If you remove all the split lock washers, you must be removing about 5
pounds. That will increase your acceleration.
I heard somewhere that Colin Chapman fired a mechanic for using washers on
their Lotus 7's or 11's because of the added weight.
Don Elliott, 1958 TR3A, Montreal, Canada
----- Original Message -----
From: "Bill Babcock" <BillB@bnj.com>
To: <FOT@autox.team.net>
Sent: Tuesday, February 11, 2003 4:08 PM
Subject: RE: Retorquing head gaskets
> By the way, here's some common stretch specs for ARP bolts, along with a
> little more discussion on torque VS stretch from a website I found. The
> angle method scares the heck out of me--I don't know why. It feels like
> "tighten it down till it breaks and back off half a turn". I don't
> remember the URL, I saved it as text in my Triumph resource file:
>
> For any fastener to supply clamp loads high enough to keep the parts
> bolted together, it must be stretched the proper amount. Torque does not
> measure bolt stretch, it measures friction. This is why we prefer the
> stretch method or the torque and angle method for tightening rod bolts.
>
> To use the stretch method, measure and note the free length of each bolt
> before tightening with a stretch gauge or a micrometer with ball end
> attachments. Then, using the chart below, tighten the bolt until the
> proper stretch is achieved.
>
> The torque and angle method uses the lead of the thread to stretch the
> bolt the proper amount. To use this method, simply torque the bolts the
> amount listed in the chart below (this low amount of torque snugs up the
> bolt and removes lash). Then, using a Snap-On #TA360 torque angle gauge,
> turn the bolt the listed number of degrees.
>
> Bolt Type Recommended Stretch Torque & Angle
> 5/16 - Oliver/ARP 3.5 .0052" to .0057" 10 ft lbs + 55 deg
> 3/8 - Oliver/ARP 2000 .0052" to .0057" 25 ft lbs + 50 deg
> 3/8 - Oliver/ARP 3.5 .0057" to .0061" 25 ft lbs + 55 deg
> 7/16 - Oliver/ARP STD (Black Bolt) .0048" to .0055" 30 ft lbs + 40 deg
> 7/16 - Oliver/ARP WSB .0053" to .0058" 30 ft lbs + 40 deg
> 7/16 - Oliver/ARP 3.5 .0060" to .0065" 30 ft lbs + 50 deg
>
> As a final check to make sure no bolts were missed: Before bolting the oil
> pan on, set a torque wrench at 50 ft lbs (use a wrench set at 30 ft lbs
> for 5/16" bolts), and check all rod bolts. If any bolt turns before
> reaching the preset torque, it has not been properly tightened. You must
> loosen these bolts and tighten them properly.
>
>
> -----Original Message-----
> From: Bill Babcock
> Sent: Tuesday, February 11, 2003 10:39 AM
> To: 'John Wilkins'; FOT@autox.team.net
> Subject: RE: Retorquing head gaskets
>
>
> I think everyone is on the right track. The complicating factor is how
> much everything moves. These are very strange engines. We have a cast iron
> block, steel sleeves, cast iron head, some very long and relatively short
> bolts, none of which are through-bolts. All these things are heated
> differently and cooled differently. Then we have a wide array of
> gaskets--composition, copper clad, steel clad, steel shim, steel shim with
> copper wire, and solid copper.
>
> One answer for all? I doubt it.
>
> I always retorque the heads--why wouldn't you? I'm not that committed a
> spectator, so I tend to fuss around my car in the pits. If I set the
> valves I usually torque the heads first. Every so often you find a bolt
> that has loosened a little somehow. If you use either composite or shim
> steel with a copper ring, you'll see a substantial change after a heat
> cycle. Not just once--you see it six months later.
>
> A bigger question is are the bolts dry or lubricated. That's a much bigger
> variable than the heat cycle. If you torque a bolt to it's published spec
> dry the chances of pulling out the threads or breaking the bolt are very
> low. If you use a very effective (for sliding friction) lubricant then the
> same torque will rip out the threads or break the bolt. I got obsessive
> about this issue after I broke a long head bolt at the base of the thread
> way down inside the block in the pits before the Monterey Historics.
>
> Most torque specs assume a motor oil lubricated bolt. If you want to
> really do it right, you need to find the stretch specification for each
> bolt you are using, lubricate it with the lube you intend to use, put the
> bolt in a fixture that will allow you to measure stretch, torque it to the
> stretch spec and read the torque value. Then always use that lube with
> that bolt.
>
> With bigger or longer bolts, motor oil or dry torquing will give highly
> variable numbers when you torque to a stretch spec. The torque jumps as
> the bolt sticks and slips. The super slick stuff supplied with high
> quality bolts is too scary to use--on a cheap bolt you'll exceed stretch
> specs way before you see any significant torque.
>
> Gear oil works okay, but I've settled on a cheap, readily available
> anti-seize compound that I use for everything. I've also gotten allergic
> to split lockwashers. Spending any time investigating bolt torque and
> stretch will convince you they are a tool of Satan. Instead I have big
> bottles of every type of locktite. I'm gradually eliminating lockwashers
> from everything.
>
> For simplicity sake I torque the long and short head bolts the same, even
> though they really do require different torques to reach spec stretch.
> With a shim steel gasket and copper wire rings with anti-seize on the nuts
> and good, hard washers (no nicks on them either) 65 pounds is good. After
> a heat cycle I remove the nuts one at a time, re-lube lightly, and
> retorque to 65.
>
> So far, so good.
>
> Sounds like too much trouble, but it only took me a couple of nights to
> make a fixture and test the bolts (I just drilled lengthwise through a 2"
> thick chunk of steel I had, put a nut and locknut on the bottom end of the
> bolts, and borrowed a big micrometer to measure bottom to top of the bolt
> at five pound increments), and retorquing takes about an hour.
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