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3K Or 4K Bore Pitch/ Spacing

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This is a stupid tangent but can you buy that sand mould stuff that manufacturers use to make parts from, cause if you could design the head and get the right parts cnc'd you could go down that road.....crazy stupid and expensive i know.....just a thought

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  • was it this guy?             ohhhh, the engine had a strange head..... :blush:

  • camerondownunder88
    camerondownunder88

    NICE that 4k + 4age is AWESOME.   My guess is he still uses the 4K crank. 4age rods on a K motor crank have a few mm side play think 6mm total so I take it bore move was minor and the play in the ro

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No. You got it wrong. In the first instance I just want to match the head of a different engine to the 3K. As a side project I am looking to make something more intricate like a whole block or head...but that is a bit more long term.

Sand casting is definitely the easiest option, if you have access to a cnc, you machine up the pattern. Or, even better, with the cost of 3d printing coming right down you could have a pattern printed. Even wax printed and investment cast wouldn't be out of the question.

 

Considering fitting a head to a different block requires relocating head bolts, water jacket ports, cam guides, oil feeds etc, and that's before you look at combustion chamber suitability, I still maintain the cast head is the easier option.

  • Author

Hi Philbey

 

Water and Oil line up, just need a slight reshape. Cam and combustion (imagine you mean cc head and clearancing pistons rather than shape and squish)...always expected to have to do that. Also need to update oil pump to cope with likely more revs.

Which raises another question, anyone know how realiable the std crank is? What kind of revs can it handle?

Theoretically the bottom end is a little behind when it comes to a high revving reliable design. It only has a partially counter balanced crank and the block is not of a deep skirt design which means that ideally you would want some extra support for the bearing caps.

 

If you look at modern high revving reliable engines you'll find they have either a complete bearing cradle attached to the caps, or a cast sump that forms the bearing caps to completely secure the bottom end.

 

Other than that the K motors have pretty reasonable rods and bolts which is a definite plus. People seem to get away with big revs out of them, but they aren't really designed for it and longevity may be an issue.

the guys that raced the ke10's from the factory stated a 8500 redline iirc stock bottom end.

Yeah a stock 5k bottom end survived 8000rpm for a number of years, so I guess that would be so.

Bore spacing center to cente on both my 4 and 5k is 90mm Close as I could get with "very near calipers".

 

 

Stu.

There was a Bloke in Shepparton that rallyed a 3k with some strange head.

There was a Bloke in Shepparton that rallyed a 3k with some strange head.

 

was it this guy?

 

worf.jpg

 

 

 

 

 

ohhhh, the engine had a strange head..... :blush:

  • Author

ROFLMAO. Love it.

 

On a more serious note. Does anyone know where, or have available some CAD drawings of an existing twincam head? I have sourced some software to make relevant templates and have them made up, but I don't have a base design. Any help/direction appreciated.

On a more serious note. Does anyone know where, or have available some CAD drawings of an existing twincam head? I have sourced some software to make relevant templates and have them made up, but I don't have a base design. Any help/direction appreciated.

waggott made a twin cam head for a Holden six(from memory was a red motor) and also the KAD unit for early a series mini. You may be able to dig up some tech drawings on the net or try the mini or early Holden forums. My mates KAD head is off getting fixed but I'd be able to get a few pics for you when it's done.

I know they would probably be a bit iffy on passing on too much info but bullet cylinders heads make billet twin cam heads. They might be worth getting in contact with.

 

Stu.

waggot also made a four cylinder engine with a twin cam head too.

 

I can scratch up some old details in print, but can't find too much online...

 

img06179pj.jpg

 

found this too... wtf

 

twin4cyl.jpg

 

turns out from Lancia triflux 16v

Edited by TE278U

Holy crap! How the hell does that work?

 

Also, if someone does have more info about the Waggott heads I'd be really curious :)

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