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Cylinder Head Disassembly/Reassembly Benches
By Larry Carley
Just because you’re used to doing things a certain way doesn’t mean there isn’t room for improvement. A change in equipment and technique can often make a time-consuming job go much quicker. It can also transform a difficult job into an easy one. These days, anything that saves you time and aggravation will make your shop more productive — and more profitable.
Accordingly, anyone who does cylinder heads knows that disassembly and reassembly can be a time-consuming and difficult job on certain heads. As one rebuilder said, "Anybody can do a Chevy 350 head with a C-clamp style valve spring compressor. But it’s too slow and clumsy for a lot of overhead cam heads. You’ve got to have a better way of doing these heads."
The better way is a cylinder head work bench. A number of suppliers now sell disassembly/reassembly equipment for handling the "hard-to-do" heads (those with overhead cams, canted valves and/or unusually stiff springs) as well as conventional pushrod style heads like Chevy 350s. The work bench approach provides table-like fixturing to hold and secure the head while supporting the valves from underneath so the valve springs can be compressed mechanically, pneumatically or hydraulically. It’s like having an extra pair of hands as well as an extra set of fingers.
Those who use work benches for this kind of work say the equipment saves time on all kinds of heads, not just the difficult ones. Many shop owners who originally bought a work bench to handle only import or OHC heads say they now use it on almost every kind of head they do. They say a dedicated work bench is usually faster and easier to use than a conventional spring compressor, even on common pushrod heads, and that it reduces mistakes and the possibility of damaging the head or valves. They also say the equipment minimizes the risk of operator injury by keeping the spring contained while it is being compressed. Anyone who has ever seen a valve spring under tension pop out of a compressor knows the damage that it can do.
Some of those who started out with a single work bench have added a second or third bench to boost productivity. They use one bench for teardown and a second or additional benches for reassembly. What started out to be a luxury for some applications has since become an indispensable tool for boosting both productivity and profitability.
In a high volume cylinder head department, a dedicated disassembly and reassembly work bench has become just as necessary as a seat and guide machine, a valve grinder, or an OHC boring and honing bar. The market is too competitive today to keep doing things the same old way. Cylinder heads are becoming more complex and costly to rebuild, so any piece of equipment that gives you an edge by making the job faster, easier or safer is well worth looking into.
What users say
John Morrisey of Jif Products in Kansas City, MO, said that he’s been using an ABS Products work station for about six years. Jif Products is a five-man shop that specializes in aluminum heads. "We currently have three machines. We use one for disassembly and two for reassembly. We’ve been using this equipment for so long it’s hard to say how much time we save compared to doing it the old fashioned way, but it’s a lot.
"There are a lot of features I like about this equipment. One is that it lets you install and adjust everything at once. You can rotate the cam with the valves in place to make the lash adjustments. On heads like Toyota, Volkswagen and others that have a shim-style valve adjustment, you don’t need any special tools to set the lash. You just hold the valves down and change the shim. On heads that have bridge-type rocker arms like the Chrysler 2.2L and Ford 4.6L, you can install the rockers after you’ve installed the camshaft.
"We’ve also found that this kind of equipment allows you to be more organized. You can record valve stem height data so when the head goes back to assembly you can tip the valves right there in the machine before you put the head together. It facilitates both shim-type adjustments and hydraulic lash compensators. You can check valve lash after you’ve assembled the head and eliminate lash problems altogether.
"It also reduces the chance of making a mistake when you’re putting things back together. You can lay out the parts, which reduces the odds of mixing up intake and exhaust springs if they’re different, or installing a progressively wound valve spring upside down. It also makes it easier to push on positive valve stem seals," said Morrisey.
Bob Pakes of Pakes’ Engine & Machine Inc., in Janesville, WI, said, "When work benches first came out, I said no way would I ever pay that kind of money just to install springs. But a year ago, I bought a Peterson Model SRA30, and now we use it on almost every head we do."
Pakes, who runs a seven-man shop and does virtually all kinds of engine work, said he had been using an pneumatic C-clamp type spring compressor with various kinds of barrel adapters. It worked fine on some heads, but took too long or didn’t work well on a lot of OHC heads with recessed valve springs. "After trying everything else, I finally decided I had to buy a cylinder head work bench. So that’s what I did, and I’m sorry I didn’t do it sooner."
Pakes said he likes the equipment he’s using because it can handle stiff springs like those in big block Chevy heads and other performance applications. "We don’t use it on big diesel heads, but we do use it on almost every passenger car and light truck head that comes in the shop. I’d say it probably saves us about 10 minutes on a Chevy V8 head, but half an hour to 45 minutes on a typical OHC head with recessed valve springs."
Bob Sweeney of Protech Engines in Mokena, IL, has been using a Sunnen CHW40 since it first came out nearly two years ago, and has since added a Sunnen CHW50 to his shop. Sweeney says he originally bought a cylinder head work station because he "had to find a better way of disassembling and reassembling heads."
