Australian Belly Tank

[Dr Goggles]

Well, you're from "Oz".....

Back to the issue at hand which is "Australian Bellytank" .As my byline says we run a 3.8litre Buick based V6, it was extensively redeveloped by Holden at the time they first used it.The very first model they used it in was the VN Commodore. For some reason they used different cranks in the manual and auto models( they are referred to as the "six bolt" crank), the crank boss was bigger in the manual....so, you can't bolt a flywheel to an "auto" motor. When we first built the car we used a VN motor and as you can imagine the auto's were more numerous by about ten to one.So, of course the motors we bought were "autos".Come time to organise a flywheel ( yeah and they want a left nut for them as you can imagine) , we got a cast iron one...yeah I know, but the motor was stock with a rev limiter on it. rather than buying one of the available crank boss adapters I had one made( hey, you all would too)...however because of concerns about the positioning of the counterweight I got the shop to drill another set of holes so the flywheel could be rotated through six positions, rather than the asymmetrical pattern that only allows it to be bolted on one way JUST IN CASE there was an issue with the balancing when it went on the auto crank.

Then, we got a one owner car from my brother which was the next model along ( the VP), by this point they had decided that that it would be a good idea to make the cranks the same...., great lot of help that was , this motor is known as the "eight bolt crank" so of course the flywheel we had didn't fit.That was the motor we ran at the 2009 DLRA meet with a home made dual throttle body manifold,nicely ported heads, heavy springs, some big home made headers and little else....I ran 161.4mph on the 150mph license run before we had to go home.

At last years meet Scott Taylor a local magazine writer and sometime drag racer offered us a VN motor ( if you're follwing ...this is us going BACK to a six bolt again) that he had raced on the quarter and written articles about the build on, he'd run it with a turbo and run it like a yo-yo for a few years.He loved that we were running a V6 and was , with many others surprised at how quick our car went with an essentially stock motor. He'd built a new motor for his( as it was known) "blown VN" but soon after retired the car and sold all the ancillaries off the motor, living in a rural area he couldn't get any takers for the bottom end because of the freight cost and offered it to us at a great price.This motor has 9.6:1 pistons, a deleted balance shaft and now a new cam (http://www.landracing.com/forum/index.php/topic,862.800.html) we are using the same heads, manifold and exhaust. Today I bought a new cro-mo billet flywheel for it....problem being we need to fit it to the adapter, because of course it's a bloody auto motor. The adapter doesn't have the holes matched to the mount holes on the flywheel but rather the new set we had drilled so it could be rotated..........the new flywheel doesn't need a counterweight because the crank is balanced..........so now I have $750 worth of steel lying around and am nervously trying to work out whether we drill the extra holes in the new billet flywheel or drill another set of holes in the crank boss adapter( which already has six holes in it and not a lot of room left)

Here are the two six bolt flywheels , the cast with the extra holes ( on the larger diameter circle)drilled is on the right , the new billet job is on the left.



next is the adapter , first is the crank side.....allen head screws go in from this side into the flywheel



then the clutch side showing the holes for the crank bolts....



why am I bothering to show you this dumb tedium?
because it shows the tiny details and the infinite detail that you have to deal with just to get the car to where you want to be......and our car is basic, really really basic...to any of you who are watching, but don't race take it from me ........IT AINT ALL BEER AND SKITTLES some of it is a complete pain in the seat.

The Colonel starts bolting the motor together on the weekend. We'll see how go from there..............if we're lucky, and lets face it we have been so far, we'll do what we hope to and get to 200 this year......

[Milwaukee Midget]

Any adapter is, by it's very nature, a weak link - I'd be cautious about swiss-cheesing it.

I see 33% more RPM in your future.

[Dr Goggles]

Any adapter is, by it's very nature, a weak link - I'd be cautious about swiss-cheesing it.
I see 33% more RPM in your future.

Ya Know, when I read 33% there was  an immediate clench. I'm not the worlds greatest engineer, yea, I'm not Plymouth on an engineer's boots.....but at anything above 7500rpm I'm thinking we're booked in for some sort of catastrophic failure, full stop.I hear the reasoning about putting more holes in that piece...however they are to be neatly spaced where you can see some circular marks between the outer ring of holes in the picture at the bottom in my last post, and it's , well, the way we're doing it now. The whole shebang(should I have used that word?) will of course need to be treated with some respect through the changes but there is a lot of metal in that thing still.

