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L28 block brace/girdle


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#21 Lurch ™

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Posted 21 November 2010 - 08:28 PM

Simon & Peter, would it be possible to cross-bolt the girdle or would gallery's get in the way?

#22 luvemfast

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Posted 21 November 2010 - 08:33 PM

Simon & Peter, would it be possible to cross-bolt the girdle or would gallery's get in the way?

What do you mean by cross bolt?

#23 Lurch ™

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Posted 21 November 2010 - 08:36 PM

Now that I think about it, it won't be possible. Carry on...

#24 peter mc

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Posted 21 November 2010 - 08:53 PM

make it out of steel it is a better material for the job. there are small spacers that are needed for the mains from memory .no big deal to make we can make them from RN26  can cnc the hole thing if you wont

#25 luvemfast

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Posted 21 November 2010 - 09:05 PM

What's RN26?
I was thinking that just turning a spacer would do the trick, even just mild steel would do the job.

Thought steel would be better, but I know what your like about your weight  ;D

#26 peter mc

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Posted 21 November 2010 - 09:10 PM

RN26 is a very hard wearing steel, when you are tightening bolts down you don't want the steel to give or wear.
That is why mild steel is not up for the job.
By the way that is enough fat jokes!!!! lol

#27 luvemfast

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Posted 21 November 2010 - 09:33 PM

But it defeats the purpose if your bolting through a mild steel plate?
Maybe I'll use 4140 (like M200) then.

#28 NZeder

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Posted 22 November 2010 - 07:23 AM

There was an engine built here in NZ that use an RB crank girdle - it was modified for the L6 block and line bored to match. I think this path was taken as it was a one off, as we know the RB bore spacing is the same as the L6, this girdle includes the main caps too. But that was a bit of engineering to get it to work as the rear main is very different between the 2 and I am not sure how it was done but heard it had been done.

#29 ozconnection

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Posted 22 November 2010 - 09:42 PM

The photo above looks more like a windage tray, than a block girdle!


Go to Google and have a look at what a windage tray looks like.

#30 nat0_240_chevZ

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Posted 24 November 2010 - 11:56 AM

yep i aggre with nzedder, yes why re-invent the wheel,
the rb is the next gen l-series and most things like size, spacing, bolt positions are exactly the same in most cases....
easier to do with an existing cast item also.
otherwise if you do go down the road of making them, just get the blank laser cut from some decent plate ie 350 grade MSteel, then machine the req'd grooves for gasket sealing etc. drill tap, c/bore/csk as req'd all in the one machining operation.
If i actually still ownerd an L-series id grab an rb item first.
otherwise if you really dont want to use struct grade alloy steels (mild / carbon) then yes you could use a cr-mo 4140/4340 or even a d2 tool steel, DO not even think about using ally however, as thermal expansion difference will cause sealing issues....eventually.
We can laser cut 40mm plate @ a real stretch ie cut defination lacks after about 30mm.
nat0

#31 MaygZ

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Posted 24 November 2010 - 03:55 PM

I've never had anything to do with a girdle before ( I know Lurch still wears one - He's actually 5'8" and fat until he puts it on  ;D ), but the pictured one would do the job pretty well if one were to tap into the bottoms of all the main caps and secure, I reckon.  After all, if I am correct, it's job is to reduce lateral movement of the mains and therefore reduce load and vibration by doing so.

I do agree that counter sinking the bolts would make the end result more asthetic, but I don't think it would improve performance in any way.

I also think that any gasket, other than a thin film of silastic, would reduce the benefit of the plate, as it would reduce the rigidity of the plate.

Just my 2.2 cents.

MaygZ

#32 luvemfast

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Posted 24 November 2010 - 04:09 PM

If you want to see what Z's are doing laps under 2minutes at the Island, have a look under them in the pits, they're the ones with the oil puddle underneath them. Due to the flex of the block.
I agree that a gasket between the block and brace would be detrimental to rigidity.
The countersunk screws are more to give clearance for the sump to be put back on, not to look pretty.
Tapping into the mains would be a BIG no no in my book. That would create weak spots in them. Using spacers and bolting through the brace, spacer and mains would be the best way to go.

I'm waiting for the CNC to be free for me to mill a timber template to check size and mods made. Then its time for some quotes from laser cutting. Hopefully this week.

#33 Gareth. J.

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Posted 24 November 2010 - 06:23 PM

No puddles under mine...... It's all along the cross members and floorpan  ;D Could you cut a grove top and bottom of it and use an 'O' ring type of seal?

#34 ozconnection

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Posted 24 November 2010 - 08:14 PM

That's a great idea in regards to gasket sealing and maintaining bolt tension.

Too bad there isn't an L sump that runs with this idea. Now I'd buy that in a second! It may negate the need for a brace or at least move the necessity to a higher power level.

Hmmmm.



#35 peter mc

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Posted 24 November 2010 - 09:32 PM

The rear main leak is from crank flex. The shaft is moving up and down this is the reason the seal is damaged.
When replacing bearings on big hp l6 engines the mains are normally out of round on 1 & 6 by 3-4thou this would indicate that the crank is flexing through its length.
A girdle will go a long way in reducing crank flex and hopefully help bearing life, as for using an RB girdle this would be a monumental and expensive way around the problem as you would need to line bore the main tunnel which in impractical and the man that built this girdle was no fool and also built some of OZ's best L series long before most of us had Z's or knew how to build motors!

#36 NZeder

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Posted 25 November 2010 - 07:42 AM

as for using an RB girdle this would be a monumental and expensive way around the problem as you would need to line bore the main tunnel which in impractical

Yep I did not say it was a good or bad idea - just that someone had under taken the task here in NZ. It would be a mammoth task for sure and having a well designed girdle that can be CNC would be a much cheaper option in the long run as more could be produced from the design work once done. As you have stated there is already a design floating around Oz so if this works why re-invent the wheel ;) (I should listen to that myself - custom one of rear brake setup...silly man...all for a internal drum for the park brake - dual purpose cars always a compromise :(

#37 nat0_240_chevZ

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Posted 26 November 2010 - 05:49 PM

lol, yes compromise or to not spare a cent or minute..........
why cnc a template in wood on a mill???
i could cnc punch a sheet/plate template to within +/- 0.1mm which would only, seriously take about 2-3 minutes if appropriate tools are already loaded into machine (ie piggyback off another job.)
just doing out of wood, sounds like checking it with a rubber ruler....lol

nat0

#38 luvemfast

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Posted 26 November 2010 - 10:25 PM

just doing out of wood, sounds like checking it with a rubber ruler....lol

Just checking hole positions, nothing more.
Doing it out of 1mm steel now anyway.

#39 luvemfast

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Posted 29 November 2010 - 08:20 PM

I machined a prototype out of 1.5mm Galvabond this arvo.
Have to adjust a few holes a mm or so. But apart from that, I'll be getting quotes from the laser cutters ASAP
Here are some progress pics.
Simon

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#40 dazzed

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Posted 01 December 2010 - 06:44 PM

Simon dont waste your time doing all that it allready been done and are currently available , they dont just bolt in too theres a fair bit of machining to do as well .contact me if you need to know more, cheers .




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