Comp 910 Valve Spring Install How-To

[ToMang07]

Ok, I'm not gonna lie.. when it comes to the calculating of this stuff.... I'm kinda retarded.

Looking at the chart... 134lbs seems to be the closest to 130. So it needs a height of 1.750 to reach that.

Installed height of the spring is 1.850, according to the chart.

So I need to shim it 0.1 correct?

What I see for shim sizes are .03 or .015. So you can shim to either .09 or .105.

I'm guessing everyone shims to .105?

or am I way off base here?

 

[davey99ps]

Wish I would've saw this thread awhile ago, shimming was where I got kinda hung up

 

[Ron's Power Stroke]

install the height micrometer instead of a valve spring, and then rotate the dial to expand the tool to seat the valve, locks and retainer.from there you can tell what shim you will need...
the way i read it.. you want between 1.750"-1.760" including seal and 1.800"-1.810" with out seal... This will get you a seat pressure between 130lb-134lb.

dont hold me to this but it sounds about right...

 

[Ron's Power Stroke]

install the height micrometer instead of a valve spring, and then rotate the dial to expand the tool to seat the valve, locks and retainer.from there you can tell what shim you will need...
the way i read it.. you want between 1.750"-1.760" including seal and 1.800"-1.810" with out seal... This will get you a seat pressure between 130lb-134lb.

dont hold me to this but it sounds about right...

^^^ you install the tool on to the valve as if you was intalling the valve sping into the head...but instad of the putting the spring in..you put the tool in its place...after you have reached you goal hight...put the spring in and lock her down, then move on...


side note: use the same retainer, keepers etc for the spring you are shimming.. each valve, retainer etc might be slightly different in size and thickness and can change your measurement...






I would also like to add that some times black soot can build up on the valve not letting it seal like it should..if you can get a drill to bite onto the valve stem without hurting it..it wouldn't hurt to spin the valve against the head by pulling up on the valve while spinning it to clean the soot off...don't go crazy..just a quick spin is all you need..I have not tried to do this yet on a 7.3 but I cant see why it wouldnt work here..my motor will be out...a motor still in could be hard to do..

 

[ToMang07]

Ok, I'm more confused now, and I don't have this tool.

If anyone who read my previous post understands it and can answer it, I would greatly appreciate it.

 

[Ron's Power Stroke]

maybe this will help you...

as the valve (seats) wear...the valve recesses further & further into the head...thereby making the springs' installed height 'taller' than on a fresh head.

OEM spec (off the top of my head) for valve recession in the head is @ .040" +/-

we've had customers supply their own 'rebuilt' heads with new valves and the "works" with the valves recessed closer to .080...

machine shop work (& knowledge), mileage, as well as how clean the air was that went through the engine (dirtier air will increase valve seat wear, further recessing the valve)

as a rough ballpark...trucks with 200k miles on them (typically) will need at least .030 shim to hit our desired installed height for the 910 springs (1.780") which equates to just under 125lbs of seat pressure.

springs installed @ 1.75" would have @ 134lbs of seat pressure.

getting much higher than @ 150lbs of seat pressure can cause the hydraulic lifter spring to collapse and start affecting actual valve lift...without doing things inside the lifter to combat this.

the factory specs are 71-79lbs of seat pressure @ 1.833" installed height, for both I&E valves.

so jusssst swapping in a set of 910's would take you from 71-79lbs to @ 99lbs with no shims.

the valve face diameter is 1.67"...

if you were running (for instance) 45lbs of boost...with stock springs...

you would have ~75lbs of force (45 x 1.67) acting on the valve to open it...without any help from the camshaft...not to mention backpressure acting upon the exh valve (which is typically higher than your boost pressure).

so...a spring is just a spring...sitting on a table..it has zero seat pressure LOL...

installing the spring to do a specific task (high boost high rpm, etc) should be the concern. so I would recommend that you consider your boost & rpm when setting up your seat load.

...and for those that think if some more (pressure) is good...than a "lot" (more) must be better...just keep in mind that the higher the seat load...the more valve wear will occur from the harder 'hit' that the valve & seat absorbs with every opening & closing.

 

[Tom S]

What we really need here are some photos.

 

[vanderchevy18]

I'd post some more but I haven't taken any more since those were taken. Next valve spring job I do I'll post pics.

 

[Rideracelivemx7]

Hey guys, I just finished mynvalve spring install with 9-10s and the jegs valve Height tool, you ins tall e tool at lowest height for ease of installing keepers. Then you extend it till it's just about snug and turn the dial towards you so you can see and turn it .05 out and that should be pretty dead nuts to Installed spring height.
I have 178k on my truck and WITHOUT the valve seal which equates to a .060 shim. My truck was what I thought in spec. All my valves measured to 1.82-1.830. So you subtract the shim which brings you to a valve up to 1.76-1.77. I added a .015 shim which brought my valves to a 1.745-1.755 which mentioned above is where we roughly want to get to our goal of 130-134lbs of seat pressure


And the reason I said with out the valve seal is because I found it doesn't exactly fit in this skinny little tool.

 

[TARM]

Yes as far as I know you always measure without the faculty seal/shim in place. I used a different spring micrometer and that is all it was a micrometer only. You still had to do it without the seal in place. Then add it back in. I went thru and measures each of them just in case there was different rates of wear as I wanted all to have the same amount of lift, timing, and tension. Took some extra time but worth it IMO if for nothing more than confidence in doing things with precision.

 

[DZL JIM]

We finally did my motor last week, motor was on a stand and was a project in itself. No way I'd ever want to do that in frame, what a pain that would be.
250k miles on motor. Most needed .050" or .060", and I think 4 of the intake valves needed .070"+.
Also, my shims from Jegs were supposed to be .015" but came as .020", so make sure to double check yours.

 

[vanderchevy18]

Hahaha!! Yeah its a tad bit harder in frame but its pretty much a wash. You spend more time and have more work pulling the engine, but you also spend more time and its harder doing it in frame. I've done all of the ones I've done in frame.

 

[SDstroker]

Hahaha!! Yeah its a tad bit harder in frame but its pretty much a wash. You spend more time and have more work pulling the engine, but you also spend more time and its harder doing it in frame. I've done all of the ones I've done in frame.

:whs:

If I was going to do springs, studs and push rods in another motor, it would be on a stand.

 

[DZL JIM]

We can have either the motor out or body up in 2 to 3 hours. Not worth doing all that work on your stomach for that...

 

[Shaw]

I was installing some 910 and shims and thought I would take a picture of the gauge so people know how to use it. This one measured at 1.848

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[Hotrodtractor]

I was installing some 910 and shims and thought I would take a picture of the gauge so people know how to use it. This one measured at 1.848

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Just to make it easier to see:

 

[RubberDuck]

Hmm, and here I thought I had every tool under the sun...... Where do I find one of those?

 

[Shaw]

RubberDuck - look up at Tarm's post. Its from Jegs.


Jason, How do you make the picture big like that?

 

[Hotrodtractor]

Jason, How do you make the picture big like that?

In Webshots there is a image code location on the right hand side where it gives you the direct link code, forum code, etc... for the particular image - across the top of that box there is about 4 different image sizes - Webshots defaults to the smallest one - just click on the one on the far right (largest one) and you get image code for a larger picture.

Hope that helps.

Jason

 

[Shaw]

Easy enough, thank you!!!