Piston Position as a Percentage of Stroke Length

    To use this table, find your rod ratio (across Row 2). Follow the column down to the crankshaft position. The number in the box is the piston position below TDC as a percentage of the actual stroke, and also the percentage of the full, nominal displacement. To get the distance in inches, multiply this figure by your stroke.
    To compare the relative effect of different rod ratios, select a crankshaft position from Column 1, then follow across for the difference between rod ratios (rods listed shortest first).
    If your rod ratio falls between two figures, interpolate to get an approximate value.
    Intake valve closing points are usually given ABDC, so use Column 2 for crank position.

Crank

Connecting Rod Ratio (Rod Length ÷ Stroke Length)

TDC

BDC

1.50-1

1.55-1

1.60-1

1.65-1

1.70-1

1.75-1

1.80-1

1.85-1

1.9-1

1.95-1

2.00-1

  0°

180°

.000000

.000000

.000000

.000000

.000000

.000000

.000000

.000000

.000000

.000000

.000000

  1°

179°

.000102

.000101

.000100

.000099

.000099

.000098

.000097

.000097

.000096

.000096

.000095

  2°

178°

.000406

.000403

.000400

.000397

.000394

.000392

.000389

.000387

.000385

.000383

.000381

  3°

177°

.000914

.000906

.000899

.000893

.000887

.000881

.000875

.000870

.000865

.000861

.000856

  4°

176°

.001624

.001610

.001598

.001587

.001576

.001566

.001556

.001547

.001538

.001530

.001522

  5°

175°

.002536

.002515

.002496

.002478

.002461

.002445

.002430

.002416

.002402

.002390

.002377

  6°

174°

.003650

.003620

.003593

.003567

.003543

.003520

.003498

.003477

.003458

.003440

.003422

  7°

173°

.004965

.004925

.004888

.004852

.004819

.004788

.004759

.004731

.004704

.004679

.004655

  8°

172°

.006481

.006429

.006380

.006334

.006291

.006250

.006212

.006175

.006141

.006108

.006077

  9°

171°

.008197

.008131

.008069

.008011

.007956

.007905

.007856

.007810

.007766

.007725

.007686

 10°

170°

.010111

.010030

.009954

.009882

.009815

.009751

.009691

.009635

.009581

.009530

.009482

 11°

169°

.012223

.012125

.012033

.011947

.011866

.011789

.011717

.011648

.011583

.011522

.011463

 12°

168°

.014533

.014416

.014307

.014204

.014108

.014017

.013931

.013849

.013772

.013699

.013630

 13°

167°

.017038

.016901

.016773

.016653

.016540

.016433

.016333

.016237

.016147

.016061

.015980

 14°

166°

.019737

.019579

.019431

.019292

.019161

.019038

.018921

.018811

.018706

.018607

.018513

 15°

165°

.022630

.022449

.022279

.022120

.021970

.021828

.021695

.021569

.021449

.021336

.021228

 16°

164°

.025714

.025508

.025316

.025135

.024965

.024804

.024653

.024510

.024374

.024245

.024123

 17°

163°

.028988

.028757

.028540

.028336

.028145

.027964

.027794

.027632

.027480

.027335

.027197

 18°

162°

.032451

.032192

.031949

.031722

.031508

.031306

.031115

.030935

.030764

.030603

.030449

 19°

161°

.036100

.035812

.035543

.035290

.035052

.034828

.034617

.034416

.034227

.034047

.033876

 20°

160°

.039934

.039616

.039319

.039040

.038777

.038529

.038296

.038075

.037865

.037667

.037478

 21°

159°

.043951

.043602

.043275

.042968

.042679

.042407

.042151

.041908

.041678

.041460

.041253

 22°

158°

.048148

.047767

.047409

.047074

.046758

.046461

.046180

.045914

.045663

.045424

.045198

 23°

157°

.052525

.052109

.051720

.051354

.051011

.050687

.050381

.050092

.049818

.049559

.049312

