[PontiacLars]

On Speedmaster website the advertised Max valve lift is 0.580 on both flat tappet and roller cam versions.
On Pontiacspeedshop.com they say this
Valve Springs Included: Yes
Maximum Valve Lift (in): 0.580 Flat tappet, .740 Roller

Anyone know what is correct?

[steve25]

The maximum valve lift a given spring can handle does not change in regards to the type of lifter used in driving the valvetrain!!
That .740” must be a misprint.

I went to the speedmaster site and looked up a BBC head listing.

These BBC heads have a 1.900” installed height and yet the springs they ship with are rated for up to .580” lift.
The stated coil bind height is .740” on these .

Like I said, I highly doubt that with there Pontiac heads and there 1.800” installed height that there as shipped with spring has a .740” coil bind spec when there max lift spec is only .580”!

If I am wrong do be it, but something is Fishy to me!

While where on the subject of springs, I can’t wait to here reports of how long the speedmaster supplied springs last in relation to the ones that Edelbrock supplies with there RPM series of heads!

Start running em folks!!

[steve25]

Also note that the springs on the Edelbrock heads are set up for hydro roller or mild solid roller with 150 psi on the seat.
This much seat pressure can not be used with a flat tappet cam, so if your running a flat tappet cam and the speedmaster springs are comparable in seat pressure then that will not work for you, so talking about what the coil bind spec is for either head is a moot point!

[grandam1979]

They advertise max .580 on both they offer hydraulic roller and hydraulic FT not solid roller. My guess is just different springs nothing else different. The set we are using now are all good so far.

[PontiacLars]

They have flat tappet version and hydraulic roller version cylinder heads, so I was hoping that the 0.580 on the roller heads where a typo and that the value is only correct on the flat tappet version.
I know a member here sells these heads, maby he chimes in later.

I am going to run a hydraulic roller in my engine, but my choices have been limited by the 0.580 lift spec, would be awsome if 0.740 was correct.

[grandam1979]

I’m sure they could be setup to run what ever cam you like.

[Steve C.]

Are their springs installed at 1.800" on the cylinder heads ?

The spring is rated at 1.800" installed height.
And it is listed with 1.060" coil bind.

https://www.speedmaster79.com/1.450-....060-Coil-Bind


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[Steve C.]

I agree with steve25, something seems fishy.

In the Speedmaster catalog on page 84 they list only one valve spring that is 1.450" diameter, rated at 1.800" installed height and 1.060" coil bind.

Both their hyd flat tappet and hyd roller heads state a spring description like that.

I'm just presuming they assemble their cylinder heads with the products listed within their catalog. If interested call Speedmaster to confirm this.

https://issuu.com/procompmotorsport/...atalog_s79_web

Not a recommendation, but presume a distance of 0.060" away from coil bind. Now do the math based on a 1.800" installed height and a 1.060" coil bind rating. Others will use .050".

To find the maximum travel of a valve spring, subtract the coil bind height from the Installed Height. (These values will be listed in the valve spring specifications.) Then, subtract 0.050 in. The answer is the maximum valve lift that spring can safely handle.

The safety margin
(full travel before coil bind) should
be kept at a minimum of 0.060”.

http://www.engineprofessional.com/ar...Q215_18-38.pdf


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[Stan Weiss]

I have seen talk of installed height and even installed pressure plus coil bind height. But without knowing spring rate I have no way of knowing opening pressure and if they will work with any cam the OP wants to use.

Stan

[Steve C.]

The Speedmater catalog for that spring....

Suggested open pressure 335 lbs at .600"

https://help.summitracing.com/app/an...ve-spring-rate




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[grivera]

Originally Posted by steve25

While where on the subject of springs, I can’t wait to here reports of how long the speedmaster supplied springs last in relation to the ones that Edelbrock supplies with there RPM series of heads!

Start running em folks!!

How long do the Edelbrock springs last/maintain their specs?

[Steve C.]

"A valvespring sees two times the stress of a connecting rod, the next mostly highly stressed engine part." — Billy Godbold

NO place to cheap out !

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[70 bird]

Originally Posted by grivera

How long do the Edelbrock springs last/maintain their specs?

