Forged internals

[austindavis1993]

I was just wondering if there are any companies that produce forged internals for a 3.0 SHO motor, this may be a dumb question but just curious.

 

[TwistedD85]

I believe the only thing that isn't forged from the factory are the pistons, they're hypereutectic. At least that's what I recall.

 

[jayro]

I believe the only thing that isn't forged from the factory are the pistons, they're hypereutectic. At least that's what I recall.

You are correct. The crank and rods are already forged and the crank is also surface hardened. You can get forged pistons with a selection of compression ratios at www.shonutperformance.com .

 

[gmail]

the bottom end will hold a lot of power but the pistons will not. the only weak link you need to worry over is the pistons.
so far no one has blown a SHO from too much power... however do not cut the crank for the oversized bearings.. some have and it removes the harden layer of the crank making it much weaker... if i recall there has been a few 2 piece cranks due to getting them cut

 

[RJ-92]

As is stated the internals are plenty stout. I'll let you in on a secret. The pistons are a lot tougher than they get credit for. Most piston failures even under boost have two main causes. 1. A shytty tune or 2. Thermal expansion of the top.compression ring that binds up and cracks off the top of the ringland. I'd be willing to bet if someone loosened up tje rings a lil on the stock pistons you could safely fun <1.0 bar on stock pistons on a safe tune with little to no issues.

 

[somedude_001]

As is stated the internals are plenty stout. I'll let you in on a secret. The pistons are a lot tougher than they get credit for. Most piston failures even under boost have two main causes. 1. A shytty tune or 2. Thermal expansion of the top.compression ring that binds up and cracks off the top of the ringland. I'd be willing to bet if someone loosened up tje rings a lil on the stock pistons you could safely fun <1.0 bar on stock pistons on a safe tune with little to no issues.

+1 after doing a bunch of research I completely back this statement up. If you care to research the subject further you could look into LS1 tech or audizine and see what some of the tricks of the trade are to make stock internals last while making massive power.

 

[zach44102]

Wiseco, and JE pistons are able to make pistons for the SHO motor.

 

[bigblock]

so can anyone confirm with say a metal analysis that the crank and rods are indeed forged? or are they just hardened? you would think if the crank is forged, cutting it down wouldn't hurt it much. but if its hardened, cutting it down could remover that layer of hardened material. in that case, just have it hardened again.

 

[yamahaSHO]

What do the casting marks tell you?

 

[jayro]

so can anyone confirm with say a metal analysis that the crank and rods are indeed forged? or are they just hardened? you would think if the crank is forged, cutting it down wouldn't hurt it much. but if its hardened, cutting it down could remover that layer of hardened material. in that case, just have it hardened again.

I have not seen any metal analysis to confirm that it is forged, but over the past 23 years there have been some people that are VERY knowledgable who have stated this. There have also been numerous people who have made high power numbers thru FI/nitrous and have not had any failures. If the internals were not forged (minus pistons) there would have been numerous cases of the rod/crank issues.

Hopefully there is someone with the actual data that can step forward.

 

[bigblock]

yes and everyone thought the sho motor was designed for the gn34 for YEARS, and that was disproved just recently. i know the crank can take alot of power in standard size, but the consensus is if you cut it down it can fail due to loss of hardened material. that leads me to believe its just hardened. this is not just my idea, i discussed this with a reputable performance machinist. i said the sho crank was forged and if you cut it down it weakens them. he said that sounds like it hardened rather than forged.

this information would be nice to have as standard size main bearings are unobtainable now, especially for high hp builds. you would think someone would have found out over 23 years huh?

i dont know how to read casting marks Jason. i just went with what everyone else said these last few years lol.

 

[yamahaSHO]

Google will show you what to look for.

 

[bigblock]

ok so according to these 2 sites www.chevytalk.org/fusionbb/showtopic.php?tid/244886/
http://forums.vwvortex.com/showthread.php?1172772-ABA-swap-help a large separating line indicates a forged crank. So i went out and grabbed a crank and rod.



so it looks like the crank and rods are forged (yay!). so why is there a belief the cranks fail if you machine them down? if they are forged and then hardened why not harden the crank after its been cut?

another support for forged "A forging will ring like a bell when tapped on the counterweight with a steel hammer, while a casting will give a dull thud." sho crank has a nice ring.

 

[rubydist]

i know the crank can take alot of power in standard size, but the consensus is if you cut it down it can fail due to loss of hardened material. that leads me to believe its just hardened...

ANY crank, whether forged or cast will be case hardened at the bearing journals. The typical way this is done is nitriding (carbo-nitriding) which deposits additional carbon and nitrogen in the surface layer of the material to allow for a harder surface than what is possible in the base crankshaft material.

The case hardening will nearly always be a very thin layer, so that any cutting down of the bearing journal will usually cut through the hard layer. I have done the calculations on the SHO crank, and if you turn the crank to the first undersize bearing available, you have a 50-50 chance of having removed all the case hardening. If you turn the crank to the second undersize bearing, you have certainly removed all the case hardened layer.

I should also point out that if the case hardened layer is too thin, under high bearing loads the hard layer can be peeled off due to the forces involved.

My point is that whether the SHO crank is forged or cast, the bearing journals should be re-case hardened if they are turned.

 

[Shovert]

Thanks all good reading. I agree too much boost and too lean will take out pistons and cylinder walls. Done it to my 2.3 turbo. Maurice

 

[SHOtime2511]

The reason no one bothers turning the crank and running under sized bearings is that the motors are not worth the metal they are made from. People can't give away 3.0L engines,literally.
Why spend the money when you can get a good used crank for dirt cheap or free?

 

[somedude_001]

The reason no one bothers turning the crank and running under sized bearings is that the motors are not worth the metal they are made from. People can't give away 3.0L engines,literally.
Why spend the money when you can get a good used crank for dirt cheap or free?

this is true. I have seen so many thrown away because complete engines cannot be given away. it is insane.

 

[kevinspann]

I think I tried to sell a complete 3.0, a 3.2 short block, and new rod bearings for like $200. No one wants it.

 

[zach44102]

I once tried to trade a low mile running 3.0 for a set of tail lights. And well LOL

 

[SHOtime2511]

I had a full 60k'd 3.0 with accessories and new rod bearings,less than 100k miles.
I tried to get $100 for it and got turned down.
Ended up tearing it down and scrapping it.