 24°

156°

.057077

.056627

.056204

.055808

.055435

.055084

.054753

.054439

.054143

.053861

.053594

 25°

155°

.061805

.061317

.060861

.060433

.060030

.059651

.059292

.058954

.058633

.058329

.058040

 26°

154°

.066703

.066179

.065687

.065226

.064792

.064384

.063998

.063633

.063288

.062961

.062650

 27°

153°

.071772

.071208

.070681

.070186

.069720

.069281

.068867

.068476

.068105

.067754

.067420

 28°

152°

.077007

.076404

.075839

.075309

.074810

.074341

.073898

.073479

.073082

.072706

.072349

 29°

151°

.082406

.081762

.081159

.080593

.080061

.079560

.079087

.078640

.078217

.077815

.077435

 30°

150°

.087967

.087281

.086639

.086037

.085470

.084936

.084433

.083957

.083506

.083079

.082674

 31

149°

.093687

.092958

.092276

.091636

.091034

.090467

.089933

.089427

.088949

.088495

.088065

 32°

148°

.099563

.098790

.098067

.097389

.096751

.096150

.095584

.095048

.094541

.094061

.093605

 33°

147°

.105591

.104774

.104009

.103292

.102618

.101983

.101383

.100817

.100281

.099773

.099291

 34°

146°

.111770

.110907

.110100

.109343

.108631

.107961

.107329

.106731

.106166

.105630

.105121

 35°

145°

.118095

.117186

.116336

.115539

.114789

.114083

.113417

.112788

.112193

.111628

.111093

 36°

144°

.124564

.123609

.122715

.121876

.121088

.120346

.119646

.118985

.118359

.117766

.117203

 37°

143°

.131174

.130171

.129232

.128352

.127525

.126746

.126012

.125318

.124661

.124039

.123448

 38°

142°

.137921

.136870

.135886

.134964

.134097

.133282

.132512

.131785

.131097

.130445

.129827

 39°

141°

.144802

.143702

.142673

.141708

.140802

.139948

.139144

.138383

.137664

.136982

.136335

 40°

140°

.151814

.150664

.149589

.148582

.147635

.146743

.145903

.145109

.144358

.143646

.142970

 41°

139°

.158952

.157754

.156632

.155581

.154593

.153664

.152787

.151959

.151176

.150434

.149729

 42°

138°

.166215

.164966

.163798

.162703

.161674

.160706

.159794

.158931

.158116

.157343

.156610

 43°

137°

.173597

.172298

.171083

.169944

.168874

.167868

.166918

.166022

.165174

.164370

.163608

 44°

136°

.181097

.179747

.178484

.177301

.176190

.175144

.174158

.173227

.172347

.171512

.170720

 45°

135°

.188709

.187308

.185998

.184770

.183618

.182533

.181510

.180545

.179631

.178766

.177945

TDC

BDC

1.50-1

1.55-1

1.60-1

1.65-1

1.70-1

1.75-1

1.80-1

1.85-1

1.9-1

1.95-1

2.00-1

 46°

134°

.196430

.194978

.193621

.192349

.191154

.190030

.188971

.18797

.187024

.186128

.185277

 47°

133°

.204257

.202754

.201349

.200032

.198796

.197633

.196537

.195501

.194522

.193595

.192715

 48°

132°

.212185

.210631

.209178

.207817

.206539

.205337

.204204

.203134

.202122

.201164

.200254

 49°

131°

.220212

.218606

.217106

.215700

.214381

.213139

.211970

.210865

.209820

.208831

.207892

 50°

130°

.228332

.226676

.225128

.223678

.222317

.221037

.219830

.218691

.217613

.216593

.215625

 51°

129°

.236543

.234836

.233241

.231747

.230344

.229025

.227782

.226608

.225498

.224447

.223450

 52°

128°

.244841

.243083

.241440

.239902

.238458

.237100

.235821

.234613

.233471

.232389

.231363

 53°

127°

.253221

.251412

.249723

.248141

.246656

.245260

.243944

.242702

.241528

.240416

.239362

 54°

126°

.261679

.259821

.258085

.256460

.254934

.253500

.252148

.250873

.249666

.248524

.247441

 55°

125°

.270212

.268305

.266523

