318 MAX fuel economy builds?

[rumblefish360]

Yes! Edelbrock RPM Magnum intake.
Unless I get a roller cam…. Friction wise, yea it’s an advantage. One that I’m not capitalizing on. At least with the above Hyd cam.

Has anyone read this book yet?

Love the title, I also own a ‘73 Cuda.

 

[rumblefish360]

Thanks for the info, I'll check them out

No problem! You got it my man.

 

[Dmopower]

Yes! Edelbrock RPM Magnum intake.
Unless I get a roller cam…. Friction wise, yea it’s an advantage. One that I’m not capitalizing on. At least with the above Hyd cam.

View attachment 1716015629

Has anyone read this book yet?

Love the title, I also own a ‘73 Cuda.

View attachment 1716015628

Ask me again next week after I read it. ;) 73 Cuda. Sexy car.

 

[Dan the man]

No problem! You got it my man.

Sorry, I didn't pay attention on everything, are you putting this cam in a teener?

 

[rumblefish360]

I want to slide it in a 2000 - 5.9 Magnum

 

[MopaR&D]

In the book "Chrysler Engines: 1922-1998" by Willem Weertman, he notes the switch to roller lifters in the 318/360 increased MPG by 2-3 due to lower friction especially at idle and lower engine speeds.

My Duster now averages about 15 with a 450-hp 360 (5.9L Mag short block), 904 trans with cheap(loose) 2600 rpm stall converter and 8 3/4" rear. When I had 2.94 gears it got about 17-18 on the highway but I recently switch to 3.55s, city mileage went up but cruising at 75 turns 3300 RPM when it really should be more like 2200 or less.

You might be able to grab 20 MPG with a 360 but you'll have to turn it really slowly. Going with the 273 heads and smaller cam with Rhoads lifters will help that work but be careful of cylinder pressures putting all 3 of those together. Idk if you mentioned aftermarket pistons but 9:1 would probably be my limit for static CR.

The lean burn system in the 80s cars actually worked pretty well all things considered, and it wasn't actually as lean as the 70s cars. The carbs were jetted lean overall but it wasn't the crazy 17:1+ like the early systems. The spark control computer was kind of nifty and really beneficial on the highway, it would gradually increase ignition advance during cruise until it detected knock (yes the 80s ones had knock sensors) or throttle opening past a certain point then return to a base setting and start the cycle over again. Honestly just for mileage you won't gain much of anything getting rid of it. It's just that the performance is so bad particularly with the super-tall rear end ratio on those later M-bodies it's frustrating to drive and not really enjoyable. You could probably get away with putting in a shorter ratio but upgrading the exhaust might make it run too lean.

 

[Dmopower]

In the book "Chrysler Engines: 1922-1998" by Willem Weertman, he notes the switch to roller lifters in the 318/360 increased MPG by 2-3 due to lower friction especially at idle and lower engine speeds.

My Duster now averages about 15 with a 450-hp 360 (5.9L Mag short block), 904 trans with cheap(loose) 2600 rpm stall converter and 8 3/4" rear. When I had 2.94 gears it got about 17-18 on the highway but I recently switch to 3.55s, city mileage went up but cruising at 75 turns 3300 RPM when it really should be more like 2200 or less.

You might be able to grab 20 MPG with a 360 but you'll have to turn it really slowly. Going with the 273 heads and smaller cam with Rhoads lifters will help that work but be careful of cylinder pressures putting all 3 of those together. Idk if you mentioned aftermarket pistons but 9:1 would probably be my limit for static CR.

The lean burn system in the 80s cars actually worked pretty well all things considered, and it wasn't actually as lean as the 70s cars. The carbs were jetted lean overall but it wasn't the crazy 17:1+ like the early systems. The spark control computer was kind of nifty and really beneficial on the highway, it would gradually increase ignition advance during cruise until it detected knock (yes the 80s ones had knock sensors) or throttle opening past a certain point then return to a base setting and start the cycle over again. Honestly just for mileage you won't gain much of anything getting rid of it. It's just that the performance is so bad particularly with the super-tall rear end ratio on those later M-bodies it's frustrating to drive and not really enjoyable. You could probably get away with putting in a shorter ratio but upgrading the exhaust might make it run too lean.

