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post #38 of (permalink) Old 08-10-2017, 06:25 AM
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Originally Posted by p76rangie View Post

ARP originally made studs that did not go far enough into the block and they were ripping out. Due to consumer complaints, they increased the length of them, but increased the torque to 100ft/lb. So after decades of consumer complaints it appears that they finally came to their senses in December last year.

To anyone considering studs, please be aware that this is incorrect information. The third or fourth party information this poster is repeating is in reference to the Buick studs that many people attempted to use on the Rover engine. As many know, the Rover engine was purchased from Buick many years ago. It shares many attributes with the Buick but there are many differences. ARP made studs for both engines and cataloged them under different numbers. However, the Buick stud was shorter. The Buick studs were somewhat less expensive and some tried to use them in the Rover engine. These people experienced failures due to the lack of proper thread engagement depth. At no time has ARP changed the length of the studs in the Rover kit.

Additionally, many of the failures related to the Rover studs were caused by incorrect installation. The original head bolt was cut for a standard head bolt using a taper tap. When studs, which are longer, were screwed to the bottom of this bore, it caused binding in the form of the stud forcing the bore to expand due to the tapering nature of the last few threads. Several of the bolt holes are very close to the edge of the block which adds to the susceptibility for cracking. The correct procedure is to fully cut the bottom threads with a proper bottoming tap. This allows full engagement without binding.

The spec sheet on any individual part cannot turn a neophyte into an experienced, competent engine builder.
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