3K Or 4K Bore Pitch/ Spacing

[Micksute]

Anyone know the bore spacing or bore pitch of a 3k or 4k engine - prefer 3k. I don't have anything to check against. From my rough estimates it looks 81mm.

Anyone have a gasket laying around?

I'd even be happy to know the outside to outside measurement for all 4 bores.

 

I am at the early stages of a crazy idea someone would have already had, but I intend to pursue it and reveal if it works out. Currently things look good :)

[philbey]

I know where this is going....

 

No can't tell you what it is sorry.

[Micksute]

Yes, motorcycle head. I have found something I am pretty sure lines up in all of the critical areas...but that is from reviewing all of the forums in the world and images. Before I make the next step (getting real pieces) I want to be reasonably confident of the solution.

[ae824ate]

But why?

[coln72]

Why not......

 

If it works good on him for thinking outside of the box.

[Micksute]

Why?

Well my last project involved engineering IRS into a Datsun ute. New front suspension and many body mods. I'd love something relatively simple to work and believe me, compared to my other ideas this is as simple as it gets.

Edited April 26, 2011 by Micksute

[snot35]

What's wrong with you people? :) If this guy works out a good easy way of 16v-ing a K block, we all benefit! :)

[philbey]

I say go for it. If you can get the right bore spacing that's a start. But it's only a start, still a long way to go from there!

 

Having worked with a bloke who designed and cast his own engine head, I reckon that it would be easier to go down that route.

 

Look up the OS Giken twincam head for a datsun L series, that's an interesting story.

[Micksute]

I considered making the head, but it is far easier to make a block to fit a motorcycle cylinder and head. I haven't ruled out that idea, but it is lots of $$ and probably a long term thing that I would slot into a lotus 7 replica or something like that.

 

Philbey I have read the OS Giken twincam L series before. There was a guy who had one in Sydney a few years ago too and he was rebuilding it...LZ 20 I believe they are called (couldn't bother googling).

 

And if I crack it I will share. I have helped a few people over the years with stuff I tried that worked...nobody ever sees all of the failures though :)

[snot35]

As long as someone else is doing the failures for you it's fine! ;)

 

The LZ20B is Nissan factory twin cam, the OS Giken head is different.

 

I'm interested in this bloke that cast his own head though, was it for an automotive IC engine? I dream of building replica LZ and 151E, 152E heads. But I'm just warped.

[kickn5k]

Do you still need these measurements? If so how accurate do you need it? I have a 4k that I could chuck in the Bridgeport and plot out with a digital read out if needed.

Otherwise can vernier it up tonight.

I believe that the center to center would be the same for 3,4 and 5k engines.

Good to see people going for something different.

Oh and if you haven't got the skills to make a pattern and core setup for a new head to be cast up expect a bill to make that of around 2k plus then getting it cast. We pay $600 to get a pattern setup for cast pistons.

 

Stu.

[kickn5k]

Sorry double iPhone post.

Edited April 28, 2011 by kickn5k

[TE278U]

there is a mad dude that has designed his own block and crank to sit under two superbike twin cam heads, you've probably seen it, makes a v8 with 2.4 or 2.6l capacity with a rev range of something spastic like 12000 rpm. I'll have to google it again to be sure. well worth the effort.

[Micksute]

I'd love the measurements. Vernier calipers will be fine.

 

After thinking about it, the idea of making the head seems equally viable. Catch 22 - make the head and you have lots of machining and intricate shapes; or make the block and you need a crankshaft, and it is the crankshaft that kind of scares me if I am aiming for serious revs...might need to work out which ones is cheaper and try that first.

[TE278U]

if the bores line up with the head... then the crankshaft should line up with the bores, but then you could use the block from the donor head, and you end up with the motor you started with...

 

i'm assuming you want a torque gain at the sacrifice of losing a few revs?