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hi guys my dad has just bought a 180sx. it has a bottom end knock and we are going to rebuild it, nothing crazy just a reliable motor. I was wondering what we should do, should we buy a new aftermarket bottom end or just replace it with a second hand crank rods and pistons and how much a new bottom end would cost and good brands to get them from thanks.

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Yeah it's a sr20det I got a price from KYP for another sr20 they want 1600 for a running one so with that is it still cheaper to buy another one or just rebuilt the bottom end of this one I have found some rebuild kits for around 700 to 1000 so I'm leaning to the rebuild idea

Pull the engine out, mount to a stand and strip the bottom end to assess damage. You might find that it doesn't need a new crank or even pistons, depending on the amount of wear / damage. I've re-bearinged engines with a bottom end knock, and as long as you get to it before the bearing's spun or worn through, the crank might not even have a mark on it.

You have to pull the engine anyway, so why not strip it and assess its condition before making a decision? Best case will be a full gasket set, rings and bearings, (plus the associated cleaning, cylinder hone etc) and timing chain / guides / tensioner etc.

Worth a shot, and a good learning experience.

...Worth a shot, and a good learning experience.

Agree. Rebuild and learn something :) I rebuilt a hemi 6 in two days with no prior engine building experience.. just made sure that I had all the parts ready to go and dis a lot of reading.. a lot of reading. Also YouTube is also a very good friend. Youll also find you'll enjoy the satisfaction of saying you did it all yourself :D it cost the same as buying a crate engine but hey, what life experience worth?

  • 4 weeks later...

You'll find that the conrod bearings may be shagged. So a crank machining may be in order. If you dont want to go full house build just hone the bores and re ring the pistons as well as new bottom end bearings. Get yourself a new gasket set with a metal head gasket.

Throw rocker arm stoppers because... well why not seeing as its already apart.

That shouldn't fail your little brother for the time he owns it. Unless he drives it like its stolen. Then you may run into a future problem.

Look for the same things as you would have on the reds.. all engines work on the same principle. i would make a note of replacing everything perishable with new stuff. Crank machining isnt always necessary but its easier to do now while its all apart than later on.. and who likes doing things twice? Do it right, do it once :D

Edited by c34Florry

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