Big cam, stiffer valve springs needed?

[CorvallisBMW]

I'm looking at getting the IE 284 duration cam. IE also makes a set of dual valve springs that they say are recommended with any high-lift cam. Does this seem accurate? 284 doesn't seem too exotic and I'd love to save the $400 it would cost to buy new springs and retainers.

[Ryann]

Do a lot of high RPM driving? What kind of shape is your current valve train in? What's the cam's lift spec over stock?

[CorvallisBMW]

Do a lot of high RPM driving? What kind of shape is your current valve train in? What's the cam's lift spec over stock?

-Not really, it's just a cruiser
-Clean enough to eat off of
-Don't know, IE doesn't publish details

[Ryann]

-Not really, it's just a cruiser
-Clean enough to eat off of
-Don't know, IE doesn't publish details

Without knowing the lift specs it's tough to say how aggressive the grind is over stock, but unless you're planning on flogging the car you should be fine with stock springs.

On the other hand why spend the money to shift your power band Northward in a cruiser?

[Bearmw]

I'd call IE and talk to Jeff. I have a cam that has .440 lift at intake valve and .430 lift at exhaust valve and advertised duration of 280 intake and 278 exhaust with new B-35 springs with no problem.

[Good & Tight]

I would contact Paul Burke about a cam before buying a regrind from IE. Info@bmwpowerparts.com.

[LJ851]

i would contact paul burke about a cam before buying a regrind from ie. info@bmwpowerparts.com.

yes.

[ZM Blue Devil]

yes you will need stiffer springs

[SkiFree]

Think we talked yesterday over the phone?

[Lurker27]

I was told that you won't need new springs if you have an m30b35 head, which already has dual valve springs. You WILL need oversize adjusters

[Bearmw]

I agree with Otis on the Paul Burke idea. Do your research but I ended up with one of Paul's N21 grinds with no oversize eccentrics needed. Big improvement over the stock B-35 piece.

[VinniE30]

I've got the schrick 284/280 cam.
Is this 284 degree IE cam the same one? Or supposedly to the same spec?

I can't speak about the IE 284 cam but the schrick 284 is known to be not much more agressive than the stock M30B35 cam.
Heres some actual data and charts to that regard:

http://www.mye28.com/viewtopic.php?t=26596

BMW probably underrates their cam specs or measures them in a slightly different way. So comparing a 284 cam to the stock B35 264 cam isin't what the numbers "284" and "264" suggest, since they are measured differently by different companies. You would actually have to measure them in the same way, like Devinder did.

It's easy to just say yes get the upgraded valve springs because they are stronger than the stock ones. But to be honest I would say you don't need them.
The B35 cam is the most agressive stock M30 cam and it has dual valve springs that were built for its cam and over-engineered just like most other engine parts. The slightly more agressive 284 cam would be fine with the stock springs. As you can see by the data the lift isin't much more than stock.

That said, I think the schrick cam definitely wakes the m30 up, it pulls noticeably harder, especially at higher rpms. But I modded the m30 in other ways at the same time so it's hard to say if it was mostly the cam or other things. Either way it's pretty fast.

[wannaBMthree]

Add Rocker Locks:

http://www.vacmotorsports.com/catalo...s--collars.htm

[VinniE30]

Add Rocker Locks:

http://www.vacmotorsports.com/catalo...s--collars.htm

Yes! Definitely get the rocker locks. I got these because of the broken rocker stories I read on the forums and the cause being the rockers having that lateral play from the springs. The stock rockers are actually very good, the reason for them breaking if you ever hear about them breaking is almost always because they move around the shaft at higher RPMs since the springs aren't strong enough to hold them perfectly still in place.
If I find any of the threads later i'll post them here.

[SkiFree]

Add Rocker Locks:

http://www.vacmotorsports.com/catalo...s--collars.htm

or here...

http://www.iemotorsport.com/bmw/E28-E24-valvetrain/02rockerlock.html

Looks like VAC stole some pictures!