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4K Crank In 3K Block?

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hi I'm rebuilding a 3k for my ke20 its the original engine but... ive been reading the faq/wiki and think it would be better if it had the stroke of a 4k crank and as i can get one for nothing i think it would be a cool sleeper obveously other mods would aply, so pretty much a 3k block with 4k gear and specs

 

is this posible,

 

cheers

 

christian.

Yes it is. No it's not easy.

 

The 4K crank will fit and spin in a 3K, but the problem lies when you put rods on it. They hit the sides of the bores. You need to get the sides machined/ scalloped out for it to fit. You then need to find suitable pistons as the stroke of the crank will have increased, but not the stroke of the block, IYKWIM. I used Charade pistons with a custom pin arrangement. We had to buy six all up because they sell them in sets of three. We ended up with about 1360cc.

 

Slight panel beating on the sump is also in order for clearance as well.

 

The ONLY reason why I did this was for competition purposes. I don't recommend it for any other reason.

Important to heed reddwarf's last line; if you're building a "sleeper" then this is a lot of money spent for little gain. It would be much cheaper to fit a 5K engine into the car, it's a direct swap and 1500cc.

  • Author

hmmm food for thought i would like it to stay the same block i think if i was to spend the cash on a other engine it would have to be 3tg/18rg BUT FRIGED IF I CAN FIND ONE FOR CHEAP :bash:

Mine was a $3000 motor 8 years ago and it was a sponsered deal. It did have other things done to it, but I also know 7 different types of pistons went in before we found some that we were happy with.

 

This is not a simple job.

 

Put a 4/5K in. same result, MUCH cheaper.

hmmm food for thought i would like it to stay the same block i think if i was to spend the cash on a other engine it would have to be 3tg/18rg BUT FRIGED IF I CAN FIND ONE FOR CHEAP :bash:

 

if cheap is what you want, no offense, throw the idea out the door. thought of a 7k?

Have a search, its been covered - including photos of what hits where and what sticks out too far.

5K, cam regrind and extractors...shouldn't cost more than $500 and will be plenty of fun in a KE20.

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