Alright my street twin is going in on Sat., and I have a couple of questions. First what exactly is the drill mod? I read about it on a couple of sites but I'm still not sure what exactly it is, or how it is done. Second, I'm doing the adjustable master cylinder as well, so where is the best place to have the clutch engaging? Closer to the floor? Finally, what is the best way to break it in? I heard 500 miles regular driving, with no hole shots or things of that nature.

Thanks,

 

Here is a link for the drill mod:
www.installuniversity.com
Look in the install documents section.
I have read that you have to have the flywheel balanced the same as your stock flywheel since the LT1 is externally balanced. Have you done that yet?

When I install my Street Twin I'm going to try to get the clutch to engage at the same spot as the stock clutch if that is possible.

 

Could you or somebody else explain, having the flywheel balanced? I was under the assumption that the McLeod flywheel just replaced the factory one.

 

I just read the install university write up about installing the Mcleod and it doesn't mention having to balnce the new flywheel. The write up was for a LS1, but would it differ that much for the LT1. I know the clutch is different.

 

Just be super-careful when taking the street twin apart. Keep the floater plate bolt's shims on them, and don't get them mixed up! Same thing for the flywheel stud's shims. Its imperitive that they go on exacly as you take them off.

Start the adjustable master cylinder even with the brake pedal, then adjust to taste. I kind like it right off the floor, but some people like it further out...its just preference.

I took it easy for the first 1k. I can't remeber what McLeod said, but it prolly isn't necessary to break it in that long though.

Ryan

 

I was kinda thinking right at the floor would be the best as well. So there is no need to have it balanced, just make sure that it all goes back together the same way.

 

Better off not knowing. . .

Yes GM thought it was a great idea and it is. It prevents the clutch from slamming together like 3 guys and Jenna Jameson in a hardcore ****. GM put the restrictor in to keep the clutch from engaging too rapidly. On the stock clutch or similar strength clutches, you won't see the difference. However on the McLeod, prepare to start replacing transmission. My Street Twin doesn't have any wear in it, because its too busy slamming together like a ****'. The discs are imprinted onto the flywheel, pressure plate, and floater disc. I talked to a guy at McLeod about this issue, he actually suggested a manual hydraulic restrictor valve (forget what the technical name was). "It will allow the flow forward go as fast as its being pushed out, but on the return it will slow it down and you can adjust it to suit your needs." Needless to say I'm putting a line with the restrictor back it. The new master cylinder that comes with the McLeod has enough power to force the fluid through the restrictor without a problem. Its in there to slow the fluid, although slightly, coming back and slows the disengagement of the clutch and lets it slip a little bit. Zero slippage, when I mean no slippage I really do mean it with this clutch, is bad. You do want the clutch to slip slightly on launch otherwise you could end up like this. . .

Click here to watch a bad launch with the Street Twin

 

What did he break, the rear? It looks like he was running et streets, or something similar, the stickiest tire I'll run will be a BFG dr, but most of the time I'll be on street tires. So what you're saying is that by doing the drill mod, it makes the clutch slame together and not slip at all. I can see this being a problem with slicks but not street tires. Also, how does it damage the tranny? I hope I don't come sounding like an ***, I just want to get all the info possible. Thanks!!

 

That was my car that I climbed my happy butt out of to push back. And no those were not slicks those were BFG DRs. I broke the output shaft on the tranny, a nice little $300 part. I've gone through 2 driveshafts. The stock steel disintegrated with just me screwing around on the highway on street tires (not fun). BTW, I also broke the stock rear end with the McLeod too on the street. The next one was the inland aluminum 3" driveshaft, the problem with that was they never installed the 1350 u bolts for the moser yoke. I took the car to the track and blew the driveshaft up, the needle bearings were crushed into dust, the driveshaft twisted, as did the splines on the driveshaft yoke, and snapped the output shaft on tranny #1. Then I bought the LPE 3.5" driveshaft and had them install the 1350 u bolts. The driveshaft held up to all my beatings then I took it to the track and as you saw there my fatal launch for tranny #2. But the LPE shaft held up without a scratch on it.

