Resolved Check My Clutch Fork Position

[GST with PSI]

I'm mating my engine and transmission together before dropping the motor in the car (91 Galant VR4). Once the transmission is bolted up to the block, it seems like my clutch fork is sitting a bit too far toward the driver side of the window in the bellhousing. I have just under a 1/4" between the edge of the clutch fork and the edge of the window. There's nothing that I can find that's abnormal about my setup, so I'm thinking the pressure plate fingers just might be taller than average. Here are all the details:

-Centerforce dual friction organic/carbon composite clutch & pressure plate
-ACT StreetLite Flywheel
-clutch fork in good condition
-New Mitsu OEM TOB
-New pivot ball (not shimmed)
-starter plate is installed

Can someone look at these pictures and tell me if the fork is ok where it is?

Just under 1/4" of space in this picture:

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[bastarddsm]

That is kinda forward. I really think it's better that way. Make sure the fork isn't hitting the pressure plate. I'd also install a slave and make sure it isn't bottomed out.

 

[GST with PSI]

Yeah, the fork seems to clear the PP fine.

I could throw a slave on too. What am I looking for? Obviously it won't be hooked up to the hydraulic system. Am I just looking to see how much travel there is until it bottoms out on the bore? I know if the slave piston is resting too far back the relief port gets blocked, but usually I check for that by pushing the slave piston in and making sure it returns. I can't exactly do that at this point.

 

[bastarddsm]

Yeah, make sure you can push it back in the bore some. The relief port is in the master cylinder though.

 

[GST with PSI]

Right, that's what I meant. I won't be able to see if the relief port is blocked with the slave off the car.

Thanks for the suggestions.

 

[97gsxIA]

Id say you'd have great disengagement but the concern would be the MC's lifespan and/or where your pedal will be at during disengagement. You might be disengaging 5-6 inches off the floor and if you adjust for it, you might be outside of spec for the relief port in the MC to work properly.

Better than clutch drag though!

 

[GST with PSI]

So new question; How can I tell of my clutch is putting unnecessary pressure on the crank thrust?

Current setup details:

- Rod on the clutch pedal to the clutch master is nearly adjusted all the way out (nut and rod are even with the end of the clevis)

- Clutch fork position is sitting on the driver side (crank/timing belt side) of the motor just as the pics show above

- When I push the clutch fork in toward the slave with my hand, there is sufficient movement and the slave returns the fork to it's original position as it should

- Flywheel was resurfaced at the proper step height

- Clutch is bleed, definitely no air in the system

- Clutch feels good and the disengagement/engagement is near the middle of the pedal travel

I've come to the conclusion the Centerforce PP is just tall, and causes the clutch fork to sit to the driver side...At least, that's the only conclusion can come to give all the $hit I've changed and/or inspected.

So, my question really is, how can I tell if my clutch is putting pressure on my crank thrust? I'd do a check with the dial indicator, but I'd think that wouldn't show the issue until there's an issue, which I'm not trying to wait around for. Also, I've always been told if the clutch slave returns with you push it in with your hand, you're good. Any truth to this?

Any help, advice, or comments are appreciated. Thanks in advance.

-Brett

 

[kchaazz]

If there isnt any freeplay at the top of the pedal travel, then there is hydraulic pressure on the pp and therefore constant pressure on the thrust bearing. This can preload the clutch, as the pp fingers will have pressure on them at all times. Freeplay is that slight pedal movement at the top before you feel it pushing the plunger in the master cylinder. Make sense? I like about .375" of freeplay at the top of the pedal.

 

[GST with PSI]

Thanks for the response. I'll check this tomorrow. I'm assuming if there's no free play, I need to back the clutch master adjustment rod out some?

 

[kchaazz]

Yep. Should be able to get some freeplay and still have a decent engagement point with that clutch.

 

[luv2rallye]

Your fork is very far over to the right which will give a LOT of T.O. bearing travel which will press the PP fingers just as far. My only concern is if it's too much, the fingers might bottom out against the disc center springs. This happened to me (http://www.dsmtuners.com/threads/thoughts-on-if-i-should-shim-or-not.485218/#post-153464000) but then I had a stock PP, disc, and T.O. bearing. Perhaps your case is different but just something to consider.

 

[GST with PSI]

Yeah, I think I'd definitely notice if the PP fingers were making contact anywhere. That doesn't seem to be happening in my case. Although, overextending the PP fingers is still a real possibility I suppose.

 

[GST with PSI]

I just wanted to post an update to this. Shortly after I get the clutch back in the car it started slipping. I pulled the transmission out again, and found the disc to be in good shape. The pressure plate was pretty cooked though, and looked like it wasn't clamping evenly. I'm not sure if the Centerforce PP was defective, worn out, or if that's just the way they normally are. Whatever the real issue was, I'm going to say my pressure plate was the culprit, which caused multiple problems with the car.

I swapped in a new ACT 2600 PP with a 6 puck sprung disc, and the car feels 1,000 times better than it did. The clutch fork is sitting dead center in the window now. When compared side-by-side, the fingers on the Centerforce PP sat significantly higher than the ACT, which I'm fairly confident is what caused my clutch fork to be so far off. The new ACT feels great, and the clutch has never felt so nice since I got the car. The 6 puck sprung disc is definitely mild enough for the street, but is nice and grabby during a launch.

Old reliable ACT

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Mods, please update this thread resolved.