Billet Girdle

[Oblivion]

What about abrasion properties of the alloy? Will it wear out quicker then the cast??

I know its a high grade alloy but I guess it is something that will show up under longer testing.. If it does pose a problem maybe it might be worth while to work out if it is possible to treat the bearing surfaces etc. Again that may raise an issue with expansion and machining surfaces.

Just an idea Ranga man.

[shanef]

What about abrasion properties of the alloy? Will it wear out quicker then the cast??

I know its a high grade alloy but I guess it is something that will show up under longer testing.. If it does pose a problem maybe it might be worth while to work out if it is possible to treat the bearing surfaces etc. Again that may raise an issue with expansion and machining surfaces.

Just an idea Ranga man.

yeh we talked about treating/coating it but ud lose the coating on the bearing surface anyway when u machine it, so at this stage we ruled it out. If we find premature wear then we'll look at something like that

[proengines]

Shane, have you thought about machining up a pattern now you have the program done and having the girdle cast in cast iron? Would only take some bulking up in machined areas to leave enough to machine back. Casting would definitely cost less than the 7075 billet and be a a lot less machine time once it was done, plus the benefits of cast iron over alloy in terms of expansion, maintaining bolt tension etc..

Just an idea, I really like what you have done here.

[shanef]

Shane, have you thought about machining up a pattern now you have the program done and having the girdle cast in cast iron? Would only take some bulking up in machined areas to leave enough to machine back. Casting would definitely cost less than the 7075 billet and be a a lot less machine time once it was done, plus the benefits of cast iron over alloy in terms of expansion, maintaining bolt tension etc..

Just an idea, I really like what you have done here.

12 months ago when i did the other girdle i was looking into that, but it never got developed that far.

I'm pretty reluctant to add in another company for the casting, as to date i've already tried 3 different companies and i've finally found one i know will give me what i want and the finish i want with no questions asked. Also i wouldnt do it at this stage as i'm not sure if the design will change, there are a few things i already want to change, like bringing the webs closer to the block, leaving more meat around the dipstick tube etc.

The other thing with cast iron is, it isn't as strong as 7075, 6061 is alot stronger than cast iron. Also i believe an alloy girdle will dampen any detenation and be nicer on the bearings. What are your thoughts on that?

I guess ultimately when all the testing is finished and we're 100% happy, we will probably go to something like casting to drop the costs.

[T04GTR]

that is very nice! did you do the cad program? ps, you should mention that a tunnel bore is definatly needed with this. and not alot of places do alloy/iron tunnel boring. let alone a 6 cyl one.

looks good but!

[shanef]

that is very nice! did you do the cad program? ps, you should mention that a tunnel bore is definatly needed with this. and not alot of places do alloy/iron tunnel boring. let alone a 6 cyl one.

looks good but!

i did the majority. I got the block and cradle digitised and then designed it from there. I also employed a mechanical engineer that specialises in racecar engineering so i could sit down and talk through various aspects of the project.

Yeh i shoulda said that, we've left 15thou on the tunnel and the caps are dead square. So the line borer only needs to take 15thou off the tunnel and machine in the radius for the bearings. For the ones i do i'll be using Jack Brothers

I'll also add that the studs used will be the longer ones as in the RB mainstuds kits, so no tapping required (hence the cutout on the top surface). Also note that the std oil pickup tube & other casting dags have been machined off so we can get full coverage across all the caps, i wasn't prepared to weaken one cap just to keep an internal pickup. So therefore you'll need to run an external pickup in the sump, no biggie really for anyone wanting to use one of these as they should be going to a custom sump anyway.

I got the invoice and to machine up more of these in 7075 they will be $2250 for the rwd girdle and $2450 for the 4wd girdle. To do them in 6061 they're approx. $400 cheaper. Ultimately we feel that the 6061 will be capable of supporting some decent hp, but we dont know as yet what that would be.

[bigmikespec]

Great work there, looks awesome. Very interested to see how testing goes on this, has there been any as yet?

Mike

[N1GTR]

Have a look here for more info;

http://www.skylinesaustralia.com/forums/in...t&p=4454123

[shanef]

No no testing yet, very soon though.