MTD 78 Series User Manual

78/83/90 Series Horizontal Shaft Engines
116
in. mm in. mm in. mm
Intake lobe height
78 1.248 31.70 1.252 31.80 1.237 31.42
83 1.281 32.54 1.285 32.64 1.269 32.24
90 1.281 32.54 1.285 32.64 1.269 32.24
Exhaust lobe height
78 1.248 31.70 1.252 31.80 1.237 31.52
83 1.261 32.02 1.264 32.12 1.249 31.73
90 1.261 32.02 1.264 32.12 1.249 31.73
Cam shaft min OD
(cylinder block side)
78 0.636 16.17 0.637 16.18 0.633 16.09
83 0.636 16.17 0.637 16.18 0.633 16.09
90 0.636 16.17 0.637 16.18 0.633 16.09
Cam shaft min OD (sump side)
78 0.636 16.17 0.637 16.18 0.633 16.09
83 0.636 16.17 0.637 16.18 0.633 16.09
90 0.636 16.17 0.637 16.18 0.633 16.09
Cam shaft bearing max. ID
(cylinder block)
78 0.638 16.20 0.639 16.22 0.639 16.22
83 0.638 16.20 0.639 16.22 0.639 16.22
90 0.638 16.20 0.639 16.22 0.639 16.22
Cam shaft bearing max. ID (sump)
78 0.638 16.20 0.639 16.22 0.639 16.22
83 0.638 16.20 0.639 16.22 0.639 16.22
90 0.638 16.20 0.639 16.22 0.639 16.22
Balance shaft min OD
(cylinder block side)
78 N/A N/A N/A N/A N/A N/A
83 0.589 14.97 0.590 14.98 0.587 14.90
90 0.589 14.97 0.590 14.98 0.587 14.90
Balance shaft min OD (sump side)
78 N/A N/A N/A N/A N/A N/A
83 0.589 14.97 0.590 14.98 0.587 14.90
90 0.589 14.97 0.590 14.98 0.587 14.90
Balance shaft bearing max. ID (sump)
78 N/A N/A N/A N/A N/A N/A
83 0.591 15.00 0.591 15.00 0.592 15.03
90 0.591 15.00 0.591 15.00 0.592 15.03
Specification New Min New Max Service Limit

MTD 78 Series Specifications

General

Brand	MTD
Model	78 Series
Category	Engine
Language	English