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HELP! NPR I.C in...now clutch problems! SOS


Jersey

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Isn't this always the way? Unreal. Last night, finally finished plumbing I.C. in around 2am, tightened up on the new downpipe and took her out for a test ride. PSI was set @ 9 before I.C. install and now was pulling strong to about 7 1/2psi. Lost about 1 1/2psi due to I.C. I'm figuring not bad. Pulled stong and clean, so i upped the boost to 10...same thing, pulling clean and hard, no detonation.WOOHOO. Cranked her up a little more - 12-13psi....pulled stong in 1st, 2nd and then...slllliiiiiiiiiippppp of the clutch at the top of third and top of 4th! UG!!! Now i'm in a jam because i'm suppose to race this thing at the track this coming Wednesday, I don't have the $ or time to get the clutch which i know is right for ME (ACT) so, here's what i'm wondering:

 

I'm using a $140 stock (not nissan) '78 2+2 240mm clutch set in there now. It was fairly new - 3 months old? It grabbed fine until the last run i made at the track about 3 weeks ago. On the last run of that night, the 14th run, she started to slip. I had just made about 4 continuous runs and just figured i heated it up too much because on the way home after she sat a bit, grabbed fine. I did do a lot of sliding of the clutch off the line that night. So, here's my questions:

 

1: Do you think i wasted my clutch at the track last time and a new replacement of the same kind will be fine or is the clamping force of the '78 2+2 PP just not strong enough to hold the new I.C. HP?

 

2: I read a few posts about the 300ZX Turbo clutch. Does anyone have any solid information about putting a 300ZXT clutch setup in a first gen Z with a BW-T5 using a 240mm flywheel? Does it bolt up to the 2+2 flywheel? Is the 300ZXT PP stronger than the 2+2? If yes to both, what year 300ZXT clutch/pp should i order?

 

3: Am i just wasting my time not using a performance clutch at this part of the game? I can order another part store 240mm 2+2 or 300ZXT clutch setup today and have it by Monday, put it in by Tuesday and get to the track by Wednesday, which i'm dying to run or, just park it in the garage until i can convince the wife that i NEED $300 more for my TOY??? That could take a while :roll::-D

 

Sorry i'm so long winded but i like to post all the info i can and the dilemma i'm having so others can share my pain. haha. Any suggestions are welcome. Appreciate it in advance. BTW - Alex, it seemed she started to run out of fuel around 12psi. I'll let you know if the new Walbro pump you hooked me up with helps me a little past this by itself. Thanks again.

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Guest Zcarsmakemyheadhurt

Top of third imagin that, resurface the flywheel (a must) use a 86 300ZXT pressure plate at least and a 6 puck ACT disc for the street. I sell the disc for $89.00 and it is in stock now. I see a nice future for that car in the 12's.

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I'm using a 2+2 240 mm pressure plate from a 280zx and a Z32 N/A clutch and pp in my 240.If you check the listings for the Centerforce clutch - there is only one part number for the clutch in 280zx turbo, Z31 turbo and Z32 N/A. The Z32 twinturbo uses a Skyline style 250 mm clutch. I went with Centerforce DF and wouldn't recommend it. A stock Z31 turbo clutch pressure plate will fit. I don't know about the disc. Alex's recommendation sounds like an economical solution - must must must resurface the flywheel. :)

Good luck - I just did a week of 2 am nights to get my car together for our Ontario Z-Car club drag day and had no time to retune the standalone SDS. So I still missed it. My wife is still talking to me though :-D

Cheers - Doug

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I would go with a performance clutch so you won't have to worry about doing it again. I am running an ACT clutch and 2+2 flywheel with basically the same setup as you. Haven't had any slipping problems but I haven't taken it to the track yet. Look into Exedy also. It may be a little bit cheaper. The clutch disc I got from ACT is an Exedy unit.

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Alex - no thanks. BTW - the 86 ZXT PP is 240mm, as does the 2+2 PP, but the surface area of each individual side is about 39mm. The 2+2 PP/clutch/flywheel measures approximately 44mm, 5 more mm than the 300zxt PP which means, the 300ZXT PP would be using the outside of the 2+2 clutch of 240mm, but the inner 10% of a wider 2+2 clutch would never be touched. Not the solution i was looking for.

 

Doug71ZT - Thanks for the info. I will have the BW out tomorrow night, pick up a clutch combo on Monday and back in Monday night. Tuning Tuesday night, track wednesday night. I've pulled those same 2-3am nights for about 4 weeks straight for the turbo swap about 2 months ago, what's 2 more nights matter??? haha. Wife understands, hey, it is fathers day :) Sorry to hear that you didn't make it with all the hard work. Hope i do...

 

Yo2001 - Thanks, will do. I had the '86 300ZXT PP and the same 2+2 240mm PP side by side and the finger strength didn't seem to be any different, and like i said before, the 300ZXT PP has a smaller surface area than the 2+2. I wonder if the N/A 300zx that Lockjaw is using is any different than the T? I'll do a search.

 

BayAreaZT - Thanks for the suggestion. Act is recommended alot. Guess they make a good product. Appreciate it.

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so you dig that ic or what? im really happy with mine, i think it will take anything the t3 has for it. having clutch issues too, but im sticking with the coupe flywheel, and probably a nice act unit thats rated too high for what i expect to put out. had a brand new clutch in mine and im experiencing the same thing, slip in third, i guess load is pretty big in the top end. oh well.

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I think the clutch disc that Lockjaw uses has a better "more grippy" surface. If I remember right it's off the 88 turbo. According to him it's held upto some major power and should have no proublem with 12 psi. He's getting close to 120 mph in the 1/4. Thats alot of power for a ZX.

