OEM vs HD rockers with Schrick 284/272 Cam

[E30-TourZing]

Hello E30 Wizards!

I am about to assemble my cylinder head and I have been loosing sleep for the past few nights on my decision to install OEM rockers vs HD rockers.

Specs
- 885 Head
- M/M recomended outer valve springs. (Apparently the revised version of beehives)
- Schrick 284/272 Cam
- OEM BMW rocker arms


Now my fear is that I break a rocker and it ruins my cam. HD rockers are something I looked into a great deal before, but after a lot of reading I decided stock would be okay. I am just second guessing myself.

I will not be racing my car, but I do expect it to be driven aggressively from time to time. Ideally my redline is at 7k. Perhaps with ITB's and a standalone next winter I will want a bit more.

I saw digger pointed out that 280/272 cam was not stressing out OEM rockers that much. He states 288 and above will show stock rockers some stress. Is that a claim others can agree with?


Advice - Should I be okay to use OEM Rockers? Or am I an idiot, and should invest in some HD rockers based on my build?

[AWDBOB]

New cam = new rockers. If your "OEM" rockers are used, you 100% should replace them when running a new cam.

New OE rockers are more than HD rockers, so HDs are the obvious choice there.

Febi/INA (same part) aren't *that* much less than HDs and the Febi/INA quality is spotty as of late, so I'd still vote for HD rockers.

Also, I don't know if you're putting that head/cam on a stock bottom end or not, but FYI if you are, check PTV. You may need to flycut your valve reliefs if so for clearance.

[mikey.antonakakis]

I'm running a 885 head on fully-eta bottom end with a 280/280/11mm cam (Enam Z45 turbo). Pistons and valves didn't hit, but clearance was tight so I cut the reliefs deeper. Also running HD rockers, essentially for the reasons given by AWDBOB, and also because I think I went with stiffer valve springs. No issues so far with a 7k redline after a few thousand miles. I lost my eccentric nut on the #6 exhaust at some point and had like 1/4" valve clearance (and a couple others loosened up with similar reaults). Rockers handled that just fine.

[digger]

OE Genuine BMW rockers will be fine, as for OEM this is not a part to be cutting cost on IMO. i know many have done it successfully though

its important to have
- the lash set correctly so the cam does not try and pound the valve open, it needs to be a gentle takeup of clearnace and set down onto seat loose clearances hugely pounds things.
- and to have appropritae valve springs to control the system so the valve doesnt float and then bounce off the seat. i'd always replace valve springs with performance cam even with a mild with just OE springs or light upgrade. depends on exact cam obviously
- have appropate rev limit/cutout paramaters, ign cut can sometime causes issues if you get alot of combustion in the exhaust due to the unburnt fuel. probably low risk as i think some OE stuff had ign cut but these days why risk it

HD have lots of issues in the past (pads falling off, the pad too short and digs into cam when you use large agressive cams) but these seem to have been resolved.

[dvallis]

I'm using that same cam. +1 on the HD rockers and upgraded valve springs

[Lugnuts]

FWIW, does the Schrick warranty state new rockers must be used?

[ForcedFirebird]

Used rockers can be reconditioned and must be ground when installing a new camshaft. We use OEM rockers in the race cars, 7100 RPM, and they have been reground several times. In the last ~7-8yr we have broken one OEM rocker and one HD rocker (pad came off several years ago).

[jeffnhiscars]

Used rockers can be reconditioned and must be ground when installing a new camshaft. We use OEM rockers in the race cars, 7100 RPM, and they have been reground several times. In the last ~7-8yr we have broken one OEM rocker and one HD rocker (pad came off several years ago).

This 100%. When we did the 731swap we bought new febis and sent them back since the eccentric holes were all drilled in different places and there was tons of casting flash. I sent the originals rockers out for a regrind and saved about $100 as a bonus. The wear faces are case hardened all the way through so a regrind is really a no brainer IMO

[ForcedFirebird]

This 100%. When we did the 731swap we bought new febis and sent them back since the eccentric holes were all drilled in different places and there was tons of casting flash. I sent the originals rockers out for a regrind and saved about $100 as a bonus. The wear faces are case hardened all the way through so a regrind is really a no brainer IMO

I have the machine to do it about 12 feet away from me as I type this lol. If you guys even need regrinds, we can take car of them here at work. :)

[E30-TourZing]

Thank you everyone for your responses!

The rockers I have came from a 325e with less then 80,000 km's and they look perfect. The pads look as super smooth and consistent, no signs of metal coming up to the top of the cylinder head and running through their function.

Do most machine shops recondition rocker arms?

I emailed Bimmerheads and likely will buy some HD rockers tomorrow. Are they the company to get them from? Or is there a better quality item at a similar price point?

[jeffnhiscars]

I have the machine to do it about 12 feet away from me as I type this lol. If you guys even need regrinds, we can take car of them here at work. :)

Glad to hear that as I shipped my last ones across the country.

[ForcedFirebird]

Thank you everyone for your responses!

The rockers I have came from a 325e with less then 80,000 km's and they look perfect. The pads look as super smooth and consistent, no signs of metal coming up to the top of the cylinder head and running through their function.

Do most machine shops recondition rocker arms?

I emailed Bimmerheads and likely will buy some HD rockers tomorrow. Are they the company to get them from? Or is there a better quality item at a similar price point?

If the machine shop has an older valve facing machine, it should have the attachments to do rocker arms. Often times the rocker side of the grinder doesn't get used, so the parts get lost etc since they share the same tool post as the valve tipping wheel. If the post is set up, it literally takes minutes to do them...

https://www.youtube.com/watch?v=k5CV3pv1Bgo

My machine works a little different, but same concept.

It really takes longer to set the machine up and square the stone than it does to grind a rocker pad. I would suggest getting them refinished, even if they "look" perfect. You would be surprised what shows up once the are squared.

[nando]

I've had Febi rockers, new stock valve springs, and the 284/272 for ages (obviously, my valve springs aren't new anymore). Of course, this was 16 years ago, so who knows what the quality is like now - I'd go HD probably. I don't think upgraded valve springs are needed with the 284/272, but you can do whatever you want.

[ForcedFirebird]

Thank you everyone for your responses!

The rockers I have came from a 325e with less then 80,000 km's and they look perfect. The pads look as super smooth and consistent, no signs of metal coming up to the top of the cylinder head and running through their function.

Do most machine shops recondition rocker arms?

I emailed Bimmerheads and likely will buy some HD rockers tomorrow. Are they the company to get them from? Or is there a better quality item at a similar price point?

Even though they "look" good, they need to be refinished for a new cam (and technically if you change them from lobe to lobe).

It's hard to capture since so little is being taken off. Tried using some layout dye but the coolant in the machine washed it off the pad for the most part.

Used rocker (m30, but same concept):



One brush on the grinding wheel:


Second pass:


And the Souix machine:

[jeffnhiscars]

There ya go