If you work on cars long enough, you pick up on certain shortcuts and ideas that can save you aggravation, time, money or — hopefully — all of the above. When we visit shops, we like to pay attention to the little things we can write down and pass it along. We certainly don’t take credit for creating these ideas, but we did take the time to write a few down with the intent to pass them along to you. You might remember a previous article full of tech tips that everyone seemed to enjoy, so here’s another installment with ten more handy tech tips.
1. Cam in First
We’ve learned to always check a new camshaft in an engine with new cam bearings for proper fit before installing the rotating assembly. A good engine builder will tell you this avoids issues of discovering one cam bearing is too tight, preventing you from installing the cam. This happens more often than you might think. Often, the bearing must be replaced, and having to work around the crank and rods is a hassle. By installing the cam first, you avoid that dilemma. This tip came from our friends at Jim Grubbs Motorsports in Valencia, California.
2. Four Flats Equals Two Jets
We learned this little tip from Phil Freelander at FST Carburetors based on his decades of experience. There are six flats on a Holley carburetor float adjustment hex-head screw. If you raise or lower the float level adjustor by four flats (two-thirds of a turn), this is the equivalent of two jet sizes. For example, raising the float level four flats would be the same as changing from 78 to 80 jets. Lowering the float level will lean the air-fuel ratio.
This is based on the height of the fuel level in the float bowl. Increasing the float-height richens the mixture because it increases the pressure on the main jets located at the bottom of the column of fuel in the bowl. This is not a carved-in-stone rule, but changing the float level will certainly affect the overall air-fuel ratio and can be used for minor changes in overall jetting. It’s best not to alter the float level beyond this point in either direction — but if you need to make a change in a hurry, it will work.
3. It’s all in the Microns
Apparently, there is great confusion out there regarding micron sizing of fuel filters. Performance fuel filters are categorized by their ability to filter out dirt — generally expressed in microns. A micron is a millionth of a meter. To put it in perspective, a human red blood cell is five microns in diameter. Expressed digitally, 1 micron = 0.000039-inch and 100 microns = 0.00393-inch. This means that a 100-micron filter will trap dirt larger than 0.004-inch. A 10-micron filter will remove everything larger than 0.0004-inch!
Here’s where the confusion begins. High-pressure electric fuel pumps need a 100-micron filter on the inlet side to remove the big chunks of dirt and debris before it gets into the pump. Because these 100-micron filters are less restrictive, this reduces the inlet restriction, allowing the pump to operate correctly. If the pump is restricted on the inlet side with a finer filter, this radically reduces the pump’s ability to function properly.
This is a common problem where the 10-micron filter is placed ahead of the fuel pump, which is not correct. The proper position for a 10-micron filter is after the pump, to screen out the tiny stuff that can clog fuel injectors. The second photo shows a 100-micron filter that should be used on the inlet side of the pump. So, to recap: The 100-micron filter goes ahead of the pump inlet and the 10-micron filter is used on the high-pressure side of the system. Now you know!
4. What is Standard Tension?
Several factors determine the definition of standard tension for an oil ring, and it is anything but consistent. The tension an oil ring creates is related to both its width and bore size. As an example, the older small-block Chevy uses 3/16-inch (0.1875) radial-width steel rings that are 0.024-inch thick. Fast forward to a typical production LS engine and the oil ring package shrinks to 3mm (0.117-inch) radial-width oil rings that are 0.018-inch thick — or 33-percent thinner than a small-block Chevy.
All of this contributes to reducing the amount of radial tension exerted by the oil ring package because the thinner ring offers a reduced contact point. A thicker ring must exert a greater outward force to create the same load as a thinner ring.
Total Seal’s Ed Law offered this analogy: a butter knife’s cutting edge is broad and blunt and has difficulty slicing hard butter.
Conversely, a thin steak knife cuts much easier because, with the same force applied, the load is concentrated in a smaller area. According to Total Seal, a 3/16-inch standard-tension oil ring generates 20 to 25 pounds radial (outward) tension while a 3mm standard LS oil ring only creates a 9- to 11-pound radial load. This is half the force. These numbers represent the radial force created by the rings, not the sliding friction force.
However, common sense dictates that higher radial tension will generate greater sliding friction — and that means lost horsepower. The point is you can gain some horsepower merely by running a thinner oil ring package. This is one reason (among many others) why a late-model LS engine makes more power (and pulls down better fuel mileage) than a Gen-I small-block Chevy. It also shows how the older small- and big-blocks can be updated with more modern components, like pistons designed to accommodate more current technology oil rings.
5. Pre-Lubing an LS
Pre-lubing an LS engine has always been a hassle, thanks to the front-mounted oil pump. In the past, we’ve used a small-block Chevy oil pump bolted into a bucket of oil to pre-lube them. That works, but building this tool is a hassle, and then you have to find a place to store the bucket and its accouterments.
