Crank gurdle for 4age

[Flannelman]

Okay, looking into making one (or more) of these for a 4age.

Im budgeting on around $500-$750 for ARP studs, and a water cut 12mm plate.

With doing some early measuring there is a potentual problem. On the 20V models there is a cast alloy support going from the base of the block to the gearbox. There is no room for the crank gurdle and this support. Either it needs to be cut away (which may still not give all the clearance I need) or remove it completely.

The 16v engines don't have this, just a small plate to keep stones out of the clutch.

Do any bad things happen when this support is removed?

[Mr Revhead]

Why do you need a crank girdle? Some pretty hi hp 4ages put there that don't need them

[crispy'86]

I'm picking it'd act as a gearbox support much like the rwd t50's etc. just your gearbox wouldn't be properly botled up to the engine at the bottom which may affect the clutch operation, not to mention the bellhousing may get cracked with the stress (not being bolted all the way round and the force being unevenly distributed

[fangsport]

I'm picking it'd act as a gearbox support much like the rwd t50's etc. just your gearbox wouldn't be properly botled up to the engine at the bottom which may affect the clutch operation, not to mention the bellhousing may get cracked with the stress (not being bolted all the way round and the force being unevenly distributed

....could also cause the flywheel bolts to stretch and loosen.
i believe lack of braces caused this on one of my engines.

[Flannelman]

Im looking an taking the engine above 10,000. It looks to be the magic number that the bottom end begins to fall apart by breaking the caps and smashing the oil pump.

As with anything like this, its design is for longivity. With such a high RPM target im putting odds im my favour that it lives. The gurdle would stiffen the whole bottom end up helping not just the caps but berrings as well.

[Bazda]

Im still planning on making a girdle for these engines later next year.
It will require a full billet cnc plate with a big step in it. A simple 12mm alloy plate prob wont work..

[allencr]

Somewhere on the WWW is a pic of the #2 & #4 maincap supports that Loyning did on FA engines. Thanks oldeskewltoy.


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This really just looks like another 10000rpm wannabe post that shouldn't be replied to.

[Bazda]

SS Works Crank girdle from Japan.
Think it costs like $1600NZD.

[Flannelman]

The gap between the gurdle and the cap would have to be filled or it wouldnt strenghten the cap. I believe I have a solution for this with a simple fill in plate.

There is someone who makes/sells basic bracing overtop of the cap of about 3-5mm in thickness but isnt interconnecting with the other caps. I see no real benifit by using this as it doent stop the caps from walking at high rpm, just extra strengh to stop the cap from breaking.

Ultimately this is experimental so I dont expect anyone wanting one until its both seen and proven its worth.

While the SS Crank Gurdle looks like its the best thing to have, the price says I can do cheaper and achieve similar results.

The wanabe 10,000rpm+ posts are always around. Reason why no-one builds then is cost as more power for less bucks can be had from forced induction. However I dont like the power delivery of turbo cars and enjoy an engineering challenge. By me doing this and having it work will lay the foundation for people like bazda to build wild 4/7age creations knowing they wont break.

[Bazda]

For a 1 piece girdle you need around 20mm thick alloy.
In that size its def not cheap esp for 6061 T6 alloy.
Plus the cnc cost after that.

It could be made with 1 flat plate laser cut then have 5 individual pieces that take up the space to the caps. That would be the cheaper way.

[Flannelman]

Thats exactly what im planning. But, it wont be out of alloy, just 12mm thick mild steel.

[atmosports]

I'd be more inclined to use either 2024 or preferably 7075(or Alumec) over 6061. Though either option would probably cost more than 6061 & ideally you'd want to anodise it or something to prevent corrosion as they aren't as corrosion resistant as 6061 generally.

Nothing wrong with a steel girdle, or could use S.G iron also, only really thing wrong is the weight of it compared to aluminium

[Flannelman]

Major stall on this, just got off the phone to ARP. Im looking at close to $8-900US just for a single set of 10 studs made to lenght or $20-30US per stud on a run of hundred. This is only on the chance that some blanks can be found at the right lenght to save cost. This also doent include the nuts and washers!

So a quick tally up sees that for a run of 100, each set will cost on worst case of $40US each stud and 2 nuts and 2 washers. Add roughly 20% for US to NZ so thats $48... Times 10 = $480... Plus GST of 15%... gets a total of $552 each set. 10 sets to make 100 is $5520.
Thats not including postage or import duty...

Ouch, I hear my wallet crying from the car outside. Or is it me?

[atmosports]

I'm pretty sure you won't pay any import duty on them,only have to pay gst on the landed cost.

Have you thought of just getting your 10 studs you need machined locally???If you get the right machine shop/machinist/engineer it shouldn't be a drama. Might have trouble finding someone who can roll rather than cut the thread diameter/pitch you want, but if you can't get them rolled a cut thread works fine & you can always play with material/heat treatment to get the strength you require. From memory something like H13 or THG2000 is probably a good start for a material, I'd have to look back at what we've used previously to be more specific

[Flannelman]

Good call. I will try localy on monday.

Thanks for the inspiration atmosports

[Adoom]

Major stall on this, just got off the phone to ARP. Im looking at close to $8-900US just for a single set of 10 studs made to lenght or $20-30US per stud on a run of hundred. This is only on the chance that some blanks can be found at the right lenght to save cost. This also doent include the nuts and washers!

So a quick tally up sees that for a run of 100, each set will cost on worst case of $40US each stud and 2 nuts and 2 washers. Add roughly 20% for US to NZ so thats $48... Times 10 = $480... Plus GST of 15%... gets a total of $552 each set. 10 sets to make 100 is $5520.
Thats not including postage or import duty...

Ouch, I hear my wallet crying from the car outside. Or is it me?

They didn't have ANYTHING off the shelf from another engine that was even close?!??
They must make hundreds of different studs....
Can you get something close, then modify other stuff so you can use those??
If they are too long, make the girdle thicker. If they are a little too big, drill and tap the block/caps for the bigger size.

I can't believe there is nothing off the shelf that will do!!!

[1I1]

Pretty sure the block has to be drilled anyway when fitting the normal ARP main stuf kit?

[Bazda]

No drilling needed. And yes there are kits which can be fitting with small mods.

[Flannelman]

A couple of ideas have come up talking to engineers.

option one, use 4130 steel bar and create the threaded studs needed, buy seperate nuts/washers
option two, buy specific grade nuts/bolts/washers of a known strengh and turning the bolts down to studs

I do have another option but will explore this more tomorow. It involves a destructive test of an original bolt to get a ballpark yeild figure. With the info gained a precise material that equals or exceeds this can be selected. Of course this is price dependant which is what I am to discuss tomorow

[sergei]

Correct me if I am wrong, but on factory made studs the thread is rolled and is stronger than cut thread? So cutting new thread is not going to be as strong....