T18/225 swap

This may have come up before, and if so I apologize for the repeat. I am swapping a T18 from a 1979 Ford F-150 into a 1968 CJ-5 with a factory installed Buick 225 V-6. The prior owner exploded the original T86AA, so I got the vehicle without a transmission, and with only an assorment of connecting parts, including the bellhousing, clutch fork, throwout bearing, pressure plate and flywheel. The original Dana 18 is present and in good condition. I used a Novak adapter to mate the T18 to the GM bellhousing.

Things went fine until I installed a clutch disc. I used a Ford 10.5 disc, 10 spline that mated nicely. However, once installed, the clutch fork does not throw far enough to disengage the clutch, and unless the clutch cable is adjusted to eliminate all slack, it sounds as if the clutch fork dings on the pressure plate. Not being a genius in installing clutchs, I probably did something wrong here.

Anyone who has done this swap, could you please advise on proper process and parts. Is a standard Ford 10.5 clutch disc appropriate? When swapping a T18 in the place of a prior T86 or similar 3-speed, is it necessary to use a different clutch fork and/or pivot ball? Will the original throwout bearing work with the Ford disc? Do the bellcrank levers need to be modified for different throw length?

Once tension is adjusted on the cable, the dingling noise stopped and the transmission turns quietly, and shifts through all gears, with the exception that it is shifting without benefit of a free clutch, and as such is hard to get into 3rd and 4th because it is spinning up the gears through the syncros, which is probably hard on the synchros. No drive shafts are installed yet, so there is no load on the transmission. I am concerned that with the cltuch cable adjusted to remove all slack, the throwout bearing is running all the time.

Because it is not really all that easy to dismount and remount a T18/Dana 18 combo for an old guy like me doing work alone, I would like to know if there is something obvious I have done wrong, so as not to have to redo this more than once more. Any and all prior experience in this swap, and suggestions from those with this experience will be most gladly accepted.

GMc.

 

Let me try to refine the question.

After reading the Novak tech site on clutch installation and setup, I removed the transmission. I have verified that the input shaft of the transmission is not bottomed against the crankshaft, the pilot bushing is not binding, and there is no interference between any of the clutch parts. However, I do find that with the pressure plate bolted flat to the flywheel, the spings on the Borg & Beck-style plate assembly are nearly fully compressed and the lever arms in the pressure plate are near the bottom of their permissible stroke.

As I backed off the retaining bolts on the pressure plate, the lever arms quickly relaxed, and with the bolts backed out about 1/16th inch or so, the lever arms now have full stroke. Using a long screwdriver to activate a lever arm, I can observe retraction of the pressure plate and see an air gap between plate and disc around .050 or better.

This suggests that the friction disc is too thick for this pressure plate, or that the plate needs to be shimmed away from the flywheel, which I hesitate to do unless it is an acceptable practice.

Anyone happen to know whether there is a significant difference in friction disc thickness between Ford and GM discs, or between brands of discs? Mine happens to be a Zoom disc, but it looks to me like any other clutch disc avaliable.

Any thoughts?

GMc

 

I had a similar problem with my conversion to a T18. The problem was the Centerforce disc I was using. I ended up using a generic disc from NAPA. You may find it a little difficult to find a separate disc and pressure plate as most a packaged as a unit now and as you know you need the Ford disc and the GM pressure plate. I can certainly relate to your mention of the difficulty of removing the T18 with the Tcase attached. That T18 is one heavy SOB. I'm using the stock clutch fork that came with the T86 setup. I have converted to a hydraulic clutch system though. You may be able to try readjusting the bellcrank setup. Adjust the bellcrank so that the arm that's connected to the fork is at TDC at exactly half of the overall movement of the arm. It really sounds like the clutch disc is a little too thick though. Also I used a diaphram type pressure plate and the adjustable pivot ball (from Novak). Novaks site mentions that the end of the clutch fork that is connected to the bellcrank must be slightly forward of right angle to the centerline when it contacts the fingers of the pressure plate. I wasn't able to get that without the adjustable pivot ball. I had that T18 in and out three times in one day before I figured out that the disc was too thick. I hope this isn't too confusing a post.

 

Not confusing at all. My first impression was that the friction disc had to be too thick, and I didn't want to compensate by using washers or shims. That sounded to me to be a bit to risky. So, I took the whole setup down to the local clutch rebuilders. They gave me the following info, which should be usable for future reference:

1. clutch discs in a given diameter range are generally the same thickness, since they are manufactured from the same components. The only difference is in the hub style, i.e., spline count, input shaft diameter, hub spring configuration. The parts that contact each other are the same.

