Help! Just got through the first race weekend with the new car. The car was making little power at the top of the rev range and low and behold, it turns out (thanks Carl) it is fitted with an “e” head. I checked the VIN (again) and confirmed the car did at least start life as an “i”. It does have an oil cooler, and did have an open diff 3.73 when I got it. It also has an “i” guage console and the ECU is one of the numbers listed as legal for use in spec e30. I am currently seeking an “i” head but I am concerned that the block may be an “e” or “eta” as well. I did find some casting numbers on the block which are 20586050. A brief search of Bentley and the web gave no answers. Local BMW dealer was clueless. Anyone?
Verifying Correct Engine
cwbaader
#2
When the head is pulled, observe the piston tops. The “e” and “i” motors are very different. You can also check the stroke…the “e” is 6mm longer. Chuck
jlevie
#5
An M20B27 block is exactly the same as an M20B25 block. So block nmbers tell you essentially nothing. The difference will be the pistons and crankshaft, or maybe only the crankshaft in the case of a SuperETA or stroker motor. The clue as to what you have will be in the stroke. An ETA and SuperETA have a longer stroke, as mentioned above.
bdigel
#6
an E head will not bolt on to an I block, the piston’s of the 2.5 i block stick out of the deck and interfere with e head!
mougl1
#7
if an i motor has a shorter stroke, why would it interfere with the head? Wouldn’t it interfere if it were the other way around (e motor block with i head?)
bdigel
#8
your over thinking this and making things way to complex,
the 2.5 i engine has completely different pistons and they stick out of the block, the e head has a smaller combustion camber . the two CAN NOT be phyicaly put together, Ive tried, had a part supplier give me the wrong head and didn’t find out till it was tooooo late. have you pulled the cam cover or the intake to verify that you have an e head???