Preparing the motor, clutch and transmission for (hopefully) final installation

Motor/Tranny Preparation

Now that things are mostly done in the engine compartment, it's time to ready the motor for final installation. Originally I didn't install the clutch or flywheel to keep the weight down.

I was planning to use a McLeod aluminum flywheel with McLeod 11" clutch and a Quartermaster internal clutch slave cylinder. I decided to go with hydraulics for the clutch, in spite of the Tremec (and Ford T5s) being configured with a cable operated clutch. I've had good luck in previous cars with the Quartermaster internal slave cylinders. If you haven't seen one, basically they are a throw-out bearing that slips over the transmission input shaft cover. Two hydraulic hoses come out, one for bleeding, and the other going to the clutch master cylinder. When hydraulic pressure is applied, the throw-out bearing presses on the clutch diaphragm on the front, and the transmission on the rear. Simple, and light.

In order to use the Quartermaster, I had to turn down the input shaft of the transmission by about fifty thousands of an inch to a diameter of 1.370".

And then shim it away from the transmission with spacers provided with the kit. However, the spacers didn't give enough distance for this transmission, so I machined a spacer that was long enough. The throw-out bearing kit includes a stainless pin that replaces one of the bolts on the front of the transmission that keeps the throw-out bearing from spinning. With my extra long spacer, the length of this was marginal, so I put a couple of washers behind the head until it extended well into the body of the throw-out assembly.

Now that the transmission was all prepared, I bolted it to the motor. However, I discovered that it was binding before the bolts were tight. It turns out that this bell housing won't work with an 11" clutch, just not enough room. So I bought a Mustang 10 ½" clutch and things all worked out. I didn't even need to set up the clutch geometry again.

I installed a Ford Motorsport 90 degree adaptor for the oil filter. Here's the motor and tranny all ready to go into the car:

Seeing the valve covers reminds me that with roller lifters and a high lift cam, standard Ford Motorsport valve covers don't fit - the rockers hit the metal sheet under the vents. Inside the valve cover, it's necessary to cut down the size of the vent cover sheet metal, and machine the bosses to be shorter. Alternatives include thicker gaskets, spacers under the valve covers, or taller valve covers. I like to use standard gaskets though and don't like the looks of spacers or the tall covers. In race motors I've even machined off the edges of the rockers to make a little more room.


Motor/Tranny Reinstallation

So, let's put that dog into the car! Here's my oh-so-nice wife (she's cute too!) helping to guide the motor in without scratching anything…

Between this and the last picture you saw her in, she's been in the car pumping pedals (with no seats in the car) to help bleed the brakes, and under the car putting out flames as I weld a panel over the rear of the shifter opening.

This part is the most fun. Everything clean and painted, most polished or powder coated. The engine slips right in there like it was made for the car. I might note that it's a good idea to lift the motor towards the front, so it is heavy on the transmission end. That gives it a more vertical attitude to drop into the car. I couldn't use my engine support that is adjustable fore and aft since it is too close to the fire wall for this installation. As I mentioned before, the engine cradle needs to be slid forward a couple of inches during the installation, then slid back once the transmission is jacked up so the motor is mostly level.

Clutch Issues

After getting the motor in, I decided to bleed the clutch and see how that works. Unfortunately, it doesn't cleanly release. Then, to make matters worse, I looked through the hole in the side of the bell housing while my trusty wife is pushing the clutch pedal (again with no seats in the car, can't be easy), and see that the release works a little different than I thought. It pushed out of the back instead of towards the pressure plate. In a normal T5 installation with a short spacer between the bearing and transmission, this is no problem. In this case however, I can see that the body of the release is moving beyond the pin that is supposed to keep it from spinning. Oh no, is this going to require the motor and tranny to come out again?

Fortunately, I was able to unbolt the transmission from the engine and slide it back far enough so that I could get the anti-spin post out. With the throw-out bearing, Quartermaster provided two nice stainless steel posts, each with different threads for different transmission applications. I cut the second one off, welded it to the one that fit on my transmission, and then turned it down to make it smooth again. Here it is in its new longer length:

I was able to get it back in without dropping it (no picking up stainless steel with a magnet), and my wife had the helpful suggestion to tie a string around it just in case – that would have saved me if I dropped it.

That solved that problem but not the release issue. Another problem I noticed was that when the clutch pedal was pressed, the firewall flexed forward quite a bit with the ¾" master cylinder. The factory cylinder is 5/8".

The solution to both these problems was to buy another Tilton cylinder, this time 7/8" bore, and install a stiffener to it. I made a master cylinder brace from 1" thin-wall square tubing that bolts to the fender well:

At last, the clutch is working fine. The clutch master cylinder moves a little, but not enough to be a problem, and probably less than when the car was stock. Flex might be completely eliminated with a brace that additionally went over to the side wall of the engine compartment.

I might mention another problem I ran across when doing the clutch. When I was under the dash installing the new cylinder (you need to tap the clevis to match the Tilton threads which are 5/16—24 and shorten the cylinder rod about 3/8"), I found that the original clutch linkage was really shot. In this picture, that's supposed to be a round hole in the clutch pedal, and a pin of consistent diameter:

A few more pedal pushes, and failure would have occurred, and it could have been bad if one were at a stop light and the clutch decided to release. I welded the oblong hole shut in the pedal, redrilled it, and made a new pin.

The clutch linkage is all tight now and has a nice release point that isn't close to the floor. Part of the problem with making hydraulic clutches work well in a 240Z is the geometry of the clutch linkage - the pedal only strokes the master cylinder about 5/8". When you subtract some flexing of the fire wall, that isn't much. It would be nice if the geometry allowed almost an inch of travel so that it would utilize most of the stroke available in the Tilton master cylinder, then you might be able to get by with the ¾" cylinder and have an easier pedal press, not that it's excessive with the 7/8" cylinder.

Things I've learned later: A couple of folks who have done similar conversions have been good enough to email me about a different clutch actuation approach that they have taken. They used a Wilwood part number 260-1333 slave cylinder that pulls, rather than pushes like a normal slave cylinder. Cost is about $75 at time of writing. Evidently this works well with a 3/4" master cylinder similar to the Tilton one I used, or the Wilwood verson (part number 260-6764). This approach sounds simpler, less expensive, and easier to service than the internal slave that I used. Here's what Michael Cole's installation looks like:

 Pull-type Slave

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