the VE table on the top and bottom to get the lifters to work and hopefully the midrange will overlap or else it will be a battle there and may need to learn how to do the dual programming part of the Gen7 I have been told about so I can get the best cruise economy if there is such a thing with a cam like this,lol.

What do you do about the timing? I keep having a problem in my head with how much timing and where? I have it at 22 degrees static right now and when I go to the programmed timing it seems to have a problem wanting to idle. The programed timing is just a bit less at idle but not much and it will go into the 30's and seem to have problems. I am running rich most of the time and am in batch fire to keep it from going lean.

I have a lot to learn about this system and it is good to have the help.

Thanks

[Skip Fix]

"If the lifters are noisy they won't work with a knock sensor if you don't have one that is not a concern."

That is what I was thinking. The one time I tried them they were noisier than my solid roller motor.

[EFI69Cam]

Thanks for the tuning advice. I was talking to someone just the other day and told them that all I should have to do is work with the VE table on the top and bottom to get the lifters to work and hopefully the midrange will overlap or else it will be a battle there and may need to learn how to do the dual programming part of the Gen7 I have been told about so I can get the best cruise economy if there is such a thing with a cam like this,lol.

What do you do about the timing? I keep having a problem in my head with how much timing and where? I have it at 22 degrees static right now and when I go to the programmed timing it seems to have a problem wanting to idle. The programed timing is just a bit less at idle but not much and it will go into the 30's and seem to have problems. I am running rich most of the time and am in batch fire to keep it from going lean.

I have a lot to learn about this system and it is good to have the help.

Thanks

It would seem to me that the problem with the idle would be the idle compensation. Maybe turn some of the settings in the compensation screen down?

[68Formula]

I think the big problem is warmup transition. As the oil temp increases the oil will flow more changing the characteristics of the cam events. Since this will not directly coincide with coolant warmup there would be a difference between what the engine wants once coolant is up to temperature vs. what it wants as oil reaches normal operating temperature. The big problem being idle and off-idle response during normal driving during the phase changes.

[Jim Nilsen]

In order to get the engine to run we had to open up the throttle plates with the adjusting screw all the way open. The engine needed the extra air to even keep running at idle. The IAC is working overtime and between the engine wanting so much more fuel to stay running and the fuel map not adjusted to keep up out of the program provided I think we will have to backtrack a bit when it comes to the idle quality.

The car is using a lot of fuel, I ran out of gas last night in the drive. The fuel pressure dropped to 40psi and I thought maybe the pump was acting up and then it went to 19 psi and I went ohhh sheet. Then it dawned on me to check the tank. Sure enough 1.5 inches of gas and a slight angle and no pickup tube in fuel. So now I know where the bottom is. I must be getting 5 miles to the gallon if that.

I made a trip to the HotRod shop yesterday. I had a few moments where it wanted to load up with fuel. I couldn't figure it out at first and then realized that when I was shifting into 4th and the rpm's went down low enough it was loading up in the traffic. Ithink my plugs need to be replaced but with what? The correct heat range is still a mystery right now.

I keep hoping the programmer will have the program he thinks will work to start done soon. I still have a bunch of things to do to finish the car but it sure would be nice to drive a bunch more before the salt hits the ground. I hope we don't have any icy weather before it snows and it takes another month for them to break out the salt. With the times the way they are maybe they will hold off because of the cost. They just layed off several of the plow operators.

So it will be another interesting day to see what I can get done with the program and see if I learn anything helpful to my situation.

I am open to any and all programming help. So far I still don't have the confidence to not do something to the program and do damage to the engine so I am keeping most of my adjustments conservative.

If the kid gets the videos up on youtube I will try to make the link from here to there.

May The Horesepower Be With You !

[Jim Nilsen]

I adjusted the rockers to .030 lash on wed. afternoon and the engine runs even smoother and I can start it up without my foot even touching the gas and it will warm up all on its own. The vacuum came up so much more that I am thinking of trying .035.

I do believe the program I have will only take a bit of tuning on the lower end but when it hits 3500 rpm it needs some more fuel for sure to keep up with the lift and duration coming on.

So far I am liking it better each time I start it and drive.