A ready-made solution is available, consisting of a small aluminum tank that contains several quarts of oil, which is pumped into the engine with compressed air. This is an elegant, compact solution, but it is also expensive if you’re only going to use it once or twice.
Summit Racing now offers a new tool (P/N: SUM-900-330) that can make pre-lubing a new LS engine a little easier. This oil pump drive socket is used to drive an LS oil pump with or without the front cover in place. This tool will only work if you are using an aftermarket timing set that uses a separate oil pump drive-collar. Factory gearsets use an integral collar on the crank gear that prevents the use of this pre-lube tool.
With the harmonic balancer off the engine, remove the oil pump gear, and slide the Summit tool in place to engage the oil pump. Spin the oil pump with a 3/8-inch-drive drill motor — we used a 1/2-inch electric impact with an adapter. The usual approach is to spin the oil pump until oil appears out of all 16 pushrods. Then remove the socket, re-install the oil pump drive collar, and install the harmonic balancer.
6. To Advance or Not To Advance
Did you know that most camshafts intended for the street are machined with built-in advance? There’s an easy way to determine this by studying the cam card. If the intake lobe centerline — expressed in degrees After-Top-Dead-Center (ATDC) — is the same as the lobe separation angle, then the cam is not advanced.
For example, a COMP Cams mechanical-roller for a big-block Chevy (P/N: 11-851-9; left cam card) lists the intake centerline at 108 degrees and the lobe-separation angle at 108 degrees. This means this cam is ground “straight-up” without advance.
But looking at a COMP small-block street cam (P/N: 12-468-8; right cam card), it has an intake centerline of 109 degrees ATDC, but the lobe-separation angle is 113 degrees. This means this cam is machined with 4 degrees of advance already built-in. This also means the engine builder should install and degree this cam “straight up” — with no advance — because the intake lobe has already been advanced. Adding more advance would only hurt power.
7. Track Day Caveat
Pro-Touring events are very popular, but not all street cars are set up for the abuse from lots of autocross or road course laps. If your plans include a track day, it is imperative to add an oil temperature gauge, especially if your vehicle is not equipped with an oil cooler. This is especially important if you anticipate running more than five or six continuous laps on a road course.
The combination of an oil cooler and synthetic oil will offer great insurance. Synthetics are capable of withstanding extreme oil temperatures, and without an oil cooler, it’s possible to see 275 degrees or higher oil temperatures. The same is true with running near-continuous autocross laps of more than five or six laps at a session.
Conventional oil begins to break down at around 250-degrees Fahrenheit. Synthetic blends improve that temperature threshold slightly, while full-synthetics are capable of handling 300 degrees or more. An oil temperature higher than 275 to 300 degrees, using conventional oil, is cause for serious concern.
8. Guide It, Seal It
We still see those hard, white plastic valve-guide seals used on street engines. These were the original PC, or hard-mounted, valve-guide seals developed for applications where clearance was reduced due to dual valvesprings, especially on engines like the small-block Chevy. Unfortunately, these hard plastic seals can quickly wear and do not respond well to situations with increased valve guide wear on street engines. The advanced seal wear allows oil to leak past the seal, which ends up in the combustion chamber.
Today, the market is packed with many high-quality Viton rubber seals, which do a much better job, and can fit inside a 1.445-inch dual valvespring for a small-block Chevy just fine. Do a little research and you can likely find a quality Viton rubber seal that will be far superior to those original hard plastic PC seals. You can even buy inexpensive tools that will allow you to modify stock heads to mount these seals and do it yourself.
9. Degree Wheel Check
It doesn’t make sense to stress over one-degree of intake centerline changes if your degree wheel isn’t accurate. Small-diameter degree wheels can be a bit off, so here’s a quick way to check accuracy. Trace a circle around your degree wheel with a Sharpie on a large cardboard box. Mark the four 90-degree positions on the circle: 0 – 90 – 180 – 270. Now turn the wheel away from the 90-degree mark. We used 15 degrees BTDC at the top.
Now, look at the remaining positions and see if the degree wheel accurately indicates an equal 15 degrees off. At the bottom, it appears here that this wheel may be off just a half-degree, which isn’t really anything to worry about. The potential error is much less with a larger diameter wheel, and that is why most pro engine builders use large-diameter degree wheels.
10. Pull Through
It’s often necessary to remove the pressed-on crank timing gear to advance or retard the cam. This can be troublesome if you don’t have the right tool. A long time ago, we cut a 1/4-inch-thick plate in the shape of a wide “U” to slip behind the crank gear. We drilled and tapped three, 3/8-inch, fine-thread holes in the plate to allow the use of a harmonic balancer puller.
Later, we discovered this nice Posi Lock three-jaw puller (P/N: 104) works very quickly and easily. This unit uses a locking mechanism to positively position the three jaws. It has a 4-inch reach and a 5-inch spread with a 3-ton capacity. You can find these pullers on Amazon for just under $120. We’ve used this tool on small-block and big-block Chevy engines, and it will also remove GM factory LS harmonic balancers.