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Category: Categories > Engines > Engine Building > Tech Tip
|Bolts and studs
Posted: Sun Feb 23, 10:36 AM EST
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|Author's Name: alteredstate||View author's other Tech Tips|
|Author's Username: alteredstate||Ask the Author a Question or View Answers|
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I operate a small engine building service call Longevity Plus! I build engines for hot street cars, circle cars, and drag cars, from very tame to pretty wild. Ive stayed away from nitro until recently but have experience with stack and hat injectors and blown alcohol. I currently have an altered with a 441 Dart small block, Enderle hat injection on a tunnel ram base, and run methanol to 30% nitro. Now if I could just get the front end to set down before the 400 mark...........Ballast maybe? The topic Id like to discuss is fasteners. Yeah, studs and bolts. The stuff that holds the really expensive stuff together. When selected and used properly they make a good engine better because it lives longer. Do you need new studs or bolts? There are tons of engines being assembled every day using fasteners that werent designed for racing and add to that the fact that many are 10-15 years old and ......... Well, see where Im going? Should you use bolts or studs? Well I try to use studs everywhere I can. The bottom end gets them, including the oil pump. Also you cant use them on the heads in many door cars since you may not be able to remove the head without pulling the engine. Less work equals more fun. Many of these tips are from the ARP catalog and website automotiveracingproducts.com. I use ARP simply because they are reasonably priced, readily available, and I feel, the best fasteners out there. Dont overbuy. Fasteners designed for top fuel engines are a huge waste of money for your normal drag car unless you have hit the lottery. Buy based on your needs. More is often not better. Before you send your block out for machine work, select your fasteners. Clean and chase your main threads and head threads. Dont use a tap. A set of thread chasers cost very little and dont modify the existing threads. Use the recommended thread lube. I use moly from ARP. If you use oil, you need more torque to fasten properly. Fasteners should be tightened to specs and loosened 5-6 times to smooth them out. On heads use a cheap or old gasket, not the new goods ones. Torque will equalize after this sequence. Main caps should be installed and torqued to specs during boring/honing cylinders with the fasteners you intend to use. The same torque should be applied during assembly as when machining. Machining of the bores should also be done with a torque plate. Again, torqueing to the same specs as you will use to assemble. Re-chase all threads after thorough cleaning when you are ready to begin assembly. Studs are installed finger tight only. DO NOT double nut and tighten them in. Make sure all threads are engaged. All should protrude about equally if they are of the same length. Many aftermarket fasteners use washers under the bolt heads or nuts. They have an up and down side. Read the directions. Lube the underside of the bolt head, threads, washers, and nuts with moly lube. Use a good quality torque wrench. I like the dial type, digital readout type and the click type. I dont like beam wrenches. They can be very inaccurate due to design and the angle you view them. Also, check calibration once a year or more often if used a lot. Also try and check your wrench with a friends, since new wrenches can be 10 lbs. off now and then. If theres a difference, one of them has to be wrong. Buy the best wrench you can afford if you dont have one. They will last a lifetime. One final tip on these wrenches. Some dont read when tightening left hand threads. Dont find that out when you go to tighten a ring gear in a rearend. Use the proper sequence in tightening and use the fastener manufacturers torque specifications, not the factory specs. Finally, remember that cleanliness is everything as is attention to detail. After all is torqued, go back a few minutes later and re-check. Good luck and safe racing.