Z-Gad Posted May 21, 2003 Share Posted May 21, 2003 I am doing an n/a stroker for my daily driver. I am using a shaved N42, LD28 crank, L28 rods, .030 over L28 dished pistons (shaved 1mm), and a 2mm head gasket, yielding a little over 10:1 compression. Just a quick note to anyone else going to try the "budget" stroker route... When I assembled the shortblock, the crankshaft counterweights would hit the piston skirt, so the rotating assembly would not turn. I am not sure whether the same problem would be had using the stock pistons, but I thought it was worth mentioning. I ended up scoring a rod journal (unrelated the crankshaft not turning) so I took my goodies back to the machine shop. Now they are shaving the counterweights to clear the piston skirt and will be rebalancing the crankshaft, along with fixing my boogered rod journal. Just once I'd like for everything to work out nicely the first time Quote Link to comment Share on other sites More sharing options...
Guest norm[T12SDSUD] Posted May 21, 2003 Share Posted May 21, 2003 I wished you had asked me before you built your motor as I would have told you to file the raised forging line off the crank counterweights. I had to do this on both my diesel cranks. Normally it is the #6 cylinder counterweight that hits the piston. Oh Well, make sure you use loc tite on the flywheel bolts and torque the harmonic damper to at least 130-150 ft lbs. and use loc tite on them also. In addition get 14 diesel main bolts as you can torque them to 58 ft lbs. instead of the stock bolt's 40 ft. lbs. Good luck on the rebuild. later,norm Quote Link to comment Share on other sites More sharing options...
Z-Gad Posted May 22, 2003 Author Share Posted May 22, 2003 Thanks Norm!! I knew you would have been the one to ask, and I was going to email you and I actually did do a search on this site as well as the Zcar site hoping to find something out regarding the L28 rods w/ the LD28 crank before I began, but came up empty... Oh well, live and learn. thanks for the helpful hints on the build. Mike Quote Link to comment Share on other sites More sharing options...
DAW Posted May 22, 2003 Share Posted May 22, 2003 I think that you'd be better off with L24 rods (133mm) instead of L28 (130.4), and better off using a piston with a lower compression ht. than the 38.1mm of the L28. Actually, you'd be better off with an LD28 block bored from 84.5mm to 86mm, Z22E rods (148.6mm) and L28ET pistons for turbo or F54 L28E pistons for na, either way with P90 head. I've described how to do this conversion in previous posts. I've been driving an LD28 shortblock/N42 10:1 engine for a couple of years. DAW Quote Link to comment Share on other sites More sharing options...
Z-Gad Posted May 22, 2003 Author Share Posted May 22, 2003 DAW, I have followed your previous posts regarding the LD28 n/a engine you have built and I am impressed with the undertaking you made. Although I may be better off w/ another set-up, I am this far in now and have to kinda follow through w/ what I started here. I really did not ntend to do this build as it is turning out, but it kinda drifted this way as I gathered parts and the next thing I know, I am right in the middle where I can't really turn back as the parts I have will now be of no use to anyone else. I realize the rod stroke ratio I will use is far from ideal, but I have my turbo stroker to drive when I really need a kick in the pants Quote Link to comment Share on other sites More sharing options...
Jeff Posted May 22, 2003 Share Posted May 22, 2003 Sorry to hear about your troubles Mike. I hope the scored rod journal wasn't because of bad machining on the parts I sold you. Let me know. Quote Link to comment Share on other sites More sharing options...
Z-Gad Posted May 22, 2003 Author Share Posted May 22, 2003 Nope Jeff, it was of my own accord. I had the bearing a little caddy-wampus and tightened down the rod bolts, scoring the crankshaft. Another expensive lesson courtesy of the school of Mike Quote Link to comment Share on other sites More sharing options...
DAW Posted May 23, 2003 Share Posted May 23, 2003 I know how that goes with the cart ahead of the horse sometimes. I don't think the 0.030" shaved L28 dished pistons are no good now because you could shave them more, (until they are flat-tops) and run them with L24 rods and an L28 crank (or sell them for that purpose). The low rod/stroke doesn't mean it's a lost cause but since that provides some low-end advantage, you might want to tune and gear in that direction rather than going for a super high redline. DAW Quote Link to comment Share on other sites More sharing options...
Z-Gad Posted May 23, 2003 Author Share Posted May 23, 2003 Thanks DAW, I'll keep the rpm's somewhat down...even in my turbo stroker I don't take it much past 6k rpm. Quote Link to comment Share on other sites More sharing options...
Guest norm[T12SDSUD] Posted May 23, 2003 Share Posted May 23, 2003 You can turn it up to 7000 RPM ...just don't miss a shift! My diesel crank survived almost 4 years of the most horrible abuse imagineable before breaking in two like the 280 cranks before it. Had the harmonic balancer not failed and the clutch not exploded and the two flywheels had not come loose it may have went for many more years!! LOL The rod to stroke ratio is not much better at all with the 240 rods , so don't let using 280 rods concern you if you wanna take her on up to 7000 rpm. later,norm Quote Link to comment Share on other sites More sharing options...
DAW Posted May 23, 2003 Share Posted May 23, 2003 Z-gad, it's not just the ultimate rpm to consider. Rod/stroke has an indirect bearing on cam duration & overlap effects due to the amount of time the piston spends around TDC vs its rate of acceleration on the stroke portion of the cycle. Check that out because certain tuning approaches can take advantage of high or low ratios. I'd follow Norm's advice on cam selection, cam timing, tuning, etc. e.g., I think he likes to run his cam somewhat retarded vs advanced, and this is empirically arrived at by his timeslips. Trust his tips more than generic advice for engines (with longer rods). DAW Quote Link to comment Share on other sites More sharing options...
Z-Gad Posted May 24, 2003 Author Share Posted May 24, 2003 I shall follow the "School of Norm" in this endeavor. It is nice to have access to someone who has been through the ringer before you Quote Link to comment Share on other sites More sharing options...
DAW Posted May 24, 2003 Share Posted May 24, 2003 A final thought...what you have is what you have; road racing for that engine is out of the question. However, It might well kick *** in an autocross car! Lots of grunt coming out of those tight corners! DAW Quote Link to comment Share on other sites More sharing options...
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