refresh951

Thanks Chris! I just want to say that I have the ultimate respect for what you have accomplished with our cars and the way you conduct your business. Thanks for sharing here as I have learned a great deal from your posts.

blade7

If I didn't already have a good 2.7 engine, S2 crank and new standard length Carrillo rods I'd definitely go the hybrid stroker route.

blown 944

You know Chris, I'd actually like to see you build one of these. I realize that you like the factory crank hardness, But as you know it can be brought back quite a ways. I firmly believe that it has helped the oiling issue to a large degree (same volume spread over less area, plus better bearing material).

I know first hand that if I spun a std crank and bearings the way I have this combo that the bearings would have been toast.

Plus the smaller big end of the rods allows for plenty of clearance on the girdle.

You probably have a ton of extra parts to make it happen easily

p5th

Rotfl!!!!

Chris White

I followed your project and I have thought about building one at some point. The 'Hybrid' engine is a good idea for technically inclined builders doing their own work - but for a commercial shop you end up trading off cost savings on less expensive parts for more labor / shipping / machining. By the time I ship the crank out to have it machined and heat treated I will have spent the savings on the rest of the parts! Projects shape up differently when you have to look at labor costs - for example I am doing a special project for my car and I have 40 hours+ into a mod that is pretty cool (I'll post soon) - but as far as a commercial version - I doubt anybody would want to cough up $3-4K for a cool boost controller!

If the problem with the oiling system and head gaskets were resolved then the push for more displacement would make some sense - but right now there is a limit to how much power the stock architecture will support (remember that I think in terms of road racing - it needs to make its 'rated' power for 30 minutes at a time).

I also tend to over do things...what I really want is a custom crank that does not have 90 degree corners in the oiling galley! I have almost pulled the trigger on that several times - but its not cheap! If I were to do that I would go with smaller rod journals.

gruhsy

How many people would it take to drop the price on the crank?

refresh951

I know this may sound crazy but I am not convinced that the nitride treatment is necessary. Our cranks are extremely hard even after the offset grind. My crank guy says our cranks are the hardest cranks he ever cross drills. I talked to the biggest crank shop in the ATL and they also said they do not believe it is necessary although it may buy a bit more margin if the oil gets extremely hot (obvious track conditions). I am looking at cutting up my 2.85L crank and having one journal nitride treated and then doing some comparison hardness testing. Hopefully I can get to the bottom of this issue.

Without nitride treatment my 3L crank was offset ground for $275

Chris White

The last pricing I got was still well over $1k with a quantity of 20. Didn't feel like having $20k of invertor!

Chris White

Yes, the stock cranks are ridiculously hard - that why I like them and don't mess with them. Even with the harness you can often see damage due to hot & foamy oil. I agree with your crank shop that hardening is overkill....for a normal engine - but if you show a damaged stock crank to the crank shop they might change their mind. Our oiling system has serious issues for performance (especially road racing) applications.

If you are lucky enough to live near a shop that can do quality offset grinding then it costs $275. By the time I build a crate and pay for shipping both ways it would cost me another $200.

I am not trying to pick on the idea - its an interesting solution - but once you look at it from a commercial/production point of view a lot of the cost savings shrink.

V2Rocket

I'd rather buy your old crank and send you two factory ones with spun bearings for that testing

refresh951

Because of the grind we also can use modern NASCAR rod bearings

That said, I get your point about man hrs. I often trade man hrs for out of pocket cost. I see how that could be an issue for a professional engine builder.