#21  
Old 10-19-2021, 07:32 AM
Chris-Austria Chris-Austria is offline
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so if I get Scorpion Race rockers with 1.65 instead of my 1.5 I should be fine?
if it moves toward the stud, I think there is some space, since it seems to be little off center at the moment with a tendency towards the other direction

  #22  
Old 10-19-2021, 09:04 AM
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looks pretty good but of course you gotta roll it over to see the entire cycle. ALSO NOTE: just because 1 clears does NOT MEAN THEY ALL DO. You are dealing with a cast opening NOT A MACHINED opening. They don't always end up "exactly" where planned....but they do end up in an acceptable place.

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Old 10-19-2021, 09:18 AM
Chris-Austria Chris-Austria is offline
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you're right, I checked some that I can easily see and they all seem to look like on the picture... but I cannot confirm that for all 16
it's good to know, that they tend to point more towards the other direction, which will give more clearance after moving them towards the studs

I'm a little bit more willing risk it and just buy a complete set and hope for the best the heads flow charts show, that they flow about 270 at .060 and 258 or so at .050... I should have bought ported heads... but I don't want to remove them and send them in at the moment

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Old 10-19-2021, 10:32 AM
Steve C. Steve C. is offline
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"the heads flow charts show, that they flow about 270 at .060 and 258 or so at .050.."

?????

What part number Edelbrock heads are in use here ?

Flow numbers here:

https://www.edelbrock.com/cylinder-head-flow-data


.

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Last edited by Steve C.; 10-19-2021 at 10:42 AM.
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Old 10-19-2021, 11:10 AM
Chris-Austria Chris-Austria is offline
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I think its 61599… but I got the test results from Motortrend which seem to be a little different from the otter flow chart.. but they are pretty close

  #26  
Old 10-22-2021, 05:53 AM
Chris-Austria Chris-Austria is offline
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A general question when increasing valve lift with 1.65 rockers:

How can I know how much lift the valve springs support apart from calculating coil bind? (which will be fine with my combination)
Do I need a certain amount of spring pressure for lets say .594 valve lift?
My pistons have -15cc and block is not zero decked, so I guess the distance valve to piston shouldn't be a problem with less than .600 valve lift.
Heads are d-port Edelbrock with stainless valves that came with it.

Any other things I should check?

  #27  
Old 10-22-2021, 06:26 AM
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The rule of Thumb is that for instance if the spring has 6 full coils then you want a minimum of .010" between each coil at max lift.

So with 6 coils you would want to be .060" away from what the springs are rated at .

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  #28  
Old 10-22-2021, 06:41 AM
Chris-Austria Chris-Austria is offline
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so the biggestet concern is coil bind, valves or other parts will not have trouble with more lift?

I think there are 6 coils so I would need to calculate 1.800 - 1.150 - 0.060 = 0.590
The max lift on the exhaust will be 0.594.

So I'm 0.004" closer than you say or 0.0007" at every coil. Springs are brand new, so I wouldn't like to change them again.... (Edelbrock 5845)

  #29  
Old 10-22-2021, 06:57 AM
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serwas Herr Fast-Furious ;-)

nice to see you here as well.

lg, Karl

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  #30  
Old 10-22-2021, 08:11 AM
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How your push rod geometry is set can change the total amount of lift by .020" in some cases.

If you want total peace of mind then check your actual amount of lift at the valve, as you may have only .585", or .600".

If it turns out that your right at .594" lift then I would not fret over that as with the motor running stuff bends a easy .003".

You'd be surprised with Aluminum heads to check your total amount of lift cold and then with the motor up at normal temp.

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  #31  
Old 10-22-2021, 08:38 AM
Chris-Austria Chris-Austria is offline
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I was told that most times the total lift is a little less than what you would expect by using only "theoretical" specs in the calculator.. with .594 lift I'm still .056 away from coil bind, so using the numbers from your post I should be safe (as long as total lift is not more than lets say max .600

  #32  
Old 10-22-2021, 08:42 AM
Chris-Austria Chris-Austria is offline
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Quote:
Originally Posted by exotec View Post
serwas Herr Fast-Furious ;-)

nice to see you here as well.

lg, Karl
hey Karl,

so klein ist die Welt

good to see I'm not the only Austrian who likes this forum! have a good one

Chris

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