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Building the Tom Henry RS

Part 5: Brake Service, More Suspension Mods, Custom Tuning and Making it Pretty
by Hib Halverson

 Image: CHpg Staff

The Tom Henry RS, 2001 Camaro project car now has a little over 104,000 miles on it. Many of those miles have been "daily driver" duty, but for rest of the time, we've beat on the car pretty hard–close to a hundred or so chassis dyno runs and plenty of road testing–so for this part of the series; we're going to mix maintenance with modification.

During the camshaft installation covered in Part Two, we installed a Rollmaster single-row timing chain. For that, we were criticized by a few "experts" (might they be "faux experts"?) on forums catering to V6 Camaro and Firebird owners. They claimed single-row chains are not reliable in a 3800 Series II with a more radical camshaft (like Comp Cam with 206/216° duration, .530" lift), higher spring pressure (Katech valve springs), higher rocker ratio (1.8:1 Yella Terra aluminum roller rockers) and a higher rpm range (6400 rpm rev limiter). The “experts” said we were foolish to use a single-row chain because our engine would experience certain failure in short order.

Installation of double row chains require removal of the engine's balance shaft. We preferred not to do because that shaft reduces engine shake at idle and low speeds which we see as a desirable quality for a street car, so we stayed with the single-row chain.

Fast forward–five years later.

After running the single-row Rollmaster for 50,000 miles–that, alone, seems a testament to the chain's reliability–we decided it was high time to put the single-row chain durability issue to rest. We pulled off the front cover, inspected the sprockets then compared any slack in the existing chain to that in a new chain.

The procedure for replacing a 3800 timing chain was detailed in Part Two, but to quickly review: Remove the drive belt, the heater hoses, the belt tensioner, the power steering pulley and the harmonic damper. The damper bolt is way tight. Even our 1/2-drive air impact wrench wouldn't break it loose. I had to brace myself and use my feet on a Matco 24-in. breaker bar (PN C24FC) to get the bolt loose. With the bolt out, the damper comes off with a standard puller, then you remove the crankshaft position sensor and its harness, lower the front of the oil pan then get the front cover off.

What did we find after five years and 50,000 miles? Were the Internet "experts" correct?


We removed the chain tensioner and measured the chain slack with a dial indicator. Then, we removed the sprockets and inspected them with a magnifier and a bright light. Only a small amount of wear was visible on the teeth. It looked more like the slight burnishing you'd get during break-in. Those sprockets are good for another 50,000 miles, at least. We reinstalled them so as not to skew the slack measurement of a new chain.

Left is the cam sprocket we took out. Right is a new Rollmaster unit we got from Engine Pro. The wear on the used part is minor–more like burnishing rather than real wear on the teeth. Image: CHpg Staff.

Like the Yella Terra roller rockers installed for Part Three, Rollmaster timing sets are made in Australia where there's a big market for 3800 Series 2 performance parts. We took a new single-row chain out of a timing set (PN CS6141) we obtained from Rollmaster's U.S. Distributor, Engine Pro, and installed it on our existing sprockets.

The Engine Pro's Rollmaster single-row chain set fits 3800 Series II engines and includes oil pump drive, sprockets and chain.  Image: CHpg Staff.

We could measure no practical difference in chain slack between the old chain and the new one. With the chain tensioner removed, chain slack of both measured 0.530-in. give-or-take a few thousandths. Clearly, the single-row, Rollmaster chains Engine Pro distributes have excellent durability in a valve train such as that of the Tom Henry RS's V6. We left the new chain in place and our used Rollmaster will make an excellent spare.

We took chain slack measurements with a dial indicator. So not to skew the measurements, we used the sprockets originally in our engine and only swapped the chains. Slack difference was negligible. Image: CHpg Staff.

Before we put the front cover on, we replaced the chain tensioner with a new GM unit (PN 24503893), then we washed parts we were going to reuse in "Extreme Simple Green Motorsports Cleaner & Degreaser". Since the service trade is moving to more environmentally-friendly, aqueous parts washing and it's slowly catching on in the enthusiast community, we've been trying Simple Green's Motorsports product for about a year. It's required a little change in our parts cleaning habits, but the results have been acceptable in the majority of parts cleaning situations we encounter.

Does periodic cooling system maintenance pay off? This is the water pump chamber in our engine's timing cover after a decade and 104,000 miles. There is no corrosion of any kind. In fact, you can still see the original coating GM put on the cover. Image: CHpg Staff.