The Colonel and I set it up yesterday after double checking the cast flywheel with the adapter bolted to it on the motor we, yeah OK the Colonel ,is building, the starter motor meshed ok so I took it home . I checked that the pcd pattern matched the flex plate pattern(remember we are using an "auto crank") and that the counterweight was in the same place(..I've made sillier mistakes) and then marked the center of the holes by using a drill press with a bit the exact size of the holes in the flywheel( this is of course all happening on the iron flywheel). It would be very difficult to maintain concentricity if I were to drill the moly flywheel to suit the adapter as neither of them have a center................... I did have one of those moments after i'd marked the holes ,  freaked out, "oh no, oh Subaru, you idiot"...then I took it off, lost my spot, then when I'd calmed down sufficiently to have another look I put the adapter on backwards as I tried to line the crank holes up.....so, when I got to the seventh position my brain started working..."six bolts, seven tries and it still don't fit , there MUST be something wrong"...... I took a few deep breaths, sat down , set the flywheel up on edge with two G clamps and concentrated, second position..it all lined up beautifully, the counterweight in the right place . Then I went to the case where I thought I'd put the set of crank bolts from the first motor we had...as if by magic there they were, things were starting to flow dude.........

Yesterday I also managed to source all the bits required to change the fire system lines to steel....speaking of engineers , BSP/BPT anyone?

[generatorshovel]

BSP , BSPF, BSPT, 1/8" or 1/4" I have a shit load of taps, and sets if you need any Goggs, gimme a call, I'll satchel bag 'em to Melb for you.
Tiny

[Dr Goggles]

I'm sorted there T'fer, just need to find mine...it's out there ....somewhere....

Just about to get out there and get started , the urgency has finally hit home....woke up at 4am, couldn't get back to sleep apart from stits and farts...lay there going over all the stuff we've gotta do...that I wish we'd knocked over a while back

49 days

[Milwaukee Midget]

My worry - and I have only a rough idea of scale here - and I ALWAYS worry -

Look at the distances between your center holes and the new holes you'll need to drill in order to line all of this up, and then take into account the distance between the holes you're no longer using.  

Looking at the crank face of the adapter, your shortest distance between the holes on the inside bolt circle and the holes on the outside bolt circle are no less than the diameter of the center hole for the pilot bushing.  The only place you can put more holes on your new outside bolt circle is in closer proximity to the holes on the center bolt circle = more force through less mass, at a higher RPM.

Think about a wheel adapter.  They're always engineered to provide maximum material between bolt circles, even if you're changing from a 4 bolt to a 5 bolt.  And this will be turning at a faster RPM than your wheels.

RPM = fatigue.
Less mass = less strength.

That's my worry.  I am no engineer, either, but maybe someone out there is and is willing to pipe in on this.  How thick is this adapter?  Is whipping up a new one completely out of the picture?  

Above everything else, I want to see you and this car hitting 200 +, and without having to test to see if the flywheel shield is adequate to the task.

[Dr Goggles]

The adapter is 3/4 inch thick..... It's taken 4 hours, I Subaru you not ,to drill and tap the six holes and dress the whole thing, that included a quick trip to get some more linishing belts, the new holes are the ones with the arrows, as you can see they are a pattern rather than the other outside ring holes which are symmetrical.As you can see I put a much finer finish on it



the good news is the Gods of Speed were in a good mood and it bolted up without the need for ANY coaxing, the bolts ran in by hand. I deburred everything so I could confidently stick my pinky in and turn it .

Now, to be candid I did very much think to myself that I may be better just getting another one made. I was in the blue corner , and I was in the red corner..... Like the battle I had over the fuel tank I paid special attention and respect to the possibility that the next one I made may have it's own problems, and cost money that should be spent elsewhere. Of course there was the obvious possibility that I stuffed it up and had to get to one made. In the big picture we could have had a whole one piece flywheel made( but it would have had a slip on ring gear rather than the machined teeth that are on the one I bought) but it may have cooked up it's own issues AND we would have had to get it balanced...as it is we have spent nearly $800, had I somehow got the measurements wrong( it has happened) we would have been stuffed.

As for the fuel tank the Colonel is half way through setting riv-nuts around the access plate we cut out of the top and cutting a gasket for same, then we'll stuff the foam into it and bolt it up again....

on we go...yea verily

[Milwaukee Midget]

Very nice work.  It's thicker than the previous pictures might lead one to believe.

Fears allayed, Captain Chrispy, standing down, over.

[Dr Goggles]

Well that's a wave of the wings Cap'n............Pushed on with other stuff, have cut the seat in order to fit the bigger fire bottle next to it, worked out how to fit a small bottle and it's attendant remote release at the back of the firewall and have also made provision for a camera mount on the top of the cab.........right now the 4am wake up is taking it's toll. Am currently trying to figure out a quick way to lengthen the brake pedal , the list is getting shorter.