Here is a pic of the piston im using. With a .027 gasket my CR will be 9.3 and get me a quench of .039. I can always back that down with a thicker gasket. The cam Will have 205 adv dur at .050. That is untill 1800 rpm or so. then 220. Same as a factory 360 at idle but with better quench. Do you think 9.3 is too much?

 

[rumblefish360]

Depending on the actual cylinder pressure and the camshaft used, it may run fine on 87. My sons 10.5-1 330 runs on 87. But much nicer on 93 with a more aggressive timing curve with more initial advance at 20 instead of 16.

My ‘00 5.9 Magnum likes 89 best. Same as above. Retard the initial time some and a lazy timing curve and it’ll run on 87.

In both cases, best power is t being made but I like the cheaper fuel costs over the premium price tag and I’ll live a few hp down.

In both cases, a larger cam would be a real boost in performance. But consume more fuel. Never mind the more aggressive accompanying timing curve.

I’m confused about what you said on cam duration. 205@050 until 1800? The 220@050?
What’s the secret there!?!?!

 

[Dmopower]

Depending on the actual cylinder pressure and the camshaft used, it may run fine on 87. My sons 10.5-1 330 runs on 87. But much nicer on 93 with a more aggressive timing curve with more initial advance at 20 instead of 16.

My ‘00 5.9 Magnum likes 89 best. Same as above. Retard the initial time some and a lazy timing curve and it’ll run on 87.

In both cases, best power is t being made but I like the cheaper fuel costs over the premium price tag and I’ll live a few hp down.

In both cases, a larger cam would be a real boost in performance. But consume more fuel. Never mind the more aggressive accompanying timing curve.

I’m confused about what you said on cam duration. 205@050 until 1800? The 220@050?
What’s the secret there!?!?!

The Rhoads lifters that I have reduce the dur 15 deg at .050 or 5 or 10 depending on your rocker adj. I set mine at .025 They don't begin to increase lift or duration till 1800 or so.

 

[rumblefish360]

The Rhoads lifters that I have reduce the dur 15 deg at .050 or 5 or 10 depending on your rocker adj. I set mine at .025 They don't begin to increase lift or duration till 1800 or so.

According to Rhoades, it’s a bit more rpm than that.

 

[Dmopower]

According to Rhoades, it’s a bit more rpm than that.

It's a sliding scale. They begin to quiet around 1800 from my experience. Then they gradually increase until at full lift and duration around 3500. But around 1800 is where I begin to hear a difference in the sound of the ticking. The 1800 start is totally my experience with them. Nothing I have seen in print.

 

[rumblefish360]

Interesting, cool. Hummmm, sounds like a tech call is in order just to know.

 

[Dmopower]

Interesting, cool. Hummmm, sounds like a tech call is in order just to know.

Good idea. They advertise that it's about the time the lifter has to drain and that the higher the rpm the less time it has to drain and that it gradually increases until full lift and duration are achieved which is not exact but is around 3500 and I think one spot on their site says full lift and duration are achieved by 4000. Share your response please.

From the page of Rhoads v pro street.

If you have adjustable rocker arms, our All New
V-Pro Street Rhoads Lifters are the best choice for all street performance applications. Unlike Original Rhoads Lifters, they are non-collapsible and fully adjustable. Typical vacuum increases range between 1 to 3 inches at idle when used with bigger cams. Adjustment is similar to solid lifters. Simply use a feeler gauge to adjust the exact amount of lift reduction you want, anywhere from .010" to .025", and that is exactly what you get at idle. Duration is reduced between 5 and 15 degrees at .050" cam lift depending on the adjustment. As the rpm increases, so does the lift and duration. Full restoration takes place at approximately 3500 rpm. They are particularly suited for all street performance applications to incease low-end torque, engine vacuum, and idle quality on performance cammed engines. For maximum low-end torque, they may also be used with stock replacement cams that are larger than .380" valve lift. Our Super Lube Groove Option is highly recommended for enhanced lubrication, greatly increasing cam and lifter life.

