Installed height

[PRH]

I totally agree.

How hard would it be to just have the advertised numbers be a closer representation of what they actually tested at?

A long time ago I used to use a fair number of K-1100’s for mild roller cams in street/strip or bracket cars.
That old K-1100 was quite a different spring than what you get when you buy that part number now.
They would always test within a couple pounds of the spec.
I bought a set a few years ago........ not too close to the new specs.
The specs are 230@1.900/555@1.250.
They test at 272@1.900/585@1.250.

I’ve found the Isky stuff tests pretty close to the published specs.

[SpeierRacingHeads]

The biggest problem is most are listed without the load of the retainer. Check a PAC once.

[PRH]

The new style K-1100 is 260@1.900/567@1.250 without the retainer.
Still not really all that close to the published specs.

The PAC springs I use the most often are 1224’s, 1225’s, 1243’s, & 1903’s.

The 1224’s and 1225’s are usually well above spec(30lbs+).
The 1243’s and 1903’s are usually within 10 lbs or so, tested with a retainer that has a .100 step.

[SpeierRacingHeads]

Just did a 1150 without a retainer.

ADV
230@2.000 - 628@1.250 - 531 rate

CHECKED
235@2.000 - 616@1.250 - 517 rate

And a 850 for a goof. No retainer.

ADV
135@1.900 - 419@1.250

CHECKED
136@1.900 - 434@1.250

[cgarb]

That makes sense. Not every retainer is the same so I guess no retainer would be more repeatable. Didn't look like it effected the coil bind height according to your test earlier Chad so it really won't matter much then. I don't think a little extra seat will hurt anything. If I suspect the valves are bouncing off the seats due to spring surge and causing the black intake runners, extra seat load should help that. Is there a general rule of thumb people use to determine seat load vs just open load? I have heard about 100lbs for every .100" of cam lift, but you can have 10 different springs with that open load but all different seat loads.

[PRH]

Doesn’t really make much sense to me to have the advertised numbers to not be representative of how they’ll be run...... as in, without the retainer step.

PAC 1243:
with retainer - 250@1.900/598@1.250
without retainer - 230@1.900/575@1.250
Specs - 240@1.900/598@1.250

PAC 1903:
with retainer - 150@1.800/387@1.200
Specs - 149@1.800/384@1.200

I do like that spring tester you have.

[SpeierRacingHeads]

I think they should rate them with the retainer, THEY SELL. I can take a Manley, PAC, KMotion, and they read all different. Step thickness, etc plays a big role. THEN, grab the same company's steel or Tool Steel. Enough to make you drink!

[PRH]

Just did a 1150 without a retainer.

ADV
230@2.000 - 628@1.250 - 531 rate

CHECKED
235@2.000 - 616@1.250 - 517 rate

And a 850 for a goof. No retainer.

ADV
135@1.900 - 419@1.250

CHECKED
136@1.900 - 434@1.250

Interesting that those two part numbers check close to spec without the retainer, yet the 1650’s are so far off.

[LSP]

Watch the bind height too, some of the PAC stuff will bind higher than advertised and could get you into trouble. Never seen that on PSI springs, always to the bind number or slightly less.

[bob460]

You mean PAC 1243?
Probably the same.
They're a bit shit, loose pressure fast.

There is an isky tool room spring I use at 1.95" installed height at around 260lb on the seat, 530lb rate & will take .730" lift.
Not cheap, but they go the distance so they end up cheaper in the long run.
I'll see if I can find the part number tomorrow.

If there is 1 component in an engine to not cheap out on or under spec it's valve springs.

I mean CT 1243 that's the PSI pn#

Isn't the isky tool room springs made by PSI?

[swampbuggy]

Yep.