M20 – Early vs. Late main bearings.
*Early = ‘e’ blocks/ SINGLE TANG
*Late = ‘I’ blocks/ DOUBLE TANG
--------------------------------------------------------------
Here’s a picture of the difference between the 2 style main bearings (note that these particular bearings have been coated).
You can see the ‘e’ main bearings (LEFT) have single “tangs” at either end that line up with the block and saddle. The ‘I’ main bearing (right) has a saddle ½ shell that is smooth (no oil journal) and has a double “tang”, but the top ½ shell is the same as the “early” style.
Combinations and why it may matter.
Why might it matter?
It does come down to availability (NOT performance). BMW used both Kobenshmidt and Glyco as OEM suppliers, which are carried by your preferred vendor (Ireland Engineering, Guten Parts, Blunt, Korman, Metric Mech., AZ Autohaus, etc.) or shop doing the work (TCMotorsports, Castro, Midnight Oil, Heritage Motorsports, Midnight Motorsports, German Motorwerks, etc.).
THE SET THAT IS NO LONGER AVAILABLE (NLA) IS THE ‘EARLY STYLE “e”’ .25-UNDER & .50-UNDER BEARINGs. All other bearing sets are still available at this time (7/19/12).
Compatibility/Solutions?
Contrary to what WORLDPAC states, you CANNOT simply retrofit a late bearing set into an early block (this has been the source of a fair amount of recent misinformation). See the picture below, the tang’s width is different and you would need to cut another tang slot in each of the bearing saddles to accommodate the second tang, the risk to too high to consider.
The BEST solution for the individual seeking NLA undersize single-tang bearings for their M20 ‘e’ block, is to purchase 2 sets of late “I” bearings and simply pair up the halves that have the oiling-groove in them. See picture.
If anything is unclear, feel free to ask. Hopefully someone can sticky this to avoid later confusion.
- Andrew @ Ireland Engineering.
*Early = ‘e’ blocks/ SINGLE TANG
*Late = ‘I’ blocks/ DOUBLE TANG
--------------------------------------------------------------
Here’s a picture of the difference between the 2 style main bearings (note that these particular bearings have been coated).
You can see the ‘e’ main bearings (LEFT) have single “tangs” at either end that line up with the block and saddle. The ‘I’ main bearing (right) has a saddle ½ shell that is smooth (no oil journal) and has a double “tang”, but the top ½ shell is the same as the “early” style.
Combinations and why it may matter.
Why might it matter?
It does come down to availability (NOT performance). BMW used both Kobenshmidt and Glyco as OEM suppliers, which are carried by your preferred vendor (Ireland Engineering, Guten Parts, Blunt, Korman, Metric Mech., AZ Autohaus, etc.) or shop doing the work (TCMotorsports, Castro, Midnight Oil, Heritage Motorsports, Midnight Motorsports, German Motorwerks, etc.).
THE SET THAT IS NO LONGER AVAILABLE (NLA) IS THE ‘EARLY STYLE “e”’ .25-UNDER & .50-UNDER BEARINGs. All other bearing sets are still available at this time (7/19/12).
Compatibility/Solutions?
Contrary to what WORLDPAC states, you CANNOT simply retrofit a late bearing set into an early block (this has been the source of a fair amount of recent misinformation). See the picture below, the tang’s width is different and you would need to cut another tang slot in each of the bearing saddles to accommodate the second tang, the risk to too high to consider.
The BEST solution for the individual seeking NLA undersize single-tang bearings for their M20 ‘e’ block, is to purchase 2 sets of late “I” bearings and simply pair up the halves that have the oiling-groove in them. See picture.
If anything is unclear, feel free to ask. Hopefully someone can sticky this to avoid later confusion.
- Andrew @ Ireland Engineering.
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