Question about Little M main cap material.

[Bwh998]

At what point does someone need to choose the steel mains over the ductile iron? Can the ductile iron mains handle roughly 1000hp reliably?

[modok]

steel is maybe 15% stiffer than iron, which is not a big deal, but if you are aiming for the moon it's that much closer.

[Momus]

'Billet Steel' is a buzz word.

Grown ups talk about the grade of the steel material so the components properties can be evaluated.

[Bwh998]

Man thanks for all the replies folks. Lots of good info to digest here but looks like you've all answered my question.

Thanks again.

[BCjohnny]

Grown ups talk about the grade of the steel material so the components properties can be evaluated.

Agreed ...... and they also talk about the grade of 'cast iron' used for similar evaluation purposes

Even with 'ductile iron' there are so many grades the tensile and yield strengths can vary by as much a 100%

With the strongest 'cast iron' grade available, ADI, I couldn't see anyone having problems directly related to the material itself, but the fact of the matter is that 'billet steel' might often be cheaper to produce

On a purely theoretical level I've always wondered if steel caps, due to their relative lack of internal resonant dampening, didn't introduce other problems themselves, particularly under detonation conditions

[Bwh998]

Problem is that manufacturers rarely go into any detail about which grade of metal is used, its almost always some vague terms like billet steel, cast iron or my favorite, "military grade aluminum".

[1972ho]

I’ll bet most the companies that make these products don’t really have a clue about what the limits are on there stuff because they have never tested the limits on any of it because if they had it would be plastered all over there sight and other internet sights bragging about.I remember when nascar tried steel main caps they abandoned it but never really gave a reason why.As the end user you just have to take chance and hope for the best.

[Krooser]

Will a Rockwell hardness test tell me much about the composition of the iron main caps on my SBM project?

Aftermarket four bolt caps are available but many in the Mopar world dont think they are needed at my target 650hp power level. Most argue good 1/2" main studs are all that are needed.

If I am going to consider this one last block mod now is the time to do it.

[mag2555]

1000 hp out of how many cylinders are we talking and what stroke,main journal size and rpm?

It's the G force loads that matter more then the hp since they go up with the square of the rpm seen.

[af2]

Good read.

viewtopic.php?t=1853

Another.

https://www.makeitfrom.com/material-pro ... r-Mo-Steel


Lots of variations to all metals.