Cam selection, duration lift etc

[zaq123]

Decided to start new thread since it's more cam than crank related.

M20 with 885 head with OEM size valves and new oem valve springs, 2.9L strocker (84mm cam with 85mm IE/Mahle pistons), Megasquirt, stock intake manifold for now.

I'm considering a few cams:
1. DBilas 284 - 11.5mm valve lit, larger than Schrick 284/272 or 288, will new oem springs survive?

2. Dbilas 276, 11.5mm valve lift - the same concern as above

3.Shrick 284/272 - 11.4/11 valve lift. Supposedly ok with oem springs but don't think I need dual pattern since my CR will be 10:1

4. IE 284°/280 11/10.7mm valve lift - I guess this is a cam IE/Mahle designed those pistons for.

Any thoughts

[digger]

this is an Alpina m20 cam approx 270 with 10.5mm lift or so vs a 288 cam on some kind of stroker in SA and was done years and years ago. this is a slightly more extreme example than your options and probably a lowish compression engine which hurts the 288 more, but basic trends are there.

Do you prefer torque at bottom end at rpm you use most often or do you like to wind it out and want performance at the topend?

The stock intake really limits how much duration you can run efficiently, its not a performance manifold only works well 3500-5500rpm so using a cam that works best closer to 7000rpm is not always a good recipe.

[zaq123]

Do you prefer torque at bottom end at rpm you use most often or do you like to wind it out and want performance at the topend?

this is going into the car that won't be be redlined 50% of the time, maybe 10% :)

seriously though, it won't be a race car ...Do you think 276 would make good match for 2.9L 10:1?


Applikation : Road 2,5 - 2,7

Duration: : 276
Peak timing: : 108
Valve lift: : 11,5
Lift at TDC: : 2,0
Valve timing: : 30/66 - 66/30
Valve clearence: : 25/25

Duration: : 284
Peak timing: : 112
Valve lift: : 11,5
Lift at TDC: : 2,1
Valve timing: : 30/74 - 74/30
Valve clearence: : 20/20

[digger]

276 is a good street cam

[zaq123]

276 is a good street cam

Dbilas 276: do you think with that much lift/short duration and as a result..crazy ramp, it won't cause durability issues when slamming around those valves like that?

[digger]

Stiffer springs like for schricks or a set from eibach wont hurt anything, as to whether stock would be upto the job long term i cant say for sure. you could email dbilas and ask for their reccomendations

[zaq123]

Stiffer springs like for schricks or a set from eibach wont hurt anything, as to whether stock would be upto the job long term i cant say for sure. you could email dbilas and ask for their reccomendations

digger, do you know how accurate is is graph?

Looks like DBilas claim their 276 has lift at TDC - 2

[digger]

It should be reasonable, it does suggest that it doesn’t match the their claims which would not be a first for a m20 cam, regardless it makes a great street cam for a mild build though, as long as youre not after a topend screamer.