the ones Jesse got were obviosly for something else, but machines shorter and supplied for an A15, but as he is using an A12 lightened Flywheel they bottomed out, all good now..

Japlish translation:


"Indirectly it influences the sudden clutch meat and at the time of high revolution the vibration of the crankshaft which occurs as the flywheel vibration. As a result it is to withstand volt/bolt the vibration and not to be cut off and to develop in looseness and to reach to very dangerous state.
This flywheel volt/bolt with the strengthening volt/bolt by the ARP corporation (USA) whose reliability is high with the tightening torque of genuine ratio approximately 1.5 times the looseness of volt/bolt holds down and is packed, to the running which is stabilized leads.



Tightening torque ・・・13.5kg/m (standard 8.0 - 9.0kg/m)

* The front [deisubitaipu] A12 crank is not attached because screw pitch differs."

ARP does not make flywheel bolts for the A-series. So the ones used were intended for a different engine.

That's good to know (about the arp ones bottoming out) !!

Another thing that can play a part in high revving 4s is the lack of damper on the front pulley. I don't know if there's anything available off the shelf, or easily adaptable, but it is certainly part of the puzzle with regard to crank bolts coming loose or snapping altogether (of course the most important thing here is proper torque-ing of the bolts, not too little not too much) On a related note, most bolts have only so many tensile cycles they can go through (can only be tensioned and undone and re-used a certain number of times before they lose some of their tensile strength,).. And on that note I'd strongly suggest new bolts for any performance engine buildup. Similar thing for rod bolts. They aren't dirt cheap but are a lot cheaper than a whole new engine (or losing part of your foot, though I must confess i don't know of anyone that has happened to).

The same thing happened to Me

I put new nissan Flywheel bolts in my a15 with a lightened a12 Flywheel and after about 2 months ,probably 4000kms I gave it a real belting and they all snapped apart from 1

So I then put ARP bolts in it and after 200 odd meters they came loose! When i pulled it apart I found they were too long and were bottoming out just before tightening up on the face of the Flywheel ,so I trimmed them up and put loctite in them again and its been all good since

I doubt it was overtightening that snapped them. Probably more the force of the f/wheel hsaking itself loose. Last time it happened to me, (At drags, on my 1st pass too!) some had come undone, and a few had broken off. By the grace of the datsun gods the same forces that broken them, also unbonded the locktite they were glued in with. I was dreading trying to drill out 12.9 tensile stregnth capscrews while groveling on the driveway under the car.

happened to me too, the bolts had been over tightened and snapped every single one just outside my house, lucky i had my old a12 to pull them out, but was a bitch to get the snapped bolts out of my crankshaft seeing as the snapped off flush with it, went through a whole set of easy-outs, using the smallest first until it ended up me and my mate with a hammer slamming the reverse screw into it :D re-tightened to 88nm but didnt use loctite, do think loctite is extremely necessary?

I had a link to a place that does new engine bolts and studs for Datto's but can't find it, it had flywheel bolt kits for about $12 or something.

I haven't pulled it apart yet but whichever crank I'm using it's getting the doweling treatment

Quote:

Me too, until I went to a class on fasteners..
All threaded studs or bolts must be tightened no more than the "stretch" component allows.

IF you pull the "stretch" out of a fastener, then the assembly is subjected to HEAT, the fastener cannot then stretch any more, failure of the assembly may result..

On flywheel bolts, I suggest Grade 8[
Au = grade 12.9]
US GR-8 will be Gold in color and have SIX marks on the head.

US and Metric Bolt Torque Guide

I suggest Red Loctite, upon removal, simply use a propane torch for a few seconds on the head, and the loctite will let go.

Fastenall Bolt Specs

BigV and A14 both have ideas feasible to me.

Lemonhead's 680 loctite is a Cylindrical Retaining products, not designed for threads.

680 Loctite

Quote:
Is it beat up or what ?

Thanks for the input guys, any word on machining the crank providing the surface isn't rounded?