 

[Bewy]

The problem with Rhoads is there are so many variables that affect their operation:
- spring tension. More spring, & they bleed down more
- rocker ratio. More ratio , they bleed down more
- oil viscosity. Thin oil they bleed down more, thicker oil they bleed down less.

 

[Dmopower]

The problem with Rhoads is there are so many variables that affect their operation:
- spring tension. More spring, & they bleed down more
- rocker ratio. More ratio , they bleed down more
- oil viscosity. Thin oil they bleed down more, thicker oil they bleed down less.

I run them daily with a 213 adv dur at .050 cam. It's 23 degrees here. in 40 plus years running them I've had none of those issues. Oil matters but the time they have to drain is a bigger factor. What set up have you had these issues with?

 

[RustyRatRod]

The Rhoads lifters that I have reduce the dur 15 deg at .050 or 5 or 10 depending on your rocker adj. I set mine at .025 They don't begin to increase lift or duration till 1800 or so.

You're using Rhoads lifters on a 205 @.050" camshaft?

 

[Dmopower]

You're using Rhoads lifters on a 205 @.050" camshaft?

I run them daily with a 213 adv dur at .050 cam. This puts my cam at idle right where a 273 2 barrel factory cam is at. Till around 1800 rpm.

 

[RustyRatRod]

I run them daily with a 213 adv dur at .050 cam. This puts my cam at idle right where a 273 2 barrel factory can is at. Till around 1800 rpm.

Knock yourself out. IMO, they are totally unnecessary on anything under 220 @ .050. I wouldn't use them anyway, because I am over and done with hydraulic lifters. I MIGHT would use the Rhoads VMax lifters, but most likely not, since the slant 6 is really not built for a hydraulic camshaft.

 

[Dmopower]

Knock yourself out. IMO, they are totally unnecessary on anything under 220 @ .050. I wouldn't use them anyway, because I am over and done with hydraulic lifters. I MIGHT would use the Rhoads VMax lifters, but most likely not, since the slant 6 is really not build for a hydraulic camshaft.

Understand that I'm running a 273 right now and larger engines respond better to more advertised duration. A stock 273 2 barrel has a 195 198 ADV duration. A 273 HP has 208. I'm running a 213 that's a 198 below 1800 rpm. There is a significant difference in how a 273 and a 360 react to the same cam. Are you saying you believe a 198 and a 213 cam on a 273 will get the same mileage?

Have you used Rhoads lifters in a 220 or 213 at .050 cam? I'm curious to know if your opinion is an educated one from experience or an assumption?

Since we are in this thread for education and attempting to MAX mileage you should share your neg experience with Rhoads lifters on cams 220 adv dur and below for education purposes, as there are a couple of us that are attempting to use them for this mileage goal experiment.

 

[RustyRatRod]

Understand that I'm running a 273 right now and larger engines respond better to more advertised duration. A stock 273 2 barrel has a 195 198 ADV duration. A 273 HP has 208. I'm running a 213 that's a 198 below 1800 rpm. There is a significant difference in how a 273 and a 360 react to the same cam. Are you saying you believe a 198 and a 213 cam on a 273 will get the same mileage?

Have you used Rhoads lifters in a 220 or 213 at .050 cam? I'm curious to know if your opinion is an educated one from experience or an assumption?

Since we are in this thread for education and attempting to MAX mileage you should share your neg experience with Rhoads lifters on cams 220 adv dur and below for education purposes, as there are a couple of us that are attempting to use them for this mileage goal experiment.

