Bimmerheads reground cams?

[ThatOneEuroE30]

Very high-tech compared to most of us low life's that use an old head. :(

lol

Pretty much lol

[ForcedFirebird]

Thats bloody brilliant

Very high-tech compared to most of us low life's that use an old head. :(

lol

[ThatOneEuroE30]

Thats bloody brilliant

[Kershaw]

[ForcedFirebird]

Very clever. Might have to steal something like that for the flow bench valve opening fixture. Right now have a piece of aluminum that bolts across the valve cover studs and has a set screw to slide shims under for quick testing at per-determined valve lifts. Something like you made would make a lot more room to put the shims in.

[zaq123]

Not a bad night in the garage:






After a little clean up:


Got 4 of 6 done last night after machining the stop and then figuring out the process. Should be done cutting reliefs tonight and have new p2v numbers. Hopefully my educated guess for how much to take off is close enough...

Cheers,

Pretty cool setup

Sent from my VS985 4G using Tapatalk

[So Live]

Not a bad night in the garage:






After a little clean up:


Got 4 of 6 done last night after machining the stop and then figuring out the process. Should be done cutting reliefs tonight and have new p2v numbers. Hopefully my educated guess for how much to take off is close enough...

Cheers,

[ForcedFirebird]

Yeah, he PM'd me asking for a cracked head. That's when I remembered the head I already cut up a while back (jogged my memory for this post... https://www.r3vlimited.com/board/sho...50#post4844750

Had the cold saw out recently and trimmed those up, chopped off a couple cyls for cuting pockets, then cut another intake and exhaust port down the center.

As far as using the head bold holes, they are all symmetrical.

[digger]

A cracked head cut up also works well, then make a cutting tool from a o/s valve. There is a thread on e30 tech

[So Live]

What did you end up using for a jig? Just realized my PM's were full. :/

Yeah haha found that out too, not a big deal though dude! Ended up fabbing two little jugs that get secured by the head studs. One for each valve as there had to be two different size cutting tools (based on the valve diameters). And I didn’t feel like trying to figure out if the valve center lines had the same spacing relative to the studs. I’ll post pictures later tonight or tomorrow. Should be done cutting the pockets tonight, I hope.

Definitely appreciate you finding a head for me though.

Cheers,

[digger]

isn't most cams spec'd (dur, lift etc) at recommended lash? just wondering

If you notice the 3 black horizontal lines these allow you to get the duration at lash (0.25mm normally) then duration at 1mm (I.e. 1.25mm on the graph) and 0.050"(I.e 1.52mm on graph)

If you put 0.25 lash in before measuring the 0 to 0 will be same duration as 0.25 to 0.25 on graph that had zero lash

It's worth noting that with pushrod stuff they use duration at0.050" tapped lift not valve lift as you do with ohc stuff. So if they have 0,050" tapper lift then valve lift is multiplied by rocker ratio so for the same duration at 0.050 a pushrod cam is bigger.

[ForcedFirebird]

That’s awesome! Thanks Digger! Cool to see next to two well known cams. Also nice to see ivc differences between all three side by side.

Pulled the head last night and put together a pair of tools to cut the valve reliefs so I can adjust the cam and also rest at night. Just need to turn a beefier drill stop so I can accurately cut the reliefs to the depths I want. Should be a fun night...

What did you end up using for a jig? Just realized my PM's were full. :/

[zaq123]

Duration kind of is. The advertised duration can be at whatever lift the manufacturer wants. Some durations are specified at .006” some are .050” some are at the recommended lash. I think mapping a cam at zero degrees probably isn’t necessary other than to see what it looks like. You can time your cam without mapping it fully but that wasn’t the intent here. My intent was to see what the cam was because there wasn’t really any info about it anywhere (including from bimmerheads). So now that the cam is fully mapped out at zero lash, I can plot accelerations and figure out what lash to use, see durations at different points and see where valves will open and close regardless of what lash I use.

Also, in this case bimmerheads’ advertised lift is at the valve, not the cam, which makes sense.

I've done some cam mapping myself, just to verify manuf. cam specs. In my case, dbilas 274 cam... which was off. https://www.r3vlimited.com/board/sho...d.php?t=409476
Advertised lift is obviously at the valve, which will obviously change with different lash numbers or different rockers (different rocker ratios to cheat the lift)
I was just under the impression that the lash needs to be set to the spec in order to really check the cam vs. the manuf. adv. values or find what the cam specs are.

[So Live]

Duration kind of is. The advertised duration can be at whatever lift the manufacturer wants. Some durations are specified at .006” some are .050” some are at the recommended lash. I think mapping a cam at zero degrees probably isn’t necessary other than to see what it looks like. You can time your cam without mapping it fully but that wasn’t the intent here. My intent was to see what the cam was because there wasn’t really any info about it anywhere (including from bimmerheads). So now that the cam is fully mapped out at zero lash, I can plot accelerations and figure out what lash to use, see durations at different points and see where valves will open and close regardless of what lash I use.

Also, in this case bimmerheads’ advertised lift is at the valve, not the cam, which makes sense.

[zaq123]

I set it to 0 and plot full profile ,

isn't most cams spec'd (dur, lift etc) at recommended lash? just wondering