The process of assembling an engine requires attention to detail from start to finish. How you approach using fasteners and hardware needs just as much thought as any other area of the build. We talked with Bob Florine from ARP to get 10 tips on how to prevent issues with your fasteners and hardware when assembling an engine.
Surgery and engine building have a big thing in common, cleanliness is vital if you want to have a successful outcome. This applies to the fasteners themselves as well as the spot you’re going to be threading the fasteners into. Dirt and debris can prevent the fastener from doing its job or even damage it.
Tip 1
The first tip that Florine brought to us was about making sure the receptor (tapped hole in the block, cylinder head, etc.) is clean and ready. ARP has special “chaser” taps that you can use to clean up a receptor. This chaser tap cleans the threads up without cutting them. A good practice is to blow air into the receptor to remove any dirt or debris that might be inside. You can also spray some brake or carb cleaner inside the hole to aid in the cleaning process.
Tip 2
The next tip Florine provided is that you thoroughly clean the fastener itself. The fasteners might look clean when you pull them out of the package, but it’s always good to take the time and clean them yourself just to be sure. You can use brake cleaner or carb cleaner on the fasteners and then wipe them off with a microfiber towel. A healthy blast of air won’t hurt either according to Bill.
Tip 3
Florine’s third tip covers why it’s so important to lubricate the fastener with the correct product. The lubricant’s job is to “control” the friction each fastener will be exposed to as you tighten it. According to ARP’s website, the friction can inhibit the ability of the fastener to reach its preload during the first few cycles. The correct lubricant will ensure you have preload repeatability and consistency for each fastener.
“ARP’s Ultra-Torque Fastener Lubricant is superior to any oil, moly, or other lubricant you can use on a fastener. It’s laboratory-proven to provide 95-100-percent of the desired preload on the first, and any subsequent pull on the fastener. This is critical to the successful installation of any ARP fastener,” Florinel says.
Tip 4
The fourth tip that Florine provided continues to cover the subject of fastener lubrication. Some people are under the impression that you need to lubricate the underside of the bolt’s head, washer, or nut. The reason is that doing this will cause preloading issues and the torque application won’t be accurate. As you can imagine, this can cause a whole host of problems that will impact the fastener’s ability to perform properly.
Tip 5
Now, the fifth tip may seem like common sense, but we all know common sense isn’t common practice. Florine recommends that you always look at the directions for any ARP fastener or piece of hardware. The reason? According to Florine, the mindset of “I’ve done this in the past” can be a problem because recommended torque values do change on occasion. You can avoid a costly failure by just taking a second to read the directions included with the product or checking them on ARP’s website.
Tip 6
Have you ever had your torque wrench’s accuracy checked? Florine’s sixth tip dives into how these delicate instruments can actually be wrong.
“For many years, ARP has done field testing at NHRA National events and found torque wrenches that were off by 30-percent or more. Check calibration periodically to make sure all is well. As tempting as it may be, never use a torque wrench as a breaker bar, unless the manufacturer says it’s OK, this could impact the wrench’s accuracy,” Florine explains.
Tip 7
At lucky number seven, we get a tip from Florine about the installation of various studs. Contrary to popular belief, you don’t need to put a herculean effort into tightening studs. “You only need to tighten studs down to the recommended specs. Actual preload is achieved by pulling up on the threads. Tightening the stud excessively when installing it can be detrimental,” Florine says.
Tip 8
For his eighth tip, Florine wanted to bring to light the proper way to achieve the correct preload for a fastener. This tip has ties to the other tips about making sure your fasteners are clean, and that you’re using the correct lubricant.
“The correct way to get the right preload is through three equal stages of torque. Here’s an example of the proper way to achieve the correct preload. A 75-pound-foot preload would involve preliminary steps of 25 lb-f. and 50 lb-ft Now remember, just because a torque wrench goes “click” at the desired setting, does not mean the actual preload has been achieved. Friction caused by improper cleaning and inherent characteristics of some lubricants can affect accuracy,” Florine states.
Tip 9
Clocking in at number nine, Florine’s next tip covers why using a stretch gauge is highly recommended for rod bolts and other fasteners. The stretch gauge is going to give you the most accurate preload reading possible for a fastener.
“A fastener must be stretched, similar to a throttle return spring, in order to provide a rebounding force. For example, stretching a typical ⅜-inch rod bolt .0060-inch to .0065-inch will provide about 10,000 pounds of preload,” Florine explains.
Tip 10
For his final tip, Florine dives into something that you wouldn’t normally think of when it comes to fasteners, record keeping.
“Prior to installing a rod bolt, measure its length in a relaxed state and jot it down. There’s a handy chart in ARP’s catalog that you can use as a guide. When disassembling an engine for routine maintenance measure the length of each rod bolt and compare it to the original length. If a rod bolt has permanently stretched by .001-inc or more it has been yielded and should be replaced immediately,” Bill says.
Just because you’ve always done something a certain way doesn’t mean it’s the best way. These tips should help you when using ARP fasteners on any project and prevent major problems.