You assume a lot. My dislike of hydraulic lifters of any kind, Rhoads or otherwise, comes from the fact that they are an inaccurate way to actuate valves. Most hydraulic lifters have a plunger range of about .100" or so. Some more. As a result, you never know how much those plungers are moving. Are they all the same? Hardly. By contrast, when I adjust the valve train of a solid lifter camshaft, I can adjust each rocker arm to the same adjustment across the board and there's no variation. Solid lifters are more conducive to efficiency and that means benefits for power and mileage if you choose a camshaft for mileage. The adjustment is more stable. Instead of the variation of a hydraulic plunger moving around to the tune of .100" plus, you have valve lash adjusted on all 16 to a much more tight tolerance. I don't like Rhoads lifters because they move around even more! That's their design. "They say" full lift and duration is restored by 4000 RPM. Is it? What's their proof? If my engine is going to make ticking noises, it's going to be with a solid lifter valve train where I can measure the clearence, not with a hydraulic plunger where I have no idea of preload amount. Sure, there are "short travel" lifters and the like, but the Rhoads lifters go the "other way". They are long travel lifters by design, unless you use the V Max. Then you can adjust the amount of preload, similar to a solid lifter. Supposedly. And that's the problem "for me". You cannot "measure" how much lift you may or may not have on a running engine due to lifter plungers moving around. Hydraulic lifters were invented for only a couple of reasons. Noise and to eliminate the need for adjustment. That's it. Performance and efficiency were not considered. Go ahead and use them It's your engine. My personal preference is I would not. ...and yes, I've used them in the past on customer builds because they insisted on the "new and shiny" thing they read about in the magazines, but there was always "somewhere" in the engines RPM range where they felt disappointed. They were all used on very mild cams, which IMO is not their intended purpose. Are you going to be happy with an engine that gets 20-25 MPG but won't pull a greasy string out of a cat's ***, or would you rather have something that's at least a little fun to drive? The 273 is kinda like the slant 6. It needs all the help it can get. I would just build one with the standard 273 compression, not Commando and put an Edelbrock 500 on it. Use that little solid cam @toolmanmike is so fond of.....what is it? The E4? Put headers and good flowing dual exhaust on it and call it done. Easy peasy.

 

[Dmopower]

Interesting, cool. Hummmm, sounds like a tech call is in order just to know.

Are you planning on running your cam strait zero or advancing it on the timing gear? Since Rhoads lifters retard the cam timing a tad at low rpm. I advance mine a couple deg and eat the 200 rpm loss at the top end.

 

[Dmopower]

Yes! Edelbrock RPM Magnum intake.
Unless I get a roller cam…. Friction wise, yea it’s an advantage. One that I’m not capitalizing on. At least with the above Hyd cam.

View attachment 1716015629

Has anyone read this book yet?

Love the title, I also own a ‘73 Cuda.

View attachment 1716015628

Got my copy today. I read a book on porting heads 40 years ago when I was in HS. It's always nice to have good intel in the home library. Thanks for the tip.

 

[rumblefish360]

Are you planning on running your cam strait zero or advancing it on the timing gear? Since Rhoads lifters retard the cam timing a tad at low rpm. I advance mine a couple deg and eat the 200 rpm loss at the top end.

Oh! Sorry! I missed this ….
I actually did t think about that… hummmm
It was planned for straight up as per the cam card since this is what I would like to have at higher engine speeds. Altering the installed point also alters the cam’s performance and I’d like to try it as is first. Extending or shorting the cams performance would be the result (of course) but not where I want to start.

Interesting thought I didn’t think of.

 

[Dmopower]

Oh! Sorry! I missed this ….
I actually did t think about that… hummmm
It was planned for straight up as per the cam card since this is what I would like to have at higher engine speeds. Altering the installed point also alters the cam’s performance and I’d like to try it as is first. Extending or shorting the cams performance would be the result (of course) but not where I want to start.

Interesting thought I didn’t think of.

I'm going to run mine adv 2 deg since I'm shooting for max mileage and will be happy with whatever I end up with at the top end.

 

[Bewy]

DMO,
Post #140. I have had NO issues with Rhoads lifters, have use a couple of sets over the years. I make my own now using stock lifters.
Also agree with others that they are a waste with very short duration cams & may well be costing mileage & performance. Short duration FT cams will have low valve lift [ compared to longer duration cams ] & will have even less lift at low rpms with Rhoads. The loss of lift might degrade performance.
Post #139 lists the variables with Rhoads which you may not feel, but is there.