"One of our guys used to spend an hour putting together an overhead cam head the old way. Now he can do it in 15 to 20 minutes. The equipment also works great on heads with compound valves, and the CHW50 can handle up to 900 lb. performance springs. It’s great and the equipment works beautiful."
Sweeney says that although the two work stations represented a sizable investment for his shop, he estimates they paid for themselves in one year. "I made a buying decision based not only on what the work stations could save me in labor, but also how they could improve shop safety. The best way to prevent accidents is to stop them before they happen. This equipment does that and protects the operator from injury."
Sweeney said would-be buyers of a cylinder head work bench or station should compare features as well as price. "There are a lot of differences between the various brands of equipment, so don’t think for a minute they’re all the same. A bench that sells for half as much as another won’t give you the same features."
Others have similar good things to say about their cylinder head work stations. Tom Nichols of Automotive Machine & Supply Inc., a shop that specializes in import multi-valve heads in Fort Worth, TX, said that his shop has been using a Newen Spring Master since early in 1992.
"It has performed well and has made assembly much, much faster and easier. We have increased our cylinder head production by about 10 to 15 percent simply by using the Spring Master. "In every machine shop there is one or two machines that are real money-makers. The Newen Spring Master has been just such a machine for our shop; it’s a real money-maker," said Nichols.
There are a variety of work bench configurations from which to choose: bench mounted, floor mounted with a stand, or part of a stand alone cabinet or table. The cylinder head may rest against blocks or be locked, bolted or clamped in place. Different methods are used to rotate or reposition the head to accommodate different valve angles, which is an important consideration on heads with canted valves like big block Chevy’s and others. You’ll also find different methods used to support the valves (some of which may be more user-friendly or versatile than others depending on the kind of heads you do).
Some benches have a foot pedal to operate the pneumatic or hydraulic spring compressor for hands-free operation. Others use a hand lever to actuate the compressor. Some have no power assist and use a foot bar and leverage system to mechanically compress the valve springs. You’ll also find differences in the rating of the spring compressor. Most can handle standard 160 to 220 lbs. springs, while others can handle 800 to 900 lbs. springs, which is an important consideration if you do performance work.
There are also significant differences in the type of spring cup holder used (offset, open foot, three-post, two-leg cage, open cylindrical and others). The more open the design, the better because it leaves more room to maneuver the keepers into position. Cup holder sizes also vary, ranging from 21mm (13/16˝) to 42mm (1-3/4˝) in diameter. Some only come with one size cup holder while others offer a variety of different sizes.
Some work benches also come with more accessories than others, things like a gauge for measuring spring pressure, valve spring keeper installation and removal tools, lights, catch pans, a tray to place parts or tools, etc.
Whether you’re a first-time buyer shopping for a new work bench to add to your cylinder head department, or an existing user who wants to add a second machine, replace an existing machine or upgrade to a bench with more features, be sure to check out the accompanying work bench product guide on page 65.
One way to shop and compare the various work benches and choose one that best suits your needs and preferences is to attend industry trade shows such as the upcoming AERA Expo ‘99 International trade show in St. Louis, MO, April 30 to May 2. Most of the manufacturers and distributors will be exhibiting their equipment at the show, and will have product specialists on hand to answer your questions and show you the various features of their benches.
Another way to figure out which bench might be best for you is to ask several equipment suppliers for names of shops in your area who are using their equipment. Then contact a couple of shops and ask them what their experience has been with the equipment. What features do they like best? What kind of heads are they doing? How easy is it to use? How much time do they save? Have they had any problems or breakdowns? What kind of service did the equipment supplier provide, and how much did it cost? The answers to these questions should help you make a better informed buying decision.
Return on investment
Cylinder head work bench prices range from about $1,700 for a basic entry level bench up to $5,000 for a top-of-the-line work station. Options that typically add to the base price include a larger, more powerful pneumatic cylinder, a separate work table or stand, additional cup holders and special valve keeper tools.
Your return on investment will obviously depend on the type of heads you machine (faster payback on OHC than pushrod), and the volume of head work that you do. Most equipment suppliers say their equipment should pay for itself in a year or less.
If you do a dozen OHC heads a week and can save half-an-hour of assembly time on each head by using a work bench rather than a C-clamp, you’ll save $84 in labor every week, assuming you pay an employee $14 per hour to assemble heads. Multiply this figure by 52 weeks a year and you end up spending $4,368 less on labor — which should pay for most benches. But that’s not all. That same half hour you save on every OHC head you assemble can now be used to build more heads (assuming you have the work to do, of course). That adds up to an additional $84 a week in billable labor, or an extra $4,368 a year — plus parts.
Increased productivity works to your benefit in two ways. It reduces your labor costs, and it allows your people to be more productive so their labor can be billed out on other jobs. Less time spent assembling heads means more jobs can be turned around in the same amount of time.