L92 heads + 4" bore...
L92 heads + 4" bore... is anyone running L92 heads on an lq4 shortblock? i just sold my ls1 camaro with intentions of building an lq4 i have, and using L92 heads in the process. i have been reading up on this, but haven't found any concrete info on this combo. it appears i might have a problem with valve to cylinder wall clearance when using the L92 heads on a 4" bore. i will be running a big duration cam with the goal of 11:1 compression. what's the most i can mill an L92 head? i would like to use the stock lq4 pistons and simply flycut to accomdate the 250ish duration cam.
nope youll be fine.. the L92's work perfect.. its the LS7 heads that wont work, the valves are too big and will clip the cylinder wall unless your bigger than 4.090 or something around there.
L92 = heads of choice for us big bore crowd.
L92 = heads of choice for us big bore crowd.
Originally Posted by NemeSS
might as well take ur block another .030 while ur at it for another 5ci 
The LQ4 has 9.5:1 compression with a 72 cc head so it will be pretty tough to get 11:1 without some serious milling and a small gasket. May have to run a pretty small duration cam to get the DCR up there which wouldn't really hurt you with as good as the L92 port is.
Nate
Originally Posted by Nate_Taufer
.030" over is 6ci...not trying to nitpick just pointing out some bad info. And for the poster I believe WMCKD (i think thats his name) was saying that there was huge problems with PTV clearance with even small cams. Might just have to figure that out for yourself though when you mock it up.
The LQ4 has 9.5:1 compression with a 72 cc head so it will be pretty tough to get 11:1 without some serious milling and a small gasket. May have to run a pretty small duration cam to get the DCR up there which wouldn't really hurt you with as good as the L92 port is.
Nate
The LQ4 has 9.5:1 compression with a 72 cc head so it will be pretty tough to get 11:1 without some serious milling and a small gasket. May have to run a pretty small duration cam to get the DCR up there which wouldn't really hurt you with as good as the L92 port is.
Nate
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Originally Posted by Nate_Taufer
.030" over is 6ci...And for the poster I believe WMCKD (i think thats his name) was saying that there was huge problems with PTV clearance with even small cams. Might just have to figure that out for yourself though when you mock it up.
. May have to run a pretty small duration cam to get the DCR up there which wouldn't really hurt you with as good as the L92 port is.
Nate
. May have to run a pretty small duration cam to get the DCR up there which wouldn't really hurt you with as good as the L92 port is.
Nate
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Originally Posted by WKMCD
These heads don't have a lot of free drop to begin with and a huge intake valve.. I think almost any cam much larger than stock is probably going to require some additional thought and consideration.
shouldnt that clear??
anyway.... who has tested PTV with these heads?? I assume with the right piston they will clear..... so basically these heads are gonna be made for boost/low compression setups.
i will flycut as needed, but if possible i'd like to run something like a 248/256 on a 106-108 with ~.610 lift. if getting compression is going to be that hard, i will slightly reduce the size of the cam. i am anticipating a sheetmetal intake setup, possibly carb...i am still exploring options, as there are MANY. i'm trying to keep a $5k budget on the motor itself, with the complete lq4 engine costing me ~$1,200 (yes, i have connections). i figure that selling the stock heads/intake setup would get me ~$500 total.
Originally Posted by WKMCD
Bret Bauer designed my cam. You might want to check with him.
It's not likely the stock LQ4 pistons will survive long in this application. The valve notches will have to be pretty deep to fit a 250ish degree cam and the stock piston crown is going to end up pretty thin. Add to that the fragile nature of the stock pistons and I think your going to end up with an engine that won't last very long. Put in some forged pistons with a small dome and proper valve notches and you've solved all your problems.
Good luck,
Richard
Good luck,
Richard
Originally Posted by Forteen3GT
Bret.... PM me specs on a cam for a 370 w/ car or carbed L92 intake options. Bigger cam the better. needs to be streetable. Going with 200 shot of nitrous for now. thru the setup below in sig..
Are you serious? And bret while you're at it give me 20 bucks.Nate
Originally Posted by Richard@WCCH
Put in some forged pistons with a small dome and proper valve notches and you've solved all your problems.
Originally Posted by SStrokerAce
LG you???? You mean I should give out cam info for free??? Sorry, I get paid to do it normally.
Bret
Bret
Yea but you owe me beer! Everyone knows you design your best cams drunk right?