Bric Rods

Holley Support

bric — Fri, 10 Sep 2010 14:18:57 +0000

Recently we’ve been working with tuning a Holley 600 to work with a Ford 289, and realized that some of this information would be very good to have posted where others could get to it. Particularly in reference to power valves. We all know what a power valve is, and anyone who has taken apart a Holley knows how to replace it, but it seems less is known about the actual workings of the power valve. First off, the basics. The higher the number on the power valve, the sooner it opens; the lower the number, the later it opens. There is a wide range of power valves, from 2.5 to 10.5, if memory serves, and the basic application is as follows. If you have a low vacuum, measured with a vacuum gauge at the base of the carb – or elsewhere there is full vacuum, with the point being that you don’t want to measure it at the metering block, as this is metered vacuum and does not give full vacuum measures – then you need a lower number power valve. Knowing this, if you have a vacuum reading at idle of say, -8 psi, then you would want a power valve rated at about 3.5. What this means is that at 3.5 psi vacuum, the power valve will be fully open, but it will have started to open at about 7. Key here is knowing that your greatest vacuum is pulled at idle and cruise conditions, and when you hit the throttle, the vacuum drops off. So if at idle the engine has 8 psi vacuum, when the throttle is opened, the vacuum will drop off, as it does so, the power valve opens. So the vacuum looks something like 8, 7.5 (power valve opening), 7, 6.5, 6, 5, 4, 3.5 (valve fully open), 2, 1, 0 (butterflies open fully, allowing all the air and fuel necessary to the engine and providing no restrictions, hence, no vacuum).

The point here is that if you have a low vacuum engine, you need a lower number power valve, not vice versa, as commonly believed. Once the power valve is figured out (and this takes some experimenting sometimes, especially if you don’t know what cam is in the engine) you can fool with the main jets to get the right mixture out of the engine. Generally factory specs on jets for the engine are pretty much what one will need to follow, but if you have just bought a performance.aftermarket carb, chances are you’ll have to do some messing around to determine just what the engine likes.

Engine Calculator

bric — Mon, 24 May 2010 23:01:42 +0000

It has recently been realized that the engine calculator designed and posted some time ago was never announced to being completed. In that light, please find the aforementioned here, as well as a link from the actual engine calculator main page here. This should be fairly helpful in determining static compression ratios and some other miscellaneous conversions.

Mustang Radiator Supports

bric — Thu, 04 Feb 2010 17:27:03 +0000

On a recent project, notably the 1970 Mustang Mach 1 shown elsewhere in this site, a decision was made to facilitate an easier method of engine removal and installation, as 385 series engines were never meant to be put in these cars in the first place. This “enhancement” involved the removal of the upper radiator support member located at the front of the car. Yes, this is a stiffening member, however, with the installation of a removable fabricated aluminum support, this support is returned to the front end. Also involved in this removal is the problem that the hood latch assembly is removed along with the upper support, as it attaches here. Therefore, this must be rectified as well.

To get to the nitty gritty of the process, cut off the support at both the left and right sides of the radiator opening, making sure to cut off the corners remaining so the remainder is flush with the fender bolts. Once that is done, one must figure out how to attach the hood so it will not flip up upon driving the car for the first time. This is accomplished a variety of ways, though the way chosen here was simply to install hood pins, as the car has a fiberglass hood and this was the previous method of fastening anyway. Again, even hood pins can be installed however one chooses, and here the desired method was to weld a threaded rod – a.k.a. Bolt – to the lower frame at the front of the car and extend a hollow rod up through the front sheet metal with female threaded portions on either end. One of these was then threaded onto the bottom male threads, and the upper end was used to thread the hood pins into. Making sure these line up correctly with the holes in the hood is really the hard part, and the most important.

Once those are installed, one can fabricate a crossmember/radiator support out of sheet stock – here aluminum was the metal of choice simply for its light weight. The important thing to remember is the 90 degree bend on the back side to mount the radiator, and a slight bend on the front just for strength. Also of note is the correct location of the holes for the hood pins (as they are used to hold the crossmember in place) and for the holes for the fender bolts on either end, as these are used to mount it as well. Once the angles are bent and the holes are drilled, it’s ready to install and there you go. Fasten radiator and drive away, knowing that the next time the engine has to come out, the job will be oh-so-much-easier.

Alignment Tech

bric — Mon, 11 Jan 2010 02:44:43 +0000

For anyone wishing to align a car in their own space and on their own time, I have a simple solution. All one needs is a set of grease plates, also known as alignment plates, to set the car on and a simple laser pointer attached to a straight-edge. This could be a piece of pipe (useful because it avoids having to figure out how to attach said pointer) or some other medium. The grease plates are somewhat more difficult to come by, and can be pricey if purchased. However, one can make one’s own if the proper tools are available. Granted, it requires a mill or lathe and a bit of engineering, but it can be done – I, however, cannot give out all my secrets, now can I?

