Too much compression with my heads and LQ9???
11-30-2009, 08:49 AM
#41
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I pulled the cam cards on two old cams I have that have a couple of chewed lobes..... If they aren't bent, i can stick both in and will check.
#1
Grind #3715R /3717R Hr 113.0
224/228 .567/.571
XE lobes
109 intake cl
Lobe sep 113
#2
Grind # 3355/3355 HR111
236/235 .550/.550
Extreme marine lobes
111 intake cl
111 lobe sep
My guess is that I will end up with something inbetween these that will fit???
Cam #2 was picked because it was when the motor was used for road racing and provided a very flat tq curve. over 400 rqtq from 3200-6000, peaking at 434. The XE lobes started at .6xx lift for 236 duration......
Cam #1 worked well with a 5.7 cartek st II X heads 430 rqhp and 389 rwtq (from what I remember from 6 years ago....)
#1
Grind #3715R /3717R Hr 113.0
224/228 .567/.571
XE lobes
109 intake cl
Lobe sep 113
#2
Grind # 3355/3355 HR111
236/235 .550/.550
Extreme marine lobes
111 intake cl
111 lobe sep
My guess is that I will end up with something inbetween these that will fit???
Cam #2 was picked because it was when the motor was used for road racing and provided a very flat tq curve. over 400 rqtq from 3200-6000, peaking at 434. The XE lobes started at .6xx lift for 236 duration......
Cam #1 worked well with a 5.7 cartek st II X heads 430 rqhp and 389 rwtq (from what I remember from 6 years ago....)
11-30-2009, 09:45 AM
#42
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I would use the #2 cam to imprint the clay because of the .550/.550 lift .
With the 408 your going to want to get as much duration and lift as you can get .
With the 408 your going to want to get as much duration and lift as you can get .
11-30-2009, 10:30 AM
#44
you are still confusing lift with PTV problems. they are completely NOT EVER related. Everyone is trying to point this out. You are sending him on a wild goose chase. Reminds me of all the SBC guys that call in asking about a cam that is "streetable" but not one of them "high lift racing cams".
11-30-2009, 10:45 AM
#45
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you are still confusing lift with PTV problems. they are completely NOT EVER related. Everyone is trying to point this out. You are sending him on a wild goose chase. Reminds me of all the SBC guys that call in asking about a cam that is "streetable" but not one of them "high lift racing cams".
The PTV will be a function of duration and agressiveness of the lobe right? If I hit on the 236/236 cam I would then know that that is too much duration regardless of the lift based off the marine lobe profile? I hope the 224/228 cam clears since I really don't want to go smaller than that......
If I determine the clearance (or lack there of...) with the two cams, will that data be enough for me to spec the largest cam that will fit?
how much does lobe seperation and centerline effect PTV?
11-30-2009, 10:50 AM
#46
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I was only saying to use the .550/.550 for testing because the duration was higher than the other cam and it had less of a split .
I was not trying to imply that lift was the only factor .
I was not trying to imply that lift was the only factor .
11-30-2009, 10:52 AM
#47
It affects it enough that if you have probs with a cam not working at 0* then it may clear just fine installed 2-4* advanced....still get the good power of them cam, allbeit a different powerband. I would not do that though for your car. Im just pointing that out.
11-30-2009, 01:05 PM
#50
there is one piece left out from alot of the CR calculators if you want a very true reading. that one does not use deck height, rod length, compression height, or height from top of piston to first ring land. all of those things will factor in as well.
this one is a little more inclusive, plus gives good info on piston speed and how elevation and boost will effect CR. http://www.zealautowerks.com/
this one is a little more inclusive, plus gives good info on piston speed and how elevation and boost will effect CR. http://www.zealautowerks.com/
11-30-2009, 01:18 PM
#51
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now that my azz is hurting from the boning I'm taking with the LQ9 and my cylinder heads......
Looks like my comp will be too high to work well on pump gas. Can't run big enough cam to lower SCR (mine keeps comming out in the high 9's low 10's)
It looks like I have a couple options:
1. Run Lq9 with stock 317s as is with biggest cam that will fit.
2. replace pistons in LQ9 for lower compression and valve clearance to use current heads.
