While I didnt "open" the clutch hydraulic system, I did bleed it until new fluid came out. I can see the throwout bearing releasing a good 1/2 away from the flexplate face when looking through the clutch fork window.
Engine Swap - Elation! Then Stumped!
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Need to get a fresh set of clutch cover bolts. Can anyone confirm size? I thought they are M8x1.25 x 13... but ARP lists M8x1.25 x 12 and M8x1.25 x 16. Thank you
update: I ordered the 16 mm long ones. The 12mm just seemed too short. These bolts are $2 each, but the local Mazda dealer quoted $50 for the set of 6 and a late June delivery!
update: I ordered the 16 mm long ones. The 12mm just seemed too short. These bolts are $2 each, but the local Mazda dealer quoted $50 for the set of 6 and a late June delivery!
Not a skill I thought I would acquire! Just measured the 2 plates. They are within 3/100 of each other.
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![Automotive tire Motor vehicle Wood Gauge Measuring instrument]()
The uninstalled height of the mounting flange to a flat surface is ~8.38mm / 0.333in, and the height of the fingers to a flat surface is ~35.15mm / 1.383in give or take human error on both - but they are nearly identical to each other. The new pressure plate may have .002-.003 more height as I would expect with no wear on the surface and new springy fingers.
The uninstalled height of the mounting flange to a flat surface is ~8.38mm / 0.333in, and the height of the fingers to a flat surface is ~35.15mm / 1.383in give or take human error on both - but they are nearly identical to each other. The new pressure plate may have .002-.003 more height as I would expect with no wear on the surface and new springy fingers.
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Lets look at this from the other end, turn the input shaft and shift through the gears and see if the diff turns or not. If not, that says its the trans.
To be clear, with the transmission separated from the engine, and with no axle shafts installed.... turn the input shaft and see if the gears turn in the axle holes as I manually shift through the gear linkage on the transmission? I just have nightmares about what the Mazda 3 guy who detailed a similar swap said about the differential gears falling out of alignment.
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Yes thats what i mean, but i dont know the specifics on that post.
So the distance between where the pressure plate comes in contact with the flywheel and the surface where the disc would touch the pressure plate are identical...
I'm puzzled, the only other thing to question is the actual pressure of each plate.
I'm puzzled, the only other thing to question is the actual pressure of each plate.
I'd try the following. I assume the transmission and axles are still on the vehicle... put the wheels on and lower them to the ground. Now try turning the input shaft while in 1st gear, you should be able to turn it. If not on the vehicle, find a way to lock the axles.
The engine and transmission are out of the car - I pull them as one unit. Regardless, I think I will install the transmission without the engine and hook up the axles just to continue this investigation. Assuming I can turn the input shaft while in gear and the wheels on the ground, I am still back at a clutch disk/pressure plate issue.
with no clutch disk, the pressure plate sits flush to the flywheel. With the disk in, the pressure plate sits 3/16 of an inch away from the flywheel. Just starting the pressure plate bolts makes the disk too hard to turn by hand, so I don’t see how it is not clamping.
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If you can turn the shaft while in gear with both wheels on the ground, then something is slipping in the transmission which would be weird as everything in there is gear driven.
You said the throw-out bearing is fully releasing, right? With the engine and transmission assembled...
What I'm thinking is, you changed the engine. The clutch, plate and flywheel are mounted on the engine. Where is the fork mounted? On the transmission? Are both engines identical in the area where the transmission attaches? Is it possible that the new engine is a bit different causing the transmission to be a bit closer to it and then changing the operation of the fork?
I'm going to ask a very knowledgeable mechanic that helps us in another forum to take a look at this thread.
yes, with the transmission mounted, axles in, and tires on ground, I could turn the input shaft and the car would creep forward. I could budge it in 1st gear but did not possess the torque to turn the input shaft in higher gears. I could push the car forward and backward a bit and see the input shaft turning.
