Monday, February 4, 2013

My 15 minutes of fame. My '36 Auburn was mentioned in the What Are You Working On section of GEARZ.

Sunday, January 30, 2011

Cadillac Catera Power Seats

The exquisite, leather-covered power bucket seats offered by Cadillac for their Catera (a re-badged Opel Omega; the same platform was also later used for the Pontiac GTO) are a great value for the streetrodder. From 1997-2001, about 95,000 were sold in the USA. The leather seats feature 6-way power (driver and passenger; some are heated) and are made by Recaro. These are some of the most comfortable seats I've ever sat in and are frequently sold on eBay for $350 a pair .

Really? Just $350 for a pair of such nice seats? Why are they so relatively inexpensive?

The passenger seat is a conventional power seat with conventional relays and wiring. Wire up +12V and a ground and you're good to go. But the driver's seat uses solid-state relays and is connected to the car's main computer. As a result, many people believe that the seat won't work unless it's installed in a Catera and hooked up to the car's main computer. They are wrong.

All you lose by not being connected to the Catera's main computer is the three memorized positions that the main computer can store. Still, many people could not get the seats to work. The secret is all in the wiring, but the solution is hidden in the Troubleshooting section of the Cadillac service manual.

First, there are three +12V connections: two thicker wires and a thin wire. The thicker red ones (#1 & #3 in the service manual) are connected to an always-powered source. The thinner red one (#4) is connected to an accessory-powered source. The brown wires (#2 and #5) are the grounds. The data control wire is #6 and is not used. The secret wire is #7, a thin grey wire. In the Catera, this is connected to the door switch that controls the courtesy lights. When this wire is not grounded (when the door is open), the seats will not move. I just grounded it permanently; it seems the GM engineers did not want you to move the seat with the doors open. It's also important to wire #4 to a circuit that is hot only when the engine is running or it will drain the battery. That's all there is to it.

There are only two drawbacks to these seats. First, the Catera was four-door car, so these seats will not fold forward. If you used them in a two-door car, you won't have access to the rear seats. Second, they are wide, so without some modification to the seat cushion and re-covering, they are not useable in most 30's-vintage cars.

But if they fit (or can be made to fit), you will have some sweet, comfortable Recaro 6-way power seats for your ride for just $350.

Friday, May 7, 2010

Adlan Eagle Shocks

Aldan Eagle shocks have an excellent, well-earned reputation, but sometimes people get in the way.

My '37 Plymouth coupe uses a ladder-bar and coil-over rear suspension installed by the owner of Hunter's Hot Rods in Pennsylvania.

The shocks are red steel Aldans from about 10 years ago when the car was constructed. The coil springs don't carry the typical Alden paint ID so it's impossible to easily tell what the spring rate is; the shocks themselves have no model ID on them other than the Aldan logo.

The original builder did a poor job selecting the shocks and springs. The springs were sized incorrectly (too light), as were the shocks themselves (too short as I later discovered) with the end result being the shocks would constantly bottom out, especially if I had any luggage in the trunk. Needless to say, the ride quality was awful and I decided to have the shocks re-built and get the appropriate rate springs (which I calculated to be 400#).

I went to the Aldan web site and sent them an email giving the specs of my installation and requesting a quote for re-building the shocks. Rather than an email address at, their email address used the NetZero domain. NetZero is a free-to-low-cost dial-up ISP. That should have been my first warning something would go awry.

After a few days, I received an email from Ferrel Alan of Alden Eagle which asked me to call him at the business number. Why give an email contact if you prefer to do business over the phone? Oh, well.

We discussed my needs and I found him to be very knowledgeable and helpful. He suggested a shock that was physically longer than what I had and he agreed with my calculation on the spring rate. He also suggested that I use flexible bearings in the upper mount vice the standard rubber bushings because of the front-to-back movement of the shock due to the ladder bars. He then asked me for the mounting stud size and I could not find my notes and was not near the car. I later emailed the measurements to him.

When we did get back together by phone, Ferrel seemed to have a difficult time recalling our conversation and did not have the stud size info, so I provided it again (5/8" top and bottom), asked that he add an ALD-20 shock spacer to the order and provided my credit card information. He shipped the shocks after I made a follow-up phone call to see why they had not yet shipped: "They went out today".