Once the aforementioned tools are obtained, one needs only to set the car on the grease plates, assuring that it is sitting in the stance it would normally take – i.e. all weight on the tires and settled – push down on the bumper a couple times to be positive. Being settled in, it is fairly basic to set the straight-edge with attached laser on a set of jackstands, placing the edge on both the front and rear sidewalls of the rear tire. This will give a straight line to the front of the car, passing by the front tires. Measuring the distance from the front and rear of the front rim to the laser will give you an idea of where your car is. Turn the wheels 20 degrees both directions and check it again to be sure it is correct, and cross-reference with your manual as to how many degrees of toe your particular car needs. That’s it. you are done. As I said, simple.

Hydraulic Clutch Conversion

bric — Sat, 12 Dec 2009 17:44:51 +0000

This particular post deals with installing a hydraulic clutch on an old Z-bar (equalizer bar) car. The old style mechanical linkage, though reliable, has one inherent problem – it takes up too much room in the engine compartment. This is explained a bit in this post which tells about the design of Mustangs in accordance with their particular engine displacement. To summarize however, this 1970 Mach 1 needs more room for headers with better flow, and to this effect a rack and pinion was installed, and then a hydraulic clutch was intsalled. There are a few ways one can go about this, which include putting in race-bred throwout bearings (slave cylinders), installing a later model Ford slave cylinder from the likes of a ‘94 pickup, or by taking the route we took here, which involved the use of (I know sacrilege) GM parts.

First allow the comparison of pros and cons among the differing systems. To go with a race bred bearing is pricey, with kits costing close to $500. The bearing itself is close to 200 for a cheap one. Also, it involves specific master cylinder applications and is mostly difficult for parts procurement short of ordering them and waiting for their arrival.

In reference to the Ford stock parts, it involves the use of a plastic mounting surface for the slave cylinder, and would involve the replacement of the input shaft bearing on the trans. This could prove detrimental to the overall reliability of the transmission, and was not an option of choice as a result.

The third option, though frowned upon by purists, is one with sound reasoning. The GM system used on ‘88 vintage full size trucks involved the use of an external slave cylinder, and a common master cylinder. What this means is that with a simple bracket, fabricated and bolted to the bellhousing, and a slight extension of the clutch fork, one can install this system on any vehicle. A couple bubble flare fittings and two flare fittings along with some brake line with a built in flex point allows the connection between slave and master cylinders, and a simple bleeding of the line produces a dramatic reduction in pedal pressure, as well as increased clearance in the engine compartment for the headers to be routed. Thus, the primary objective is achieved, and for a grand total of roughly $120.

A bit on Rack and Pinions

bric — Sat, 12 Dec 2009 17:18:58 +0000

With the onset of winter in Illinois, it is time to tackle some long-running modifications to one of the constants in the shop, the old 1970 Mach 1. First allow me to explain a few inherent problems with the Mach. The biggest problem (and biggest asset interestingly) is the big 385 series 429 in the engine compartment. For those of you unfamiliar with the Mustang chassis, they were produced specific to the engine installed, i.e. if it was manufactured for a 302, the engine compartment was sized accordingly, if for a 428, or other big block, the shock towers were modified to accept the larger width. In the case of the only Mustangs to get the 429, the Boss 429, the whole front end was modified by an outside contractor to fit the monstrous engine.

Back to the point though, is the fact that this Mach was originally a 351 car, and so the shock towers were cut down at some point to accommodate the big block. Unfortunately, this was done some time ago and was not done specifically for the 385 series engine, which causes problems procuring headers. It is to this end that a rack and pinion was desired, to allow for more room in the engine compartment to design headers with better flow.

First off was the removal of the old steering components, including the gearbox, the center link, and all the tie rods. Next on the agenda was the fabrication of brackets to install the rack and pinion itself, making sure that it was low enough to clear the oil pan, an issue with this larger engine. Also of note is the retention of the rear steering, rather than a full on conversion to front steering components. once the brackets were fabricated out of steel, with solid aluminum bushings for the rack to eliminate any movement, the measurements had to be taken for the overall length of the rack. This turned out to be a bit long, and short of ordering a custom (and more expensive) rack, we simply machined the threads farther up the rod ends and cut off the ends to shorten it up a bit, roughly 1.5 inches. Once this was done, the daunting task of assembling a linkage to the steering column was tackled. This involved lengthening the stock shaft by about 9 inches, cutting off the end of the steering column that protrudes into the engine bay for added angular clearance, and assembling the knuckles. All told, this is fairly simple, just a matter of measuring the distances and drilling a few retention holes in the DD bar. Of note is the fact that we used a short pinion rack to allow for the most clearance.

