Author Topic: Seat pressure  (Read 1349 times)

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Offline Clayton24

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Seat pressure
« on: February 09, 2018, 03:22:22 PM »
What would be the ideal or optimal  seat pressure on valve springs for cams under .600 lift (mild cams ) ? Thanks

Offline kd

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Re: Seat pressure
« Reply #1 on: February 09, 2018, 03:26:58 PM »
Clayton, you should indicate the cams (if you know), riding style, rpm range and the number of times you visit the rev limiter for the best possible response.
KD

Offline Clayton24

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Re: Seat pressure
« Reply #2 on: February 09, 2018, 04:31:14 PM »
Ok sorry . I have 57 h cams may go to woods 777 or s&s 585s in the future ! I do hit the rev limiter at least 1 time every day i ride hot intermittent hot rodder ! Lol. But i do want to keep valve train noise down and wear as much as possible does 140 to 150 sound legit ? Stock did work ok ! Thanks

Offline Clayton24

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Re: Seat pressure
« Reply #3 on: February 09, 2018, 05:18:28 PM »
I called andrews and they couldnt tell me !

Offline Nutoy

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Re: Seat pressure
« Reply #4 on: February 09, 2018, 05:21:19 PM »
Clayton something you should keep in mind is the rate of the spring, you need enough pressure to control the valve and lifter on the nose of the cam. If you use a spring with to low of rate you will loft the lifter off the cam at high rpm.

Offline Nutoy

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Re: Seat pressure
« Reply #5 on: February 09, 2018, 05:35:55 PM »
clayton you can have a behive spring with 130lbs on seat and 320lbs at full lift, or a duel spring with 115lbs on the seat and 360lbs at full lift.

Offline Clayton24

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Re: Seat pressure
« Reply #6 on: February 09, 2018, 05:42:12 PM »
I should have stated beehives is what i will be using

Offline Nutoy

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Re: Seat pressure
« Reply #7 on: February 09, 2018, 05:44:21 PM »
The spring I have in my motor are 130 on the seat and 385 at full lift of .580 and the motor has very little valve train noise. They are a duel spring I hope this helps.

Offline Clayton24

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Re: Seat pressure
« Reply #8 on: February 09, 2018, 09:27:42 PM »
Yes it does help i thank you!

Offline HD Street Performance

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Re: Seat pressure
« Reply #9 on: February 10, 2018, 07:32:06 AM »
No way of knowing without the valve weight and then a range at best

Online 1FSTRK

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Re: Seat pressure
« Reply #10 on: February 10, 2018, 11:53:53 AM »
No way of knowing without the valve weight and then a range at best

I would expand on this to say proper spring pressure is determined by valve train weight, cam being used and rpm range. This is one of the values of going to one of the cylinder head specialists that work with Harleys.   
"Never hang on to a mistake just because you spent time or money making it."

Offline koko3052

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Re: Seat pressure
« Reply #11 on: February 10, 2018, 11:59:47 AM »
I was afraid of opening this, thinking that Preacher had posted in the wrong section. :embarrassed:

Offline Clayton24

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Re: Seat pressure
« Reply #12 on: February 10, 2018, 05:17:04 PM »
What ever happened to spring pressure specs recommended coming on a cam card from the cam manufacturer ! Lol

Offline Ohio HD

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Re: Seat pressure
« Reply #13 on: February 10, 2018, 05:27:04 PM »
Gary Wallace at Andrews can tell you the recommended pressure. I've spoken to him several times getting info like this.

gwallace@andrewsproducts.com


Andrews
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Offline Clayton24

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Re: Seat pressure
« Reply #14 on: February 10, 2018, 05:56:45 PM »
Ok thanks ! I did call them before this thread but not sure who i talked to . I will call them again and talk to him

Offline HD Street Performance

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Re: Seat pressure
« Reply #15 on: February 10, 2018, 05:57:37 PM »
The largest contributors are the cam lobes' intensity both open and closing and the weight of the spring, retainer and valve.

Online 1FSTRK

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Re: Seat pressure
« Reply #16 on: February 10, 2018, 06:07:30 PM »
The largest contributors are the cam lobes' intensity both open and closing and the weight of the spring, retainer and valve.

And the pushrods, rockers type and ratio, lifter,  so now we are back to the entire valve train like I said.
 :doh: I tried to throw you bone there.
"Never hang on to a mistake just because you spent time or money making it."

Offline HD Street Performance

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Re: Seat pressure
« Reply #17 on: February 11, 2018, 06:57:53 AM »
We don't agree or perhaps we do but I think the majors I hit the others are of less influence but also contribute

Offline itsafatboy

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Re: Seat pressure
« Reply #18 on: February 18, 2018, 05:44:59 PM »
i run the woods 160 , with the woods 9bg and seem to run great and not so noisey, when i ran the roller x lifters and the andrews 3/8 push rods my bike would spool up faster than any HD i have seem , loved it  but just did not trust he roller x lifter being aluminum, i just wish there was a way to safely lighten the pushrod and lifter weight and still be dependable 

Offline prodrag1320

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Re: Seat pressure
« Reply #19 on: February 19, 2018, 05:22:45 AM »
for the cams you mentioned,kibblewhite or AV&V .600" lift springs will be fine, don't (or let others) over complicate stuff

Offline Clayton24

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Re: Seat pressure
« Reply #20 on: February 19, 2018, 07:50:36 AM »
Prodrag - thanks very appreciated !

Offline HD Street Performance

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Re: Seat pressure
« Reply #21 on: February 19, 2018, 08:05:00 AM »
I would not use the AV&V spring with 7mm valves and less than .600 lift. Too much preload puts undue side thrust on lifter bores and stress on rollers. I like stock beehives which I set at 1.800 +.015 -.010

Offline Clayton24

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Re: Seat pressure
« Reply #22 on: February 22, 2018, 07:15:00 PM »
I ended up using my oem beehives on the cnc heads the set up at 1,820 im hoping they will do alright ! Rev limiter is set at 6200 rpms! Thanks for every ones replies !

Offline Clayton24

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Re: Seat pressure
« Reply #23 on: February 23, 2018, 08:14:12 PM »
Ok sumthin dont seem right! I put stock springs on my se cnc factory heads installed height was 1,820 vs 1,840 on oem heads i had the front intake was 1,835 so i put a .015 shim to bring it to 1,820 like the rest so im thinkin seat pressure should be alittle more than they were at 1,840 on my oe heads. Motor is quieter which was what i was tryin to achieve and runs GREAT! Except sounds like a valve maybe floatin at 5800 rpm so now im lost uugh! Anything below 5800 is great . If any can think of sumthin i missed all help info and replies are greatley appreciated thanks ! Maybe not a valve floatin ? Im not sure what else it would be? Thanks again !

Offline Ohio HD

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Re: Seat pressure
« Reply #24 on: February 23, 2018, 08:22:38 PM »
What's the RPM limiter set to? 
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