View Full Version : Need Technical Data; cam timing, balancing, etc.
Fill in the yellow blanks :-D
I could sure use some technical data regarding Stage III cam timing as I don't know if the grind has any timing mods relative to crank dead center positions. I'm guessing it's the same as stock, but prefer not to guess. So, need some expert assistance.
Also need other weight info as highlighted in yellow.
http://i190.photobucket.com/albums/z224/A26B/BrngLoadCalcSurveyMissingData.jpg
It won't let me write in the yellow so i wrote on the white.
Inlet opening primary & secondary 32
Inlet closing primary & secondary 80
Exhaust opening primary & secondary 80
Exhaust closing primary & secondary 32
Above would be set at 114.
Pete
tpepmeie
12-08-2010, 02:38 PM
It won't let me write in the yellow so i wrote on the white.
Inlet opening primary & secondary 32
Inlet closing primary & secondary 80
Exhaust opening primary & secondary 80
Exhaust closing primary & secondary 32
Above would be set at 114.
Pete
292 degrees seat duration? I didn't think Stage III's were that large. I had 283 or 285 degrees in my head for some reason. Has anybody actually measured these? I am glad Jerry is asking, because seat duration is the important figure impacting performance of the cams. 0.050" is nice to know, and how they are advertised, but lots of intake / exhaust flow happens from zero to .050.
Seat duration, for hydraulic lifter cams, is usually measured at 0.004" lobe lift to account for some lifter deflection.
Todd
Todd, i was just doing an estimate of what it is.
If at 285 i would minus 3 degrees on either side.
I will have the Stage III's measured,i know i had the Stage II's checked i just don't remember what they were i have the info somewhere.
Todd,do you remember what the Stage II's were? that might give some insight.
Jerry,can i ask you why the interest on cams.
Pete
Pete, Todd & Ryan,
Thanks for chiming in in this. I can't think of any better guys to call on!
Pete,
The info is for bearing load calculations.
Any idea when you might get the Stage III cams measured?
tpepmeie
12-12-2010, 12:08 PM
Jerry,
I weighed up a stock 90 bottom end parts. The pistons actually came it at an average 710g, but close enough to your figure. Range was 708-713.5g.
I had in my notes around 538g for rotating weight on the rods. I didn't measure it, though, so can't be sure where I got that from. Probably took the % from a prototype lotus build sheet I saw. Should get you pretty close. That includes the bolts.
Jerry,
I weighed up a stock 90 bottom end parts. The pistons actually came it at an average 710g, but close enough to your figure. Range was 708-713.5g.
My sampling of bare piston weight:
"A" pistons @ 483~487gr, avg of 484gr
"B" pistons @ 479~483gr, avg of 482gr (2gr lighter)
Pins, retainers & rings are much more consistent, so the variance probably comes down to the bare piston and the basis GM used for sorting pistons in "A" & "B" groups.
I had in my notes around 538g for rotating weight on the rods. I didn't measure it, though, so can't be sure where I got that from. Probably took the % from a prototype lotus build sheet I saw. Should get you pretty close. That includes the bolts.
Much needed info Todd. Thanks!
flyin ryan
12-13-2010, 12:00 AM
seat duration is the important figure impacting performance of the cams. 0.050" is nice to know, and how they are advertised, but lots of intake / exhaust flow happens from zero to .050.
I'll use the spread between 'Seat' & '.050"' to sometimes gauge how aggresive a cam is...Or at the same time, lazy. How much overlap & how much cylinder pressure may be staying in the chamber or being lost. Still doesn't beat measuring, but if you only have a cam card to look at it can help give a guy a little of the characteristic's of a particular cam grind.
This is some information I dug up out of my files. I don't have any reference point for valve seat/opening, but from the short durations, I would imagine 0.050".