2. my pressure plate (clutch cover) looked okay on visual inspection. I told the guys what it was doing, they agreed that wasn't right, and put it on a clamp bench to see what it would do. They were able to exactly repeat the problem I had when installed, i.e., when drawn down to the flywheel, there was not enough throw left in the levers, and you could press the levers down until they hit the hub springs and still no release. They could find no explanation for this unless it was simply set up wrong or had been previously modified to accomodate some non-standard clutch setup. Apparently the point of release is adjustable by a professional within a narrow range. Don't try this mod at home without experience.

3. We substituted two new clutch covers, one a Borg & Beck 3-finger and one a cone diaphragm style. Using the Ford friction disc I supplied, both new covers released easily with a minimum of travel, and with lots of travel left over, which is as it should be.

Conclusion: my clutch cover was boogered and it was not visible from the outside what the issue was. Nothing obviously bent broken warped or missing, it just didn't work. Rather than fool with it, I purchased the diaphragm style to get a lighter clutch just to give the old bellcrank assembly a break, and to give my left leg a break.

According to the clutch repair experts, either style clutch cover should work with the same installed heights. You only need to use the correct bearing for each different style of cover. Most use a flat-faced bearing. The one I had was rounded or crowned, and I was advised that this was not the correct bearing for either the 3-finger I had or the cone-diaphragm Chevy style I bought. Flat faced was correct, so I got one.

We will see if this fixes the issue. I know that each of the new covers we tried released perfectly on the clamp stand with an allowable degree of movement, so there is hope.

Bottom line is that the Ford friction disc is correct for the T18 transmission, and that the stock-style Ford disc will work with the GM clutch cover of the same diameter, no problems. This weekend I should have the time to find out. If you had trouble with a Centerforce disc it could be that they are made to different tolerances, and are intended to be used as a matched set. Probably if you used a Centerforce GM cover and a Centerforce Ford disc it would work, but that would mean you have to buy two sets or find a source for separate parts.

I have no certain idea how heavy the trans/transfer case assembly is, but I am guessing around 140 to 150 combined. That's way more than I can lift these days, so it is now ratchet strapped to an ATV lift to get it into proximity, and from there I use a heavy beam across the door sills for a lift point, and a heavy ratchet strap under the belly of the trans to lift into position and swing forward into place. It is like docking a space station in the blind except that the whole thing is certainly not weightless.

Thanks for your input.

GMc.

 

Good to hear you are on track. I was trying to use the Centerforce cover and disc. The difference between the disc that worked and the Centerforce appeared to be in the spacing of the splined center hub. Laid side by side with the stock disc the Centerforce appeared to be slightly higher off the deck. Good luck and let us know how it turns out. I have a good friend wo used to live in Wasilla. His name is Joe Garcia. He used to run a dog sled up there for entertainment.

 

Small world. The wife and I will be moving next year to Prescott after 26 years in Alaska. Looking forward to some warmer weather and time spent searching out trails. I've been thinking that an old CJ-5 with the Dauntless engine and a T-18 would be about right for getting around in the back country.

 

It's certainly working for me!

 

Glad you're getting it figured out. The T-18 with adapter and top weighs in at 157 lbs. Shipped a few of them. Not sure of the weight of the 18 transfer but probably around 50 lbs or so. Nickmil.

 

Just wanted to say that the T-18 is in and working. The new hi-cone diaphragm clutch works perfectly with the standard Ford friction disc, and has a good feel to the pedal. There is a high point in the pressure about half way to the floor, then it backs off a bit for the rest of the stroke, something like a compound bow lets off.

As soon as the new drive shafts are ready, I can take it for a drive. Then I can start on the body work. This one needs a whole new tub, but for now I will be building floor panels from scratch.

Anyone have any input on changing out the rear diff from the 19 spline to a 31 spline/ARB unit? I have used the ARB's for years in my race CJ-7 with excellent results and thought perhaps if used in the CJ-5 it would give me a bullet-proof rear carrier, selectable locker (I don't like dedicated lockers) and one-piece or full-float choices for axles. Then the brakes, shocks, top and whatnot. No end in sight.

I was also thinking a Warn 9.5ti winch, which I suppose is overkill for so light a car, but I have become addicted to line speed and strong recoveries, and the 9.5ti uses less amperage than my 8274 with just about the same line speeds load for load. If anyone is using this winch, I would be interested in hearing about your take on it.

 

I am biased, but my vote is for the full floater.

 

i know this post is kind of old, but i have been having this same problem for a while now. madizell is there any way you could tell me specifically where you got the pressure plate, disk and throwout bearing that worked and what the part numbers were. thanks!