.264854

.263288

.261816

.260429

.259120

.257882

.256710

.255599

 56°

124°

.278816

.276859

.275032

.273321

.271715

.270205

.268783

.267441

.266172

.264971

.263831

 57°

123°

.287487

.285481

.283609

.281855

.280210

.278664

.277207

.275832

.274532

.273302

.272135

 58°

122°

.296220

.294167

.292249

.290455

.288771

.287188

.285697

.284290

.282959

.281700

.280506

 59°

121°

.305012

.302912

.300950

.299115

.297393

.295774

.294249

.292810

.291450

.290162

.288942

 60°

120°

.313859

.311712

.309708

.307832

.306072

.304418

.302860

.301389

.300000

.298685

.297438

 61°

119°

.322757

.320565

.318518

.316602

.314805

.313116

.311525

.310025

.308606

.307264

.305991

 62°

118°

.331702

.329464

.327376

.325421

.323588

.321865

.320242

.318712

.317265

.315896

.314597

 63°

117°

.340690

.338408

.336279

.334286

.332417

.330661

.329007

.327447

.325973

.324577

.323254

 64°

116°

.349716

.347392

.345223

.343193

.341289

.339501

.337816

.336227

.334726

.333305

.331958

 65°

115°

.358778

.356412

.354203

.352138

.350200

.348380

.346666

.345049

.343521

.342075

.340704

 66°

114°

.367870

.365464

.363218

.361116

.359146

.357295

.355552

.353908

.352354

.350884

.349491

 67°

113°

.376990

.374544

.372261

.370126

.368124

.366242

.364471

.362801

.361223

.359729

.358313

 68°

112°

.386133

.383649

.381330

.379162

.377129

.375219

.373420

.371724

.370122

.368605

.367168

 69°

111°

.395296

.392774

.390422

.388221

.386158

.384220

.382395

.380674

.379049

.377510

.376052

 70°

110°

.404474

.401917

.399531

.397300

.395208

.393242

.391393

.389648

.388000

.386440

.384962

 71°

109°

.413665

.411073

.408655

.406394

.404274

.402283

.400409

.398641

.396972

.395392

.393894

 72°

108°

.422863

.420238

.417790

.415500

.413354

.411338

.409441

.407651

.405961

.404361

.402846

 73°

107°

.432065

.429409

.426932

.424615

.422444

.420404

.418484

.416674

.414964

.413346

.411813

 74°

106°

.441268

.438582

.436077

.433735

.431539

.429477

.427536

.425706

.423977

.422342

.420792

 75°

105°

.450468

.447754

.445223

.442856

.440637

.438554

.436593

.434744

.432998

.431345

.429780

 76°

104°

.459662

.456921

.454365

.451975

.449735

.447631

.445652

.443785

.442022

.440354

.438773

 77°

103°

.468845

.466079

.463500

.461088

.458828

.456706

.454709

.452825

.451047

.449364

.447769

 78°

102°

.478015

.475226

.472625

.470193

.467914

.465774

.463760

.461862

.460068

.458372

.456764

 79°

101°

.487168

.484357

.481736

.479285

.476989

.474833

.472804

.470891

.469084

.467375

.465755

 80°

100°

.496300

.493469

.490829

.488362

.486050

.483879

.481836

.479910

.478090

.476369

.474739

 81°

 99°

.505408

.502559

.499903

.497420

.495094

.492909

.490853

.488915

.487084

.485353

.483712

 82°

 98°

.514489

.511624

.508953

.506456

.504116

.501919

.499852

.497903

.496063

.494322

.492672

 83°

 97°

.523540

.520660

.517976

.515467

.513115

.510908

.50883

.506872

.505023

.503273

.501615

 84°

 96°

.532557

.529665

.526969

.524449

.522088

.519871

.517784

.515818

.513961

.512204

.510539

 85°

 95°

.541537

.538635

.535929

.533400

.531030

.528805

.526711

.524738

.522874

.521111

.519440

 86°

 94°

.550478

.547567

.544853

.542316

.539940

.537708

.535608

.533629

.531760

.529991

.528316

 87°

 93°

.559376

.556459

.553738

.551196

.548814