Edelbrock's parts are looked down on around here too . Your supposed to buy eheads bare then send them to a Pontiac builder.

[Flattrack88]

I recently got a set of the "hydraulic roller" Speedmasters from the black friday sale. I'm going to use a SFT cam, so I knew I didn't want the HFT version, and thought there was a chance the hydraulic roller springs would work for me. I just tested all 8 springs from 1 head. The average install height was 1.785 on this head. The average seat pressure (1.785) was 135 lbs and average "open" pressure at .500 lift (1.285) was 290 lbs.

Before anyone asks, I'm not a shop and don't have high-end equipment. I tested the springs in a hydraulic press using a new pressure based tester from Speedway Motors. The tester zeros well and the seat pressure was close to what SM advertises, so I think it's at least fairly accurate. Just using the two seat and open values above, these springs only tested to have a rate of 310lbs/in which seems a little low.

Even though I'm overall happy (so far) with the heads, I'm pretty sure I'm going to install a set of comp springs.

[Steve C.]

"The average install height was 1.785 on this head"

That's a good tid bit of information. Again, it could be presumed the springs are at 1.800" according to what you read regarding the Speedmaster head.

A similar situation with the Edelbrock head that is advertised with a 1.800" installed height. But when measured by some it will vary.
That and even springs in the same batch can vary slightly in height.

An installed height of +/- 0.020" is acceptable depending on the source.

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[Flattrack88]

Originally Posted by Steve C.

"The average install height was 1.785 on this head"

That's a good tid bit of information. Again, it could be presumed the springs are at 1.800" according to what you read regarding the Speedmaster head.

A similar situation with the Edelbrock head that is advertised with a 1.800" installed height. But when measured by some it will vary.
That and even springs in the same batch can vary slightly in height.

An installed height of +/- 0.020" is acceptable depending on the source.

.

For those looking at max lift, you can easily make the install height 1.800 or even a good bit taller (assuming your springs still give you the pressure you need). Each exhaust spring had 4 shims, totaling around .115" (I only measured the stack, not each shim individually) and each intake had 5 shims, totaling around .135".

Also for what it's worth, since we're talking max lift, the distance between the bottom of the retainer and the top of the valve seal was .807 on exhaust and .833 on intake. I only measured that at 1 cylinder and did it rather quickly. I remember this mattering almost as much as coil bind on my Iron D-port heads with much less installed height. Doesn't look like it's near an issue on these.

Other random observations: Every straight machined edge on these heads is razor sharp...be careful. Check your helicoils. One for a rocker stud was higher than the adjacent boss (i.e., not threaded in far enough). My exhaust bowls also had some of the "casting shift" discussed in one of the other recent Speedmaster threads. The bottoms of the intake ports have to be enlarged slightly to line up with a fel-pro 1233 intake gasket. I would have just left that alone but I had already opened up my intake to match the gasket.

[Steve C.]

Now the question what valve length was used !

On Edelbrock heads the two different chamber sizes use a different length valve to arrive at their advertised 1.800" installed height.

Some will suggest using too many shims is not a good idea. To many loose parts under the spring to promote "dancing".

Related thread.....
https://www.google.com/url?sa=t&sour...DEyr6y27qI3XTv


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[Steve C.]

Here are the lengths for early round port version of the Edelbrock RPM heads as delivered by Edelbrock.

I e-mailed Edelbrock tech in 1999 and asked for their specific valve lengths, this was the reply direct from Edelbrock:

87cc version
5.093" intake / 5.110" exhaust

72cc version
5.213" intake / 5.230" exhaust

Keep in mind these are the reported lengths of the valves used by Edelbrock themselves in their assembled cylinder heads, again in 1999.

Some aftermarket valve lengths will vary slightly for the same application.

From this I will presume the springs seats were probably not machined deeper....

"Looks like water is fairly close under the spring seats. Probably wouldn't risk cutting down more than .030" or so for clean-up."

This comment made here on PY just after they were introduced.


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[Flattrack88]

The valves are marked 1074 and 1075. Per SMs website those part numbers should be 5.210 Int and 5.255 Exh. I'll try to confirm.

[grandam1979]

Out of the box Edelbrock heads are good for .575 so I’m guessing the parts are going to be comparable.