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| Blooze Own: An F355 Six Speed N* Build Thread (Page 105/126) |
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Bloozberry
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MAY 04, 10:24 PM
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Thanks for the idea Fieroguru... I just might try that out. 
As for the boot clamps Reallybig... I was thinking the same thing... these clamps don't seem to be able to be tightened enough to work properly. Have you found a source for the good ones?
As I mentioned before, even though I took a bit of leave from posting in here over the past couple weeks, I've been busy nonetheless. While waiting (for forever) for my axles to be re-splined, I got to work researching what I was going to do for the flywheel and clutch. Many moons ago Zac88GT came up with an innovative idea for mating the Northstar to the F40 transmission... in fact, I think he was the first, and I don't believe anyone else has attempted it. He bought a SPEC aluminum flywheel to place the ring gear at the right depth for the starter. Then, he designed an elaborate spacer disk in Solidworks, had it machined out of aluminum, and bolted it to the transmission side of the flywheel. Next, he installed a steel wear plate and the clutch stack to his spacer disk, essentially moving the clutch deeper into the transmission bellhousing where the hydraulic throw out bearing (HTOB) could reach it. His thread is here for those that want more info: www.fiero.nl/forum/Forum3/HTML/000030-2.html
Obviously Zac's solution was my preferred option since it's tried and true, and because he was nice enough to send me his Solidworks file. That was several years ago though and since then, Fieroguru designed a one-piece aluminum flywheel to mate his LS4 to an F40. Fieroguru machined a single aluminum part (with a steel wear plate) based on critical dimensions from an aluminum LT1 Fidanza flywheel, which seemed like an improvement over Zac's two-piece aluminum flywheel with a steel wear plate. If Fieroguru's design could be made to work with the Northstar, it would also cost less since one could avoid buying a SPEC flywheel.
My plan was to contact Fieroguru to see if he would machine a flywheel for me based on the specs for my Northstar engine... but first I needed to get savvy about what I needed. I spent a whole whack of time researching various dimensions of the interface between the transmission, engine, and clutch assemblies and drew up some schematics. The first one shows the key relationships between these components:
The drawing is made from a mix-mash of dimensions that Fieroguru posted in his LS4 build thread, and ones I took from my own flex plate and engine. The amazing thing that fell out of this exercise was that the Northstar is essentially identical to the LS4 for the purpose of mating the F40. That meant Fieroguru's flywheel would only need to be modified for the Northstar crankshaft bolt pattern and the flywheel centering hole. It also meant that I wouldn't have to worry about solving the four key areas that he had to contend with through trial and error. Here's a schematic showing some of the challenges he faced and that I was glad I wouldn't:
In area:
A. the ring gear must be able to fit inside the bell housing diameter and it must be set at the correct depth;
B. the depth of the flywheel, clutch, and pressure plate stack must not exceed the depth of the bell housing;
C. the fingers on the pressure plate must sit at a depth that allows the HTOB to operate within it's range; and
D. the F40 transmission has a differential housing bump that protrudes into the bell housing... the pressure plate must also clear that.
It all sounds easy enough if you've got all the dimensions and drawings sitting in front of you, but there isn't a parts supplier out there that can give you the stack height of a clutch and pressure plate, nor the required throw on the fingers to get full disengagement, nor a whole bunch of other data you need to figure out if it'll work or not. That's why I thought it was appropriate to give credit where it's due. Fieroguru came up with a flywheel design, and a clutch and pressure plate combination that are tried and proven to work with the F40 transmission. He deserves a hearty pat on the back. 
The other nice thing about Paul is that to save me money, he figured that it would be much cheaper if I were machine the flywheel up here in Canada and avoid shipping, handling, and duty. So with a gentleman's agreement not to share or otherwise profit from his design, we negotiated an excellent price and he transferred everything I needed to make my own flywheel. Woo-who! This was one of two huge hurdles still left ahead of me and it was solved over a couple days. (The last hurdle is engine management). Next post is when the fun began... I love watching CNC machines do their stuff.
