amazing m10 cam lope

[funcrew]

Repost? I did search first:

http://www.youtube.com/watch?v=xUhq8gFqVDc&feature=related

[LJ851]

304's should idle smooth, it's the common plenum that is upsetting that engine. Now, a 336 Schrick has an aggressive idle!

[SkiFree]

That's Ken Blasko's engine. He's doing something right because he's usually top of the pack in VARA. There's at least 8-9 2002 racing this weekend out at Willowsprings.

Here's a nice save by him a couple of months ago out at Chuckawalla.

http://www.youtube.com/user/vintagebmwracing#p/u/4/ux4m_6WQ-gU

Seven race prepped BMW 2002, plus an Alfa by andrewadamsdesign&auto, on Flickr

[funcrew]

304's should idle smooth, it's the common plenum that is upsetting that engine. Now, a 336 Schrick has an aggressive idle!

Educate me. On an M20, a 288 cam is hot enough to have substantial cam lope. Do M10's use higher-duration cams than M20? Both being ancient 2-valve engines, it seems like they would be similar as as far as cam timing. What's up?

[Ryann]

Here's a nice save by him a couple of months ago out at Chuckawalla.
http://www.youtube.com/user/vintageb.../4/ux4m_6WQ-gU

Holy shit! Very nice.

[Jaxx_]

Educate me. On an M20, a 288 cam is hot enough to have substantial cam lope. Do M10's use higher-duration cams than M20? Both being ancient 2-valve engines, it seems like they would be similar as as far as cam timing. What's up?

derp come on bro, i think you can figure this one out on your own. it doesn't have to do with valves/cyl but what is the BIG difference between an M10/M42 and M20?

[petrolhead]

derp come on bro, i think you can figure this one out on your own. it doesn't have to do with valves/cyl but what is the BIG difference between an M10/M42 and M20?

If you really have an answer to why M10 needs a lot of duration to make power / why it'll still idle with a 304 (which is a LOT of degrees for any engine) , please tell us.

What are you getting at by mentioning M42? M42 has two tiny inlets (33mm) and even tinier outlet valves (30,5) , and ofcourse with that engine you're free to try pretty much anything with valve timings (relative to each other).

As for M20 and why it throws emissions of the scale with milder cams, I suspect it has to do with most people having the timing way off (shaved head and not bothering with an adjustable cam gear).

[digger]

derp come on bro, i think you can figure this one out on your own. it doesn't have to do with valves/cyl but what is the BIG difference between an M10/M42 and M20?

4 vs 6?

dual plane m20 would be better?

[LJ851]

Educate me. On an M20, a 288 cam is hot enough to have substantial cam lope. Do M10's use higher-duration cams than M20? Both being ancient 2-valve engines, it seems like they would be similar as as far as cam timing. What's up?

Your comparison is apples and oranges. The main reason for unstable idle is overlap. You can have 288 cam with more overlap than a 304 depending on the LSA.

The main reasons a 288 is lopey on a M20 is Motronic doesn't like it and the common plenum. A M20 with ITB's would idle much better.

The same is true for the 2002 engine except it doesn't have Motronic to get upset. That same 2002 engine with sidedraft webers would idle smoothly.

My last 2002 had a 284 cam and it idled exactly like stock (264)

[Jaxx_]

it's 4 vs 6. Don't get upset. I was just trying for you to have an epiphanic moment

[funcrew]

derp come on bro, i think you can figure this one out on your own. it doesn't have to do with valves/cyl but what is the BIG difference between an M10/M42 and M20?

Bigger bore and valve size (M10)?

[visionaut]

Yeah, my 304 Schrick equipped M10 with dual DCOEs idles a fair bit smoother than that...

An M10 'symphony'