.546577

.544472

.542488

.540615

.538843

.537164

 88°

 92°

.568229

.565306

.562582

.560035

.557649

.555408

.553301

.551313

.549437

.547662

.545980

 89°

 91°

.577033

.574108

.571380

.568831

.566443

.564200

.56209

.560101

.558223

.556446

.554762

 90°

 90°

.585786

.582860

.580132

.577582

.575192

.572949

.570838

.568849

.566970

.565192

.563508

TDC

BDC

1.50-1

1.55-1

1.60-1

1.65-1

1.70-1

1.75-1

1.80-1

1.85-1

1.9-1

1.95-1

2.00-1

 91°

 89°

.594486

.591560

.588833

.586283

.583895

.581652

.579543

.577553

.575675

.573898

.572215

 92°

 88°

.603128

.600206

.597481

.594934

.592548

.590308

.588200

.586213

.584336

.582561

.580879

 93°

 87°

.611712

.608795

.606074

.603532

.601150

.598913

.596808

.594824

.592951

.591179

.589499

 94°

 86°

.620235

.617324

.614610

.612073

.609696

.607465

.605365

.603385

.601516

.599748

.598073

 95°

 85°

.628693

.625791

.623085

.620556

.618186

.615961

.613867

.611894

.610030

.608266

.606596

 96°

 84°

.637085

.634194

.631497

.628977

.626616

.624399

.622313

.620346

.618489

.616732

.615067

 97°

 83°

.645409

.642530

.639845

.637336

.634985

.632777

.630700

.628741

.626892

.625142

.623484

 98°

 82°

.653662

.650797

.648126

.645629

.643289

.641092

.639025

.637076

.635236

.633495

.631845

 99°

 81°

.661842

.658994

.656337

.653855

.651528

.649343

.647287

.645349

.643519

.641787

.640147

100°

 80°

.669948

.667117

.664478

.662010

.659698

.657527

.655484

.653558

.651739

.650018

.648387

101°

 79°

.677977

.675166

.672545

.670094

.667798

.665642

.663613

.661700

.659893

.658184

.656564

102°

 78°

.685927

.683137

.680536

.678105

.675826

.673686

.671672

.669773

.667980

.666284

.664676

103°

 77°

.693796

.691030

.688451

.686039

.683779

.681657

.679660

.677776

.675998

.674315

.672720

104°

 76°

.701584

.698843

.696287

.693897

.691657

.689553

.687574

.685707

.683944

.682276

.680695

105°

 75°

.709287

.706573

.704042

.701675

.699457

.697373

.695412

.693563

.691817

.690164

.688599

106°

 74°

.716906

.714220

.711714

.709372

.707177

.705114

.703174

.701343

.699615

.697979

.696429

107°

 73°

.724437

.721781

.719303

.716987

.714815

.712776

.710856

.709046

.707336

.705718

.704184

108°

 72°

.731880

.729255

.726807

.724517

.722371

.720355

.718458

.716668

.714978

.713378

.711863

109°

 71°

.739233

.736641

.734223

.731962

.729842

.727851

.725977

.724210

.722540

.720960

.719463

110°

 70°

.746495

.743937

.741551

.739320

.737228

.735263

.733413

.731668

.730020

.728460

.726982

111°

 69°

.753664

.751142

.748790

.746589

.744526

.742588

.740763

.739042

.737417

.735878

.734420

112°

 68°

.760740

.758255

.755937

.753769

.751735

.749825

.748027

.746331

.744728

.743212

.741774

113°

 67°

.767721

.765275

.762992

.760857

.758855

.756974

.755202

.753532

.751954

.750460

.749044

114°

 66°

.774607

.772200

.769954

.767853

.765883

.764032

.762289

.760644

.759091

.757621

.756227

115°

 65°

.781396

.779030

.776822

.774756

.772819

.770998

.769284

.767667

.766139

.764693

.763323

116°

 64°

.788087

.785763

.783594

.781564

.779661

.777872

.776187

.774599

.773097

.771676

.770329

117°

 63°

.794680

.792399

.790269

.788277

.786408

.784652

.782998

.781438

.779963

.778568

.777245

118°

 62°

.801173

.798936

.796847

.794893

.793060

.791337

.789714

.788183

.786737