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Hey guys. Happy Fathers day to all fathers or soon to be ones :D I'm loving the new found power that i could jack the PSI to with the I.C. Although, i only drove the Z for only about a total of 45 minutes and now just finished pulling the trans/clutch/PP out about 15 minutes ago. The clutch that i pulled out is fine. Basically no real signs of wear. So.....I'm thinking it's definetly the PP being to weak. I figured out some more information on the different clutch/PP sizes -

 

The 240Z ('73 240) coupe PP/clutch is 225mm and each side measures aproxiamtely 39mm.

 

The 280ZX turbo ('82 ZXT) coupe PP/clutch is 240mm and each side measures 39mm.

 

The 300ZXT ('86) coupe PP/clutch is 240mm and each side measures 39mm.

 

The 280Z 2+2 ('78 ) is 240mm and each side measures 44mm.

 

So, the best solution that i found so far IMO, is to go with the 280Z 2+2 PP/clutch because of the 240mm overall size and the added 5mm per side for the larger surface area contact. Now i have to find which PP out of the 300ZX or ZXTT that has both the 240mm and 44mm sizes and see if their PP are stronger. I would think that they would be considering the power increase compared to the earlier versions of the Z but, the '86ZXT didn't seem any different than the '78 2+2 PP. I'm wondering if any of the 2+2 versions of the 300's, either N/A or T or TT, are both the 240mm and 44mm? Cody, i think a grabby clutch would grab a bit better but i think the majority of MY problem stems from the PP. I wonder which PP Lockjaw is using. I did find an old post of his but i think he may have re-drilled his flywheel to accept a 300ZXTT PP. Not sure if this is his most current setup. If anyone has more info on PP/clutch's, it would be appreciated. Hopefully i'll get what i need tomorrow and back on the raod by Tuesday morn! Thanks in advance and thanks for the replies guys.

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I know he redrilled the flywheel. I think they are 250mm from what he told me. IF you do a search on Dial-a-clutch you can see what I'm running. It's rated at 103% greater than stock holding power for the 82&83 turbos. Right now I'm at about 330 crank HP and I love it. Easy to drive and very firm feeling. The test I use is if my wife can drive it. With a lightened flywheel and this clutch she has no proublems with it. If you can get the flywheel lightened while your at it. You'll be glad you did. I personally don't recommend the puck style clutchs. Yes , they hold the power but, they suck for everyday driving in my opinion.

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Thanks Cody for the info. The post i found from Lockjaw - "I had my turbo pressure plate redrilled to use the 300ZXTT pressure plate and use the 89 300ZXT disc, and I have not slipped it under boost yet" - i'm assuming he meant he drilled the flywheel as you mentioned. I'd rather not drill my 2+2 plate, but just find out which 300ZXT or TT bolts up to my flywheel, is 240mm, has the 44mm side surface area and has a stronger clamping force. There's got to be one!!! haha. BTW - the '86 300ZXT PP does line up bolt wise (all 9) with my flywheel but does not have the surface area of the 2+2 PP and doesn't seem to be any stronger. Was '90 the first year of the TT's? Did they make them right up to '96? Sorry, i'm not up on my 300 knowledge :) but i will be searching for info after i post this. I would have to bet that Nissan up'd the clamping force on that PP Lockjaw is using and is why he is having luck with it. Do you know what year TT PP he's using? Asking because possibly the earlier ones, like '90-'91 may bolt up. I do know it's a '89ZXT clutch from his post. Hmmmmm.....Tanks again.

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Hello.

 

You can use any of the 300ZXT clutches, no problem, but if memory serves, they are all 600KG units, but should work on a mildly modified engine.

 

I went to the 300ZXTT pressure plate with the 89 disc, and it works well, but only works with the BW T5 trans. You will have to grind down some of the ribs on the inside of the bellhousing, but it is no big deal. It works well to I might add, and it rated at 780 to 800 KG, far more then the single turbo unit. I did have to have the flywheel redrilled, but it is just the dowel pin holes if memory serves.

 

I am likely going to go with the ACT soon, and you can order one of theirs from Coximports.com, or something like that. I believe they were 299.99 and were rated to 512 ft-lbs. Of course I think that is a solid hub, so if you drive the car alot, you may not want to go there.

 

One thing to keep in mind, on the 300ZXTT clutch, the disc material was different then prior years due to the anticipation that asbestos would not be allowed, and they just aren't very grippy. If you go 300ZXNA, make sure to get the earlier model disc. The right one will look silver.

 

One thing to consider is what Alex said, and just get a 300ZXT preessure plate and the ACT disc. Most souped up clutches have a different material on the disc, not a tweeked pressure plate. Some do, but most just go to a more aggressive material on the disc. That is the only change I made, and it makes a difference.

 

Mine has made moire then a dozen drag passes on the drag radials, and the clutch easily handles that sort of thing. I smoked the stock disc bad, but the nice thing about that is after it cooled down, it worked fine, but I would not have trusted it to make more passes.

 

I would run the big pressure plate if you can since it is easy to replace if it breaks. Just go to the nissan dealer.

 

I am really going to test it soon, race gas, and some Giggle gas. See what happens then. :lol:

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Thanks Lockjaw for all the information. I just got back from picking up an ACT Kit, with the street modded disk. I was going to go 6 puck but the Z is mostly for street use and i figured the 6 puck would be to on/off for semi-traffic driving. I'll have the clutch in tonight but wont be able to push it because of this damn rain. Seems to be raining every other day here in NJ for the last 2 months! Walbro pump to come in tomorrow and will be in by the weekend. I'm hoping the rain will let up for next Wednesday night and i can get to the track. I'll let you know how the Act PP and clutch hold up. And oh yeah, i wouldn't consider a damn thing what Alex says. Nothing against you. Thanks again for the reply.

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