Other Franklin Information

Bad running Franklin

Several of you have helped me search for a solution difficulties in getting my Franklin engine running properly. As a brief recap, I bought the PZL Franklin new about 5 years ago and flew it for about 26 hours. It never ran well which I attributed at least partially due to plug fouling. The rings never seated properly. I finally decided to re-sleeve the cylinders to get a softer grade of steel as liners. I sent the cylinders to Davis Aviation for new sleeves. I fly out of an elevation of 8200 ft and it is difficult to get manifold pressure.

After reassembly of the engine and re-installation, the engine ran worse than ever - back firing and popping and difficulty getting RPMs above 1500. I checked everything - induction leaks, carburetor function, mags, wiring, plugs - you name it - nothing helped. I tried to locate centerline intake valve angle but had difficulty locating these number. Eventually, Phil Davis of Davis Aviation located these numbers and sent them to me.

Saturday, mechanic John Welty and I used these numbers to check the center line angle for the intake valve on #1 cylinder and found the angle to be off 6 degrees. Instead of 104 degrees, the angle was 98 degrees. So, the engine was pulled once again. We took off the mags and accessories at the back of the engine and took off the rear cover. Then, we pulled the starter ring, revealing the cam gear and crank gear.

When rotated, the mark on the crank gear meshed between the two marks on the cam gear (or the other way around) just like the book said it should but the center line angle was wrong. We pulled the crank and cam gears and reset them so that the angle was correct. We had to move the gear one tooth - about 6 degrees.

After reassembly and reinstallation, we started the engine and it now appears to be running well. I have not yet flown it but intend to do so this week. It has been a frustrating - and expensive - several months trying to get this resolved.

I'm not sure why this happened but have a guess. It appears that the cam gear or crank gear was miss-marked. When the engine was test run at the factory, it likely did not run at all well. It appears that they opened the valve lash enough to run. When we reset the valve lash to the proper amount, the engine would not run. Now that the cam timing is correct, it runs with the proper valve lash. Sounds incredible but I can't think of any thing else.

If anyone needs or wants a copy of the valve lift versus angle, please contact me and I will e-mail the table to you. Thanks to each of you for your suggestions and help.

Jerry Teitsma
Granby CO
jerryteits at comcast.net

Valve Lift versus Engine Angle

Here is Jerry's data that I OCR'd and corrected. It is not exactly thesame because I took some liberties of pasting in the closed valverange. The open timings should be correct.

For reference, this is an unknown Franklin 6A-350-C1R. The title has: TITLE = NEWF
CYLINDER # = 1
FILENAME=NEWF16
12-20-12
TEST # 16
ADD -.34 TO CRANK DEG.

