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Old 02-05-2005, 05:52 PM
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Doktor Bert Doktor Bert is offline
Das Sturm Uberdoktor
Join Date: Jan 2005
Location: Palm Springs, CA.
Posts: 2,670
Originally Posted by Pete Burton
I have to take issue with 2 things here. I would NOT remove the thermostat unless you have a specialized purpose in mind, like drag racing. The thermostat in your SD, which typically fails by opening early, has an intended purpose. It reaches ideal operating temperature quickly and maintains it, for the benefit of the engine's reliability and passenger comfort (heat). Second, I would warn you NOT to replace your fasteners with stainless steel ones. Stainless fasteners are typically 18-8 stainless, a soft, austenitic metal. While you might avoid some corrosion problems, you introduce a few others. Stainless steel is notorious for galling, especially in aluminum. This feature alone leaves you in a undesirable condition when you load the fastener up with anti-sieze and tighten it. The threads deflect much more than they are intended to against the hole (and deflect the threads in the hole as well) Torquing fasteners under ideal conditions has enough variability in it, but the same torque value can easily provide too much preload. Reducing the torque to compensate can cause the fastener to loosen and fall out. Moreover, many of the fasteners on the 617 are allen heads (like the M6 screws holding the upper oil pan and the vacuum pump) The 60 degree pressure angle on the head is frequently not strong enough to withstand the forces needed to tighten and later loosen it. In other words, they can cam out. Hell, even the alloy steel screws can cam out under certain conditions. If you remove any corroded screws by all means replace them, but with original type, cad plated, alloy steel screws. PLEASE!
Grade 8 Stainless is available. I took all these maters into consideration many years ago when I started using SS fastners. No reduction in torque is required.

I also test bolts in a batch by torquing them to the breaking point and recording the force required. So far, they have performed in identical fashion to plated Grade 8 Fastners.

Over the years, I have installed SS fastners on literally hundreds of engines with positive results.

As previously posted, one should check the material used in the production of the fastner.

Also..I don't use thermostats in my own vehicles. I simply install a hollowed-out thermostat body that will offer slight restriction to coolant flow in exactly the same percentage as the stock thermostat at full open.

All engines build a certain amount of residual heat and they will create this heat energy no matter what action you take.

Thanks for the informative post...Bert

Last edited by Doktor Bert; 02-05-2005 at 10:52 PM.
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