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  #61 (permalink)  
Old 06-24-2016, 09:40 AM
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Quote:
Originally Posted by jokerZ71 View Post
No. Valve size does not have any effect on lift.
Yea thats what i thought. I talk to the mechanic that built the engine he said that cause stock heads are 1.94 n mine are 2.05 that adds .110 on the lift.

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  #62 (permalink)  
Old 06-24-2016, 09:53 AM
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X 2... Joker is correct... I suspect what the mechanic actually told you was that your valves have an overall LENGTH (not lift) 0.100" longer than stock... common with high performance aftermarket heads with thicker decks/taller springs/etc...

http://www.alexsparts.com/stainless-...-single-groove .. (+.100") ... (+.200" size is also sometimes used)

LIFT is how far the cam sends your valves down into the combustion chamber... How far it 'lifts' them off the valve seat... I know, 'lift' going DOWNwards is kinda strange...

We hotrodders also buy containers to store nothing... aka vacuum...

Last edited by BuzzLOL; 06-24-2016 at 10:06 AM.
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  #63 (permalink)  
Old 06-24-2016, 10:21 AM
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Originally Posted by BuzzLOL View Post
X 2... Joker is correct... I suspect what the mechanic actually told you was that your valves have an overall LENGTH (not lift) 0.100" longer than stock... common with high performance aftermarket heads with thicker decks/taller springs/etc...

http://www.alexsparts.com/stainless-...-single-groove .. (+.100") ... (+.200" size is also sometimes used)

LIFT is how far the cam sends your valves down into the combustion chamber... How far it 'lifts' them off the valve seat... I know, 'lift' going DOWNwards is kinda strange...

We hotrodders also buy containers to store nothing... aka vacuum...
No. He clearly said we didnt count in the valves. They are .110 difference from stock which is 1.94 and mine are 2.05 which is .110 added lift. Then he calculated in front of me 1.6 rockers x .334 lobe lift = .5344 + .110 = 6.444 lift so i know there was no confusion on my part and i also have a vacuum storage can

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  #64 (permalink)  
Old 06-24-2016, 10:42 AM
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1.94" a common stock valve head diameter
+.110 just so happens, can be other numbers
_________
2.05" .. mine are 2.080" diameter in my SBC 405" with MoTown heads...

.334" lobe lift times stock 1.5 rockers = .501" ... 1.6 rockers = .5344" .. 1.6 rockers give ~.033" more lift... ... 1.6 rockers also give slightly more effective 'cam duration' as seen at the valves... 'duration' means number of crankshaft degrees of rotation that the valves are held open... valves are held open longer than theoretically assumed (180 degrees) to give the air/fuel mixture more time to move into the combustion chamber and exhaust more time to move out... and to compensate for the 'ram effect' of rapidly moving gases...

Mechanic was confused or you heard/remembered/understood wrong...

These are the facts from this retired GM automotive engineer... draw your own conclusions...
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Old 06-24-2016, 11:03 AM
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I understand but he specifically said .110 cause i upgraded to 2.05 when stock is 1.94 and the difference of .110 in valve size must be added to max lift which didnt sound right to me at all. I also have the sheet where he did his calculations and i know i heard him correctly

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Old 06-24-2016, 11:08 AM
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All of you have been of great help and i appreciate it.

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Old 06-24-2016, 11:18 AM
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Quote:
Originally Posted by HiGhDRo View Post
I understand but he specifically said .110 cause i upgraded to 2.05 when stock is 1.94 and the difference of .110 in valve size must be added to max lift which didnt sound right to me at all. I also have the sheet where he did his calculations and i know i heard him correctly
Well then, there is only one conclusion to come to....you've been dealing with an idiot. Valve head diameter has nothing at all to do with valve lift.

Think of the valve head size as a door. If you have a 1.94" door, you can let in a certain amount of air/fuel mixture. If you have a larger 2.05" door, you can let in more mixture, assuming that the edge of the valve does not come close enough to the cylinder wall to create turbulence and thus limit flow.

