Commonly Missed Clutch Issue 1G

[havoc742]

I keep reading these threads about the ACT 2100 vs 2600. I also keep seeing threads about clutch slippage and engagement/disengagement issues. There is alot of good advice and great troubleshoooting tips in these threads but I've noticed a major issue that is being overlooked and could possibly be costing alot of DSMers unnecessary headaches and dents to the wallet.

About 3 weeks ago I called up R//RE to order my new ACT 2600 with race disc to replace the POS exedy clutch the previous owner had in my '93 TSI AWD (of which 2 have exploded in less than 7k mi). The guy on the other end asked the usual what do you have done to your car and what are your plans. I told him I have a ported 2G mani, 16g, custom full turbo back cat eliminated straightline exhaust, etc and rev limit launch my dsm. Much to his dropped jaw surprise nothing has broke in 3 years of hard launching abuse on my stock drivetrain.

To no suprise of my own he recommended 2 options in his professional opinion. 1)2600 with street disc, 2)2100 with race disc. Obvious reason is to alleviate some stress on the stock drivetrain. Not so obvious reason is an issue already surfacing due to the pressure plate that the previous owner used. The pedal box Z bar linkage.

This issue only applies to 1G pedal boxes. I know alot of people have never had any issues to there knowledge of bent linkages in the pedal box. However, the guys at R//RE see this quite a bit. The linkage in question is the one that goes from the clutch pedal to the master cylinder behind the gas pedal. This linkage is pretty susceptable to bending and twisting due to heavy pressure plates such as the 2600 and 2900. The two most common fixes are to remove the linkage and weld in a stiffer thicker bar or rod or to just spend the $100 and buy a new linkage.

I see alot of recommendations for washers behind the pivot ball, bad clutch fork, imroperly adjusted pedal throw, bad slave cylinder, and over torqued pressure plate. I am not saying any of these issues are not valid in anyone particular case. I am just recommending that the next time anyone has an issue with slippage or engagement/disengagement to never forget to check your pedal box or recommend to someone else to do so. You could save yourself or a buddy alot of labor, money and headaches.

One other issue I see missed alot and is more common with the Fidanza flywheel mated with the 2600, is the warping our bowling of the flywheel. The added pressure from the 2600 and up pressure plates causes the flywheel to bend towards the block in a bowl like fashion. As many know aluminum is not very flexible and has very little tendancey to return to shape once deformed. The only way I know to check for this problem is to remove it and lay a perfectly flat object across its surfaces. a 6" metal ruler works rather well, so does a small torpedo level.

EDIT: Also, You should always replace your fork and pivot ball when replacing your clutch assembly. Its only $70 at R//RE and it eliminates any question about those parts being faulty. Also don't forget to put a decent washer behind the pivot ball.

I hope this helps some out there having clutch issues in their 1G.

 

[DSM Jeff]

Advertise for RRE much? 1g pedal issues are very common. I have done several pedal swaps over the years. The problem usually isn't so much as the rod twisting but at the end of the linkage. The clutch bar attaches to the clutch rod by a circular hole with 2 flats. This is a poor design and over time with any clutch this area tends to wear.
Also most know about buying a new clutch fork and pivot ball, but for $58 from say JNZ. Also by replacing these parts along with a new clutch you really shouldn't need the washer.

 

[DECODER22]

ya but on say a ACT 2600 shimming the pivot ball is a must for good engagement Evan TRE has it on there site this is from there site


The reasons behind shimming the clutch pivot ball are often misunderstood. Ultimately what you're doing is correcting the offset geometry of the clutch fork so that it's optimized for the clutch you are using. When it comes to aftermarket flywheels, clutch disc's and pressure plates there tends to be some variance in the final offset distance of where the spring plate fingers are in relation to the throw-out bearing. This distance will also vary whenever the flywheel is resurfaced. If the machine shop had to take .030" off your flywheel, your whole clutch assembly will now be .030" further away from the transmission. This is when you need to shim the clutch fork pivot ball.

When to shim the pivot ball? Right after you install the transmission but first things first: Inspect your clutch fork for excessive wear. Inspect the finger tips that push against the throw-out bearing. They should be round, without any flat spots. The clutch fork pivot ball socket should not show signs of wear. If it does, replace it. 1st gen owners take note: You can upgrade to the 2nd Gen clutch fork, part# MD770506. It's much stronger than the 1st Gen fork and we have them in stock.

Why shim the pivot ball? Because you want to keep the clutch fork at the optimum angle so that it sits in the proper location and doesn't make contact with the transmission case when you push the clutch pedal down. If it does make contact you will risk breaking the transmission case where the slave cylinder bolts on. Another benefit of shimming the pivot ball is reduced thrust load on the throw-out bearing post.