Rebuild time

[darinz]

So I'm rebuilding my engine. Since I'm getting the crank ground, what are peoples thoughts on getting an offset grind with new rods and pistons to increase the capacity a bit? Take into account it will still be turboed so I really should be fitting forged pistons anyway and one rod at least needs replacing.

Are there any common rods and pistons that can be used for this? If so then those being cheaper will basically pay for all the other extra work!

Thoughts, ideas?

[PanzerAce]

I'd say go for the offset grind. It's a fairly common modification in L series Datsun engines, and I've never heard of it leading to any problems if it is done by a competent shop.

If you're rebuilding anyway, why not swap all the rods? Forged H beam rods will also let you get a larger clearance b/w the big end and the crank (which the thread on spinning bearings seems to indicate is a good solution if you run heavier oil as well).

[95si4]

what do you estimate the increase in stroke would be?

[PanzerAce]

what do you estimate the increase in stroke would be?

How wide is the crank case?

Seriously though, if a shop knows what it's doing with welding and grinding, the only real limit is harmonics and the physical space that the crank has. I know on L series straight sixes, that a 85mm weld/grind isn't *uncommon* as these things go (which is 6mm more stroke than stock), and I know of atleast one person in the US recently (in the past few years) built a 89mm crank (10mm over stock [stock is 79mm]). I know that in Japan in the 70s they could get up to 3.5 liters out of these engines (which at max overbore equates to almost 92mm in stroke).

So it comes down to how much you want to spend, and how much room you have to work with. I guess in theory if you went with smaller diameter rod journals you could push it even more....

[Mettler]

Do it! It'll be cool!

[SuperHatch]

IIRC, SBC rods are slightly longer and have a slightly smaller big end than the stock VH rods. Seem like perfect candidates for an offset grind solution to me.

[PanzerAce]

What's the pin height of a standard VH piston? That's the only problem that you start running into with long rod + long stroke combos. The pin height is the ONLY thing you can cut into at that point.

[Aus450zx]

so did anything come of this? Anyone done an offset grind on the VH?

[darinz]

Not me the crank was screwed so starting from scratch.