A Bevy of Helpful Hints That Will Make Car Building a Little Easier
Words & Photos Jeff Smith
It’s an interesting question, whether all those car shows on television are a help to our sport or a hindrance. While it exposes non-car people to the world of high-performance automobiles, those same people get the impression it only takes a couple of hours to build a car. Sure, the shop is full of expensive tools and can place a dozen people on the project, but what they don’t share is that the crew slavishly puts in 16- to 18-hour days to complete these projects. The show producers conveniently overlook that part of the story.
The whole truth is it takes time, money, and skill to build a performance car. If you work on cars, we don’t need to tell you that. So, instead of the glossy overviews of the TV shows, we thought we’d share a few notable little tech tips we’ve learned since we offered up our last batch of tips. Often, swapping engines and installing a trans is easy, but it’s the little things like making a charging system work or applying the proper torque to a head bolt that can eat up hours and hours of your time. And then when you finally overcome that problem, the solution is usually something simple, or at least not nearly as complex as you might have guessed.
Some of these tips are just interesting things that might make your work look a little better. Or maybe these tips will help you complete a task with less drama. Either way, the idea is to make working on cars a little bit more fun with less aggravation. That gives you more time to enjoy your latest project instead of just sweating over it in the shop. It’s all about having fun with cars!
1. Shrinkage is a Good Thing
We learned this trick from our fabricator buddy Scott Gillman, who works at Galpin Auto Sports in Van Nuys, California. He places shrink wrap over the open end of a quality stainless steel hose clamp and then heats the wrap over the clamp to give it a high-tech appearance. Then he places the business end of the clamp at the bottom of the hose, where it is out of sight. The result is simple and looks great.
2. Temp Accuracy
Ever wondered why your infrared temperature readouts sometime seem inaccurate? Our friend Keith Chauvie calibrates tools for a living and showed us something called emissivity. This is defined as the ratio of reflectivity of energy of a reflective surface compared to that of a black body with perfect heat radiation. Emissivity directly affects the accuracy of those IR temp guns and is measured on a scale of zero to one, with one being best. Asphalt tar paper has a rating of 0.95 (according to the Fluke instrument company), so it’s really good. Flat black spray paint is rated at 0.89. Polished aluminum has a rating of 0.09, and oxidized aluminum is rated at 0.30, which is not good. As the reflectivity of a material (even a dull aluminum radiator) increases, this lowers its emissivity rating — which drastically affects accuracy of the IR thermometer.
To test this concept, we first measured a dull aluminum thermostat housing, and the meter read 166 degrees. The car’s water temperature gauge reported roughly 195 degrees. Then, we applied a small piece of everyday masking tape to the same spot and tested the temperature again. The tape altered the emissivity, with the temperature report increasing to 203 degrees! That’s a difference of 37 degrees, which equates to a full 18-percent error. A black-painted copper brass radiator tested within 8 degrees of the indicated coolant temperature, with less than a ½ -percent error. Isn’t science interesting?
3. A Flair for Flaring?
A fabricator friend, Mark Bohlen, owner of Bent Custom and Performance, recommends avoiding a tubing cutter when trimming tubing because it dimples the tubing. Instead, he trims tubing with a hack saw or cutoff wheel and then carefully smoothes the end to make sure it is perpendicular. The critical point is the tubing end must be perpendicular. Finally, always debur the inside of the tubing once cut. Polishing is an even better idea; we use a convolute wheel on a bench grinder to accomplish this.
4. Micron Management
Make sure you do not mix up the 10-micron and 100-micron filter elements when building or repairing a fuel system. The filter elements will look identical. If a 10-micron filter is positioned on the inlet side of the pump, the pump will very quickly burn up due to the restriction on the inlet side. The proper 100-micron filter is designed to restrict only large debris that could damage the pump. It’s incredibly easy to mistakenly install the incorrect (fine) filter upstream of the pump. The only way to know for sure is to look at the end of the filter element – the filter’s micron rating is laser-etched in the end of the filter.
5. Get Your Cable Straight
When mounting any aftermarket cable throttle — like a Lokar, for example — make sure the firewall fitting boss is perfectly aligned with the throttle cable from the pedal. If the cable enters the firewall fitting too low or too high, the cable will act like a hack saw and eventually cut a slot in the firewall adapter, and the throttle will stick! Not good!
6. ECU Flash
When you buy a Painless wiring harness for a GM LS engine, the company offers a service that is not common knowledge. The stock GM computers often need to delete the VATS (Vehicle Anti-Theft System) software to allow the engine to start. Plus, you might want to set the idle speed slightly differently from the factory settings and perhaps alter the speedometer setting with your vehicle’s gear ratio and tire size. If you purchase a specific wiring LS wiring harness (Painless publishes their accepted list; find the info at painlessperformance.com), you simply send them your LS ECU and they will re-flash it for you at no charge. This generally saves you anywhere from $100 to $250. The only cost is the price of shipping your ECU to Painless in Texas. It’s a good deal!