3. Sell Lq9 and build another motor (might as well if I have to buy new pistons and possibly rods.... I already have a Callies stroker crank anyway)
4. Buy new heads for Lq9 motor (still can't run that big a cam due to PTV)
Since money is tight, I am leaning towards Opt #1. I can always put a milder cam in it down the road and put it in my Silverado when I can afford a REAL engine.
The other options seem to not be cost effective. I bought a low mile LQ9 because I didn't want to tear it appart. I have a 5.7 block and stroker crank already.... just don't want to drop the extra $$$ to build another motor.
So much for being able to use my ported heads and stuff...... this sucks!
Now I get to search what the biggest cam is that will fit in a stock Lq9.....
Looks like my comp will be too high to work well on pump gas. Can't run big enough cam to lower SCR (mine keeps comming out in the high 9's low 10's)
It looks like I have a couple options:
1. Run Lq9 with stock 317s as is with biggest cam that will fit.
2. replace pistons in LQ9 for lower compression and valve clearance to use current heads.
3. Sell Lq9 and build another motor (might as well if I have to buy new pistons and possibly rods.... I already have a Callies stroker crank anyway)
4. Buy new heads for Lq9 motor (still can't run that big a cam due to PTV)
Since money is tight, I am leaning towards Opt #1. I can always put a milder cam in it down the road and put it in my Silverado when I can afford a REAL engine.
The other options seem to not be cost effective. I bought a low mile LQ9 because I didn't want to tear it appart. I have a 5.7 block and stroker crank already.... just don't want to drop the extra $$$ to build another motor.
So much for being able to use my ported heads and stuff...... this sucks!
Now I get to search what the biggest cam is that will fit in a stock Lq9.....
11-30-2009, 07:44 PM
#52
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now that my azz is hurting from the boning I'm taking with the LQ9 and my cylinder heads......
Looks like my comp will be too high to work well on pump gas. Can't run big enough cam to lower SCR (mine keeps comming out in the high 9's low 10's)
It looks like I have a couple options:
1. Run Lq9 with stock 317s as is with biggest cam that will fit.
2. replace pistons in LQ9 for lower compression and valve clearance to use current heads.
3. Sell Lq9 and build another motor (might as well if I have to buy new pistons and possibly rods.... I already have a Callies stroker crank anyway)
4. Buy new heads for Lq9 motor (still can't run that big a cam due to PTV)
Since money is tight, I am leaning towards Opt #1. I can always put a milder cam in it down the road and put it in my Silverado when I can afford a REAL engine.
The other options seem to not be cost effective. I bought a low mile LQ9 because I didn't want to tear it appart. I have a 5.7 block and stroker crank already.... just don't want to drop the extra $$$ to build another motor.
So much for being able to use my ported heads and stuff...... this sucks!
Now I get to search what the biggest cam is that will fit in a stock Lq9.....
Looks like my comp will be too high to work well on pump gas. Can't run big enough cam to lower SCR (mine keeps comming out in the high 9's low 10's)
It looks like I have a couple options:
1. Run Lq9 with stock 317s as is with biggest cam that will fit.
2. replace pistons in LQ9 for lower compression and valve clearance to use current heads.
3. Sell Lq9 and build another motor (might as well if I have to buy new pistons and possibly rods.... I already have a Callies stroker crank anyway)
4. Buy new heads for Lq9 motor (still can't run that big a cam due to PTV)
Since money is tight, I am leaning towards Opt #1. I can always put a milder cam in it down the road and put it in my Silverado when I can afford a REAL engine.
The other options seem to not be cost effective. I bought a low mile LQ9 because I didn't want to tear it appart. I have a 5.7 block and stroker crank already.... just don't want to drop the extra $$$ to build another motor.
So much for being able to use my ported heads and stuff...... this sucks!
Now I get to search what the biggest cam is that will fit in a stock Lq9.....
11-30-2009, 10:18 PM
#56
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11.3:1 and below have been safe on Pump gas for me before. The tune just has to be dialed in really well, plus its 93 octane in Chicago. 91 is a deal breaker.
