outstanding work from the bimmer guys - my son has an E30 with a 4 valve 3 liter "Frankengine" that runs really well - all stock mostly. Have any of you done any serious work on the M30 B35 2 valve cylinder head? I am curious if that head has anywhere near the potential that the M20 head has, i.e. nice straight ports, room for bigger valves, etc. The M30 engines are becoming really cheap - from Pull -a Part for instance here in the states, and if there is any sort of similar potential, they could make a real sleeper.
Thx,
ccsc
The BMW M20 engine
Moderator: Team
-
morerevsm3
- New Member
- Posts: 25
- Joined: Tue Jan 10, 2012 6:11 am
- Location: Australia
-
Cinnabar325is
- New Member
- Posts: 31
- Joined: Fri Aug 05, 2016 5:20 pm
- Location: Bechtelsville, Pennsylvania
-
KnightEngines
- Guru
- Posts: 2690
- Joined: Fri Jan 09, 2009 8:51 pm
- Location: Australia
Re: The BMW M20 engine
Doing another head at the moment, it's a 885 BMW casting & I've done things a little different this time around.
It's only got 43 & 36mm valves & I've used a different valve job on the intake side in an attempt to compensate for the smaller valve, the results have been suprising so far, I was expecting flow loss at lower lift & maybe 210cfm max, but flow loss down low was less than I expected & from .4" lift the thing really moves some air:
Intake flow:
.1 - 55cfm
.2 - 117
.3 - 154
.4 - 191.5
.45 - 198
.5 - 205
.55 - 210
.6 - 214
.65 - 217.5
.7 - 219.5
.75 - 221
.8 - 221
I'm gonna call that exceptional on a 43mm valve & it's got me thinking about doing a head with a 44mm intake, new valve job & filling the floor of the port with epoxy to reduce the port taper & improve the velocity profile. I think there is still HP waiting to be found.
It's only got 43 & 36mm valves & I've used a different valve job on the intake side in an attempt to compensate for the smaller valve, the results have been suprising so far, I was expecting flow loss at lower lift & maybe 210cfm max, but flow loss down low was less than I expected & from .4" lift the thing really moves some air:
Intake flow:
.1 - 55cfm
.2 - 117
.3 - 154
.4 - 191.5
.45 - 198
.5 - 205
.55 - 210
.6 - 214
.65 - 217.5
.7 - 219.5
.75 - 221
.8 - 221
I'm gonna call that exceptional on a 43mm valve & it's got me thinking about doing a head with a 44mm intake, new valve job & filling the floor of the port with epoxy to reduce the port taper & improve the velocity profile. I think there is still HP waiting to be found.
-
KnightEngines
- Guru
- Posts: 2690
- Joined: Fri Jan 09, 2009 8:51 pm
- Location: Australia
-
KnightEngines
- Guru
- Posts: 2690
- Joined: Fri Jan 09, 2009 8:51 pm
- Location: Australia
-
daimlersteve
- HotPass
- Posts: 14
- Joined: Fri May 09, 2014 2:57 am
- Location:
Re: The BMW M20 engine
Tony, good stuff on the BM,
I'm surprised there was no takeup on the 134 cfm /mcsa achieved without major work on the port.
So i'll be the first. --- good one. ---
As an aside , We've got 145.2 cfm @0.400 lift out of a .93 mcsa which gets it int the mid 150 s sq. " on the Daimler 2.5 ltr. v8 3.150 bore x 2.75 st. Ports have been reduced and reprofiled on both intake and exhaust. Exhaust valve reduced frm. 1.47 to 1.25 , Inlet up frm. 1.50 to 1.560 " Throats at 85% both. Exhaust port vol. reduced 30 %, Inlet same vol. but with port lifted 5mm to give a better ssr. Looking to double factory hp and still be roadable.
regards steve
I'm surprised there was no takeup on the 134 cfm /mcsa achieved without major work on the port.
So i'll be the first. --- good one. ---
As an aside , We've got 145.2 cfm @0.400 lift out of a .93 mcsa which gets it int the mid 150 s sq. " on the Daimler 2.5 ltr. v8 3.150 bore x 2.75 st. Ports have been reduced and reprofiled on both intake and exhaust. Exhaust valve reduced frm. 1.47 to 1.25 , Inlet up frm. 1.50 to 1.560 " Throats at 85% both. Exhaust port vol. reduced 30 %, Inlet same vol. but with port lifted 5mm to give a better ssr. Looking to double factory hp and still be roadable.
regards steve
-
Hairyscreech
- Member
- Posts: 91
- Joined: Sat May 05, 2012 3:50 pm
- Location:
Re: The BMW M20 engine
When I still had flow bench access I did manage to push about 180cfm at .4 lift but that 210+ is really moving some air Tony.
When I was looking at them they did seem to respond well to careful choice of seat profile, I machined up some seats that were only a light push fit and had lots of different profiles, this meant on the bench I could swap between seat profiles on the same port in seconds.
I found standard ports were happy with different angles to a developed port. You might be able to pick up some more by playing about with the seat angles.
I also filled the floor with clay on a few head, the flow change was practically nil, the middle of the floor near the intake flange was not doing a lot.
I filled the floor at roughly the same angle as the roof of the port and smoothed it in at/just before the short side. Velocity was up nearly everywhere and short side attachment seemed to be better.
From what I could tell there was loads more to.come from these lumps, I take it you have seen the 300hp 2.8 street motor Byron put together based on the key ingredients we have all found and my old test head (must get that back), a reliable street motor using 97 octane as well.
For what it's worth I put together a head for a turbo motor about 12 months back, it was for a drift cup car so a wide spread of torque was key to keep the wheels spinning. Kept the ports small and high velocity but went up to a 43mm valve, softened the chambers a bit and kept the CR around 9:1. Its cranking out 200lbft at 2000rpm before coming onto boost and on to 534hp at the wheels, not bad for a pump gas turbo 2.8@17psi.
When I was looking at them they did seem to respond well to careful choice of seat profile, I machined up some seats that were only a light push fit and had lots of different profiles, this meant on the bench I could swap between seat profiles on the same port in seconds.
I found standard ports were happy with different angles to a developed port. You might be able to pick up some more by playing about with the seat angles.
I also filled the floor with clay on a few head, the flow change was practically nil, the middle of the floor near the intake flange was not doing a lot.
I filled the floor at roughly the same angle as the roof of the port and smoothed it in at/just before the short side. Velocity was up nearly everywhere and short side attachment seemed to be better.
From what I could tell there was loads more to.come from these lumps, I take it you have seen the 300hp 2.8 street motor Byron put together based on the key ingredients we have all found and my old test head (must get that back), a reliable street motor using 97 octane as well.
For what it's worth I put together a head for a turbo motor about 12 months back, it was for a drift cup car so a wide spread of torque was key to keep the wheels spinning. Kept the ports small and high velocity but went up to a 43mm valve, softened the chambers a bit and kept the CR around 9:1. Its cranking out 200lbft at 2000rpm before coming onto boost and on to 534hp at the wheels, not bad for a pump gas turbo 2.8@17psi.