Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2021 Acura ILXFACTORY OEM SERVICE PROCEDURE
Engine Block
(R20A5)
| Item | Measurement | Qualification | Standard or New | Service Limit |
|---|---|---|---|---|
| Block | Warpage of deck | 0.07 mm (0.002 in) max. | - | |
| Bore diameter | 81.000-81.015 mm (3.18897-3.18956 in) | 81.070 mm (3.19173 in) | ||
| Bore taper | - | 0.05 mm (0.0020 in) | ||
| Reboring limit | - | 0.25 mm (0.0098 in) | ||
| Piston | Skirt O.D. at 14 mm (0.55 in) from bottom of skirt | 80.98-80.99 mm (3.1882-3.1886 in) | 80.93 mm (3.1862 in) | |
| Clearance in cylinder | 0.010-0.035 mm (0.00039-0.00138 in) | 0.05 mm (0.0020 in) | ||
| Piston ring | Ring-to-groove clearance | Top | 0.045-0.070 mm (0.002-0.002 in) | 0.13 mm (0.005 in) |
| Second | 0.035-0.060 mm (0.002-0.002 in) | 0.13 mm (0.005 in) | ||
| Ring end gap | Top | 0.20-0.35 mm (0.008-0.013 in) | 0.60 mm (0.023 in) | |
| Second | 0.40-0.55 mm (0.016-0.021 in) | 0.70 mm (0.027 in) | ||
| Oil(except RIKEN) | 0.20-0.70 mm (0.008-0.002 in) | 0.80 mm (0.031 in) | ||
| Oil(RIKEN) | 0.20-0.50 mm (0.008-0.019 in) | 0.55 mm (0.021 in) |
| Item | Measurement | Qualification | Standard or New | Service Limit |
|---|---|---|---|---|
| Piston pin | O.D. | 19.960-19.964 mm (0.78583-0.78598 in) | 19.960 mm (0.78583 in) | |
| Pin-to-piston clearance | -0.004-0.003 mm (-0.00016-0.00012 in) | 0.006 mm (0.00024 in) | ||
| Connecting rod | Pin-to-rod clearance | 0.005-0.015 mm (0.00020-0.00059 in) | 0.02 mm (0.0008 in) | |
| Small end bore diameter | 19.969-19.975 mm (0.78618-0.78642 in) | - | ||
| Big end bore diameter | 48.0 mm (1.890 in) | - | ||
| End play | 0.15-0.35 mm (0.006-0.013 in) | 0.45 mm (0.017 in) | ||
| Crankshaft | Main journal diameter | No. 1, 5 journals | 54.980-55.004 mm (2.16456-2.16551 in) | - |
| No. 2, 3, 4 journals | 54.976-55.000 mm (2.16441-2.16535 in) | - | ||
| Rod journal diameter | 44.976-45.000 mm (1.77071-1.77165 in) | - | ||
| Rod/main journal taper | 0.005 mm (0.00020 in) max. | 0.010 mm (0.00039 in) | ||
| Rod/main journal out-of-round | 0.005 mm (0.00020 in) max. | 0.010 mm (0.00039 in) | ||
| End play | 0.10-0.35 mm (0.0039-0.0138 in) | 0.45 mm (0.0177 in) | ||
| Total runout | 0.03 mm (0.0012 in) max. | 0.04 mm (0.0016 in) | ||
| Crankshaft bearing | Main bearing-to-journal oil clearance | No. 1, 5 journals | 0.017-0.033 mm (0.00067-0.00130 in) | 0.043 mm (0.00169 in) |
| No. 2, 3, 4 journals | 0.018-0.034 mm (0.00071-0.00134 in) | 0.040 mm (0.00157 in) | ||
| Connecting rod bearing-to-journal oil clearance | 0.024-0.042 mm (0.00094-0.00165 in) | 0.055 mm (0.00217 in) | ||
| Balancer shaft | Journal diameter | No. 1 journal, front and rear shafts | 19.958-19.970 mm (0.78575-0.78622 in) | 19.94 mm (0.7850 in) |
| No. 2 journal, front shaft | 25.969-25.981 mm (1.02240-1.02287 in) | 25.962 mm (1.02212 in) | ||
| No. 2 journal, rear shaft | 19.958-19.970 mm (0.78575-0.78622 in) | 19.94 mm (0.7850 in) | ||
| No. 3 journal, rear shaft | 25.969-25.981 mm (1.02240-1.02287 in) | 25.962 mm (1.02212 in) | ||
| Journal taper | 0.05 mm (0.0020 in) max. | - | ||
| End play | Front | 0.07-0.12 mm (0.0028-0.0047 in) | 0.135 mm (0.00531 in) | |
| Rear | 0.07-0.12 mm (0.0028-0.0047 in) | 0.135 mm (0.00531 in) | ||
| Shaft-to-bearing clearance | No. 1 journal, front and rear shafts | 0.030-0.062 mm (0.00118-0.00244 in) | 0.08 mm (0.0031 in) | |
| No. 2 journal, front shaft | 0.04-0.10 mm (0.0016-0.0039 in) | 0.13 mm (0.0051 in) | ||
