questions about installing milled ls6 cnc heads
10-29-2002, 01:19 PM
#1
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questions about installing milled ls6 cnc heads A buddy is installing some CNC ported Ls6 heads from SDPC on his 2001 Z06. I thought I might post a few questions he had.
He ordered the cnc ls6 heads from SDPC. He has a 2001 z06. The heads have been milled .055 and have a 60cc combustion chamber.
First off, the stock Z06 cam is .525-in. lift on the intakes and .525 is intake duration is 204° and exhaust is 211°.
I don't know what the stock combustion chamber CC is exactly and if the CNC work opens it up any. So, by milling .055 if the chamber is otherwise the same size as stock should up the compression from 10.5 to somewhere in the 11's.
He is worried about PTV clearance with these heads and the stock cam. Ayone see any issues? He is also considering installing 918s so that if he adds a cam they are ready to go. Would you consider PTV clearance issues with an X1 cam?
Since the heads have been milled .055 but the stock '02 valves are .100 longer, any idea on what length pushrods would need to be ordered?
He ordered the cnc ls6 heads from SDPC. He has a 2001 z06. The heads have been milled .055 and have a 60cc combustion chamber.
First off, the stock Z06 cam is .525-in. lift on the intakes and .525 is intake duration is 204° and exhaust is 211°.
I don't know what the stock combustion chamber CC is exactly and if the CNC work opens it up any. So, by milling .055 if the chamber is otherwise the same size as stock should up the compression from 10.5 to somewhere in the 11's.
He is worried about PTV clearance with these heads and the stock cam. Ayone see any issues? He is also considering installing 918s so that if he adds a cam they are ready to go. Would you consider PTV clearance issues with an X1 cam?
Since the heads have been milled .055 but the stock '02 valves are .100 longer, any idea on what length pushrods would need to be ordered?
10-29-2002, 05:03 PM
#2
Re: questions about installing milled ls6 cnc heads I checked on the Grand Am cam -.570",239/251@.050" and 106LSA with the LS6 CNC heads. SDPC calculated compression at 11:1 and said PTV should be fine with.570 lift and .055" milled heads. This was for a 2001 LS6 motor.2002 valvea are 0.60 mm longer, which is 0.023"( change to lifter is 0.014"). Stock pushrods are 7.400 , so 7.350 should work as heads were milled 0.055". <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />
<small>[ October 30, 2002, 08:47 AM: Message edited by: binksz06 ]</small>
<small>[ October 30, 2002, 08:47 AM: Message edited by: binksz06 ]</small>
10-30-2002, 11:02 AM
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Re: questions about installing milled ls6 cnc heads ..i also looked into this head,,,,SDPC told me you need to change the metal pins that align the intake to the heads...they sell these separate but you can file/sand the old pins too...
...i thought there were some aftermarket head gaskets that are thicker than stock so you could get less than 11.1 compression...I think you should call SDPC and ask them before you start the tear-down...
I'll be interested in the results since the heads are new, do not require a core and are much less expensive than ported old heads from the various dealers...the heads also flow better than old ported LS1 heads ...so, except for the unknown about the high compression, how could you go wrong?
...i thought there were some aftermarket head gaskets that are thicker than stock so you could get less than 11.1 compression...I think you should call SDPC and ask them before you start the tear-down...
I'll be interested in the results since the heads are new, do not require a core and are much less expensive than ported old heads from the various dealers...the heads also flow better than old ported LS1 heads ...so, except for the unknown about the high compression, how could you go wrong?
10-31-2002, 12:51 AM
#4
Re: questions about installing milled ls6 cnc heads Assuming a 60cc combustion chamber and .055" gasket thickness, you'd be looking at slightly over 11:1 compression. IMO, that's pretty nice. It will work just fine on pump gas with proper tuning. I've run 11.5:1 on pump gas before with an LS1.