We replaced the coolant pump with a new GM unit (PN 19209288). We added a new front cover gasket out of a FelPro timing cover set (PN 45971) then reinstalled the front cover. After that, we installed a new front seal using a Kent-Moore seal installing tool (PN J 35354). While it's possible to "knock" the seal in place with a hammer, the Kent-Moore tool does the job faster and prevents mangled seals or damage to the aluminum cover.

For a while, we'd noticed the oil pressure gauge was either pegged or fluctuating, a sign of the "bad oil pressure sender syndrome", so we screwed in a new GM sender (PN 19244510). The chain tensioner, the water pump and the oil sender came from our GM Parts source, Tom Henry Racing.

The final major task in our timing chain validation session was reinstalling the harmonic damper. It's a modest press fit onto the crankshaft and you pull it on using the stock damper bolt. Once the damper is on, that bolt needs to be very tight–111 ft/lbs plus another 114° measured with a Matco torque angle meter (PN TAG281). Done by hand, the strength of a body builder is required. Clearly, I need to spend more time at the gym because, again, I had to put my feet on the Matco breaker bar to get 114° additional torque angle.

Upper End Service

Some discount long-term durability of aluminum roller rocker arms. Our position is that if the design is sound, the materials are high-quality, the use does not exceed design limits and there is proper lubrication, after market roller rockers last a long time. We decided see if our Yella Terra, Ultralite 1.8:1 rockers, which had been in place for three years and 38,000 miles, showed any wear.

Roller rocker arm. We neither saw nor felt any wear. The valve stem ends of our Manley valves, our Katech titanium retainers and Katech valve springs all looked good. Image: CHpg Staff.

We pulled the spark plugs, removed the plug wires, unbolted the ignition system, then popped off both rocker covers and removed all the rockers. On the work bench, we inspected each under bright light and felt how the trunnion needle bearing and roller tip worked. We could detect nothing other some modest wear of the pushrod seats so we reinstalled the rockers, stuck some new Fel-Pro rocker cover gaskets (VS50080R) in the covers, bolted them back in place and reinstalled the ignition system. Since the plug wires had been installed for Part One of this series seven years and 59,000 miles ago, we added a fresh set of MSD Super Conductor plug wires (PN 32089) which we like for their high level of RFI suppression but low resistance. On the plug end of each wire we use a Design Engineering "Protect-a-Boot" which is a double-stitched, two-ply glass-fiber "sock" that goes over the spark plug boot and can withstand 1200°F direct heat. Protect-a-Boots are great for preventing thermal damage to the plug boots on engines with headers. DEI markets these only in sets of two or eight so we ordered three sets of two in silver (PN 010501).

Since the beginning of the project, we've used Denso Iridium Power IT-20 spark plugs in our 3800. While Denso recommends the IT-16, considering its level of modification and how hard we drive the engine, our three-eight runs better with plugs one heat range colder. We prefer Densos because the Iridium Power design incorporates a small, 0.4-mm center electrode and a cut-back, u-shaped ground electrode. Both these features expose more of the combustion chamber's charge to the spark. The Denso's iridium center electrode has lower resistance and better durability than platinum. We reinstalled our Denso plugs and pushed the Protect-a-Booted plug wires in place.

A Denso reman alternator solved our charge voltage problem and we completed the installation with a new Goodyear Gatorback drive belt. It's about a 15-minute job to change both. Image: CHpg Staff.

Continuing our maintenance, we replaced the alternator. For a couple of months, we observed an intermittent problem with high charge voltage and when it's up high, the voltage fluctuates causing the interior lights to flicker. Often this is a sign of a bad voltage regulator, so we replaced the 10-year old, 100,000-mile stocker with a Denso Remanufactured unit (PN 210-5118) which solved the problem. We also installed a new Goodyear Gatorback (4060945) drive belt which we prefer for its diamond-checked backing which allows the belt to run cooler and last longer. We were on a roll–wanting to preempt any starting troubles, we replaced the car's original starter with a new Remy Gold unit (PN 96211) obtained from Internet parts source, RockAuto.com, which we choose for its great web-based catalog, competitive prices and quick service.

Cooler Cooling

About a 40% increase in power and, once we add nitrous oxide, a 75% increase, means we need modifications–beyond the Hypertech 180° thermostat we'd installed a while back–to improve cooling.

