Tony D Posted July 31, 2007 Share Posted July 31, 2007 Ever notice the LD28 Crank has a dowel hole in the end? If anybody is really slamming the clutch hard, I'd recommend dowelling the flywheel to crankshaft BEFORE balancing, and using an 'offset' dowel pattern, that way the flywheel only goes on one way: the way it was balanced! Three .250" or .375" Dowels in a 120 degree offset pattern between bolts should pin it just fine. You could use 6 .250" Offset one dowel half a diameter off from the geometric index (Similar to the SPG Dowel Pattern used on VW Engines). The dowels take a lot of the shear worries out of the bolts, and stop a lot of the shear that causes the loctite to fracture, or loosen the bolts. Just a thought... Quote Link to comment Share on other sites More sharing options...
OlderThanMe Posted July 31, 2007 Author Share Posted July 31, 2007 hmm... I have had this happen with 2 different dampners. I had it happen with my old one with very little rubber left and then I replaced it with one off a low mile 240z in the junkyard that had the rubber in perfect condition. I haven't revved much over 6000 since getting this motor back together. I hit 6500 the last time I drove it and that was the highest it has been... TimZ: They are original flywheel bolts that held in the stock flywheel. I'll check the crank on teardown. Hairline cranks sound scary. About 2 years ago I blew out a tranny gear selector fork retaining pin and the tranny went into neutral when I tried to shift, dropped clutch at 5k RPMs and WOT. This was all before the light weight flywheel and clutch. The tach passed 8,000 RPMs for around a second or two. I have been worried about that for a while but it all seemed fine. It didn't blow the head gasket out but it did make a big black cloud (from way rich carbs??) and a little white puff. That is probably what stretched my head bolts and caused three to break off upon disassembly. I noticed a small area around the #5 piston where it looked like some water leaked around the gasket once. TonyD: I just noticed the dowel on the LD28 I am tearing down. Also read it in the "how to modify youd datsun OHC engine" book... Quote Link to comment Share on other sites More sharing options...
Dragonfly Posted July 31, 2007 Share Posted July 31, 2007 I'll check the crank on teardown. Hairline cranks sound scary. How far are you going to tear it down? No matter how far, you should at a minimum take the flywheel to a machine shop and have it wet magged, if you go so far as to pull the crank take it as well. I think I paid about $40 for crank and flywheel wet mag and about $15 for the block to be magged, don't remember how much the rods cost because that was part of the cost of bushing, sizing, shot peening etc. but any way it is not expensive and it is well worth it IMHO. Dragonfly Quote Link to comment Share on other sites More sharing options...
Tony D Posted July 31, 2007 Share Posted July 31, 2007 Agreed! Magnetic Particle Inspection is the thing to do when it's apart, and BEFORE you go any further with modifications. Nothing sucks worse than to put a bunch of hours into hand-prepping something only to have it magcheck and find a crack! Quote Link to comment Share on other sites More sharing options...
OlderThanMe Posted July 31, 2007 Author Share Posted July 31, 2007 I'm going hybrid now... v8. I'm fed up with this motor and don't want to spend another 12 hours pulling the tranny and flywheel if it will be coming out anyway for a completely different engine. Quote Link to comment Share on other sites More sharing options...
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