You shouldn't have any problems with the stock LS6 cam and these heads milled .055". We installed these heads milled .040" with a Comp XE-R 228/228, .588"/.588", 111 LSA on a customer's car, and we had to fly-cut the pistons for proper clearance. I would expect you to be in the clear with quite a bit of room to spare with the stock '02 cam, but it never hurts to check. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />
Trevor
You shouldn't have any problems with the stock LS6 cam and these heads milled .055". We installed these heads milled .040" with a Comp XE-R 228/228, .588"/.588", 111 LSA on a customer's car, and we had to fly-cut the pistons for proper clearance. I would expect you to be in the clear with quite a bit of room to spare with the stock '02 cam, but it never hurts to check. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />
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10-31-2002, 01:12 PM
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Re: questions about installing milled ls6 cnc heads </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Trevor D:
<strong>
You shouldn't have any problems with the stock LS6 cam and these heads milled .055". We installed these heads milled .040" with a Comp XE-R 228/228, .588"/.588", 111 LSA on a customer's car, and we had to fly-cut the pistons for proper clearance. I would expect you to be in the clear with quite a bit of room to spare with the stock '02 cam, but it never hurts to check. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />
Trevor</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">What numbers did you guys see on that car (dyno and track)?
<strong>
You shouldn't have any problems with the stock LS6 cam and these heads milled .055". We installed these heads milled .040" with a Comp XE-R 228/228, .588"/.588", 111 LSA on a customer's car, and we had to fly-cut the pistons for proper clearance. I would expect you to be in the clear with quite a bit of room to spare with the stock '02 cam, but it never hurts to check. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />
Trevor</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">What numbers did you guys see on that car (dyno and track)?
11-06-2002, 10:34 AM
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Re: questions about installing milled ls6 cnc heads Any updates on the performance with these heads? I was also thinking about them but was worried over clearance issues as well. I have a 2001 LS6 block with a Comp Cams 220/226 .563/.570 and 7.350" rods. Will there be any clearance issues and will these heads preform well with this cam?
11-06-2002, 01:41 PM
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Re: questions about installing milled ls6 cnc heads I bought these heads from SDPC last week but did not want the high compression (planning on adding light boost later). SDPC assembled a pair of the CNC bares for me (70CC) with Manley internals and milled .030 to yield 65CC and approx 10.3:1 compression. Cost was only slightly more $$ than the assemled heads. That should eliminate some of the clearance concerns mentioned above and eliminate the need to shave pistons. I did speak with them today and they said the were runninbg out of the bare 02' CNC LS6 heads and would not be getting anymore so you better hurry if you are thinking of going with this option.
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11-06-2002, 04:34 PM
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Re: questions about installing milled ls6 cnc heads We don't have any #'s yet from the customer's car. He is supposed to take it to the track this Friday with the new heads/cam setup and TCI 4400 stall. It should run well if his trans will cooperate. He has a LOT of stereo equipment in a full-weight '99 T/A! <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> Hopefully he'll get it on a dyno soon.
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11-06-2002, 04:55 PM
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Re: questions about installing milled ls6 cnc heads Trevor, when you say "we installed these heads", are you specifically talking about the CNC'd LS6 heads available from GMPP? Or are you talking about GM LS6 heads in general. The question people are wanting to know is how the CNC'd GMPP heads work.
11-06-2002, 04:57 PM
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Re: questions about installing milled ls6 cnc heads </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by binksz06:
<strong>I checked on the Grand Am cam -.570",239/251@.050" and 106LSA with the LS6 CNC heads. SDPC calculated compression at 11:1 and said PTV should be fine with.570 lift and .055" milled heads. This was for a 2001 LS6 motor.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Dude, a 239 intake duration cam with 570 lift on heads milled 0.055" sounds to me like a recepie for DISASTER. If *anybody* puts together a combo like that, they better plan on measuring P/V clearance and IMO they should have the flycutting tool handy.
<strong>I checked on the Grand Am cam -.570",239/251@.050" and 106LSA with the LS6 CNC heads. SDPC calculated compression at 11:1 and said PTV should be fine with.570 lift and .055" milled heads. This was for a 2001 LS6 motor.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Dude, a 239 intake duration cam with 570 lift on heads milled 0.055" sounds to me like a recepie for DISASTER. If *anybody* puts together a combo like that, they better plan on measuring P/V clearance and IMO they should have the flycutting tool handy.
11-07-2002, 03:22 PM
#11
Re: questions about installing milled ls6 cnc heads JMX-thanks for the post! I called SDPC ,again and they said I would need 0.040" - 0.060" valve relief. Saved me a lot of aggravation.! <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />
<small>[ November 07, 2002, 03:23 PM: Message edited by: binksz06 ]</small>
<small>[ November 07, 2002, 03:23 PM: Message edited by: binksz06 ]</small>
