243s on an LQ9

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Mar 26, 2012 | 10:26 AM

TransAm Mania

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243s on an LQ9

Putting 243s on a LQ9. Cam is a 226/236 .525 110 LSA. What is the largest valve size I can use without PTV issuses. Pistons are not fly cut.

Mar 26, 2012 | 10:43 AM

outkast6991

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A 230 intake lobe with .633 lift on 110 lsa had .052 clearance with stock valves on unmilled 243's with a .051 gasket

Mar 26, 2012 | 12:18 PM

TransAm Mania

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What is the clearence limit?

Mar 26, 2012 | 06:28 PM

outkast6991

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.080 intake is the standard. People do run less though

Mar 26, 2012 | 06:32 PM

SweetS10V8

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Quote:

Originally Posted by TransAm Mania

Putting 243s on a LQ9. Cam is a 226/236 .525 110 LSA. What is the largest valve size I can use without PTV issuses. Pistons are not fly cut.

You MUST check for yourself, way to many variables.....

Mar 26, 2012 | 07:28 PM

badazz81z28

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Quote:

Originally Posted by outkast6991

A 230 intake lobe with .633 lift on 110 lsa had .052 clearance with stock valves on unmilled 243's with a .051 gasket

Something doesnt seem right there. I'm sure people have ran more duration with milled 243s and cleared just fine.

.052" With a stock gasket and stock heads with that cam doesnt make sense.

Mar 27, 2012 | 06:09 AM

outkast6991

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From: lancaster,pa

Quote:

Originally Posted by badazz81z28

Something doesnt seem right there. I'm sure people have ran more duration with milled 243s and cleared just fine.

.052" With a stock gasket and stock heads with that cam doesnt make sense.

thats what you would think but i can tell you it is correct. the cam was bought from Ed Curtis and he sent the flycutting tools with the cam because he knew it was too close. he guessed .045, i measured .052. really makes you wonder what some people actually run doesn't it

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Mar 27, 2012 | 09:09 AM

dodson55

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my question is why change valve size for the ammount it would cost to do it you could put a good down payment on a set of aftermarket heads

Mar 27, 2012 | 01:24 PM

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bugy

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Quote:

Originally Posted by dodson55

my question is why change valve size for the ammount it would cost to do it you could put a good down payment on a set of aftermarket heads

when talking about piston to valve clearance minimum are .080 int .100 exh, regarding to cam duration, lift and all that stuff, you can't make a rule for all cams, it also depends on cam architecture from factory, how lobes are located onto that cam from fac, you just can not figure or state all cams with same specs are gonna to show same clearances, as some said you have to check by urself, having or not head milled u better check it before u go with that cam.

Mar 27, 2012 | 01:30 PM

#11

TransAm Mania

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So if I check my PTV clearance and its not enough, what can I do other than fly cutting? Push rod length?

Mar 27, 2012 | 01:33 PM

#12

TransAm Mania

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From: Cicero IL

So if I check my PTV clearance and its not enough, what can I do other than fly cutting? Change push rod length?

Mar 27, 2012 | 01:51 PM

#13

outkast6991

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From: lancaster,pa

Fly cutting or changing the valve events are the only ways

Mar 27, 2012 | 01:52 PM

#14

bugy

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Quote:

Originally Posted by TransAm Mania

So if I check my PTV clearance and its not enough, what can I do other than fly cutting? Change push rod length?

you could either get thicker head gaskets or advance/retard cam (depending on what you need) changing push rod length won't work since they're hydraulic.

Mar 27, 2012 | 08:49 PM

#15

TransAm Mania

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From: Cicero IL

Thanks guys

Mar 27, 2012 | 08:58 PM

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06X6spdGTO

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Just to through some more variables at ya, went 240/244 613 596 109LSA +2 No flycutting, 64cc heads, GM .051 gasket, 2.04 Intake valve. about .063 clearance. STOCK Bottom LQ9!

Mar 27, 2012 | 09:07 PM

#17

TransAm Mania

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From: Cicero IL

Damn that cam is huge compared to what I'm running. Is that with flat tops with no reliefs at all?

Mar 27, 2012 | 09:08 PM

#18

06X6spdGTO

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From: Kearney, NE

STOCK BOTTOM LQ9 flat tops!! (I cheated tho, Trickflow 220 heads helped me a little)

Mar 27, 2012 | 09:13 PM

#19

TransAm Mania

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From: Cicero IL

DUH! I should have comprehended that when I read it. Thanks that info is what I was looking for. Still going to check when I do the swap.

Mar 27, 2012 | 10:28 PM

#20

06X6spdGTO

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From: Kearney, NE

Check out the LS2 GTO site if you want. LQ9 and LS2 are twins on rotating assembly.

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243s on an LQ9

243s on an LQ9

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