Perform Better
By the time we got to Dale Pulde’s shop, HP Racing, in Sylmar, California, he had already made a baseline Dyno run, removed the seat, the fuel tank, and the air filter assembly. He was in the process of stripping the top end down to the cylinders, according to the manual’s instructions, before he tore into the bottom end.
After removing the cam cover, Pulde used JIMS Cam Chain Tensioner tools to unload the chain tensioners. Then, he put a JIMS Sprocket Locker in between the rear cam sprocket and crank sprocket so that he could loosen the bolts. Pulde marked the outside of the chain, so that when he reinstalled the assembly the chain would run in the same direction of rotation.
Pulde used magnets to hold the lifters up so he could pull the cam support plate and cams out of the crankcase.
Since we were increasing the displacement, we figured we should change out the stock oil pump (left) for this Feuling SuperPump (right). The Feuling pump has an oversized gerotor design, which allows for increased pumping and scavaging.
Here’s an interesting trick Pulde showed us. Rather than using a press to remove the cams from the support plate, Pulde used a torch to heat the surface areas of the plate around the cams. This caused the metal to expand, and then he was able to just pull the cams out of the plate by hand.
This is a shot of the new Edelbrock Performer Camshafts (front) and the old cams (back). Other than being obviously larger and more radical, the new cams have an intake and exhaust lift of 0.619 inch at top dead center, and an intake and exhaust duration of 246 and 254 at 0.053 inch.
After heating up the cam plate with the torch again, Pulde pushed the new cams into the cam support plate and aligned the two punch marks on the cams so they would face each other, to ensure proper alignment. Before he bolted the cam support plate to the crankcase, he replaced the inner cam bearings and slid the new Feuling oil pump into position, and then…
…followed the manual’s instructions on the proper tightening sequence and torque specifications of the cam support plate screws and oil pump screws. Since we put in the Feuling oil pump, we decided to go with a set of Feuling lifters as well. Pulde made sure he installed the lifters with the oil holes on the inboard side, and then he set the anti-rotational pin in place.
Since we put in the Feuling oil pump, we decided to go with a set of Feuling lifters as well. Pulde made sure he installed the lifters with the oil holes on the inboard side, and then he set the anti-rotational pin in place.
After mounting the crank, cam sprockets, and chain assembly to the cam support plate, Pulde pointed out how the crank and rear cam sprocket’s punch marks were lined up. Then, he torqued down the sprocket bolts per the manual’s instructions.
Moving to the top end, Pulde removed the cylinders and stuffed towels in the crankcase so that nothing could fall in while removing the pistons and clips. Pulde used a hammer and a piece of Delron (a solid piece of plastic tubing) to tap the piston pin out of the piston.
To accommodate the new 95ci Edlebrock/JE Pistons, Pulde had to bore and hone Cirrelli’s cylinders. With one of the cylinders tightened down in torque plates, Pulde made a final honing pass. When tightened down to the engine case, the cylinders take on a slightly different shape than when they are in their relaxed state. Therefore, torque plates are necessary to simulate the pressure and create the tightened shape, so that proper boring and honing can take place.
Here are the new 95-inchers (right) compared to stock (left). The new pistons have a 10.25:1 compression ratio and come with pins, rings, and locks.
Before sliding the freshly bored cylinders back into position over the new pistons, Pulde washed them to get all the dirt and metal out. When they were dry, Pulde wiped them down with some Marvel Mystery Oil. He says he uses the Mystery Oil because it not only helps the cylinders slide over the pistons, but it also thoroughly cleans out any metal and debris that didn’t come out when he washed them.
With the pistons on the connecting rods, new O-rings were slid over the base of the cylinders, and then Pulde used a ring compressor to put it all together.
On the left is the new Edelbrock black finish CNC-ported cylinder head with a 72cc combustion chamber. Notice the different shapes of the two intake ports. Edelbrock uses square ports because you can get more airflow into a smaller port with flat sides. The square port also helps air traveling through the top and bottom of the port keep the same velocity.
When tightening down the head bolts, Pulde first dabbed some oil on them to prevent binding and give accurate torque readings.
Don’t forget that it’s important to put the map sensor on the new manifold
Pulde ground down the exhaust side of the rocker boxes to prevent the valve springs from interfering.
Then, the lower box covers went on.
Here are the new Edelbrock adjustable pushrods that we used.
Pulde started at the rear cylinder and turned the motor over several times until the cams were TDC on the compression stroke. Then, he lowered the pushrods into their respective positions and tightened down the rocker arm support plate. Once all the slack was taken out of the rods, Pulde opened them up 3-1/2 more turns. With the pushrods properly adjusted, Pulde removed the rocker arm support plate and pulled out the pushrods. Next, he installed the pushrod tubes before dropping the rods back in and finally tightening down the rocker arm support plate one last time.
Pulde poured some assembly lube over the rocker arms before he bolted down the top of the rocker box covers. By the time Pulde finished up the rear cylinder, the lifters had bled down enough for him to turn the motor over so that he could repeat the process with the front cylinder.
At first glance, one might assume that this is a stock Twin Cam, but upon closer inspection, you’ll notice that the fins on the Edelbrock heads are much thicker than those on the cylinders, thus revealing the secret that this isn’t your average TC-88.
Although it doesn’t come with the Performer RPM Package, we decided to switch out the stock carburetor with this new Edelbrock 42mm Performance Series carb (left).
We were able to use the stock throttle cables with the new carb, and the multiple mounting holes on the flange made it easy to mount the Screamin’ Eagle air filter backing plate.
On the right-hand side of the air filter back plate, you can see a little notch that was made between the two breather bolts. Pulde notched the plate so that the idle jet could easily be adjusted, without having to remove the back plate.
The last upgrade that we made to Cirrelli’s bike was replacing the stock ignition with a new Daytona Twin Tec plug-in ignition module for carbureted Twin Cams. The Twin Tec ignition features simple plug-in installation, wide timing advance adjustment range for stock-to-highly-modified engines, selectable multi-spark mode for quick starting and smooth cruising, and an optional PC link cable and software that allows you to program custom advance curves to your own needs.
After 350 miles of breaking everything in, Cirrelli returned to Pulde’s shop for a final Dyno run. During the baseline Dyno run, Cirrellli’s bike put out 73.4 hp and 82.3 lb-ft of torque. When we saw the new numbers, our jaws dropped to the floor. At 109.2 hp and 109.9 lb-ft of torque, the results were way beyond what we would’ve expected. What really blew us away were the numbers that the bike was putting out between the 2,500- and 3,500rpm range. Obviously, we weren’t disappointed with the results, and neither was Cirrelli.
In the continuous quest for better performance and more horsepower, bigger is better, especially when it comes to your motor.
Our friend, Danny Cirrelli, has an ’00 Heritage, and after about 10,000 miles of riding with hop-ups consisting of nothing more than a Screamin’ Eagle air filter and a D&D; pipe, he began to get the itch for more horsepower.
When he asked us for suggestions on how he could get the performance he wanted out of his Twin Cam, with a sly grin we offered him two words of advice: GO BIG. Cirrelli sort of hesitated for a minute, and then his eyes lit up as he realized that we meant increase the displacement.
With the Twin Cam market continually growing, more and more companies are striving to offer owners the ability to achieve the larger displacement they desire. The Edelbrock Performer RPM Power Package kit consists of heads, cams, adjustable pushrods, and all gaskets necessary to complete the hop-up.
It had been a while since we’d used any of Edelbrock’s products for a hop-up article, and we wanted to see if it had improved since the original kits for Evos.
Read on and see just how much it improved.
