Aftermarket factory-appearing Duramax block

[zakkb787]

Zach, not a dis, but you've never heard of Siamesed cylinders in an engine?


PS, Jon is a very intelligent and creative guy. :hug::thumb:

No sir I haven’t. Tho I think without researching I understand the concept. Maybe. I grew up wrenching on sbc and the first motor I built was a 440 with my dad. A lot of this is new to me. I usually spend about 2-3 hours each night just looking stuff up and learning things here and there. One reading why I love this forum. I actually read every single thread that anyone posts any given day. Learn something new all the time :thumb: I’m assuming Jon is Fingers? If so, I know he’s a freaking genius just from reading his posts.

 

[$chultz38]

No sir I haven’t. Tho I think without researching I understand the concept. Maybe. I grew up wrenching on sbc and the first motor I built was a 440 with my dad. A lot of this is new to me. I usually spend about 2-3 hours each night just looking stuff up and learning things here and there. One reading why I love this forum. I actually read every single thread that anyone posts any given day. Learn something new all the time :thumb: I’m assuming Jon is Fingers? If so, I know he’s a freaking genius just from reading his posts.

Not to derail but the 400 small block chevy was siamese cylinder...

 

[zakkb787]

Not to derail but the 400 small block chevy was siamese cylinder...

Never messed with a 400. Mostly only 350, 327, and 305. But I’ll be doing research on this. Sorry to derail guys. Carry on. Ready to learn more

 

[RPM Motorsports]

Lol, honestly if it works out I'd love a solid aluminum one for the rail car I have sitting in the barn...

That’s the easiest one to do out of all of them, we could do a solid billet block of 6061 . This 1/2 water jacket stuff is where it got tricky and requires a $10k mold.

Jon/Fingers, the larger bores were intended for the solid stuff, I hear ya

 

[D1rty-max]

Pretty sure the 6.7 Cummins is Siamesed in between cylinders and that’s why they have the head gasket problems from hot spots in the block. I guess you could see excess cylinder wear from slight warpage due to hotpotting? Doesn’t seem to be an issue with the Cummins guys though. Correct me if I’m wrong!

 

[2004LB7]

That’s the easiest one to do out of all of them, we could do a solid billet block of 6061 . This 1/2 water jacket stuff is where it got tricky and requires a $10k mold.

Jon/Fingers, the larger bores were intended for the solid stuff, I hear ya

Wouldn't 7075 be better for a n aluminum block? I know it is harder to machine but it has much better mechanical properties. If one was going all aluminum I would think that they would at least want to get all they can out of it

 

[Chevy1925]

any reason LS engine bolt holes couldnt be added? would make swapping into other vehicles easier i would think but never really looked into it.

 

[Dave c]

Cast aluminum wont live long at high performance cylinder psi. The LS guys block them apart at nearly half the pressure.

 

[Fingers]

Siamese bores are just bores that share the metal between the cylinders. That is, there is no water jacket where they meet. They are found in most modern engines these days.

It compacts the motor a great deal as well as reduces the weight.

The main limiting factors are:

There is only so much metal between the cylinders for a given bore spacing. That area can get too thin if you go too big. Causing a weak spot.

The area along the siamese is not cooled directly by the water jacket or the mass of the surrounding block in the case of a solid block. Being thinner, it also heats up faster. In extreme cases, the metal here will actually wrinkle because of the temperature differential.​

 

[zakkb787]

Siamese bores are just bores that share the metal between the cylinders. That is, there is no water jacket where they meet. They are found in most modern engines these days.

It compacts the motor a great deal as well as reduces the weight.

The main limiting factors are:

There is only so much metal between the cylinders for a given bore spacing. That area can get too thin if you go too big. Causing a weak spot.

The area along the siamese is not cooled directly by the water jacket or the mass of the surrounding block in the case of a solid block. Being thinner, it also heats up faster. In extreme cases, the metal here will actually wrinkle because of the temperature differential.​

Thank you for the explanation. That’s what I was thinking it’d be. Pretty common sense if you compare it to Siamese twins i.e. joined at the side

 

[MAXX IT OUT]

What about getting a crank designed that will actually hold up to 2000+ HP reliably and make this block based around it? If your going to buy this block, your probably will be using an aftermarket crank anyway. You probably will end up need different rods to fit this crank, but in the end you get a way stronger competition engine.

 

[IOWA LLY]

I was under the impression that the new narrowed rod journal was holding up great at elevated horsepower levels? Is that information incorrect?


Sent from my iPhone using Tapatalk Pro

 

[MAXX IT OUT]

I was under the impression that the new narrowed rod journal was holding up great at elevated horsepower levels? Is that information incorrect?


Sent from my iPhone using Tapatalk Pro

I can't say personally, I am coming in from the point of view that your spending 6000 dollars for maybe a 10-20% gain in block strength which might or might not help with a crankshaft life, narrow journals or not. Again I am referring to a 2000+ HP competition engine not a hot street engine making 1200HP.

 

[DAVe3283]

So why not go to a fractured block or bedplate? If you are designing a block from the ground up, wouldn't that gain a ton of strength and rigidity?

 

[RPM Motorsports]

So why not go to a fractured block or bedplate? If you are designing a block from the ground up, wouldn't that gain a ton of strength and rigidity?

Others have one off design blocks out already.., in the $10-15k + range. Thoughts on this are for the guys that want stronger than factory, still need a water jacket for street use, or have to have a “factory appearing” block, without breaking the bank. We are not “designing from the ground up”, we are modifying an existing platform. I’ve thought about a one piece main cap/girdle setup, but would be later on down the road. Cost of machining that one piece alone is quite a bit, and 90% of the guys building don’t need to go that extreme. The bottom 1/2 of this block is solid, mains/pan rail/cylinder jackets/lifter area/front cover/ rear cover & valley all have added support.

 

[DAVe3283]

That makes sense. I didn't realize it would increase the cost that much.

Sent from my Cat S60 using Tapatalk

 

[RPM Motorsports]

any reason LS engine bolt holes couldnt be added? would make swapping into other vehicles easier i would think but never really looked into it.

Dmax swap mounts using Dmax & LS mounts are already available as a bolt on kits. There are a couple company’s making them, that utilize the Dmax four bolt pattern.

 

[dordtrecht5]

What's bore spacing? Just curious.

Sent from my Moto Z (2) using Tapatalk

 

[Byeezylb7]

why couldnt I have seen this before I built my motor hahaha

 

[ikeG]

What's bore spacing? Just curious.

Sent from my Moto Z (2) using Tapatalk

The distance between the centerlines of each cylinder bore. If it wasnt stock, you would also have to manufacture your own crankshaft, heads and rocker shafts etc for it to work. Stock bore spacing is required in all pulling classes.
If you look at big, big cubic inch gasoline stuff, like Sonny's, they change the bore spacing so the bore size can be humungous and still have material between the cylinders.