2 0.1002 4 0.1080 6 0.1157 8 0.1235 10 0.1314 12 0.1393 14 0.1471 16 0.1549 18 0.1620 20 0.1705 22 0.1782 24 0.1858 26 0.1933 28 0.2007 30 0.2080 32 0.2150 34 0.2220 36 0.2286 38 0.2354 40 0.2418 42 0.2481 44 0.2542 46 0.2600 48 0.2658 50 0.2712 52 0.2765 54 0.2815 56 0.2863 58 0.2909 60 0.2954 62 0.2996 64 0.3035 66 0.3073 68 0.3108 70 0.3141 72 0.3172 74 0.3200 76 0.3226 78 0.3250 80 0.3270 82 0.3289 84 0.3300 86 0.3319 88 0.3330 90 0.3340 92 0.3347 94 0.3352 96 0.3356 98 0.3358 100 0.3359 102 0.3360 104 0.3360 106 0.3360 108 0.3359 110 0.3356 112 0.3352 114 0.3347 116 0.3340 118 0.3331 120 0.3321 122 0.3308 124 0.3293 126 0.3276 128 0.3257 130 0.3235 132 0.3211 134 0.3185 136 0.3156 138 0.3124 140 0.3092 142 0.3056 144 0.3000 146 0.2979 148 0.2935 150 0.2890 152 0.2843 154 0.2794 156 0.2743 158 0.2690 160 0.2635 162 0.2579 164 0.2521 166 0.2460 168 0.2398 170 0.2333 172 0.2267 174 0.2199 176 0.2100 178 0.2056 180 0.1984 182 0.1909 184 0.1834 186 0.1758 188 0.1680 190 0.1602 192 0.1523 194 0.1445 196 0.1366 198 0.1287 200 0.1209 202 0.1133 204 0.1057 206 0.0983 208 0.0900 210 0.0842 212 0.0776 214 0.0713 216 0.0652 218 0.0595 220 0.0541 222 0.0490 224 0.0443 226 0.0399 228 0.0358 230 0.0321 232 0.0287 234 0.0258 236 0.0232 238 0.0209 240 0.0191 242 0.0175 244 0.0163 246 0.0152 248 0.0142 250 0.0133 252 0.0125 254 0.0117 256 0.0109 258 0.0102 260 0.0095 262 0.0088 264 0.0082 266 0.0080 268 0.0070 270 0.0060 272 0.0060 274 0.0050 276 0.0040 278 0.0040 280 0.0030 282 0.0030 284 0.0020 286 0.0020 288 0.0020 290 0.0020 292 0.0020 294 0.0010 296 0.0010 298 0.0010 300 0.0010 302 0.0010 304 0.0010 306 0.0010 308 0.0010 310 0.0010 312 0.0010 314 0.0010 316 0.0010 318 0.0010 320 0.0010 322 0.0010 324 0.0010 326 0.0010 328 0.0010 330 0.0010 332 0.0010 334 0.0010 336 0.0010 338 0.0010 340 0.0010 342 0.0010 344 0.0010 346 0.0010 348 0.0010 350 0.0010 352 0.0010 354 0.0010 356 0.0010 358 0.0010 360 0.0010 362 0.0011 364 0.0010 366 0.0010 368 0.0010 370 0.0010 372 0.0010 374 0.0010 376 0.0010 378 0.0010 380 0.0010 382 0.0010 384 0.0010 386 0.0010 388 0.0010 390 0.0010 392 0.0010 394 0.0010 396 0.0012 398 0.0012 400 0.0010 402 0.0010 404 0.0010 406 0.0010 408 0.0010 410 0.0010 412 0.0010 414 0.0010 416 0.0010 418 0.0010 420 0.0010 422 0.0010 424 0.0010 426 0.0010 428 0.0010 430 0.0010 432 0.0010 434 0.0010 436 0.0010 438 0.0010 440 0.0010 442 0.0010 444 0.0010 446 0.0010 448 0.0010 450 0.0010 452 0.0010 454 0.0020 456 0.0020 458 0.0020 460 0.0020 462 0.0020 464 0.0020 466 0.0020 468 0.0020 470 0.0020 472 0.0020 474 0.0020 476 0.0020 478 0.0020 480 0.0020 482 0.0020 484 0.0020 486 0.0020 488 0.0020 490 0.0020 492 0.0020 494 0.0020 496 0.0020 498 0.0020 500 0.0020 502 0.0020 504 0.0020 506 0.0020 508 0.0020 510 0.0020 512 0.0020 514 0.0020 516 0.0020 518 0.0020 520 0.0020 522 0.0020 524 0.0020 526 0.0020 528 0.0020 530 0.0020 532 0.0020 534 0.0020 536 0.0020 538 0.0020 540 0.0020 542 0.0020 544 0.0030 546 0.0030 548 0.0030 550 0.0030 552 0.0020 554 0.0020 556 0.0020 558 0.0020 560 0.0020 562 0.0030 564 0.0030 566 0.0030 568 0.0030 570 0.0030 572 0.0030 574 0.0030 576 0.0030 578 0.0030 580 0.0030 582 0.0030 584 0.0030 586 0.0030 588 0.0030 590 0.0030 592 0.0020 594 0.0030 596 0.0030 598 0.0030 600 0.0030 602 0.0030 604 0.0030 606 0.0030 608 0.0030 610 0.0030 612 0.0030 614 0.0030 616 0.0030 618 0.0030 620 0.0030 622 0.0030 624 0.0030 626 0.0030 628 0.0030 630 0.0030 632 0.0030 634 0.0030 636 0.0030 638 0.0030 640 0.0030 642 0.0030 644 0.0030 646 0.0030 648 0.0030 650 0.0030 652 0.0030 654 0.0040 656 0.00358 658 0.00362 660 0.00366 662 0.00374 664 0.00382 666 0.00394 668 0.00406 670 0.00429 672 0.00453 674 0.00488 676 0.00531 678 0.00591 680 0.00661 682 0.00748 684 0.00858 686 0.00992 688 0.01154 690 0.01354 692 0.01591 694 0.01862 696 0.02181 698 0.02551 700 0.02961 702 0.03417 704 0.03921 706 0.04465 708 0.05047 710 0.05673 712 0.06339 714 0.07031 716 0.07756 718 0.08496 720 0.09256