Tell me what this installed height please

[434nova]

I just checked my installed height on my gn1 heads and this is what I got. Cam is a hydraulic roller and springs are supposed to be 1.750 installed height. With 140 #s on the seat. Tell me what I am reading. I have a feeling that these heads were ordered for hydraulic flat tappet and not a roller cam. Thanks

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[Chris Hogeland]

Your retainer is down in the gage. It needs to set on top. Measure how deep the step is on the gage and then add that to your reading.


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[434nova]

Ok now I am at around 1.700 what will happen if I leave it at that ? Will I loose lift on my springs ? My cam is around .540 lift. The old springs are kmotion 750 and they were installed at 1.700 and now I am running pac 1201 which are rated .550 lift and installed height of 1.750 @ 140 on the seat. And the old k motion 750s are rated to .600 lift and 1.700 @ 130 on the seat. Thanks

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[Chris Hogeland]

What is your coil bind?


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[earlbrown]

Ok now I am at around 1.700 what will happen if I leave it at that ? Will I loose lift on my springs ? My cam is around .540 lift. The old springs are kmotion 750 and they were installed at 1.700 and now I am running pac 1201 which are rated .550 lift and installed height of 1.750 @ 140 on the seat. And the old k motion 750s are rated to .600 lift and 1.700 @ 130 on the seat. Thanks

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does that mean the cup on your height mic is .150"?

on your next question..... no idea. height and poundage are two different things. Yes, the sticker on the box tells you what the poundage will be and the spring rater per inch.... BUT in my personal first hand experience the sticker and real life never match.


If you want to set them up right, shim them to the poundage you want, not the height. Of course that requires a spring tester. If you don't have one, don't loose a lot of sleep over it. There's been many a turbo Buick haul ass over the decades with less thought in the valvetrain than you've already shown.

 

[434nova]

Yes it is .150 with my installed height I have now its 130#s on the seat. What I find weird is my old springs were 125#s on the seat but at open pressure it was only 285 they say it should be 395 open. That is probably why I am getting valve float , also all my dampers on the old springs were broken too. My new springs are at 400 #s open so I should see a major difference on topend.

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[SHADOWII]

Does that .150" include the thickness of the retainer? It seems the seat pressure would be increased if the installed ht is reduced. It also seems you have discovered your topend problem.

 

[Chris Hogeland]

Need to know where the spring coil binds at. Should be on the spec on the box the spring comes in. Or you can put the spring in A vice and close it to the coil start touching then measure the spring and that will be coil bind.


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[434nova]

Coil bind is 1.115

 

[forcefed3.8's]

You will be fine installing at 1.70.