| No. 2 journal, rear shaft | 0.030-0.062 mm (0.00118-0.00244 in) | 0.08 mm (0.0031 in) | ||
| No. 3 journal, rear shaft | 0.04-0.10 mm (0.0016-0.0039 in) | 0.13 mm (0.0051 in) | ||
| Balancer shaft bearing | I.D. | No. 1 journal, front and rear shafts | 20.00-20.02 mm (0.7874-0.7882 in) | 20.03 mm (0.7886 in) |
| No. 2 journal, front shaft | 26.021-26.029 mm (1.02445-1.02476 in) | 26.05 mm (1.0256 in) | ||
| No. 2 journal, rear shaft | 20.00-20.02 mm (0.7874-0.7882 in) | 20.03 mm (0.7886 in) | ||
| No. 3 journal, rear shaft | 26.021-26.029 mm (1.02445-1.02476 in) | 26.05 mm (1.0256 in) |
(K24Z7)
| Item | Measurement | Qualification | Standard or New | Service Limit |
|---|---|---|---|---|
| Block | Warpage of deck | 0.07 mm (0.002 in) max. | - | |
| Bore diameter | A or I | 87.010-87.020 mm (3.42558-3.42598 in) | 87.07 mm (3.4279 in) | |
| B or II | 87.000-87.010 mm (3.42519-3.42558 in) | 87.07 mm (3.4279 in) | ||
| Bore taper | - | 0.05 mm (0.0020 in) | ||
| Reboring limit | - | 0.25 mm (0.0098 in) | ||
| Piston | Skirt O.D. at 13 mm (0.51 in) from bottom of skirt | No letter or A | 86.980-86.990 mm (3.42440-3.42480 in) | 86.930 mm (3.42243 in) |
| Letter B | 86.970-86.980 mm (3.42401-3.42440 in) | 86.920 mm (3.42204 in) | ||
| Clearance in cylinder | 0.020-0.040 mm (0.00079-0.00157 in) | 0.050 mm (0.00197 in) | ||
| Piston ring | Ring-to-groove clearance | Top | 0.060-0.085 mm (0.003-0.003 in) | 0.13 mm (0.005 in) |
| Second | 0.020-0.045 mm (0.001-0.001 in) | 0.13 mm (0.005 in) | ||
| Ring end gap | Top | 0.20-0.30 mm (0.008-0.011 in) | 0.60 mm (0.023 in) | |
| Second | 0.20-0.32 mm (0.008-0.012 in) | 0.75 mm (0.029 in) | ||
| Oil | 0.20-0.50 mm (0.008-0.019 in) | 0.55 mm (0.021 in) | ||
| Piston pin | O.D. | 21.961-21.965 mm (0.86460-0.86476 in) | 21.953 mm (0.86429 in) | |
| Pin-to-piston clearance | -0.005-0.002 mm (-0.00020-0.00008 in) | 0.005 mm (0.00020 in) | ||
| Connecting rod | Pin-to-rod clearance | 0.005-0.015 mm (0.00020-0.00059 in) | 0.02 mm (0.0008 in) | |
| Small end bore diameter | 21.970-21.976 mm (0.86496-0.86520 in) | - | ||
| Big end bore diameter | 51.0 mm (2.008 in) | - | ||
| End play | 0.15-0.35 mm (0.006-0.013 in) | 0.40 mm (0.015 in) | ||
| Crankshaft | Main journal diameter | No. 1 journal | 54.984-55.008 mm (2.16472-2.16566 in) | - |
| No. 2 journal | 54.984-55.008 mm (2.16472-2.16566 in) | - | ||
| No. 3 journal | 54.976-55.000 mm (2.16441-2.16535 in) | - | ||
| No. 4 journal | 54.984-55.008 mm (2.16472-2.16566 in) | - | ||
| No. 5 journal | 54.984-55.008 mm (2.16472-2.16566 in) | - | ||
| Rod journal diameter | 47.976-48.000 mm (1.88882-1.88976 in) | - | ||
| Rod/main journal taper | 0.005 mm (0.00020 in) max. | 0.010 mm (0.00039 in) | ||
| Rod/main journal out-of-round | 0.004 mm (0.00016 in) max. | 0.010 mm (0.00039 in) | ||
| End play | 0.10-0.35 mm (0.0039-0.0138 in) | 0.45 mm (0.0177 in) | ||
| Total runout | 0.03 mm (0.0012 in) max. | - | ||
| Crankshaft bearing | Main bearing-to-journal oil clearance | No. 1, 2, 4, 5 journals | 0.017-0.041 mm (0.00067-0.00161 in) | 0.050 mm (0.00197 in) |
| No. 3 journal | 0.025-0.049 mm (0.00098-0.00193 in) | 0.055 mm (0.00217 in) | ||
| Connecting rod bearing-to-journal oil clearance | 0.032-0.066 mm (0.00126-0.00260 in) | 0.077 mm (0.00303 in) |
Factory Service Tools
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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