Can someone tell me the valve drop on a stock L92 head?
04-22-2010, 01:36 PM
#1
TECH Junkie
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Can someone tell me the valve drop on a stock L92 head? I'm just hashing through some calculations and wanting to know what the stock free valve drop is on an untouched L92 head. I'd also be interested to know for those of you running the L92 heads on a LQ4 shortblock, what's your PTV clearance like? (please state cam specs as well)
04-24-2010, 12:46 PM
#3
Do you have a theory on why the L92s have dropped a valve? Do you see the valve or bad lock as the culprit? Have you seen these happening on LY6 engines too?
thanks,
Jim
04-25-2010, 06:23 PM
#4
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04-26-2010, 10:48 AM
#5
I've seen a few threads pop up with the dropped valve problem and there was no smoking gun that I saw. Im chalking it up to crappy workmanship or insufficient valve springs for those particular failures until someone proves otherwise. Lots of guys running these heads on stock valves without issue
04-26-2010, 11:43 AM
#6
We've not seen many L92 heads with broken valves. Both the solid stem and hollow LS3 valves seem to be holding up nicely.
Richard
04-26-2010, 01:07 PM
#7
Richard,
What is the valve drop on one of your CNC ported L92/LS3 heads? With many people interested in running them with larger cams and no valve reliefs, it would be good to know how much room we're dealing with. Thanks!
What is the valve drop on one of your CNC ported L92/LS3 heads? With many people interested in running them with larger cams and no valve reliefs, it would be good to know how much room we're dealing with. Thanks!
__________________
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2018 Cadillac Escalade 6.2L A10 Pat G tuned.
LS1,LS2,LS3,LS7,LT1 Custom Camshaft Specialist For custom camshaft help press here.
Custom LSX tuning in person or via email press here.
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2018 Cadillac Escalade 6.2L A10 Pat G tuned.
LS1,LS2,LS3,LS7,LT1 Custom Camshaft Specialist For custom camshaft help press here.
Custom LSX tuning in person or via email press here.
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04-26-2010, 02:12 PM
#8
The "valve drop" the OP was refering to is the dimension from the shallow edge of the valves to the deck of the head. It's a vertical measurment that is used to calculate valve to piston clearance.
We've not seen many L92 heads with broken valves. Both the solid stem and hollow LS3 valves seem to be holding up nicely.
Richard
We've not seen many L92 heads with broken valves. Both the solid stem and hollow LS3 valves seem to be holding up nicely.
Richard
I figured that out. I didn't mean to hijack the tread, but I figured you might return to comment again and you to enlighten me/us.
thanks,
Jim
05-02-2010, 09:38 PM
#10
Wow, better than stock valve drop. That helps for guys not wanting to fly-cut. One of your competitors is selling a ported LS3 head that only had .089" free valve drop on the intake side (making it impossible to run anything larger than a cam in the 210s at .050").
__________________
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2018 Cadillac Escalade 6.2L A10 Pat G tuned.
LS1,LS2,LS3,LS7,LT1 Custom Camshaft Specialist For custom camshaft help press here.
Custom LSX tuning in person or via email press here.
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2018 Cadillac Escalade 6.2L A10 Pat G tuned.
LS1,LS2,LS3,LS7,LT1 Custom Camshaft Specialist For custom camshaft help press here.
Custom LSX tuning in person or via email press here.
