Assembly requires cookies to securely sign you in. On iPhone or iPad, open Settings → Apps → Safari → Advanced and turn off “Block All Cookies.” Then fully close Safari, reopen it, and reload this page.
Reliable naturally aspirated torque and a noticeably stronger midrange than the B34 — not a high-rpm race build
•
Preserve cold start, idle, heat management, serviceability, and highway drivability
•
Retain the existing Motronic 1.3 / Bosch 179 DME architecture unless a later decision explicitly changes it
•
Premium pump fuel assumed if the chosen chip requires it
•
Prefer an early dual-pattern block that accepts the stock E28 passenger-side mount arm without an adapter
•
No irreversible build decision until the donor block, head condition, and existing Motronic hardware are inspected and documented
•
Budget target and contingency: TBD
•
Target completion date and driving season: TBD
Decisions & Unknowns
What I need to figure out:
•
D-001 Donor mounting strategy: early dual-boss block direct-fit, or late block plus a right-side support/adapter. Decide from a photo of the passenger-side boss pattern, never from the donor's year.
•
D-002 Air metering: keep the Bosch 027 flap AFM (baseline), convert to MAF, or go standalone. Settle this before buying any tuning parts.
•
D-003 Camshaft: leaning Schrick 284/280 (00220184004, $828.99). Alternatives: stock B35, IE 270 billet at $360, or 292-plus. Still decided after the head inspection, not before.
•
D-004 Exhaust: reuse the B34 cast manifolds, run B35 manifolds with an adapted downpipe, or headers. Default is to defer headers to a later phase.
•
D-005 Clutch: reuse only if demonstrably good, OE-equivalent Sachs kit as the default, or higher clamp load if future power justifies the pedal.
•
D-006 Engine mounts: stock rubber, HD rubber, or stiffer.
•
D-007 Machine-shop scope, set by what the head inspection finds: clean and seals only, valve job, guides, or surfacing.
•
Final DME chip and tune, matched to B35 + 179 DME + injectors + AFM or MAF state + final cam + octane. No generic performance chip.
•
Conditional purchases if the block fails the direct-fit test: right-side E28 late-M30 support/adapter, and B35 lower intake manifold bracket. Both long-lead.
•
Does the donor oil pan and pickup clear the E28 subframe and steering linkage, or do the B34 parts transfer?
Tasks
What I need to do:
•
00.01 Fill in the budget target, contingency, and target driving season in Goals above.
•
00.02 Photograph and document the current baseline: DME and chip labels, AFM, injectors, ignition, transmission tag, flywheel and clutch behavior, driveshaft, guibo, center bearing, diff ratio, radiator and fan, exhaust configuration, mount arms, engine bay, and the C101/C103 wiring.
•
10.01 Run the donor acceptance checklist before any money moves: model and build date, VIN, odometer, casting marks, compression or leakdown, oil condition, overheat history, valve-cover-off photos of cam, rockers, shafts and spray bar, and exactly which accessories come with it. Photograph the oil cooler, its thermostatic filter housing and both lines if the donor has them - that is the cheapest route to a factory oil cooler.
•
10.02 Verify the early dual-pattern E28-compatible passenger mount bosses: close-up photo of the boss pattern, threads intact, and a test-fit of the E28 mount arm if the donor is on a stand.
•
10.04 Verify oil pan and pickup clearance, alternator, power steering, A/C brackets, belt alignment, and starter type and wiring before ordering anything.
•
20.01 Long-block health inspection gate: compression or leakdown, bore condition, crank endplay, pan and pickup if condition is unknown. A poor result stops the refresh-only path and opens a rebuild-scope decision.
•
20.02 Order the full reseal and cooling refresh package: valve cover, upper and lower timing covers, front crank and rear main seals, oil pan, filter housing, thermostat housing, water-pipe O-rings, intake and exhaust manifold gaskets, injector seals, water pump, thermostat, belts.
•
20.04 Oil spray bar: inspect, clean the oil return passages, and positively retain the fasteners with safety wire or engineered bolts. Photograph before the head goes together. Safety-critical.
•
30.01 Cylinder-head inspection and machine-shop measurement package: pressure test, deck flatness, guides, seats, stem clearance, installed spring height, cam journals, all 12 rocker arms, and the rocker shafts.
•
30.03 Valvetrain compatibility checklist for any non-stock cam: 12 rockers verified, shafts, springs to the cam supplier's spec, retainers and keepers, valve-to-piston clearance, lash spec documented, cam lube and break-in process.
•
40.01 B35 induction and vacuum refresh: manifold cleaned and threads checked, throttle body shaft play and full opening, throttle switch idle and WOT contacts, intake boot, idle control valve bench test, and every vacuum and crankcase hose replaced and labeled.
•
40.03 Injector clean and flow test with before and after numbers, plus fuel rail, regulator pressure, filter, hoses, and fuel pump evaluation.
•
40.04 Verify the existing Motronic 1.3 rather than re-engineer it: record DME and chip numbers, check crank sensor gap and trigger wheel integrity, test each sensor and relay, verify every ground, and document the C101/C103 interface.
•
50.01 Confirm the exhaust path once the block is mounted: gaskets, new studs, copper nuts, O2 sensor type matched to the existing harness, and heat shielding for the starter and steering.
•
60.01 Flywheel, clutch, pilot bearing, and rear main inspection while access is open: friction surface, ring gear, disc thickness, pressure plate, release bearing, fork and pivot, slave cylinder and hose.
•
70.02 Cooling-system installation package: radiator core and necks, hoses planned before install, heater hoses and valve, gauge sender matched to the E28 cluster and DME coolant sensor matched to the harness, fan strategy, and bleed procedure recorded.
•
80.01 Pre-start checklist: fluids filled and recorded, lubrication primed, oil pressure on crank, fuel pressure and leak check, throttle returns to idle, fan operation verified, extinguisher on hand.
•
80.02 First start and heat-cycle log: date, ambient, cold start behavior, idle rpm, coolant temp, oil pressure, charging voltage, leaks, injector and valvetrain noise, belt tracking, vibration.
•
80.03 Road validation: short low-load drive, cooling recheck after a full heat cycle, progressive load testing, throttle and idle response, wideband review if breathing changed materially, underside inspection, and 100-mile and 500-mile checks.
•
90.01 Final build sheet: donor identification, mounting path, cam and valvetrain details, intake and metering configuration, injectors, DME and chip revision, exhaust, clutch and flywheel, cooling, fluids, odometer and install date.
•
90.02 Final cost report by category, including machine-shop labor, fabrication, tuning, consumables, and contingency.