All of this sutff that us hot rodders do to motors should be a balancing act to find the sweet spot in all the parts and have them act in concert to produce the most twist on the crankshaft. The sore spot in your combination is the cam. Everyone has told you that. All of us understand that you want the motor to lope like a race motor, but we also understand that using that type of cam is probably not the best way to do it. Personally, I'd like to see you sling that garbage cam over the fence and install what the motor really wants and needs, but I can't come over there and twist your arm to make you do it.
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  #68 (permalink)  
Old 06-24-2016, 11:25 AM
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Quote:
Originally Posted by HiGhDRo View Post
I also have the sheet where he did his calculations and i know i heard him correctly
I started this thread a couple days ago where I found a written mistake in an article... didn't want anyone to "learn" it... something got lost in the 'translation' from mechanic to journalist... LOL! .. it happens:

https://www.hotrodders.com/forum/deck...es-440033.html

Don't get us wrong, if the mechanic said that, he was wrong, and you are correct...

Last edited by BuzzLOL; 06-24-2016 at 11:33 AM.
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Old 06-24-2016, 11:33 AM
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Originally Posted by techinspector1 View Post
Well then, there is only one conclusion to come to....you've been dealing with an idiot. Valve head diameter has nothing at all to do with valve lift.

Think of the valve head size as a door. If you have a 1.94" door, you can let in a certain amount of air/fuel mixture. If you have a larger 2.05" door, you can let in more mixture, assuming that the edge of the valve does not come close enough to the cylinder wall to create turbulence and thus limit flow.

All of this sutff that us hot rodders do to motors should be a balancing act to find the sweet spot in all the parts and have them act in concert to produce the most twist on the crankshaft. The sore spot in your combination is the cam. Everyone has told you that. All of us understand that you want the motor to lope like a race motor, but we also understand that using that type of cam is probably not the best way to do it. Personally, I'd like to see you sling that garbage cam over the fence and install what the motor really wants and needs, but I can't come over there and twist your arm to make you do it.
Oh im gonna change the camshaft to a lunati voodoo 60101 but he trying to get me to change heads to 1.94 stock heads, change rockers to stock stamped 1.5's and the camshaft. Car is at home but he trying to get me to take it back to change all of this.

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Old 06-24-2016, 11:40 AM
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Im really starting to think he didnt check up on anything before putting the engine together. Just put it together and thats it. I couldve done that myself

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Old 06-24-2016, 11:54 AM
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Keep the heads and rockers if you can afford them... won't hurt anything with the new cam

Although 1.94"/1.5" valve stock iron Vortec heads and Summit 1.6 stamped rockers work great and save a lot of money...
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Old 06-24-2016, 11:57 AM
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Oh im keeping them. Cant afford to get another set of heads. Im not even letting that idiot touch my car again.

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  #73 (permalink)  
Old 06-30-2016, 05:24 PM
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Ok so from futher research i found out the valves in my aluminum heads are over .200
But the install spring height on both old and new heads are 1.750 which i found to be stock install spring height. Im guessing which i dont like to guess, is that the valves are over .200 to compensate for the difference in height between the alluminum and stock heads which from what i understand shouldnt add any extra lift. If i am wrong someone please correct me

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  #74 (permalink)  
Old 06-30-2016, 05:56 PM
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DON'T LET THIS GUY TOUCH YOUR MOTOR AGAIN!!! I would be really concerned about the rest of the engine & how it will hold up after hearing the remarks this "mechanic" has made.Knowing your "actual"compression ratio is very important.To calculate the compression, you need to know head chamber volume, piston volume,& how far down the bore the piston sits @ TDC,& yes, the headgasket thickness DOES MATTER. I wouldn't be surprised if the pistons are sitting .045" down the hole & a .041" headgasket is there, putting the actual SCR at 9:1, or, maybe lower.
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Old 06-30-2016, 06:00 PM
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He isnt touching my car ever again. Im just trying to gather all the correct information so i can go at it myself. Any idiot can put an engine together. The hard part is getting it to run properly which if put together correctly it shouldnt be to hard to get it to run properly.

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