Long overdue for the Tom Henry RS was an improvement in cooling performance. On pursuing that, we compared two aftermarket alternatives. Image: CHpg Staff.

We evaluated two aftermarket radiators capable of better cooling. The first is a Spectra Premium radiator (PN CU1485) sold by RockAuto. Like the OE radiator, the Spectra is a single-row, aluminum-core/plastic-tank design but it has a 1-in thick core offering an increase in cooling over a stock 0.625-in. core. This radiator is for cars with either manual or automatic transmissions. The Spectra drops right into the stock cooling stack and RockAuto's price is quite reasonable. In fact, you can get the Spectra Premium with its thicker core from RockAuto for less money than an O.E. replacement ACDelco radiator which has a thinner core. The result? A useful improvement in cooling performance at reasonable cost. If you have 3800 modified to the 250-300-hp level, RockAuto's Spectra Premium radiator makes great sense.

Rear is the OE V6 radiator. Middle is the Spectra Premium radiator we ordered from RockAuto.com. Front is the FLUIDYNE High-Performance unit. CHpg Staff.

The second radiator we tried, capable of an even greater cooling improvement–but with an understandably higher price–comes from FLUIDYNE High-Performance. Some may know FLUIDYNE as a maker of radiators used in NASCAR racing, but the company custom builds radiators for modified street, street/track as well as all-out race cars. It recently announced an all-aluminum, two-row radiator ideal for '93-'02 Camaros with V6es having significant modifications such as, superchargers, turbochargers or big doses of nitrous oxide. 

This radiator (PN FHP-20-34322-CAMV6) is a serious piece–incorporating technology FLUIDYNE uses in making its NASCAR radiators. It uses the "Thin-Line" core which is a two-row, 1.5-inch, high-fin-count, mini-tube cooler. The Thin-Line core provides better cooling from: two rows of tubes, dense fin count and increased water turbulence inside the smaller tubes. The Thin-Line core is also very light, resulting in a radiator weighing only 11-pounds. This part is manufactured with the Nocolok, furnace-brazing process which offers superior reliability and durability compared to products using welded construction and epoxy sealing. Typical of most FLUIDYNE High-Performance products for use in production-based applications, it drops right into the stock radiator mounts, accepts the stock electric fan assembly, stock hoses and offers a significant increase in cooling compared to the weak-suck, skinny-cored stocker. This radiator would probably support 450-hp.

Both the Spectra and the FLUIDYNE bolt into the stock Camaro radiator mounts and accept the stock fan assembly and the upper support. Image: CHpg Staff.

This project car is ten years old, so we scrapped the stock coolant hoses and finished the radiator installation with new, Goodyear, radiator hoses (PNs 62153, 62154) and heater hoses (PNs 63301, 64268, 63906). All that Goodyear stuff we ordered from RockAuto.

Since we were changing the water pump as well as the radiator, we started with a dry cooling system which we filled with a mix of distilled water and a bottle of Red Line Water Wetter. Since straight water is a better coolant that 50/50 mixes of water and antifreeze and because this car is based in the coastal Southern California where sub-freezing temperatures are rare and never occur long enough to freeze the coolant, but hot weather abounds; we run water and Water Wetter for coolant. While that mix works quite well from a cooling performance standpoint, there are some limitations: first, you must change coolant every two years regardless of mileage. Second you need Red Line Water Wetter for its package of corrosion inhibiters and anti-foaming agents which is similar to that used in GM Dexcool. Third, if the temperature where the car is parked or stored goes below freezing for more than a couple of hours, you must add antifreeze. The combination of either the Spectra Premium or the FLUIDYNE radiator, distilled water, Red Line Water Wetter, a Hypertech 180 thermostat and lower fan-on temperatures in the ECM calibration has the Tom Henry RS running cooler and with a large cushion of cooling performance.

The FLUIDYNE is an all-aluminum design. It's connections are in the stock locations and it has stock type of mounts for the HVAC condenser and the electric fan assembly.
Image: CHpg Staff.

Red Line Water Wetter is mandatory if you use straight water for coolant. Its main ingredients are 1) a surfactant, or wetting agent, which improves heat transfer from the engine's metal parts to the coolant and 2) a corrosion inhibitor package similar to that used in Dexcool. Image: Red Line Synthetic Oil Corp.


We had occasional problems with DTC P0128 setting in the ECM memory. On a temporary basis we carried an Actron AutoScanner in the glove box to clear codes when 0128 set. The little Actron is our favorite entry-level scan tester. Image: CHpg Staff.