The fork is mounted to a pivot in the bell housing which appears to be in good shape. The fork/bearing are moving effortlessly on the input shaft. The bearing does fully release as I can see it move 1/2inch away from the pressure plate while looking through the fork window.
I was thinking maybe the input shaft was not fully seating into the crank bearing, and therefore not fully being engaged by the clutch disk. The transmission does easily bolt to the engine, so nothing is binding on the install. I have both engines nearly side by side and can look for any differences to the transmission mounting surfaces. I will also measure the distance from the transmission mounting flange to the input shaft and ensure it is fully seating into the crank bearing.
The previous times I have tried to get the car to move, when releasing the clutch and expecting to go, I notice a slight spinning/slipping noise similar to a breakpad rubbing against a rotor as it turns slowly. The noise does speed/slow with engine RPM. The noise is faint but distinct, and only when the clutch is engaged. When the pedal is pushed in, the noise stops. This still leads me to believe the disk is not fully clamping, but with the parts exchanged being identical (part numbers and appearance), I am not seeing any reason for that.
Appreciate all the help I can get on this one.... everything I look at says it should be working.
The fork is mounted to a pivot in the bell housing which appears to be in good shape. The fork/bearing are moving effortlessly on the input shaft. The bearing does fully release as I can see it move 1/2inch away from the pressure plate while looking through the fork window.
I was thinking maybe the input shaft was not fully seating into the crank bearing, and therefore not fully being engaged by the clutch disk. The transmission does easily bolt to the engine, so nothing is binding on the install. I have both engines nearly side by side and can look for any differences to the transmission mounting surfaces. I will also measure the distance from the transmission mounting flange to the input shaft and ensure it is fully seating into the crank bearing.
The previous times I have tried to get the car to move, when releasing the clutch and expecting to go, I notice a slight spinning/slipping noise similar to a breakpad rubbing against a rotor as it turns slowly. The noise does speed/slow with engine RPM. The noise is faint but distinct, and only when the clutch is engaged. When the pedal is pushed in, the noise stops. This still leads me to believe the disk is not fully clamping, but with the parts exchanged being identical (part numbers and appearance), I am not seeing any reason for that.
Appreciate all the help I can get on this one.... everything I look at says it should be working.
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That was gonna be my next guess, input shaft isnt seating.
nope. Just measured. The splines of the input shaft sit recessed in the bell housing 1inch, the front of the clutch disk sits proud of the engine/transmission mounting surface by 2 1/8 inch, so there should be an inch plus of engagement of the input shaft into the clutch disk.
And the input shaft should insert into the crank bearing by 5/8 inch.
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126 Posts
I hope I have this right, with alignment tool installed to line up disc with CS pilot bearing, the line up tool should not be able to spin the clutch because the pressure plate is forcing it against the flywheel. If the disc can be spun, the disc is in backwards or wrong disc.
You are correct in that the disk cannot be turned by hand when installed. My references to the disk turning were only when I held it up to the flywheel to ensure it wasn’t hanging up on the flywheel bolts, or when I held the pressure plate up to the flywheel to ensure the disk was being clamped sufficiently.
Here are the comments from the Tech:
That is interesting. First thoughts are just the possibilities and how to test them. I'm betting it's a part issue, either comparability problem or bad part. I wouldn't just take the machine shops word at this point. Can't trust new parts, so you can't trust used ones either without knowing with certainty that they are good.
If the speed sensor is in the transmission like that one guy said, then they are linked and it has to be axle compatibility I would think. Not sure if there is a transmission control module, but if there is, I'd see if there is any data that would indicate that the transmission is moving.
Maybe bypass the neutral switch and see if it will start in gear. Maybe try that one in the air first so nobody gets killed.
I like all of the suggestions you made. A friend of mine had a fox body mustang and we put a clutch in it since his original one was soaked in oil and slipping. The new slipped worse. Turns out it was machined wrong. Spec clutch too. $$$.
So far I'm thinking massive slippage or axle issue
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