[SPARKY]

they are around here somewhere ----in red neck is---- "thys round here summers"   

[Dr Goggles]

they are around here somewhere ----in red neck is---- "thys round here summers"  

funny yer should mintion thayte cuzzin Bill, I jiss dun sum WITTLIN!!!!

We miscalculated a little with the frame during our build and there is a frame bar that runs across what should be the front of the seat but it turnmed out that I ended up with my coccyx resting on it and at the end of Speedweek I was real sore....here it is with the floor plate in place, the flat section to the right of the aluminium has a half inch thick neoprene pad that is supposed to be the seat squab, my backside tended to end up on the curved section  in the middle of the shot....



here is the bar itself, the groin belt mount are through it...., the belts mount to the left of the bar



here I have sectioned a piece out of the top and then welded in some 3/16 flat, we'll modify the floor plate as well next weekend.



I also lengthened the brake pedal by an inch and a half Colonel, now we'll be able to lock 'em up and flat spot the tyres..

All in all it's been a good day.

[wobblywalrus]

Really critical parts like connecting rod bolts are installed new and tightened down once.  They are not loosened and retightened a second or third time.  Over the years I have seen other critical bolts treated in the same manner.  "One use bolts" we call them.  It may be a good idea to use the old bolts to check and make sure the adapter fits and use a set of new good quality bolts to install it.

Imbalance can be a problem with homemade items that rotate very fast.  It is caused by parts that are out of true (not concentric), a weight imbalance, or both.  If available, it is a good idea to run the tank on a dyno to make sure everything will hold together and not shake apart.

If you like your new setup, it is worth it to have a new flywheel made and balanced after this year's Gairdner runs.  Shift slow and easy.    

[Dr Goggles]

Really critical parts like connecting rod bolts are installed new and tightened down once.  They are not loosened and retightened a second or third time.  Over the years I have seen other critical bolts treated in the same manner.  "One use bolts" we call them.  It may be a good idea to use the old bolts to check and make sure the adapter fits and use a set of new good quality bolts to install it.

Imbalance can be a problem with homemade items that rotate very fast.  It is caused by parts that are out of true (not concentric), a weight imbalance, or both.  If available, it is a good idea to run the tank on a dyno to make sure everything will hold together and not shake apart.

If you like your new setup, it is worth it to have a new flywheel made and balanced after this year's Gairdner runs.  Shift slow and easy.    

Absolutely, on the flywheel bolts, they'll be unused items.The ones I mentioned are new 8.8 allen heads that have the knurling turned off and are a very close fit in the adapter so they are a flush fit.we never used the six bolt motor we first had.

The adapter was made by a gear shop specializing in well, gears, if you read the detail, it was made so as to be able to be rotated, so a symmetrical bolt pattern was put into it and a new set of holes drilled in the flywheel. I didn't want to drill the cro-moly flywheel I have just bought but used the old one as a template...anything can happen of course but I'm confident it will be balanced.

We'll be moving to a different motor next year so whatever happens it will be a different set-up.

Tonight I saw a friend who has an engine tuner based next to his factory who has an engine dyno , he's seen video of the tank and wants to help with our mapping and EMS.

....that's gonna be handy

[Geo]

Absolutely, on the flywheel bolts, they'll be unused items.

The adapter was made by a gear shop specializing in well, gears...

Tonight I saw a friend who has an engine tuner based next to his factory who has an engine dyno , he's seen video of the tank and wants to help with our mapping and EMS.

Wow!  Stars seem to be aligning near the Southern Cross!   

I am practicing my 200 mph dance so as to be looking smart when the celebration commences.

I love the comments everyone.  You are not only helping the tank boys here. 

Geo

[Seldom Seen Slim]

Back in the mid-60's my dad was the sales manager for Premier Industries - a firm that made "Supertanium" fasteners -- which were marked and sold as "8-line" bolts and such.  It was great for me as a teen - because Premier had a garage/shop at Indianapolis - to supply fasteners to the racers -- so Dad and I would get garage passes for the time trials.  We went every year for a while -- got to see Andy Granatelli  helping start up the Novi, for instance, and saw the turbine car run and on and on.

But that's not why I'm writing this.  Dad taught me that Premier's guys had researched and learned about fatigue of fasteners -- that after 4 or 5 uses, properly torqued, they would have lost up to 80% of original strength due to stretching.  So that's why you should carefully consider reusing stuff that's absolutely critical.

By the way -- Dad also got pretty much unlimited free samples of the Supertanium bits and pieces -- so when I'd rebuild the Briggs and Stratton mower, for instance, I'd let him know what sizes I needed -- and viola, great stuff for free.  I remember rebuilding the engine in the '58 Olds with Supertanium.  One time a while later we had the hood up at a gas station and the mechanic darn near swallowed his chew when he saw those fancy nuts and bolts throughout the engine.