Stock Cams
Intake .214 .229 .389 .389
Exhaust .214 .214 .389 .389
SGC Cams
Stage I .228 .228 .415 .415
Stage II .237 .237 .440 .440
Stage III .242 .242 .450 .450
LPE Cams
A Cams
Intake .221 .236 .399 .445
Exhaust .221 .221 .399 .399
B Cams
Intake .239 .239 .445 .445
Exhaust .221 .221 .399 .399
C Cams
Intake .239 .239 .445 .445
Exhaust .239 .239 .445 .445
This is some information I dug up out of my files. I don't have any reference point for valve seat/opening, but from the short durations, I would imagine 0.050".
Stock Cams
Intake .214 .229 .389 .389
Exhaust .214 .214 .389 .389
SGC Cams
Stage I .228 .228 .415 .415
Stage II .237 .237 .440 .440
Stage III .242 .242 .450 .450
LPE Cams
A Cams
Intake .221 .236 .399 .445
Exhaust .221 .221 .399 .399
B Cams
Intake .239 .239 .445 .445
Exhaust .221 .221 .399 .399
C Cams
Intake .239 .239 .445 .445
Exhaust .239 .239 .445 .445
Looks about right Jerry
I would like to know the power difference between LPE B and C cams.
I have tested SGC Stg II's In & Ex replaced exhaust with a .224 .420 picked up 25RWHP,i'm starting to think we don't need more then .225-+ exhaust cam.
Pete
tpepmeie
12-13-2010, 12:21 PM
Looks about right Jerry
I would like to know the power difference between LPE B and C cams.
I have tested SGC Stg II's In & Ex replaced exhaust with a .224 .420 picked up 25RWHP,i'm starting to think we don't need more then .225-+ exhaust cam.
Pete
I have in my notes, from an old LPE catalog, that they also made a larger cam. 244 or 246 duration @ .050, and .454" lift. Anybody else heard of those? I've long since thrown the catalog away.
SAM/CH ZR-1
12-15-2010, 04:52 AM
This is some information I dug up out of my files. I don't have any reference point for valve seat/opening, but from the short durations, I would imagine 0.050".
Stock Cams
Intake .214 .229 .389 .389
Exhaust .214 .214 .389 .389
SGC Cams
Stage I .228 .228 .415 .415
Stage II .237 .237 .440 .440
Stage III .242 .242 .450 .450
LPE Cams
A Cams
Intake .221 .236 .399 .445
Exhaust .221 .221 .399 .399
B Cams
Intake .239 .239 .445 .445
Exhaust .221 .221 .399 .399
C Cams
Intake .239 .239 .445 .445
Exhaust .239 .239 .445 .445
Jerry
Aaron gaved me some time ago the following specs about his cams.
Stage 1 .230 .230 .420 .420
Stage 2 .236 .236 .440 .440
Stage 3 .242 .242 .454 .454
I post in the next weeks a dyno sheet about my customers 427 with stage 3 cams.
Sam
Jerry
Aaron gaved me some time ago the following specs about his cams.
Stage 1 .230 .230 .420 .420
Stage 2 .236 .236 .440 .440
Stage 3 .242 .242 .454 .454
I post in the next weeks a dyno sheet about my customers 427 with stage 3 cams.
Sam
Hi Sam,
I wonder if my data is wrong or if he may have modified the grind a bit.
Looking forward to the 427 results!!
Jerry
Aaron gaved me some time ago the following specs about his cams.
Stage 1 .230 .230 .420 .420
Stage 2 .236 .236 .440 .440
Stage 3 .242 .242 .454 .454
I post in the next weeks a dyno sheet about my customers 427 with stage 3 cams.
Sam
I measured the Stage II's from what i remember they are .237 no big deal for 1 or 2 degrees.
Most tuners will say 1 or 2 degrees difference just so they are different from there competitors cam grind.
It could be same cam and same manufacturer most customers don't check/measure cams.
Pete
flyin ryan
12-16-2010, 10:50 AM
Most tuners will say 1 or 2 degrees difference just so they are different from there competitors cam grind.
It could be same cam and same manufacturer most customers don't check/measure cams.
PeteTrue story. I measure every single cam(s) I install. Sometime the numbers can be surprising, right along the lines as what Pete mention's.
vBulletin® v3.8.11, Copyright ©2000-2025, vBulletin Solutions Inc.