new guy-what are the popular engines?

Do you feel that some form of cross bolting would be beneficial versus what MBR is doing now? I ask only because I'm thinking of having some MBR-like blocks built and have been asking myself the same question as you have posed. The nice thing about building custom blocks is that the design board is wide open until the big billet chunk is loaded into the CNC mill. Thoughts from all would be appreciated.......

 

The cast panrail is there...might as well cross bolt it for more strength. If it's strong enough without the crossbolt make a sheet metal panrail, lose weight and you have a BBC bottom end.
I run a KB olds with crossbolts and the caps seem a lot happier than when we ran splayed caps with no crossbolting.

 

The worst thing about a MBR engine is the thing shares the cam height of a Chevy. You have to cam cut the rods if running strokes 4.375 or more(without running a small base circle cam.

TOL give me a call, I'd like to talk about the block.

Dale
970-302-1232

 

Super side rails

the new cn blocks also have billet side rails, and very sturdy ones also. i have a 10.2 cn block that the crank broke into many pieces and broke every single main cap and pan stud clean off at the block and shoved the crank into the diaper with the pan. the rods only dented the side rails, and they could be straighted and reused by puting into a press and fixing the dents. the old mag ones it would punch a window into, and you could put a patch over the hole on both sides, and it would be ok. the heights of the two are about .300 thousands different, so they are not interchangeable. but this test proves how strong that material is to break off and not pull any threads out the block or rails. pretty tough material i would say, but they are much heavier than the mag ones too.

 

Mbr

What would be the best trans (not talking brand) for this engine 2 speed or 3 as we have had good luck with a 2 speed with a chevy and 3 speed behind a hemi. Just thinking out loud.

 

What about doing something like the Donovan 416? They have replaceable side rails that are cross bolted to the main caps. Having something like that would probably make it a little easier to line bore also, should you need to.

 

Got a picture? Thanks.....

 

http://highspeedmotorsports.com/2010MM/Block-2-DE.jpg

I think there is a video on Donovans website about the new 417 also.

 

Theres no need to cross bolt the rails the splayed caps are strong enough. The weight of the rails are not that much of an issue plus they also act as part of the mounting surface of the front cover. They are made to be replaced and take the hit in a rod failure. Easier/cheaper to replace/repair one than your block and pan.

 

Got it, and found the video too. Very similar to an Arias 8.3 but with cross bolts thru the side plates. Interesting........ Thanks.

 

I assume when you say "small base circle cam" you mean stock BBC diameter?

What cam core size are most of the MBR blocks?

If you ran 4.250 stroke could you run a 60MM cam without cam cutting the rods?

 

Main Caps

What size are the main studs, 1/2"?

How much steel is in the main cap directly beneath the main journal at the thinnest? I assume it would be about 1.250"

 

You do realize you are responding to a thread that is 2.5 years old?

 

It's not the size of the journals that matters, but the size of cam lobe-core size.I think a 4.25 stroke would clear.The MBR 525 funny car motors have a 4.50 bore and a 4.125 stroke, the short stroke, to have enough cam clearance, and the big bore to allow the use of 2.60 intake valves. Keep in mind that the size of the cam (lift and duration) has effect on it too, and the motor I had was the 4-7 swap design and had only to trim one bank of the rods. It had 55 mm journals.

-Dale

 

Right now our cams lift can't be more because they would be larger then the journal. The only way to get more lift is to make the base circle (cam lobe core size) smaller.

So the way I see it, to get our cam more stiff (aka larger cam lobe core size) I need the journal sizes to be larger.

Or am I not thinking of this correctly?

 

You are correct.

-Dale