BA
Pro
Posts: 1592
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posted June 05, 2005 08:38 AM
Stock Cam Timing numbers
Does anyone have the stock cam timing numbers? ie. valve opening and valve closing numbers? (intake and exhaust)
I'll try a search on old posts later tonight when I can put some good time into it.....
Thx!
  
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rac4it
Needs a job
Bergie
Posts: 3009
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posted June 05, 2005 05:52 PM
Should be in the service manual
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oldkawboy
Needs a job
Posts: 2125
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posted June 06, 2005 04:10 AM
BA,
Mine were at 104/102 best I remember.
Dan
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BA
Pro
Posts: 1592
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posted June 06, 2005 10:26 AM
 Edited By: BA on 6 Jun 2005 11:26
they weren't in my service manual Bergie. I looked, a lot.
Cam specs on the order of valve openings aren't usually in the book to the best of my knowledge. :-/
Sometimes the overlap, or the centerlines, like Dan mentioned, are in there.
On that note, I was thinking of using a 103I/105E, due to old posts I've read here.
But, back to the Opening and Closing numbers, they would be much much lower.
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rac4it
Needs a job
Bergie
Posts: 3009
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posted June 06, 2005 10:46 AM
See I knew I could get you to go look in that book for no reason 
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BA
Pro
Posts: 1592
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posted June 06, 2005 11:23 AM
You Suck Bergie!!! :-) lol!
anyone else?!?!
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Lorcan
Expert Class
Posts: 327
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posted June 07, 2005 03:13 AM
It's in the book 
Inlet
Open 46 BTDC
Close 74 ABDC
Duration 300 degrees
Exhaust
Open 69 BBDC
Close 45 ATDC
Duration 294.
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BA
Pro
Posts: 1592
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posted June 07, 2005 04:35 AM
I Know my eyesight is going and going fast, but, I found all kinds of specs and couldn't find it!
Thanks Lorcan!
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psycho1122
Pro
Posts: 1608
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posted June 07, 2005 07:16 AM
Why Run the 103/105 combo??
____________
You say PSYCHO like it's a BAD thing!!
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BA
Pro
Posts: 1592
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posted June 07, 2005 08:58 AM
well, my goal is to have ideal numbers for drag-racing, as opposed to a need for mid-range torque to pull out of corners. My drag times would probably benefit more from increased centerline, wouldn't it?
So, that being said, the 103I / 105E is what I have read from old posts here as an ideal setting.
***IF IT"S NOT DESIREABLE, I NEED INPUT!!!
I seem to recall that you used something more like 101 or 102 on your 1270, is that right? You definitely had some impressive numbers, but, you also had a better than normal static compression ratio right? (i don't remember the exact CR)
all input/thoughts are appreciated!
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BA
Pro
Posts: 1592
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posted June 07, 2005 09:01 AM
just saw this in your new thread:
"I am currently running 105 in / 100 ex. on my 1270 and my cold psi is 245 a hole."
Compression ratio?
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psycho1122
Pro
Posts: 1608
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posted June 07, 2005 09:08 AM
The #'s were and are 105 in. / 100 ex.
The current engine with the "New" cam chain has a cold compression # of 245 psi per hole!
Even though the engine Architecture remains the same.
TOO MUCH. GREAT Torque, but peak power (190) occurs at 10,300 rpm.Then it drops off all the way to redline. That is too soon on this engine. I have 1,200 wasted rpm for stock gearing.
I feel that bleeding off some pressure(10 psi) might free up more HP above 10,300. Hopefully not removeing too much TQ.
Anybody want to contribute??
____________
You say PSYCHO like it's a BAD thing!!
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BA
Pro
Posts: 1592
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posted June 07, 2005 11:08 AM
from what humbly little I know about cam timing, I think you are in the right direction.
I would think that the tight exhaust timing you have is boosting torque, and thereby limiting the upper rpm "breathe-ability".
Creating more intake/exhaust overlap would certainly bleed some of that off, but here I'm trying to apply old-school V8, single cam knowledge to a DOHC engine.
Having the exhaust do it's chores later in the cycle would seem to help upper rpm breathing while sacrificing some low-end.
Hopefully some peeps smarter than I will chime into these threads. I need to feel good about the 103/105 timing on a 1290.
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