.785367

.784069

119°

 61°

.807567

.805374

.803327

.801411

.799614

.797925

.796335

.794834

.793416

.792073

.790800

120°

 60°

.813859

.811712

.809708

.807832

.806072

.804418

.802860

.801389

.800000

.798685

.797438

121°

 59°

.820050

.817950

.815989

.814153

.812431

.810812

.809287

.807848

.806488

.805200

.803980

122°

 58°

.826139

.824086

.822169

.820374

.818690

.817107

.815616

.814209

.812879

.811620

.810426

123°

 57°

.832126

.830121

.828248

.826494

.824849

.823303

.821846

.820471

.819171

.817941

.816774

124°

 56°

.838009

.836052

.834225

.832513

.830908

.829398

.827976

.826634

.825365

.824164

.823024

125°

 55°

.843789

.841881

.840099

.838431

.836865

.835392

.834005

.832696

.831459

.830287

.829176

126°

 54°

.849464

.847606

.845870

.844245

.842719

.841285

.839933

.838658

.837452

.836310

.835226

127°

 53°

.855036

.853228

.851538

.849956

.848471

.847075

.845759

.844517

.843343

.842231

.841177

128°

 52°

.860502

.858744

.857102

.855564

.854120

.852762

.851482

.850274

.849132

.848051

.847025

129°

 51°

.865864

.864157

.862561

.861067

.859664

.858345

.857102

.855928

.854819

.853767

.852771

130°

 50

.871120

.869464

.867916

.866466

.865105

.863824

.862618

.861478

.860401

.859381

.858413

131°

 49°

.876271

.874665

.873165

.871759

.870440

.869199

.868029

.866924

.865879

.864890

.863951

132°

 48°

.881316

.879762

.878309

.876948

.875670

.874468

.873335

.872265

.871253

.870294

.869385

133°

 47°

.886255

.884752

.883347

.882030

.880794

.879631

.878535

.877500

.876521

.875593

.874713

134°

 46°

.891088

.889636

.888279

.887007

.885813

.884689

.883629

.882629

.881683

.880786

.879936

135°

 45°

.895815

.894415

.893105

.891877

.890724

.889640

.888617

.887651

.886738

.885872

.885051

TDC

BDC

1.50-1

1.55-1

1.60-1

1.65-1

1.70-1

1.75-1

1.80-1

1.85-1

1.9-1

1.95-1

2.00-1

136°

 44°

.900436

.899086

.897824

.896641

.895530

.894484

.893498

.892567

.891686

.890852

.890060

137°

 43°

.904951

.903652

.902437

.901298

.900228

.899221

.898272

.897376

.896527

.895724

.894961

138°

 42°

.909360

.908111

.906943

.905848

.904819

.903851

.902938

.902076

.901261

.900488

.899754

139°

 41°

.913662

.912463

.911342

.910291

.909303

.908374

.907497

.906669

.905886

.905143

.904439

140°

 40°

.917858

.916709

.915634

.914626

.913679

.912788

.911947

.911153

.910402

.909690

.909015

141°

 39°

.921948

.920848

.919819

.918854

.917948

.917094

.916289

.915529

.914810

.914128

.913481

142°

 38°

.925932

.924881

.923897

.922975

.922108

.921292

.920523

.919796

.919108

.918456

.917837

143°

 37°

.929809

.928806

.927868

.926988

.926161

.925382

.924647

.923953

.923297

.922674

.922084

144°

 36°

.933581

.932626

.931732

.930893

.930105

.929363

.928663

.928002

.927376

.926783

.926220

145°

 35°

.937247

.936338

.935488

.934691

.933941

.933235

.932569

.931940

.931345

.930780

.930245

146°

 34°

.940807

.939945

.939138

.938380

.937669

.936999

.936366

.935769

.935204

.934668

.934159

147°

 33°

.944262

.943445

.942680

.941963

.941288

.940653

.940054

.939488

.938952

.938444

.937962

148°

 32°

.947611

.946838

.946115

.945437

.944800

.944198

.943632

.943096

.942589

.942109

.941653

149°

 31°

.950854

.950126

.949443

.948803

.948202

.947635

.947100

.946595

.946116

.945663

.945232

150°

 30°

.953993