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fieroguru
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MAY 05, 11:26 AM
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Blooze, you have been more than helpful sharing all your detailed drawings of the 88 suspension (which I have used quite a bit), so sharing the print for my flywheel was one way to return the favor. Hope you like it!
Those drawings are pretty cool and really show how tight everything is within the bellhousing and all the factors one must review to find a workable solution. However, there is another critical dimension not mentioned - the placement of the clutch disk spline hub to the splines on the input shaft.
Also, did you remember to insert the bleeder assy into the HTOB to release the check valve and allow the fluid inside to be removed. If you don't do this, the HTOB will not fully retract and it will throw off the fully retracted measurements... been there, done that...
Let's see some machining pics!
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Will
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MAY 05, 12:43 PM
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| quote | Originally posted by Bloozberry:
Thanks for the idea Fieroguru... I just might try that out.
As for the boot clamps Reallybig... I was thinking the same thing... these clamps don't seem to be able to be tightened enough to work properly. Have you found a source for the good ones?
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There are a variety of tools that can tighten the horrid aftermarket clamps. That's what the parts store nincompoops don't know... a tool IS required.
I've used this one:
http://www.amazon.com/gp/pr...1QRQE833QHSCW5C7WAD7
This one looks better, but I have no experience:
http://www.amazon.com/GearW...rench/dp/B0002SRDDC#
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Will
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MAY 05, 01:03 PM
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| quote | Originally posted by Bloozberry:
The amazing thing that fell out of this exercise was that the Northstar is essentially identical to the LS4 for the purpose of mating the F40. |
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All of the engines with the FWD pattern (Northstar, 60degreeV6, 3800, 4.9, etc.) are identical in that regard... the crank flange is coplanar with the bellhousing mounting face.
A 40.3mm (or 41.275 or 47.625) thick flywheel--even made of aluminum--will be quite heavy.
I recommend using a stock flexplate to carry the starter gear, then a steel hub spacer ~27mm thick, but only as large as the Northstar crank flange, then a 10mm thick steel friction surface the full diameter of the clutch, to which the clutch bolts. Assuming the flexplate is 3mm thick at the hub, these numbers add to 40mm. Adjust the hub spacer thickness to arrive at the desired total stack thickness.
In addition to being lighter, this will get aluminum out of the equation. I don't like the use of aluminum in a clutch/flywheel application. Aluminum creeps under stress at high temperatures. The heat from friction in the clutch can cause the fasteners that hold the friction surface to the flywheel to relax... it can even cause the flywheel bolts themselves to relax. This is a demonstrated reliability problem on the 2003 Mustang Cobras that had aluminum flywheels from the factory.
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mwhite
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MAY 05, 08:01 PM
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| quote | Originally posted by Will:
All of the engines with the FWD pattern (Northstar, 60degreeV6, 3800, 4.9, etc.) are identical in that regard... the crank flange is coplanar with the bellhousing mounting face.
A 40.3mm (or 41.275 or 47.625) thick flywheel--even made of aluminum--will be quite heavy.
I recommend using a stock flexplate to carry the starter gear, then a steel hub spacer ~27mm thick, but only as large as the Northstar crank flange, then a 10mm thick steel friction surface the full diameter of the clutch, to which the clutch bolts. Assuming the flexplate is 3mm thick at the hub, these numbers add to 40mm. Adjust the hub spacer thickness to arrive at the desired total stack thickness.
In addition to being lighter, this will get aluminum out of the equation. I don't like the use of aluminum in a clutch/flywheel application. Aluminum creeps under stress at high temperatures. The heat from friction in the clutch can cause the fasteners that hold the friction surface to the flywheel to relax... it can even cause the flywheel bolts themselves to relax. This is a demonstrated reliability problem on the 2003 Mustang Cobras that had aluminum flywheels from the factory.
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Just a note before you go down the road of designing a spacer that utilizes the crank bolt pattern for clamping everything together. Source the fasteners first. I am guessing that the Northstar has a similar flywheel bolt to the LS engines in that it an 11MM thread with a fine pitch. GM performance does not carry any long 11MM fasteners the longest shank is about 1". You may be able to source some studs that will fit the bill, or you may have to get some custom fasteners. Also keep in mind they need to be super strong, if I recall correctly 10.9 spec.