In fact, the FLUIDYNE occasionally is "too good" at cooling. During winter, code P0128, one of GM's enhanced diagnostic trouble codes (DTC), sometimes has set our the PCM. This happens when the PCM decides the engine is taking too long to warm-up. This code is one of the odd DTCs which does not turn on the check engine light, but when it sets, the temperature gauge goes to zero and the cooling fans stay on.

This problem occurs on cold days, after a cold start followed soon after, by highway driving. The high cooling airflow, coupled with the FLUIDYNE's cooling ability, has the engine warming up too slowly and that causes the system to flunk the diagnostic test and set the code. We carry an Actron "AutoScanner" (PN CP9575) in the glove box. While it only displays generic OBD II codes, this handy little scanner can erase any code in the ECM. The first couple of times P0128 set, we used it to clear codes. Later, in this article we’ll reprogram the ECM such that this code won’t set.

Restriction Reduction

The exhaust system on the Tom Henry RS was one of the first modifications we made and its Flowmaster "American Thunder" cat-back has worked quite well. The system has been on the car since 2004 and after seven years, it was rusting in a few places and its silver paint was a bit natty. We pulled the system off and sent the parts to Extreme Performance Heat Coatings in Oxnard, California to have them grit blasted then coated with Extreme’s “Cermachrome” which is a durable metallic-ceramic material with chrome-appearing finish. We reinstalled the system then admired the brilliant, Extreme-coated, Flowmaster parts.

As cool as it looked, one thing bugged us about the car’s exhaust: while the Flowmaster system has 3-inch pipe back to the muffler, the S-bent section between the catalytic converter and catback’s inlet is 2 1/4-in pipe. To get rid of that restriction required a new, three-inch S-pipe and the folks at Flowmaster were kind enough to make the pipe for us. Because the car has 100K+ miles on it and the stock catalytic convertor's case was damaged, we, also, wanted a new cat from Magnaflow. This replacement unit (PN 46006) is legal for sale in California. We took the larger diameter S-pipe and the new cat to Big John's Performance, an exhaust system specialist in Valencia, California, and had its ace fabricator, Steve Munson, install both.

At Big John's, first step was to cut some short sections of 3-inch tubing which would be used to connect the S-pipe and the cat. Image: CHpg Staff.

The catylitic converter is a "universal fit" pare, so welding is required and having an experienced exhaust fabricator, like Steve Munson, doing the work, ensured the S-pipe installation and the cat replacement were done right and in a short about of time. Image: CHpg Staff.


Once the S-pipe/cat assembly was tacked in place, we checked alignment and clearances of the entire exhaust. Then, Munson did the final welding. Image: CHpg Staff.


With the welding done, we bolted the cat to our Y-pipe, installed the rear oxygen sensor and reinstalled the center exhaust hanger. Thanks to Big John's Performance for a job well-done. Image: CHpg Staff.

We returned to the Westech Performance Group for another session on its Superflow AutoDyn chassis dynamometer. Three more runs on the AutoDyn showed that, compared to our last visit to Westech for Part Four, performance increased by an average 4.5-rwhp and 5.5-lbs/ft  rear-wheel torque in the mid range and 3.6-rwhp/3.4-lbs/ft at high rpm. Our best run with the new S-pipe and cat was 223.3-rwhp@5780-rpm and 218.4-lbs/ft@4630-rpm. There was another benefit of the 3-in. S-pipe and new cat: the THRS sounded even better than before–the sound was deeper and a little louder.

After the exhaust work, we had the Tom Henry RS back at Westech Performance Group to validate the lower-restriction S-pipe. It was worth about 4.5 horses–more than we expected. Image: CHpg Staff.


Some of the tools we come to use a lot working on the Tom Henry RS are Gear Wrenches. We were familiar with Gear Wrench but just never got on the bandwagon until lately. Now that we've used them, we don't know how we got along without them. In fact, nowadays we hardly use our traditional combination wrenches. We have two sets of the flex-head, ratcheting combination wrenches, metric and SAE. All use Gear Wrench's ratcheting box-end which needs as little as 5 to turn the fastener before it can be ratcheted. Their serrated beams allows us to feel which way to pull. The flex-head tilts up to 90 each way and the flex-head has adjustable tension using a set screw. Each set comes in a handy storage/carrying rack. We love these Gear Wrenches. Image: CHpg Staff.

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