[Vwdiesel] Smokey, bubley engine

[James Hansen]

> -----Original Message-----
> From: vwdiesel-bounces at vwfans.com [mailto:vwdiesel-bounces at vwfans.com]
> On Behalf Of William J Toensing
> Sent: Sunday, November 01, 2009 10:24 PM
> To: vwdiesel at vwfans.com
> Subject: [Vwdiesel] Smokey, bubley engine
> 
> Mark, you suggested loosen & re-torque to 90 # psi, nothing to loose.
> My question is, at what point will the bolts or studs brake, or the
> block crack or the threads strip? 

Block cracks are from oil or something dead ending the stud in the hole,
causing a hydraulic failure. The force has nowhere to go but out the weakest
point, the side of the block. I'm real hesitant to just loosen and retorque,
I like making the sure the holes are free of debris, oil, etc. before
yarding them tighter, and if it doesn't seal at stock torque, it's unlikely
more clamping force will help.
Torque to yield studs are a single use item because they yield when tight
enough, the elastic strength of the steel regulates the clamping force.  You
get to do this once, and when you hit the elastic limit, they feel like it-
like you are torquing a rubber band.
If a gasket can't seal at the correct torque, a mechanical issue is keeping
it from sealing.  No amount of nothing to lose will fix it either usually,
but we all keep trying anyway.


On my '81 Dasher diesel, I torqued
> the original head bolts to the factory/Bentley recommended 50 or 55
> #psi, would have to look back in the bentley,but the right front bolt
> caused the block to crack. On my Model A Ford, several years ago, I was
> torquing to the recommended (50#psi, I think) & a couple of the studs
> broke.

Yep, 50ft-lb lightly oiled for the model A. That's a 1/2" fastener, and if
they can't withstand that, better they break on installation. That would
equate to 70 or so with dry threads btw.
-james

 China or Taiwan sourced from Sacramento Vintage Ford. They
> replaced the broken studs but not the new gasket I had to buy. That is
> why I am afraid of over-torquing. From what I recall, on the Model A,
> it took progressively more strength to bring it up to 50 #psi & then it
> started getting easier. If that happens again, I will stop when that
> happens. I raise this question because I think allot of you are far
> more experienced than I, & would like comments on this as I haven't
> started trouble shooting my
> Bill Toensing, Nevada City, CA
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