Awesome build by the way.
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Bloozberry
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MAY 05, 10:05 PM
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| quote | Originally posted by fieroguru:
...there is another critical dimension not mentioned - the placement of the clutch disk spline hub to the splines on the input shaft. |
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Yeah... I thought about that one after I posted... but then there are lots of other little issues to consider as well like whether low profile crank bolt heads are needed, finding a friction disk with the right number of splines, the correct diameter, and the right offset hub... and the list goes on and on.
| quote | Originally posted by fieroguru:
Also, did you remember to insert the bleeder assy into the HTOB to release the check valve and allow the fluid inside to be removed. If you don't do this, the HTOB will not fully retract and it will throw off the fully retracted measurements... been there, done that... |
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I didn't need to because I read your thread and got my measurements from your experience. I haven't installed the flywheel yet, though I would imagine I'll need to do as you described otherwise I'll be fighting against the HTOB on the fingers when I try to mate the transmission to the engine.
| quote | Originally posted by Will:
In addition to being lighter, this will get aluminum out of the equation. I don't like the use of aluminum in a clutch/flywheel application. Aluminum creeps under stress at high temperatures. The heat from friction in the clutch can cause the fasteners that hold the friction surface to the flywheel to relax... it can even cause the flywheel bolts themselves to relax. |
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Unless you're slipping your clutch regularly, I can't see the heat build up as a significant problem. As for the wear plate fasteners relaxing, they're not screwed into the aluminum... the fasteners are through-bolts with lock nuts on the reverse side so I don't see that as a problem either. Your idea of a thick, small diameter flywheel spacer with a larger diameter steel disk to mount the clutch to is interesting but sounds cumbersome with the number of pieces being aligned and bolted together. To each his own.
| quote | Originally posted by mwhite:
I am guessing that the Northstar has a similar flywheel bolt to the LS engines in that it an 11MM thread with a fine pitch.... |
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The Northstar actually has eight M8 x 1.25 flywheel bolts so they're not the same as the LS engines. Thanks for the compliment, BTW. 
So, on to the flywheel fabrication. I did a bit of research to figure out the best aluminum alloy to make the flywheel out of and found that 7075-T6 would have been ideal from a properties perspective. The problem with that alloy is that it's not very common around here in 12" diameter billets, and it's not cheap either. After seeing that nearly all the aftermarket flywheels are made from 6061-T6 aluminum, and after finding that the local metal supplier had some in stock, I decided to go that route instead. I ordered up a 2" thick billet from Metals "R" Us and got it the next day for a measly $124 including shipping and taxes.
The Northstar engine uses a 142 tooth flex plate for the starter so rather than attempting to remove the ring gear from flex plate (which I'm not certain could be done anyways), I ordered a new ring gear. For $47 all inclusive, it was delivered within a couple days:
I needed the ring gear in advance because the machine shop would use it to gauge how large the seating surface should be on the flywheel in order to get a nice tight interference fit. Here's the part number for anyone considering going this route:
I spent a couple hours modifying Fieroguru's drawings to change the crank bolt pattern from a six bolt to an eight bolt pattern, and to change the diameter of the centering hole in the middle of the flywheel to match the Northstar's much smaller centering flange. Then, with drawings in hand, I made a trip to my favorite machine shop and watched as the owner's eyes filled with delight as I gave him the instructions. He's up to his eyeballs in "mundane" engine machine work so when he gets a chance to use his CNC lathe and mill for something special, he sets everything else aside. Here's the lathe, and if you look closely, you'll see my aluminum disk already mounted to the chuck:
This particular lathe has an automated head with eight different cutting tools mounted on it for different types of cuts. Only one cutter was used for all of the turning work done on my flywheel though. Here's a close up of the preliminary cut that was made to gain enough clearance for the remaining operations:
From the drawings, the machinist sat at his computer for 15 minutes and programmed the profile of the front face of the flywheel, then stuck the diskette into a port on the lathe. That's when this screen on the lathe lit up and showed the path the cutter would take:
Once that was done, all that remained was for him to close the door...