7. Washer Tech
The performance world is changing. Things that worked 10 years ago often are not the best approach today. A quick torque of the head bolts, even when using ARP’s dedicated head bolt washer, isn’t enough anymore. ARP’s research reveals the smooth spot face finish on the cylinder heads of some late model engines creates a smooth enough surface that the head bolt washer may spin, acting like a tiny Torrington bearing. If the washer spins on the head, this can lead to a significant reduction in friction. This might sound good, but it isn’t. ARP torque specs are designed around the fact the washer does not move. If the washer spins, it will reduce the friction load.
This is important because a significant portion of the torque spec is designed to overcome the friction between the head of the bolt and the washer. If this friction is reduced, this puts excessive torque into the bolt itself. This can potentially lead to exceeding the bolt’s or stud’s yield point. If that happens, this permanently stretches the fastener, and it must be replaced.
To combat this possibility, ARP suggests lightly sanding the head side of the washer with 36-grit sandpaper. Three passes across a length of 36-grit paper is sufficient to prevent the washer from spinning. ARP has also noted it appears the factories are noticing this situation. The second photo shows a new Chrysler hemi head bolt. Notice the slight raised edges on the washer (arrow) that are intended to dig into the head and prevent the washer from spinning.
It’s also important to note all ARP head bolt washers are designed with a countersink that is designed to match the radius of the bolt head to the shank. This radius should always be positioned to match the under-head radius of the bolt. This means you need to sand the opposite side of this washer. Then, coat the under-head side of the bolt and countersunk side of the washer with ARP’s Ultra-Torque. Thoroughly clean the cylinder head, and do not put any lubricant between the washer and the head. Then, torque the fastener to ARP’s specified torque in the usual three-step fashion. This will maximize the fastener’s clamp load and give the head gasket the greatest chance to seal all that monstrous cylinder pressure you’re making.
8. Let’s Make an Overdrive Deal
We’ll bet you didn’t know you can buy for a mere $1,558.97 through Summit Racing a remanufactured 4L60E with a 2,400 rpm converter from Chevrolet Performance (PN 24216083) that also includes a 2,300 rpm stall speed converter. Because this is a remanufactured piece, it also demands a $350 core charge. If you have a 4L60E that’s bitten the dust, it might cost roughly $150 to $200 to ship the core to avoid the core charge. But, even just including the core charge, the trans and converter is still less than $1,910. Of course, you still need a slip yoke, trans controller, and shortened driveshaft on a ’60s or ’70s muscle car swap. That might add between $700 and $800 to the cost of the conversion, but it’s still a pretty good deal.
9. You’re Grounded
Does your new alternator suffer from poor output performance? If the alternator case has been powder coated, it may not be properly grounded. One quick test is to ground the alternator with a 10-gauge wire and see if the output improves. This same poor ground problem can also affect starter motors. Clues to poor grounding can be seen as scorch marks between the starter or alternator and the engine block. This is a dead giveaway there is a poor ground circuit between the engine and the battery.
10. Counter Sunk
Melling offers both replacement and performance oil pumps for LS engines, and one of the advantages is the cast iron pump cover is more durable than the stock aluminum and the performance pumps do not cavitate at speeds above 6,500 rpm. Another advantage is the cast iron cover uses counter-sunk bolts, which offer more timing cover clearance when using a dual roller timing set. Dual roller chains come with a 0.125-inch spacer to move the oil pump forward, and factory pump cover bolts can sometimes interfere with the timing cover. The Melling pump countersunk fasteners eliminate this issue. Also be aware that when moving the pump forward, this will also require slight elongation to the pickup tube mounting flange hole at the back of the engine.
11. The “More is Better” Theory
Many enthusiasts believe more oil pressure is always better. In the ’60s, the common recommendation was 10 psi per 1,000 rpm — which is still useful. But, that evaluation is changing. This also suggests that at an idle of 850 rpm, you would need less than 10 psi of oil pressure. We also noticed the latest Corvette gasoline direct injection (GDI) 6.2L engine has a minimum spec for hot idle oil pressure of only 6 psi. At 4,000 rpm, the spec is only 24 psi. While these are minimums, they reveal an engine rated at 450 hp running 5W-30 oil doesn’t need a ton of oil pressure. So, perhaps this will make you feel better about having “only” 20 psi of idle oil pressure when the engine’s hot. In this case, less can be more.
12. The Amperage Game
All alternators are output tested when the alternator is at ambient air temperature, rather than at normal under-hood operating temperature, which could easily be 120 to 130 degrees. We called Powermaster, and they told us they do test at room temperature and that when the alternator achieves normal operating temperature, it will generally lose about 15 percent output to heat. So, with a 100-amp rated alternator, it may only produce about 85 amps at maximum output. Powermaster supplies a dyno sheet with each alternator, and generally, they make slightly more than their rated power.
13. O-Ring Sing
We’ve recently seen several situations where Holley carbs that have sat dormant for months suffer what appears to be a stuck float, where fuel rushes out of the vent tubes. At first, we assumed a chunk of debris was stuck between the needle and seat. But, closer inspection revealed the rubber O-ring on the needle and seat assembly had shrunk, allowing the fuel to leak past the needle and seat. The fix is easy enough — just swap the little O-ring. Or, you can replace the entire needle and seat with a new cartridge that comes with a new O-ring. Holley’s PN for the standard needle and seat assembly is 6-506 ($14.32, Summit Racing).