Clutch Confusion

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Clutch Confusion

Postby EvanGSprite » Sat Aug 20, 2011 9:22 am

Hi, I am so confused with my Sprite. The body is a 59, the engine a 1098CC with a ribcase, and I do not know what clutch is in there. There is a 1275 clutch slave cylinder, but I have the dual bore 948/1098 master cylinder. I am trying a new clutch pipe from the master cylinder to the clutch slave but who ever had the car before me had tons of adapter pipes - a hot mess. The clutch slave has the shorter pushrod too. I am utterly confused and do not know the proper way to buy new parts to make things work smoothly again. Please, any suggestions on how I can ID the clutch, or which slave unit I should use (1" bore or 7/8" bore). I ordered a whole much of new parts from moss motors for the 1275 1" bore clutch slave, but none of which attach to the master cylinder. Help! thanks everyone :?
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Re: Clutch Confusion

Postby Charlie Tolman » Sun Aug 21, 2011 12:49 am

If the engine is not in the car, then it is easy to determine the clutch model. However, if it is in the car, then one must peek through one of the oval holes in the transmission bellhousing, from under the car, where the one on the lower left (driver's side) is the easiest. Use a small diameter flashlight for illumination.

A 1098 clutch is rather large, while the 948 and 1275 clutches are smaller and close to each other in size. A 1098 clutch housing is about two inches larger in diameter than the smaller clutches.

If a steel flywheel is on the crankshaft, then, most likely, the 1098 engine will have the 1098 clutch. If there is an aluminum flywheel, then there is the possibility that the clutch is a 1275 unit. There is the remote possibility that the steel 1098 flywheel was re-drilled to accept a 1275 clutch.

A 1098 clutch is big and heavy, and I had slippage problems with it. A 1275 clutch worked much better.

With the dual-bore master cylinder, it might be best to use the smaller diameter clutch remote (slave) cylinder.

If you install a 1275 clutch, use the release (throw-out) bearing for the 1275, since the offset is different.

Charlie T.
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Re: Clutch Confusion

Postby EvanGSprite » Sun Aug 21, 2011 10:28 am

Hey Charlie, thanks for the reply. The engine is still in the car so this is going to be difficult. I took off the rubber dust cover and tried to see what was in there. I can see the clutch release lever, which is kind of wobbly, and the release bearing. The clutch housing appears to be large, but I have nothing to compare it to. There is probably about .5 in clearance between the clutch housing and the bottom side of the case. I plan on taking out the engine in the winter when its too cold to drive the car but for now, I just want to get it up and running so I can enjoy the rest of the nice weather here in New Jersey. Can I use the smaller size clutch slave even if the clutch is the 1275? If anything, the smaller size clutch slave will match the dual-bore master cylinder and I can buy the proper piping for it, instead of the mess that is on there now. Let me know what you think. Thanks again!


Charlie Tolman wrote:If the engine is not in the car, then it is easy to determine the clutch model. However, if it is in the car, then one must peek through one of the oval holes in the transmission bellhousing, from under the car, where the one on the lower left (driver's side) is the easiest. Use a small diameter flashlight for illumination.

A 1098 clutch is rather large, while the 948 and 1275 clutches are smaller and close to each other in size. A 1098 clutch housing is about two inches larger in diameter than the smaller clutches.

If a steel flywheel is on the crankshaft, then, most likely, the 1098 engine will have the 1098 clutch. If there is an aluminum flywheel, then there is the possibility that the clutch is a 1275 unit. There is the remote possibility that the steel 1098 flywheel was re-drilled to accept a 1275 clutch.

A 1098 clutch is big and heavy, and I had slippage problems with it. A 1275 clutch worked much better.

With the dual-bore master cylinder, it might be best to use the smaller diameter clutch remote (slave) cylinder.

If you install a 1275 clutch, use the release (throw-out) bearing for the 1275, since the offset is different.

Charlie T.
EvanGSprite
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Re: Clutch Confusion

Postby Charlie Tolman » Mon Aug 22, 2011 1:15 am

If the clutch cover diameter is only 0.5" from the transmission case, I can almost guarantee that it is the 1098 design.
Since you have the dual-bore master cylinder, it might be important to use the smaller diameter clutch slave cylinder. The 1275 slave might work, however, but the required pedal pressure and depression distance will be somewhat different.

I used the dual-bore master cylinder and the smaller clutch slave cylinder, with a 1275 clutch assembly, on 948 and 1098 engines, and the combination worked very well for many years.

If you have a new clutch line, install it, and determine how well the existing set-up operates. It is unfortunate that the two slave cylinders have different connections and lines.

I have seen high-pressure steel-braided flexible hose used for a clutch line, from the master cylinder all the way to the clutch slave cylinder. Fitting adapters were probably needed at each end.
When removing and engine and transmission, the assembly was partially withdrawn from the car, and then the clutch cylinder could be easily removed from the transmission housing. It was not necessary to get under the car to unbolt the cylinder, nor to remove the fluid line, which would eventually need to be reconnected and then bled to eliminate air in the line.

Charlie T.
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Re: Clutch Confusion

Postby EvanGSprite » Mon Aug 22, 2011 7:13 am

Thanks! I am going to order the smaller slave unit. It is a bummer that all the fittings are different, but I'll make it work.
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