Start the lathe and the coolant jets, and press the GO button for the cutting head to come alive:
It looked more like an aluminum spaghetti factory in there after a few minutes. Every so often he'd shut the lathe down to remove the strands because they'd start to interfere with the coolant spray pattern. At one point he reached in, grabbed a handful and muttered something like "Bionic Woman's pubic hair"...
As it neared the end of the run, it re-traced its path to clean up any edges and without the coolant jets it made taking pictures a little easier:
Here's the completion of step one of seven... but don't worry, I won't be documenting them all.
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ericjon262
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MAY 05, 11:22 PM
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but we want to see all of them....
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Will
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MAY 06, 08:09 AM
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| quote | Originally posted by mwhite:
Just a note before you go down the road of designing a spacer that utilizes the crank bolt pattern for clamping everything together. Source the fasteners first. I am guessing that the Northstar has a similar flywheel bolt to the LS engines in that it an 11MM thread with a fine pitch. GM performance does not carry any long 11MM fasteners the longest shank is about 1". You may be able to source some studs that will fit the bill, or you may have to get some custom fasteners. Also keep in mind they need to be super strong, if I recall correctly 10.9 spec.
Awesome build by the way. |
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| quote | Originally posted by Bloozberry:
The Northstar actually has eight M8 x 1.25 flywheel bolts so they're not the same as the LS engines. Thanks for the compliment, BTW. |
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As BLooze mentioned, the Northstar has an 8 bolt circle with 8mm bolts.... weird. GM used 10.9 bolts with a 15+50 (IIRC) torque sequence. They are TTY. TTY only takes 50 degrees because the bolts are so short. I use 12.9 hex head bolts from general industry for my flywheel. The standard heads just barely fit under the clutch disk. ARP doesn't have any 8mm thin head flywheel bolts. When I get around to making the button flywheel for a Tilton clutch, I'll enlarge the holes to 10mm for better fastener availability.
| quote | Originally posted by Bloozberry:
Unless you're slipping your clutch regularly, I can't see the heat build up as a significant problem. As for the wear plate fasteners relaxing, they're not screwed into the aluminum... the fasteners are through-bolts with lock nuts on the reverse side so I don't see that as a problem either. Your idea of a thick, small diameter flywheel spacer with a larger diameter steel disk to mount the clutch to is interesting but sounds cumbersome with the number of pieces being aligned and bolted together. To each his own. |
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Are you going to drive your Ferrari slow enough to drive Miss Daisy? 
Even when cold, but especially when warm, the aluminum can flow out from under the bolt heads. Creep means that the material flows so as to reduce the stress on it. As the aluminum flows to reduce the compressive stress on it, this obviously reduces the tensile stress on the bolts as well.
The way the two-piece steel flywheel would have to work is that the hub would be bolted to the friction disk from the engine side. The bolts would be secured with either red lock tite, metal staking or tack welding. The assembly would be trued in a Blanchard grinder and then bolted on top of the flexplate through the hub from the clutch side. The two piece construction means that the hub can be turned from a piece of 4" round bar and the friction surface laser or water jet cut from 3/8" plate... cheaper machines and materials keeping the buy/fly ratio high and the machining time low. The disk could even be plasma cut, but the edge would have to be machined true to ensure balance.
| quote | Originally posted by Bloozberry:
The Northstar engine uses a 142 tooth flex plate for the starter so rather than attempting to remove the ring gear from flex plate (which I'm not certain could be done anyways), I ordered a new ring gear. For $47 all inclusive, it was delivered within a couple days:
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Always check The Google:
http://www.summitracing.com/parts/pio-frg-142w
Although shipping to Canada is the great equalizer, isn't it?[This message has been edited by Will (edited 05-06-2014).]
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aaronkoch
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MAY 06, 02:20 PM
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Reallybig
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MAY 08, 04:02 AM
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| quote | Originally posted by Bloozberry:
As for the boot clamps Reallybig... I was thinking the same thing... these clamps don't seem to be able to be tightened enough to work properly. Have you found a source for the good ones?
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No
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