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Rebuilding A 4K Some Stupid Questions


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Hey Guys,


I'm just starting to tear apart a 4k of unknown miles that I'm planning on dropping into my ke10. As i want to basically do as much myself as possible on the car but have limited knowledge i was hoping someone could help out with the below questions.


So what i have planned is


Bigger Cam


twin su's 1 1/2 on lynx manifold

New gaskets all round


Now where i am unsure is should i start messing around with new pistons and rings / Cam chain upgrade to the twin chain version / porting head and spring upgrade?


See when i start getting into that level of tear down I'm outside my comfort zone, the cost isnt an issue but i would either have to 1) send to a mechanic to do or 2) find someone willing to come round and supervise


I would prefer to find a mechanic who would be willing to come and make sure i put everything back in the right places etc but let me do the work I'm just not sure if i need to.


Also i need to find 4k engine mounts and have seen the below but not sure if they are correct as don't have any pics of 4k mounts so if anyone has an engine out and can snap a pic it would be great.





Thanks in advance

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Hi Paul,

As the mileage on your 4K is unknown, the first thing you should do before spending any money at all, is ascertain it's condition. If the engine is in a running car, then a compression test & oil pressure test will tell you a lot initially. If it's out of a car, as I suspect, then it's off with the head & sump, and check bores for "top of bore lip", scoring, or general condition of bores, and sideways movement of piston in the bore. If they look good to you, then take it to an engine rebuilder & have them measure it accurately. Then you need to check the big end journals on the crankshaft. The journal diameter & ovality will soon show whether crankshaft needs a regrind. Engine rebuilder will require to measure top & bottom of bore to work out whether it has previously been rebored, and what the wear is.


Don't waste a any money, before you have this important checks made.


Cheers Banjo.

Edited by Banjo
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Do it all yourself- 4Ks are cheap enough if you fk it up and you need to learn for the future


Banjo is dead right, get it all measured first, then you now what needs to be done.


If you're lucky it needs a hone then new rings and bearings on the bottom end. If you're not lucky it might need a bore and a crank grind. Bore it to take 5K pistons in that case, and get the flywheel lightened & the whole rotating mass balanced.


The head will need the valves & seats machined, some porting to match the Lynx manifold and a skim for extra compression.


The cam gets ground at any of the 5 or 6 major cam grinders in Aussie. Don't go silly, 280deg will do a daily.


The cam chain can be tested for droop to see if it needs replacing.


Then you put it all together.


See this-



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If you have the motor out all you need to do to change rings is take off the sump and unbolt the conrods from crank . Take the head off (you prolly wanna take it to head recon place ). Then just use wooden hammer handle to tap em out. Measure the bore size and order rings to suit. If pistons look ok just reuse em . Clean them up with brush and some solvent . Good test is to put the rings into ring grooves from side. And wiggle the ring up and down if it moves too much you need new pistons if the grooves are still tight piston is prolly ok. The motor sits in a cradle type thing that runs across between the two beams. It's easy to remove just remove the nuts on each side. Then take off the gearbox cross member and gear shifter

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We knock up a cheapo rebuilds for cam testing.

  • First thing to do is find a block where there is no lip between the top ring and the face of the block, my theory here if it has a lip then needs a rebore, Yeh I know you can ridge remove but I seem to get leaky bores when I do this.
  • Number rods and caps when removing from block. re-install in same order
  • Measure bores and crank.
  • Run a dunny brush hone down each bore, never use 3 prong hones as they change the bore shape, hone cost is about 80 bucks.
  • Wash block really good heaps of soapy water and then dry really good with air compressor, then oil bores really good and keep all dirt out.
  • Buy on ebay pistions ($60) rings ($60) bearings ($80) gaskit kit ($80) timing chain kit($80) prices are just guesses of what they normally sell for.
  • If the block is not chemically cleaned I will reuse cam bearings.
  • Cam regrind will cost about $120 and lifter reface about $40.
  • Flywheel lightened about $80.
  • When assambling be sure to time the cam in makes big difference.
  • Make sure head bolts and threads, main brearings and threads, and big end bearings and threads are clean and oiled prior to torquing down.
  • Get yourself a 3k yellow book from ebay.


Hope this helps, if you are melb based PM me I'm rebuilding a 3k in the next few weeks you can come around and see how its done.

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Get a rebuild book on the motor, known as the k series yellow book.

If its a standard rebuild then you should be ok but if it modified its another story,

its all about getting a balanced package in the end and finding / modifying parts

to suit which is half the fun and half the pain :P Check the how to build a tough k

motor guide on here for some good info.

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