When they arrived, the bearings were not included, nor were the ALD-20 mounting spacers that I ordered. When I spoke with Ferrel, he apologized and sent the bearings without additional charge but suggested that I contact the manufacturer of the spacers, Paul Horton of Welder Series in Canada, since Aldan did not have any in stock. I did as he suggested and everything arrived in a few days.

When I went to install the bearings, I discovered that the bearings only accommodated a 1/2" stud, not the 5/8" stud I had. I called Ferrel who said that the 1/2" bearing was all that would fit in the shock without extra machining and suggested that I contact Horton's or SpeedWay Motors to obtain a 1/2" shock stud. I have to wonder why he didn't tell me all that to begin with since he had the stud sizes?

The shocks are now mounted and the ride is great, but I'm left in amazement at the customer service that Aldan's provided. The process should not have been so haphazard, drawn-out and frustrating, but maybe I should have expected nothing less from a business that uses NetZero to get their email.

Saturday, September 5, 2009

Older Holley 4150 and 700R-4 TV Cable Problems

I'm in the process of mocking up my re-built Chevy small-block to find unanticipated problems and have been very successful: I've run into a big problem.

I'm using a Weiand 142 blower "kit" P/N 6500-1 and Weiand's recommended Holley carb, P/N 80572 (it's a boost-referenced Holley 4150; tech info can be found here and a HOWTO on modifying one can be found here).

The problem is that I'm also using a 700R-4 transmission and the Holley carb, according to the instruction manual, " ... is NOT designed for use with ANY automatic overdrive transmissions." (Of course, they only disclose this in the installation instructions; it's mentioned nowhere else. Farging bastages.) This incompatibility with an AOD is my big problem.

Obviously, what they are really referring to is not a Hatfield-McCoy (or PC-Mac) kind of incompatibility, but the lack of any appropriate bracketry associated with the throttle cable attachment point so that a TV cable can even be attached. This also means that Holley's "solution" (P/N 20-121, their 700R-4 kickdown throttle bracket) has NOTHING to mount to. Even if it did (and have one), the geometry is all wrong, only pulling the TV cable through a 30 degree arc instead of the required 78 degrees. That may be why others have had a problem with their 700R-4s even when using the Holley bracket.

Working from info at Sumner Patterson's site, I found I could modify/construct a bracket to add the 700R-4 functionality that Holley left out. You'll need to construct a diagram of the sweep of the TV cable stud following the drawing, but Sumner's directions weren't clear to me at first. You'll need a compass, a protractor and a ruler that reads in 1/10ths of an inch. The TV cable stud moves in an arc whose center is 1.094 " to 1.125" from the throttle shaft center. From closed throttle to WOT (wide open throttle), the arc is 78 degrees. First, mark a point on some card stock; this is the center of the throttle shaft. Draw a vertical line through this point. Set our compass between 1.094 " to 1.125"; Sumner used 1.1" which is about the middle of the two and draw a circle. This circle represents the arc that the TV cable stud follows. Using your protractor, make a line 55 degrees from the vertical line just like in the drawing. Now make another line 78 degrees from that just like in the drawing. One reason the drawing is confusing is that you'll never see the cable sitting on that vertical line; that's just used as a reference to get the other lines drawn in the correct location. To finish, make a horizontal line at 90 degrees to that vertical line about 1.25" below the shaft center point. That horizontal line must be held parallel to the bottom of the carburetor. Cut the card stock like Sumner shows here and read his detailed version of the process here.

To work through the details, I constructed a piece of card stock with the correct geometry , located the correct placement of the TV cable stud, and mocked up a solution. I noticed that the Holley bracket, if installed according to their directions on a newer 4150 carb that has an extended bracket will not track the correct geometry. I will simply cut up the otherwise-useless Holley 20-121 bracket and welded it to the carb in the appropriate place. Based on my mock-up, the TV cable stud will move through the correct geometry from closed to WOT. In theory, I've solved my problem, but there's a lot more to understand.

It's also important to position the TV cable bracket at the back of the carb correctly in relation to the stud on the carburetor. The distance will vary because there are different length cables in use. The way to measure yours is detailed here. The cable needs to run parallel to the base of the carb as well. My next step is to modify the bracket I have to get the correct location. No one said this was going to be easy, but and improperly installed cable will ruin your 700R-4 in short order.