A summary of parts is simply this – rack and pinion, two knuckles, a length of DD rod – 3/4 inch, and a couple Mustang II outer tie rod ends. That’s really all it takes. Of course, this still needs to be road tested, and a bearing may need to be installed at the base of the steering column to maintain alignment, but that remains to be seen. Currently there appears to be very little slop in the system and so it will be left as is for now. Parts total was just upward of $500.

Notes on 351 Cleveland Identification

bric — Thu, 05 Nov 2009 02:09:51 +0000

It has recently come to our attention here at Bric Rods that quite a few people do not know the visual differences between four barrel Cleveland heads and two barrel Cleveland heads for the 351. To that effect, here is a quick determination. First off, if it has an aftermarket aluminum manifold on it, most of the 4V variations have that information cast into the manifold, particularly Edelbrock. These will indicate on the top, just behind the distributor whether the manifold is for the 4V or 2V with the appropriate 2V or 4V cast into it.
If the manifold fails to show this, a somewhat more labor intensive process is required, as no significant difference is noted on the outside of the heads themselves. One can tell by removing the valve covers and looking at the intake runners in the heads, as they will be slightly higher/larger, but this is a difficult determination if a comparison is not readily available. Otherwise, removal of the manifold is required, and recommended, at which point one can simply compare the size of the intake ports to the size of one’s fist. Though somewhat non-technical, it is a good determinate, as 4V heads will be close to the overall size, knuckle to knuckle, whereas the 2V heads are blatantly undersized when compared to the average fist.

Dialing In a Bellhousing

bric — Wed, 21 Oct 2009 01:41:02 +0000

It has come to my attention that I mentioned dialing a bellhousing without ever explaining what that is exactly, necessitating this post.
To dial in a bellhousing is to center the nose-cone hole to the center of the crankshaft rotation. To do this one can either remove the flywheel and clutch of leave it on, though for adaptation purposes it is much easier and definitive with the clutch removed and the flywheel in place. This allows for the maximum surface area to attach a dial indicator base to. Which brings me to the necessary equipment for this little procedure, which is a dial indicator and a base – preferable of the magnetic type. Mount the bellhousing like you would normally, and affix the dial indicator to the flywheel, maintaining an off-center orientation so as to get a good reading. Put some preload on the indicator and spin the motor over. Watching the indicator will tell you where the hole sits and to what degree it is off. If it is more than .010″ you should probably look into getting some offset pins to better align the bellhousing.

Dana Disassembly

bric — Tue, 06 Oct 2009 14:40:50 +0000

Today’s topic differs from some of the more ‘old school’ topics normally covered, but most of the information herein can be transferred to most Dana assemblies. The 9.25″ rear differential used in 90’s era Dodge trucks has a basic assembly, though it can prove difficult to remove. What goes wrong with these differentials is housed in the center section, among the shims used to correctly space the limited slip gears. One of these shims on each side is load bearing – taking the majority of side loads incurred from cornering forces, otherwise known as lateral movement. These then wear and crack, sending little pieces of shrapnel throughout the assembly. Luckily there is a magnet to catch most of this, however, the longer this continues, the worse the damage.
That said, to disassemble, one must remove the cover plate, remove the rear wheels and brakes (for ease of removal, though this can be done without the removal of the brakes), and remove the retaining pin in the center of the housing. Once this pin is removed, push either axle inward, remove the C-clip, and pull the axle out; repeat this process for the other axle. once these are removed, one can attempt to remove the differential assembly simply by pulling it out. If it does not come out easily, one must turn the adjusting collars in either axle, which necessitates a special hex tool. Once it is all removed, it is a simple matter of replacing the shims (which are not just shims, but that’s another matter) and reversing the same steps to reassemble the rear end. Don’t forget to fill the case with gear oil though, or you’re back at it shortly.

Transmission Support

bric — Tue, 30 Jun 2009 23:53:54 +0000

In the interim of finding something more interesting to write about, we shall look into the removal and installatin of a manual transmission on pretty much any car. It is a fairly simple procedure, yet one that most people decide not to tackle due to the daunting nature associated with transmissions. In reality all one has to do is appropriately lift the vehicle, unbolt the u-joints at the rear end and slide the driveshaft out. At this point the trans fuid will drain, most likely all over you, but it may be stopped with a plug or simply drained. Then if one so decides, the bellhousing provides a good place to support the rear of the engine, facilitating the removal of the transmission crossmember, the speedometer cable, the shifter (an important piece that one) and then the four bolts securing the transmission case to the bellhousing. One can then simply slide the transmisison out with a bit of grunting, and get on with whatever reason the trans needed to be removed in the first place. This whole process can be accomplished in just a few hours. and the installation is simply the reverse. And don’t forget to fill the trans with fluid/oil, that can be catastrophic.