BayAreaZT Posted November 19, 2003 Share Posted November 19, 2003 I'm thinking about swapping my stock clutch master cylinder that crapped out with a Tilton or Wilwood 7/8" unit. I'm running an ACT clutch and pressure plate on a L28 turbo. Clutch pedal is adjusted all the way up and is a little heavy causing the firewall to flex so I'm trying to relieve that a little bit. My question is what is involved in connecting the stock clutch line to the Tilton MC? This is on a '71 240Z. Quote Link to comment Share on other sites More sharing options...
johnc Posted November 19, 2003 Share Posted November 19, 2003 The Tilton MC uses a 5/16" fitting and the brake line on the 240Z uses a very similar sized 8mm fitting. You'll need an adapter. Earl's sells them. Quote Link to comment Share on other sites More sharing options...
preith Posted December 6, 2003 Share Posted December 6, 2003 Even though this concerns brakes, it still applies. On my project I used a Tilton dual master cylinder, which has the 5/16 fitting as well. I replaced the brake lines and simply flared one end with the 5/16, and the other with the 8mm. Worked out great except it was a real bear flaring stainless. Quote Link to comment Share on other sites More sharing options...
Dan Juday Posted December 6, 2003 Share Posted December 6, 2003 I've installed two Tilton clutch master cylinders. Fine units. Keep in mind you will need to make some minor mods at the rod-to-pedel connection. The JTR book explains this very clearly. I know you're an inliner but I bet you've got a copy hidden away somewhere. Quote Link to comment Share on other sites More sharing options...
BayAreaZT Posted December 6, 2003 Author Share Posted December 6, 2003 I still have the bible Quote Link to comment Share on other sites More sharing options...
blueovalz Posted December 7, 2003 Share Posted December 7, 2003 Clutch pedal is adjusted all the way up and is a little heavy causing the firewall to flex so I'm trying to relieve that a little bit. If the OEM MC is 5/8" and this is heavy (understood by me to mean a bit stiff or hard to push being the firewall is flexing), then installing a larger diameter MC will only exasperate the problem. Pedal movement will shorten with a larger MC, but pedal pressure will increase appreciably. A 7/8" bore (with no other changes made at the slave cylinder) change from the OEM 5/8" bore will double the pressure at the pedal, which means even more firewall flexing. I am a bit surprised the OEM bore is a problem. I run a 3/4" bore (but I cannot say what the comparable bore of the hydraulic thowout bearing is) with a stiff Long style PP using only a light to moderate effort. It appears from your post that with the statement of the pedal being all the way up, that it can be assumed that you are also using full pedal travel to disengage your clutch. Is this a new problem since a part change-out? In regards to the lines themselves, I did as mentioned above and cut, installed an 5/16" fitting, and re-flared the tubing and all worked fine. Quote Link to comment Share on other sites More sharing options...
BayAreaZT Posted December 7, 2003 Author Share Posted December 7, 2003 If the OEM MC is 5/8" and this is heavy (understood by me to mean a bit stiff or hard to push being the firewall is flexing)' date=' then installing a larger diameter MC will only exasperate the problem. Pedal movement will shorten with a larger MC, but pedal pressure will increase appreciably....... It appears from your post that with the statement of the pedal being all the way up, that it can be assumed that you are also using full pedal travel to disengage your clutch. Is this a new problem since a part change-out?[/quote'] I was thinking about that today and that was my next question. I knew it would shorten pedal movement but I was not sure what it would do to pedal pressure. If I did swap the MC, I would go with 3/4" not 7/8" but if it increases pedal pressure then I don't want to go that route. Yes, I am using full pedal travel. I had to raise the pedal when I put in the ACT clutch and PP. Is there any way to relieve pedal pressure without changing the pressure plate? Quote Link to comment Share on other sites More sharing options...
blueovalz Posted December 7, 2003 Share Posted December 7, 2003 Can't answer that final question, but I hope someone chimes in here that can. I'm not familar with your PP and disc, but with that said I am puzzled that you are required to use full travel AND apparently, a lot of pressure to operate your clutch. Normally it is one, or the other, but not both (except for poorly designed systems, or those badly mismatched). I'd look over your system one more time and make sure there is nothing obvious that is causing problems. I'd also talk with the manufacturer and get the specific movement required of the throwout bearing to fully disengage the clutch, or what the SC movement should be with the recommended pedal travel. Then you can compare this to what your system is doing. As you describe it in your first post, you'll have a worsening problem with any increase in MC size. It makes me wonder if something is not binding up on the way from your foot to the clutch. Quote Link to comment Share on other sites More sharing options...
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