As I said before I talked to a McLeod tech about this because it was expensive to replace output shafts. I've also talked with many people on the board about their McLeod setups. As soon as I disassemble my tranny to get the gears out of it, all that stuff and the new output shaft is being sent off to be cryoed (frozen at 300 below) to strengthen the output shaft. Don't be wary of this procedure if you think you must do it, I suggest anyone to do it. Its very cheap!!! Also another thing to check is if your running a moser 12 bolt, CHECK your driveshaft length under suspension load. Too long of a shaft will cause bind on the output shaft. If you haven't already gotten an aftermarket driveshaft I strongly suggest a 3" chromoly driveshaft. Along with the new master cylinder from mcleod I also suggest a new slave cylinder, just so everythings fresh. A bad slave can destroy a tranny.

Also, I know others may not have this problem, but its definitely a cost effective safety measure. The bolt that holds the throwout fork onto the tranny. On both trannies my started to strip the threads after a short time. So what I did was put heli coils in there. A heli coil will be much stronger than the original thread. It'll distribute the pressure amungst most surface area. Doesn't cost much and it wouldn't hurt for that extra safety precaution. I also used a stonger bolt as well, allen head 170,000 tensile strength. Any local hardware stores has that stuff.

 

So my best bet would be to not do the drill mod, and also replace the slave cylinder. I have a brand new slave that I bought a while ago, so thats no problem. Also, I still have the stock ds and rear.

 

The stock driveshaft you can make live. The rear, I'm afraid will soon be departing on anything forceful. I broke the stocker when I powershifted to 2nd, it was on the street and I was already driving in first, hit it, shifted to 2nd and BOOM! The driveshaft broke when I was messing around on the highway and powershifted into 3rd and it literally blew apart. My best MPH was 114 mph and ET was 12.55 w/ HORRIBLE 2.09 60's, only ran it one day and didn't get a chance to tune it before it went down agian. Obviously I don't have the most powerful car on the planet but the clutch is more than making up for that in destroying parts like it was a 800hp monster.

The stock driveshaft will be fine with the moser I believe as long as you get the U joints replaced with 1350 joints to fit the moser 12 bolt rear if you so happen to get one. You MIGHT hafta get the stock shaft shortened 3/4" or so. From my experience, any local shop should be able to do that for you at a good price.

But to answer you drill mod, you'll be 100% fine without it. Like I said GM designed it in there for a reason. The stock clutch obviously won't have problems like this, nor would a beefy clutch like a RAM clutch, but nothing upon NOTHING grabs like the McLeod Street Twin. With the other clutches I give a thumbs up for the drill mod, with the street twin the last thing you'll be worry about is the clutch engaging all the way ASAP it'll do that just fine on its own.

 

You should get your entire clutch balanced. My McLeod flywheel was way off. Resulted in a pretty bad vibration.

If you motor hasn't been rebuilt I would suggest having your flywheel balanced the same as the stocker. If you motor has been rebuilt and internally balanced then remove the weight on the McLeod flywheel and then you HAVE to balance it.

DaveW

 

Have the flywheel balanced at a machine shop before you install it. I had to learn the hard way, on the freakin dyno! It was vibrating pretty bad. I was very disapointed, given this damn thing's price

 

I bought mine used (had it rebuilt) and it had a small weight bolted on. Works fine with my stock motor.

Probably not a bad idea to have it checked, although at this point your check book is starting to feel McCleod'$ wrath .

Good luck. Best mod I have done so far .

btw..bleed the master cylinder via unbolting the slave, and compressing it with your hands. Do this before pumping the pedal.

Ryan

 

What all is involved in having the flywheel balanced? Do I have to take the whole clutch assembly to a machine shop or just the flywheel? Does the shop need the car too, or just the McLeod? I've never had to do anything like this before, so any help you guys can give would br great.