hey, my buddy and I are trying to figure out a good cam for his car.
hes got a stock bottom end, and bought a set of used LE2 heads.
I was looking at the comp lobe chart and picked the following:
-------------------.006"--.050"--.200"
Intake Duration - ID 276 | 224 | 152 | comp 3192 XE lobe .605” w/ 1.6
Exhaust Duration - ED 282 | 230 | 157 | comp 3194 XE lobe .622” w/ 1.6
Lobe Center Angle - LSA 110 | 110 | 110
Intake Centerline - ICL 110 | 110 | 110

Intake Valve opens - IVO 28 | 2 | -34 | BTDC (- indicates ATDC)
Intake Valve closes - IVC 68 | 42 | 6 | ABDC
Exhaust Valve Opens - EVO 71 | 45 | 8.5 | BBDC
Exhaust Valve Closes - EVC 31 | 5 | -31.5 | ATDC (- indicates BTDC)
Exhaust Centerline - ECL 110 | 110 | 110 |
Overlap 59 | 7 | -65.5 | degrees

hows that look?

I also need to know what the stock LT1 piston dish is. I used 7cc as a guess.

then I used the following:
Bore 4"
Stroke 3.48"
Rod Length 5.7"
Number of cylinders 8
Deck Height 0.02
Piston Dome or Dish 7
Compressed Head gasket thickness 0.026 mr gaskets
Cylinder Head Chamber Volume 55cc (also a guess, mine are 55cc so im thinking his are)

static compression ratio: 11.03:1
dynamic compression ratio: 8.56:1 with the IVC at 68 ABDC

basically looking for strong mid range torque and good top end without spinning the engine too high, since this is a stock bottom end. idle quality isnt a big issue but it shouldn't be too bad with only 7 degrees of overlap at .050. my LE3 cam had more than triple that

theres also lower lift lobes that are .536" intake and .544" exhaust that also cuts the .200" duration from 152 to 145 for the intake and 157 to 151 for the exhaust. trying to maximize area under the curve so I'd rather use the high lift lobes.


hows that look?

1racerdude, waiting on you

 

If the valve reliefs will take it, it looks good.
The stock 4 valve relief pistons are more like 8CC's. If there was someway to bring the DCR compression up .30+ it would be some better.
Don't get into a big head milling project to do it.
Get the intake ported and matched and run a K&N CAI with the 12" long filter and a 58MM TB.
The more lift the better IF ya got the P/V clearance. Get some beehive springs(if ya have none already)If ya got springs and they are right for the lift and coil bind and pressure then no need to change.Make sure ya got good retainers.
Put 150 on the seat and 375 on the nose as they will loose 15/20lbs after break in.

 

I come up with 10.76 Static and 8.36 DCR.
If ya advance that cam +4* ya get 8.63 DCR.

 

Thanks for the help guys (we're choosing this cam for my car). All those numbers are just mumbo jumbo to me, but I'm learning, I swear!

 

Good luck with it.

 

Is it too obvious to suggest that you ask Lloyd Elliott (Mr. LE) who ported the heads to recommend a cam to match them and your car?

www.eportworks.com

Depending on your other mods, gears, trans, etc. you might be a good candidate for an LE-1 or LE-2 cam.

Or you could pick out one, or two or five yourself and try each to see what one suits your situation.

Good luck to you.

 

I guess we just like to figure things out for ourselves, although I would trust Lloyd just as soon as I would trust my friend.

 

Don't let ego get in the way of power I always say. Well, I've said it at least once now.

You could always slip in the cam Lloyd recommends and tell folks you picked it yourself. When they ask you for the specs, tell them they are secret...you won't be lying.

 

Haha, I shot Lloyd an email just to see what he suggests.

 

Is it possible to decode the mess of numbers at the top for me, I too have no idea what they mean. Unless it would still be over my head than never mind

 

I did not know that if you bought a set of lloyd's heads used that you could get a cam directly from him. I'd rather see spitfire go that route than use something I picked out.

 

Ok I'll try and help you out the best I can.
if I missed anything/screwed something up theres plenty of people on here infinitely more knowledgeable than I that can help you out.

 

Thanks, but that post confirmed I'm a dumb****

 

I changed to 8cc valve reliefs. did you use a deck height of .025? I forgot if it was .020" or .025" stock but when I put in 8cc and .025" I get the exact same numbers as you.
I didn't want to go really high on the DCR since he has a stock radiator/cooling system with a 160 degree thermostat. I remember a while back you suggested running close to 9:1 with a GOOD cooling system. I don't know what your definition of good is but I wanted to play it on the safe side.
we aren't really in a hot area but it gets to 95-100 tops in the summer. would the cooling system be able to handle that or should we stay on the safe side? upgrading the radiator would be out of the budget really.
also the quench is a little on the high side at .051 with a .025" deck height and a .026" gasket.

oh and advancing the cam 4 degrees, basically changing the intake centerline from 110 to 106, right?

 

And a electric waterpump.