71 Duster 360 turbo build
- Thread starter turbovan
- Start date
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Are you running a 904 or 727?
abdywgn
dismantler
better safe than sorry with blown trans parts under/in the car
It’s a 727 with crt rebuild kit, 5 clutches up front, bolt in sprag and their manual reverse valve body. If I rebuild it will be a full roller setup with their drag sprag and a billet front drum. Still not positive the trans is hurt, but better safe then sorry. To the best of my knowledge the low bad apply in their valve body would hide a faulty sprag?
Pulled the trans and found metal shavings in the pan and filter. After tearing everything down I can’t find anything wrong so I assume I’m missing something. The shavings seem to be aluminum; non magnetic. Bands look new, clutches are “okay” but the steels definitely got some heat in them. I’ll get a better look at it this week, and I’ll ship the torque converter out to get checked, and have the stall dropped 1000rpm. My logs show it flashes to 5k at 10psi.
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The sprag looks okay?
Looks and functions as new. So I have no idea what the one time whirling noise may have been.
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That’s very strange then. Maybe something let go inside the converter? I’ll be interested in hearing what you find out.
dusted
Well-Known Member
My trans guy told me that a little metal near the pickup is usually from the converter unless the trans is toast. Mine had a little metal after I did a converter swap and then changed fluid and filter months later
I believe I found the source of the metal. The front planetary seems to have been rubbing up against the back of the rear clutch retainer/input shaft. My transmission Knowledge is very limited. Could this be caused by using the wrong selective snap ring(too much clearance) on the planetary set? Reading through the 727 transmission handbook I also see that 1978 and up transmissions had a thrust washer and steel race. Mine only has the single #3 thrust washer and I’m wondering if that isn’t providing enough clearance.
Called John Cope who was extremely friendly and helpful. I’m very happy to spend my money with him. He informed me that my interference can be caused by excessive clutch clearance, or play from too thin a belleville spring. So parts will be ordered, and since the downpipe is removable with the trans out I’ve decided to upgrade the turbo. Billet 7875 Gen 2.5 on the way.
Hell yeah! Upgrade! What turbine housing did you opt for?
1.25 T4
I read non stop because I just don’t feel that the 75mm exhaust wheel is enough for a 360, but I’ve seen lots of success on 6.0 LS setups. I REALLY wanted to go s480 with the big 88mm wheel, but I didn’t think it would fit without a massive revamp of my entire hot side…if it would even fit.
I read non stop because I just don’t feel that the 75mm exhaust wheel is enough for a 360, but I’ve seen lots of success on 6.0 LS setups. I REALLY wanted to go s480 with the big 88mm wheel, but I didn’t think it would fit without a massive revamp of my entire hot side…if it would even fit.
I think you’re right
Can’t wait to see how it spools
TT5.9mag
Two atmospheres are better than one
I’m right. You’ll be fine. With room to grow. I am intimately familiar with that turbo. I currently have 3 of them running and am building and engine for a friends drag week car using a 4th.
Found out the gt45 was trashed. Tons of side to side play, and both wheels were hitting the housings. You can see how much clearance there is on the compressor side now. So far it’s looking like the 7875 will fit nicely with nothing but a new vband flage on the downpipe.
Matts440
Well-Known Member
Oh man, that sucks to find but at least you were upgrading anyways. Where did you get the gt45 from?
dusted
Well-Known Member
My GT 45 lasted a while after I got rid of the oil restrictior. It wants the oil. Good choice on the 78/75, that’s my next step.
Matts440
Well-Known Member
Oh okay
TT5.9mag
Two atmospheres are better than one
Holdener has had pretty good luck with those. But he doesn’t subject them to too much run time. How long have you run it?
This I believe is the reason the turbo failed. It comes with an oil restrictor that is probably better off in a bb turbo.
I can’t imagine it has more than 400 miles of run time.
Matts440
Well-Known Member
When I plumbed my turbos non ball bearing I just used 4an line and 10an return.
After receiving all my goodies from CRT I realized I had a 1989-199? 727 case that has a 6 bolt rear support vs the normal 4 bolts. It’s a narrower spacing too so I wouldn’t have been able to install my new sprag or rear roller support. Took a couple months to find a small block 727, but the trans is finally all back together.
I sent the converter out to be re-stalled, and was a little surprised when I heard back from the shop. It had been flashing to 5k rpm and I asked that it be dropped to 4k. Once they were ready to ship it back they informed me the new setup would likely flash to 4500rpm, but that it is now setup in the tightest configuration possible. It’s a billet cover 9.5”.
The downpipe needed to be altered for the new turbo, which is complete, and once it’s wrapped everything will be going back together. Getting hot here in Phoenix so I’ll find out quick how well my half filled block stays cool in 100°+ temps!
I sent the converter out to be re-stalled, and was a little surprised when I heard back from the shop. It had been flashing to 5k rpm and I asked that it be dropped to 4k. Once they were ready to ship it back they informed me the new setup would likely flash to 4500rpm, but that it is now setup in the tightest configuration possible. It’s a billet cover 9.5”.
The downpipe needed to be altered for the new turbo, which is complete, and once it’s wrapped everything will be going back together. Getting hot here in Phoenix so I’ll find out quick how well my half filled block stays cool in 100°+ temps!
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