There's a good overview of how the 700R-4 throttle valve works here. A nice FAQ about the 700R-4 here. And a speedometer gear calculator for both the 700R-4 and 200-4R here. It seems the best way to check if your 700R-4 is adjusted correctly is to hook a pressure gauge up to it and observe the readings from idle to WOT. BowTie Overdrives provides a PDF document describing the installation and setup of a 700-R4 or 200-4R transmission plus info on measuring for a driveshaft and wiring a lockup switch and brake relay switch. They recommend a 0 to 300 PSI gauge and 7 feet of hose and a 90 degree 1/8" NTP fitting. The pressure gauge is attached to the direct pump pressure port on the driver’s side of the transmission which is about 3-1/2" above the manual shifter shaft. They don't provide the "full Monty" of the test (or the pressures), but do offer a briefer "field test" on pages 16 and 17. The suggested pressure is 65 to 80 lbs at idle for either transmission; too high a pressure at idle will start you in second gear; too low a pressure will cause it to slip. The pressure should spike when you leave a stop light and if it doesn't, the tranny is slipping. A good discussion is here.

I used the "standard" method:
  1. Depress the adjustment button and collapse the adjustment sleeve.
  2. Releasing the button, move the throttle to WOT; the cable self-adjusts.
  3. Attain adjustment Nirvana.
You raise the pressure by pushing the cable adjuster back into the cable, preferably doing it a click or two at a time. What seems to be critical is the distance the cable travels from closed to WOT and doing it at a steady rate. That's why the geometry is so important; bad geometry moves the cable at an uneven rate and so varies the pressure at an uneven rate causing improper shifting and resulting damage. From "To raise throttle pressure (and raise shift points, and make "kickdown" more responsive) move the cable housing towards the firewall (away from the throttle linkage), as you simultaneously depress the button on the cable housing, move the cable housing away from the carburetor or (throttle body) to increase throttle pressure. Move the cable housing adjustment a small amount at a time (1 click or 1/16" or so), a small adjustment can often make a world of difference. Naturally, to lower the pressure (and lower shift points, and make "kickdown" less sensitive), move the cable housing towards the front of the truck.

Here is a good discussion of not only adjusting the TV cable, but measuring critical distances including the length of the cable itself.

You should always use a transmission cooler with a 700R-4 because heat is a killer for transmissions. The stacked-plate coolers are superior to the serpentine coolers. I always use the B&M #70264, rated at 14,400 BTUs; it's their biggest one. You can find stacked-plate coolers on Volvos in the wrecking yards. B&M also makes a fan-cooled remote-mount version, # 70297, but you should be able to fab something up for less that the $250 they sell theirs for. Ugh.

Problem solved; the transmission works great!

Thursday, April 30, 2009

Keeping Your Compressor Quiet

Air compressors are noisy machines. The two most commonly used ways to quiet them down are to locate the air intake outside (not good for the neighbors) or to build some type of enclosure with sound deadening material inside; that usually causes overheating problems due to poor circulation.

The best solution is to construct a silencer that uses the same principles as a gun silencer. But isn't that illegal? Only if you use it on a gun. We're using it on an air compressor. Still, this topic seems to be controversial, mostly by people who have a bury-your-head-in-the-sand approach to security and safety.

Here are the materials:

  • Pipe the same size the air compressor port will use, 16"-18" long.
  • Some exhaust pipe, the same length as the other pipe.
  • Some washers you have to make with a hole saw, enough to put one on each end and one every 1-1/2" that will fit around the air compressor intake port pipe and fit inside the exhaust pipe.
  • Steel wool to fit between the washers.
  • A drill and a 1/4" drill bit to drill holes in the smaller pipe between the washers.
  • A welding machine to weld the washers to the small pipe and to the large pipe at the ends.

Since the silencer will be heavy, use a 90-degree fitting and mount it vertically.

Some links to sites that describe how silencers work and how to construct silencers can help you understand how the Air Compressor Silencer is constructed. If you Google for "gun silencers", you'll find lots of sites, so we're not divulging secret, hard-to-find information and, unless you're dumb enough to build one for a gun, not breaking any laws. If you think so, the terrorists have already won and you are not thinking of the children.

What Pipe to Use for Your Shop's Compressed Air?