.953307

.952665

.952062

.951496

.950962

.950458

.949982

.949532

.949105

.948699

151°

 29°

.957026

.956382

.955779

.955213

.954681

.954180

.953707

.95326

.952837

.952435

.952054

152°

 28°

.959955

.959351

.958786

.958256

.957758

.957288

.956845

.956426

.956030

.955654

.955297

153°

 27°

.962778

.962215

.961687

.961192

.960726

.960288

.959874

.959482

.959112

.958760

.958427

154°

 26°

.965498

.964973

.964481

.964020

.963586

.963178

.962792

.962427

.962082

.961755

.961444

155°

 25°

.968112

.967625

.967169

.966741

.966338

.965958

.965600

.965261

.964941

.964637

.964348

156°

 24°

.970623

.970172

.969750

.969354

.968981

.968630

.968298

.967985

.967688

.967407

.967139

157°

 23°

.973029

.972614

.972225

.971859

.971516

.971192

.970886

.970597

.970323

.970064

.969817

158°

 22°

.975332

.974950

.974593

.974258

.973942

.973644

.973364

.973098

.972847

.972608

.972382

159°

 21°

.977531

.977182

.976855

.976548

.976260

.975988

.975731

.975488

.975258

.975040

.974833

160°

 20°

.979626

.979309

.979011

.978732

.978469

.978222

.977988

.977767

.977558

.977359

.977171

161°

 19°

.981618

.981331

.981062

.980809

.980571

.980347

.980135

.979935

.979746

.979566

.979395

162°

 18°

.983507

.983248

.983006

.982778

.982564

.982362

.982172

.981992

.981821

.981659

.981505

163°

 17°

.985293

.985061

.984845

.984641

.984449

.984269

.984098

.983937

.983784

.98364

.983502

164°

 16°

.986976

.986770

.986578

.986397

.986227

.986066

.985915

.985771

.985636

.985507

.985385

165°

 15°

.988556

.988375

.988205

.988046

.987896

.987754

.987621

.987495

.987375

.987262

.987154

166°

 14°

.990033

.989875

.989727

.989588

.989457

.989333

.989217

.989107

.989002

.988903

.988809

167°

 13°

.991408

.991271

.991143

.991023

.990910

.990803

.990703

.990607

.990517

.990431

.990350

168°

 12°

.992680

.992564

.992454

.992352

.992255

.992164

.992078

.991997

.991920

.991847

.991777

169°

 11°

.993851

.993752

.993660

.993574

.993493

.993416

.993344

.993275

.993210

.993149

.993090

170°

 10°

.994919

.994838

.994761

.994690

.994623

.994559

.994499

.994442

.994389

.994338

.994289

171°

  9°

.995885

.995819

.995757

.995699

.995645

.995593

.995544

.995498

.995455

.995413

.995374

172°

  8°

.996749

.996697

.996648

.996602

.996559

.996518

.996480

.996443

.996409

.996376

.996345

173°

  7°

.997511

.997471

.997434

.997399

.997366

.997334

.997305

.997277

.997250

.997225

.997202

174°

  6°

.998172

.998142

.998115

.998089

.998065

.998042

.998020

.997999

.997980

.997961

.997944

175°

  5°

.998730

.998710

.998691

.998673

.998656

.998640

.998625

.998611

.998597

.998584

.998572

176°

  4°

.999188

.999174

.999162

.999151

.999140

.999130

.999120

.999111

.999102

.999094

.999086

177°

  3°

.999543

.999536

.999529

.999522

.999516

.999510

.999505

.999500

.999495

.999490

.999486

178°

  2°

.999797

.999794

.999791

.999788

.999785

.999782

.999780

.999778

.999776

.999774

.999772

179°

  1°

.999949

.999948

.999948

.999947

.999946

.999946

.999945

.999944

.999944

.999943

.999943

180°

  0°

1.00000

1.00000

1.00000

1.00000

1.00000

1.00000

1.00000

1.00000

1.00000

1.00000

1.00000

TDC

BDC

1.50-1

1.55-1

1.60-1

1.65-1

1.70-1

1.75-1

1.80-1

1.85-1

1.9-1

1.95-1

2.00-1

Crank

Connecting Rod Ratio (Rod Length ÷ Stroke Length)