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Potential piston to valve clearance issues?

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Old 10-23-2013, 10:05 PM
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Default Potential piston to valve clearance issues?

Planning to send my 243s to TSP or TEA for stage 1 of one of the two. But the heads I'm planning on running are an extra set I have that are milled .030". The cam I'm planning to run is a comp cam 228/230 .571/.573 112 LSA. Should I be worried about piston to valve clearance issues?
Old 10-23-2013, 10:13 PM
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so do you have two sets of heads, post is a little confusing? Also what gasket thickness are u planning to use?
Old 10-23-2013, 10:36 PM
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Won't know til you measure. You'll probably be okay, but it'll be close. Also, depends on what the installed ICL is. Only way to know that is to degree the cam in and see what it specs out to in your block with your timing set and crank.
Old 10-23-2013, 10:45 PM
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Yes I have two sets of 243s. I'm asking because I don't know if I should send the stock ones in or the milled ones. Especially since I'll probably end up milling the stock ones if I do send them in. My train of thought is that it would be easier to sell stock 243s vs .030 milled 243s
Old 10-23-2013, 10:46 PM
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Also I'm planning to use gm mls head gasket
Old 10-23-2013, 11:04 PM
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TEA or TSP will mill the heads when they port them to whatever cc you want. If you send in the milled heads, they may have to mill them again .005" or so to true them up after being ported.

But you're right, the stock, unmilled 243s will sell for more.
Old 10-24-2013, 06:57 AM
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With a 228/232 .615 cam I had .120 and .100 clearance with .010 milled heads. I had them milled .030 more to cut my clearance down to .090 and .070. You should be fine.
Old 10-24-2013, 05:13 PM
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Man, why do people insist on doing things backwards?
1- install and degree cam at desired ICL.
2- Install heads you wish to run
3- measure ptv
4- Decide if clearances reasonable and then mill accordingly
5- measure ptv again after desired chamber volume and SCR reached. Watch ur DCR for type of fuel used.
Old 10-26-2013, 08:47 AM
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Originally Posted by PREDATOR-Z
Man, why do people insist on doing things backwards?
1- install and degree cam at desired ICL.
2- Install heads you wish to run
3- measure ptv
4- Decide if clearances reasonable and then mill accordingly
5- measure ptv again after desired chamber volume and SCR reached. Watch ur DCR for type of fuel used.
because these are all parts that are off the shelf and its been done a million times. to do what your saying i would have to buy a bunch of tools ill probably never use again. and if i dont torque the bolts down to full torque specs then it would all be pointless since the mls gasket compresses. 01ssreda4 gave me the answer i needed as i expected someone to have done similar things.
Old 10-26-2013, 03:08 PM
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Then you are not ready to mod if you do not wish to spend the time, money and effort to do it right.
01ssredA4 did not give an answer for YOUR motor, he told you what you wanted to hear and now you 'feel better'.
Good luck!
Old 10-26-2013, 11:42 PM
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No, I gave him a ballpark. While I can't promise him my results one can make a reasonable deduction that his results would be similar. How similar? Who knows exactly, I didn't know so I measured and I have results to share with him. Weird circle of life we follow ain't it
Old 10-27-2013, 03:21 AM
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Originally Posted by 01ssreda4
No, I gave him a ballpark. While I can't promise him my results one can make a reasonable deduction that his results would be similar. How similar? Who knows exactly, I didn't know so I measured and I have results to share with him. Weird circle of life we follow ain't it
How can I argue with your logic?
The problem is that he is not going to measure and he will be taking multiple 'ballpark' guesses.
Well I've seen the results of such assemblies and sometimes it ain't pretty.
Old 10-27-2013, 10:45 PM
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Well Pred that's his choice. He has been warned and I will again: MEASURE to be safe. But in the end people do what the hell they want. I'm not losing sleep over him not listening!
Old 10-28-2013, 03:42 PM
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Pred is right .. Measure measure and measure again.. Mill the heads or whatever then flycut if need be, pretty simple.. But I wouldn't wanna take the liability if saying yes go for it.. Results may vary.. You could muff up the alignment of the cam and it don't matter anyway.. You gonna bend ****.. Measure your pushrods too!!!!
Old 10-28-2013, 03:58 PM
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Originally Posted by PREDATOR-Z
Man, why do people insist on doing things backwards?
1- install and degree cam at desired ICL.
2- Install heads you wish to run
3- measure ptv
4- Decide if clearances reasonable and then mill accordingly
5- measure ptv again after desired chamber volume and SCR reached. Watch ur DCR for type of fuel used.
great advice, totally agree!

Another thing I'll throw in there is to measure the piston deck height at TDC, and factor that into the comp ratio, quench, and gasket thickness parameters.

Old 10-28-2013, 05:45 PM
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Originally Posted by 01ssreda4
With a 228/232 .615 cam I had .120 and .100 clearance with .010 milled heads. I had them milled .030 more to cut my clearance down to .090 and .070. You should be fine.
I am assuming u were running stock pistons that were not fly cut. Is this correct?

If so then I should not have a problem unless the cam I have has been ground way off which I doubt.

For those of you who keep saying measure measure measure, I understand the importance of this, trust me more than you ever know, but the reality is that there is nothing special about my build. It's off shelf cam and off shelf head with common milling, porting and valve job. I think it's logical to gage the forum for this answer.

If you look at the quoted setup, it is a considerably more aggressive cam and milling. Remember my cam is a 228/230 .571/.573 112 LSA
Old 10-29-2013, 09:10 AM
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Yes it was/is a stock 2004 LS1 shortblock from a GTO.



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