Many people use Schedule 40 PVC pipe and that choice is - OSHA ALERT - potentially dangerous. Under pressure, PVC can explode when it becomes brittle with age or exposure to UV light or when struck by an object. But there are a lot of shops piped with Schedule 40 PVC. If you choose to use it against all advice, at least consider the stronger Schedule 80 pipe and fittings, keep the pipe protected from things that may fall on it and don't hammer near it. PVC is smooth inside which means less pressure drop from friction.

There are ABS pipes, Dura-Plus and Chem-Aire, that are rated for compressed gas use. The cost is roughly twice that of Schedule 80 PVC. Dura-Plus comes in a metric size (colored blue) and an industrial size, colored gray; the blue pipe cannot be threaded for standard pipe threads. Chem-Aire pipe is green.

Schedule 40 black iron pipe is a popular choice and is very sturdy and durable. It's also heavy and awkward to install and will rust inside, not only adding scale to the air, but increasing friction and causing increasing pressure drops over time. Galvanized Schedule 40 is a better choice, but more cumbersome to work with and also requires some specials tools.

Copper pipe is lighter and easier to install, and comes in three types. Type L is identified with blue markings and Type K is identified with green markings; both are strong enough to use. Type M is marked red and is not recommended since it is only rated for 125 PSI; that won't leave much of a margin for error. Copper is smooth inside which means less pressure drop from friction; this matters for long runs of pipe.

Of course, you could always use stainless steel pipe and compression fittings or even the very cool (but ridiculously expensive) Garage Pak system which uses a coated aluminum pipe and special fittings. All that expense does buy a product that is easy to use.

There is also Compressed Air Systems which sells coated aluminum pipe. This looks like what I saw at Harbor Freight.

Wednesday, April 29, 2009

The Science Behind Piping Your Air Compressor

How many of us have spent hours examining compressor horsepower and CFM ratings, reading shop forum posts and comparing prices to decide what the "perfect" compressor for our shop will be, but then connect a few Harbor Freight air hoses and wonder why the tools don't run well and spit water everywhere?

A well-written article at the website delves into the science behind piping your shop's air compressor. In brief, our problems arise because we do not have a properly-sized pipe system to deliver the air to the tool.

Compressed air will lose pressure because of the friction from the walls of the pipe. This is expressed in pressure drop per 100 feet of pipe at a particular pressure for a specific diameter of pipe. Of course, designing a proper system is not simple because there are many factors that affect the performance other than pipe size.

Another point made in the article is that the velocity of the air through the system is rarely considered. Why does it matter? When the velocity is less than 20 FPS, moisture and debris are not pushed past traps and can be easily drained away. When the velocity is greater than 30 FPS, all the moisture and debris is blown out of the tool you're using. So if you have a long run of small diameter pipe or hose,the velocity is high and stuff shoots out of the tool along with the air. Does that sound familiar?

To further complicate matters, the tables are designed under the assumption that un-compressed air is being pushed through the pipe. Compressing air increases the volume of air that flows through the pipe, so some more calculations are necessary to adjust the figures and you'll need to determine the ration of atmospheric pressure to the pressure of the compressed air. You'll need to know the average air pressure in PSI where you live; at sea level it's 14.7 PSI and that will drop as elevation increases. What's yours? Remember, Google is your friend.

Generally speaking, the larger the diameter of the pipe, the better of you'll be. A table of inner and outer pipe diameters can be found here. A table showing the pressure drop per 100 feet of Schedule 40 pipe is here. You can see the problem we face: using a small diameter pipe (or hose) to reduce pressure loss will increase the velocity of the air which explains why so much water gets past those filters and traps. But if we use a large diameter pipe, we need higher pressure at the receiver (the tank) to compensate for the pressure drop. The benefit is less water and debris blown out the tool, but a more powerful compressor is more costly.

The Quick Soultion
At some point, somebody sat down and calculated a rule-of-thumb guide to piping you shop, based upon quite a few assumptions that probably aren't correct for your shop. That "rule" is 3/4" for the mains and 1/2" for the drops. That usually works OK for a small garage shop, but maybe not.

Read the article, work the math (you can get your kids to help), and you'll be able to see why you have so much trouble with compressed air at your shop. Having understood well enough to have done the math, you'll be able to understand how to go about improving your own system and improve it. Better yet, it can help you design a good system from scratch.