Thread:

Cam intake center line advice

I could use some icl advice for a 540 street strip engine i'm buliding it is 10.8 compression, afr 315 heads, the cam is a Lunati Voodoo sold roller with 255* 263* at .050 with .680 lift and on a 110 lobe seperation angle, the cam card calls for the icl to be set at 104 but that would be 6* advance which just seems like a lot to me but I live at 5500 feet so maybe a little extra advance is better, I've call Lunati and one guy said to go 106 or 108 and another guy said to stay with the 104 so any help from you cam gurus would be great
Thnks John

Originally Posted by sport

I could use some icl advice for a 540 street strip engine i'm buliding it is 10.8 compression, afr 315 heads, the cam is a Lunati Voodoo sold roller with 255* 263* at .050 with .680 lift and on a 110 lobe center, the cam card calls for the icl to be set at 104 but that would be 6* advance which just seems like a lot to me but I live at 5500 feet so maybe a little extra advance is better, I've call Lunati and one guy said to go 106 or 108 and another guy said to stay with the 104 so any help from you cam gurus would be great
Thnks John

I think your confusing the lobe seperation angle of 110* with the recommended 104* intake centerline.
Lobe sep. angle is degrees from intake lobe centerline to exhaust lobe centerline. The 104* intake centerline is a reference from TDC of the piston to the exact centerline of the intake lobe.
Advancing the cam will ususally give a little more bottom end and maybe kill a tiny bit of top end, retarding does the opposite. Check piston to valve clearances. Advancing/retarding changes clearances.
I would stay with the 104 myself.

Sorry I ment 110 LSA, I would like to get a little more top end because I think it is going to have alot bottom end any way and the car is a 69 camaro so it is not that heavy, I am hoping to get peak power in the 6300-6500 range, I'm just not sure how much differance 2* will make.

Run it like it is. Nothing wrong with that cam and your combination.
Just out of curiosity, where does the intake open and close?

Originally Posted by steelcomp

Run it like it is. Nothing wrong with that cam and your combination.
Just out of curiosity, where does the intake open and close?

I'll second that.


S CP

Originally Posted by sport

intake opens at 23.5* closes 51.5* at .050 so are you saying run it at the recommended 104 ICL

Luke here is how I came up with 10.8
custom JE piston 19cc dome
Bore 4.5
Stroke 4.25
Head gasket .039 X 4.540
Piston down in the hole .005
Head volume 120cc
what do you come up with

Yep. I'd leave it right where it is. Compression is correct. If you take into consideration the area around the piston above the top ring it might be 10.78...close enough.

Originally Posted by Sleeper CP

I'll second that.


S CP

x3 on the cam being ok . would think in your camaro if your intake and exhaust are working i'd go with 108 ic/l

Originally Posted by luke

sport,

I don't doubt that your math is correct, I think my point is that 90% of people that bring their motor in to me when I check it the compression it's almost always lower then they think it is. That being said I always fill the cylinder up when motor is fully assembled and CC it that way, I just think that is more acurate. Anyway a half point either way is not the real issue I see. I think that 255@ .050 means the cam wants to run in the 7500 rpm range. I think if you are going to error I would rather error towards the small and of the scale. A cam with 245@ .050 would probably be a much better selection and on a 106-108 would be much funner to drive and act like a raped ape to 6500.
Just my thinkin, good luck

luke

Keep in mind that this thing is 540 CI... 245 @ .050 might get you to the grocery store or church on sunday .... 255 @ .050 WILL pull to 7500RPM.... in a small block... JMO...

Originally Posted by luke

sport,

I don't doubt that your math is correct, I think my point is that 90% of people that bring their motor in to me when I check it the compression it's almost always lower then they think it is. That being said I always fill the cylinder up when motor is fully assembled and CC it that way, I just think that is more acurate. Anyway a half point either way is not the real issue I see. I think that 255@ .050 means the cam wants to run in the 7500 rpm range. I think if you are going to error I would rather error towards the small and of the scale. A cam with 245@ .050 would probably be a much better selection and on a 106-108 would be much funner to drive and act like a raped ape to 6500. Just my thinkin, good luck

luke

Curious how you know this simply by the .05 numbers.

Originally Posted by sport

Sorry I ment 110 LSA, I would like to get a little more top end because I think it is going to have alot bottom end any way and the car is a 69 camaro so it is not that heavy, I am hoping to get peak power in the 6300-6500 range, I'm just not sure how much differance 2* will make.

You still arent getting it. The LSA is ground into the cam and cant be changed. The ICL is where the cam is in reference to the crank and can be changed. Stick with the 104 that the card asks for.

When doing the NASCAR engines they had to be no greater than a certain compression, to prevent embarrassment and loosing a race due to over compression we whistled every engine! This is done with rocker arms off and engine temperature as close to operating range as possible.

Good luck!