type 1 performance engine torque specs? finger tight case studs?

Just doing some studying in the manuals. I will soon be assembling a long block. I'm on a budget and so can't afford a specialist to assemble, however as a graduate engineer i think its my obligation to learn the workings hands on 🙂.

Engine is 2054cc Alum case, 74mm CW crank, 94 P&B's, SP heads (39x35.5mm), CT26 turbo, dual 32DIS Solex carbs, Scat C25, magnaspark II dissy. Wierd combo, but goal is torque monster for baja, with turbo to 'pick up' the typical SP top end drop off and extend the power curve.

For a non-stock engine, should factory torque specs still be adhered to for all studs/fasteners? Or should greater torque be applied in some instances?

I read that case studs should be installed 'finger tight' only. Is this all? no torquing with wrench what so ever?

Thanks,
Chris 🙂.

Build to come on here soon! Rotating assembly is at Crankshaft ENgineering Browns Plains at the moment and heads at mick motors getting some work.

Finger tight only ???.... I think you may be thinking of the stud installation which could be that way with loctite.

matberry wrote:Finger tight only ???.... I think you may be thinking of the stud installation which could be that way with loctite.

Yea the case studs when installed into case. So its true? I won't be using loctite on teh case studs, i will be useing Permatex 3H sealer though. Just seemed a bit bizarre to have no preload, bit counter intuitive. I read it in "how to rebuild your volkswagen" by Tom Wilson, and "how to keep you volkswagen alive' doesn't specify case stud torque in their torque table. I will look at the 'scientific publications' manual tonight, but the one I got only covers up to 1500cc.

Thanks Matt.

I only install the head studs in the case finger tight with a bit of never sieze then double nut them and nip them up, do not forget to lubricate the threads with a engine assembly lube or engine oil when you torque them up the heads other wise you will not achive the best clamping force. factory torque for the 10MM studs is 23 Ft LB, 8 MM studs is 18 FT LB.

vwo60 wrote:I only install the head studs in the case finger tight with a bit of never sieze then double nut them and nip them up, do not forget to lubricate the threads with a engine assembly lube or engine oil when you torque them up the heads other wise you will not achive the best clamping force. factory torque for the 10MM studs is 23 Ft LB, 8 MM studs is 18 FT LB.

Thanks mate. so 23 ft lb for 10mm is for the nuts on the studs? or the studs themselves into the case when you double nut them after finger tight screwing?

23/18 is for the nut during assembly, but as Shayne has said, VERY important for good assembly lube to be on the threads AND between nut and washer, up to 700% increase in clamp force when lubed against dry threads.

I'm still perplexed as to what the finger tight studs your talking about. Any case studs (M12) I've removed have been very tight for much of the thread. The loctite I mentioned was foy stud into case, not the nuts, as for sealant, that goes UNDER the washer, between case/head and washer on the M12 case studs and the lower head studs.

If your components are at CE, you should have also discussed it with Craig as it is imperitive to be using the same specs as he does to replicate the same tensions/bearing crush etc..

matberry wrote:23/18 is for the nut during assembly, but as Shayne has said, VERY important for good assembly lube to be on the threads AND between nut and washer, up to 700% increase in clamp force when lubed against dry threads.

I'm still perplexed as to what the finger tight studs your talking about. Any case studs (M12) I've removed have been very tight for much of the thread. The loctite I mentioned was foy stud into case, not the nuts, as for sealant, that goes UNDER the washer, between case/head and washer on the M12 case studs and the lower head studs.

If your components are at CE, you should have also discussed it with Craig as it is imperitive to be using the same specs as he does to replicate the same tensions/bearing crush etc..

THanks Matt. I'll have a chat to him when i pick it up; all CE is doing is balancing of new components, no reconditioing.

The finger tight studs are the 16 x head studs, i have 10mm ready to screw into the case savers, sorry i didn't explain it very well. I read that installation of these case studs prior to slotting on the barrels though em is just a matter of dabbing sealant on the threads and screwing them in finger tight.

Ooohhhhhhhh.... "head studs" 😀

I'm of the finger tight into the case with loctite school

Screw em in till they leave enough threads past the the 15mm head nuts and proper thick flat washers (use correct quality) during a dry/mock build. Back thm out 2 full turns, add loctite red, screw em back in. This will save damaging the case inserts and head studs via over tightening