Hyd Roller vs Hyd Flat tappet on SM heads

[Cuda416]

I was over looking at the SM heads and noticed they have the fully assembled heads advertised for hyd roller, and hyd flat setups.

My understanding was that rollers needed heavier spring pressure due to weight, but these two pages show what appears to be the opposite.

Mopar Chrysler SB 318 360 170cc 65cc Hydraulic Roller Assembled Cylinder Heads
Max Lift: .600
Coil Bind: .1.150
Intake Install: 135lbs @ 1.8
Exhaust Install: 135lbs @ 1.8
Closed Sear Pressure: 135lbs
Open Seat Pressure: 325lbs


Mopar Chrysler SB 318 360 170cc 65cc Hydraulic Flat Assembled Cylinder Heads
Max Lift: .600
Coil Bind: .1.060
Intake Install: 145lbs @ 1.9
Exhaust Install: 145lbs @ 1.9
Closed Sear Pressure: 145lbs
Open Seat Pressure: 360lbs

These seem to contradict what I've read. Is it just a mistake or is there something I am missing?

 

[MOPAROFFICIAL]

Spring pressure for hyd roller can vary, but usually fall into the 135 seat and 360 open range. Solids..depending on ramp speed and app can be 120 to 160 seat
depends on the cam. Always follow cam manufacture recommendations for spring pressure.

 

[Cuda416]

Spring pressure for hyd roller can vary, but usually fall into the 135 seat and 360 open range. Solids..depending on ramp speed and app can be 120 to 160 seat
depends on the cam. Always follow cam manufacture recommendations for spring pressure.

Thanks MO, but just to be clear, these are both slated as hydraulic lifter heads (springs). I also noticed the spring height is different on these as well. 1.8 (hyd roller) vs 1.9 (hyd flat tap).

 

[rumblefish360]

I almost always throw the springs away and use quality spring pressures for the cam I’m using. I don’t always know where the springs come from on complete heads.

The spring height recommendation is always followed. I don’t care how the head came or with what springs are on it. It all gets adjusted.

Don’t worry about the spring height they state. Both listings are rather tall compared to stock.

 

[PRH]

I highly doubt either of those head packages come with the springs installed at 1.900”.
I’m not saying it’s impossible, just not likely.

 

[fishmens67]

almost always throw the springs away and use quality spring pressures for the cam I’m using.

I also toss the valve keepers, I want to personally remove them from a Comp package.
Valve seals are usually junk too.
oh heck I'm going through the whole assembly.

 

[Cuda416]

Sounds like the best bet is to get the bare heads and start with that .lol

 

[Cuda416]

Thanks guys, your input is always appreciated.

 

[ValiantRacing]

I highly doubt either of those head packages come with the springs installed at 1.900”.
I’m not saying it’s impossible, just not likely.

I run the SM, bought them bare, and then purchase the springs for a hydraulic roller, and run them with my solid flat tappet, they came in at 1.90 installed height, and 400lbs open

 

[Bewy]

Probably a misprint translating from Chinese......

 

[Yellow Duster]

My SM heads installed height came in at 1.875. Seat pressure is 130 and 315 at .650 lift.

 

[PRH]

My SM heads installed height came in at 1.875. Seat pressure is 130 and 315 at .650 lift.

Were those bought as for use with HFT cams or HR cams?

 

[cookietruck]

We’re those bought as for use with HFT cams or HR cams?

285lb spring rate?
Is that common?

 

[PRH]

Not with much of anything I do.

One fundamental problem I see with that spring is, for the type of cam that works well with something in the 275-ish open load range(mild street cam around .500” lift), you end up with a spring thats really far from coil bind……..which can be problematic for controlling upper rpm harmonics.

 

[rumblefish360]

Sounds like the best bet is to get the bare heads and start with that .lol

Do the SM have the flow rates your looking for?
Weigh the costs.

 

[Yellow Duster]

Were those bought as for use with HFT cams or HR cams?

The HR, CNC heads.

 

[rumblefish360]

The HR, CNC heads.

Like this head here you can purchase it bare or fully assembled?

Shocker 185 Mopar CNC (Sold in Pairs) - PROMAXX Performance Products

 

[PRH]

The HR, CNC heads.

Seat pressure is 130 and 315 at .650 lift.

That’s pretty low spring loads for a HR set up.

If you shimmed up the springs to 145 closed and paired that with a .550 lift cam, you’d still only be barely over 300 open.

 

[Yellow Duster]

I was originally planning a mild camed 408 for my Power Wagon. That has changed and they will eventually go on something more serious for my Duster. I plan to change the springs to whatever matches that build.

 

[cookietruck]

Did a quick search and i guess the SM heads do have light springs.

Post in thread 'ProComp/Speedmaster aluminum heads'
ProComp/Speedmaster aluminum heads

 

[turbovan]

I’d also suggest buying them bare. I purchased the assembled HFT heads because of the listed higher spring pressures. Using magnum lifters I encountered significant valve float at a little under 5800. New springs solved the problem.
600/550 lift

 

[cookietruck]

I’d also suggest buying them bare. I purchased the assembled HFT heads because of the listed higher spring pressures. Using magnum lifters I encountered significant valve float at a little under 5800. New springs solved the problem.
600/550 lift

What springs did you install?

 

[crackedback]

Don't recall if the SM heads have the same pushrod hole dimensions as ede's, best check for pushrod interference in the holes with a Hyd Roller set up.

 

[turbovan]

What springs did you install?

Edelbrock 5845

I believe they’re what comes on the assembled edelbrock hydraulic roller heads.

 

[rumblefish360]

Don't recall if the SM heads have the same pushrod hole dimensions as ede's, best check for pushrod interference in the holes with a Hyd Roller set up.

I experienced pushrod interference with a hydraulic roller cam, and the Mopar hydraulic roller lifters with the Speedmaster heads and 1.6 rockers