I think its spun a big end

Working on the 240 shifter adjustment for the reverse lights yesterday which I sorted by slotting the tab to slide the switch back slightly. Started the car to reverse back into the garage and a considerable amount of blue smoke came out the back. Not unreasonable for an old turbo etc after sitting for a few days I thought. Gave it a little rev and it cleared.

Went to start it this morning and its got an almighty knock which sounds like a big end. Nothing yesterday as all. Full knock this morning.

Can the oil pumps pack up?

Do they sometimes drain out and struggle to prime them selves?

Am I in denial and it actually needs a rebuild?

Its the quietest b230 Ive heard and has done under 200k. It was low on oil while I was a away a year or so ago and the better half missed it before it was lets say “really fing low!’

Im assuming the was damage done a while ago and now that its got the turbo on it its given up under the new ‘reauirements’.

Anyone got a spare b230ft fk sitting about??

I will remove this one and fix it up but need the car on the road asap for the wife and her business.

Fun times. Slightly stressed out




  • You say it chugged a whole bunch of smoke and now its knocking? How sure are you that it hasnt ingested a whole bunch of oil from the valvetrain or the turbo through the intake? It may be possible that there is a whole lot of oil and fuel in a cylinder and its knocking on detonation from that.

    Before panicking I would pull all the plugs, crank it to make sure there is nothing in the cylinders then pull the intake and make sure its not filled with oil. If all that checks out then start it up and let it clear its throat to see if the knock returns. These motors are pretty stout and I havent seen one throw a big end from adding a turbo but more from low, no oil and constant abuse. Throwing a big end with good oil quality and level would indicate the clearances have increased which would come back to bad oil/low oil or no oil causing the clearances to increase.

    Dont panic yet. It might be another sound you are hearing.

  • Great advice. I will definitely check that out.

    It did run very very low on oil for a few days . Barely registered on the dipstick with I eventually check it. That was a year or so and 8-12k ago.

    Will know more this arvo when home.


  • Dont feel bad about it. I seized the very first motor I ever built with @VolvoHordz and @Philia_Bear. It was about 11pm at night and I had work the next day at 7am. Fired up the motor, ran fine and started getting hard to idle. Gave it more throttle and it began bogging until it locked up. One set of bearing in the rebuild kit were slightly oversized and naive and inexperienced us didnt even notice and just installed it. Rummaged through the bin for the old bearings and fitted it to the seized rod. Went great for the next 5 years after that until I retired the whole setup.

    These motors arent complicated. It will be fine.

  • Yea Im sure it will be ok.

    Happy to pull it out and have a look at the bearings etc. if it needs a set and a regrind of the crank or similar its worth it. Top end is quiet as u like.


  • Have u confirmed there is not a rat attached to the radiator fan?

  • Yes. Its got an Efan so tules that out.

    It definitely sounds like a knock. Dare I say piston hitting the head almost. Its loud, crisp and wooden in sound.

    Back home this arvo to suss out the plugs and oil etc.


  • SpacSpac (@Spac) Canberra-ish.

    A crook big end will may be quiet or may be noisy at idle, but will definitely get much noisier when the revs come up.

    For example, if you have one that is just a ticking sound at idle, by 3,000rpm it will usually sound (and feel) like Armageddon.

  • Sounds like a bomb at idle as soon at it starts. Having a look at it soon pending light!

  • edited February 18

    Turn it over by hand without the plugs in, checking for something to hit.

    When you're about 1/2 way between TDC (i.e. crank is horizontal) try rocking the crank clockwise a bit and then anticlockwise to see whether you can feel any clunk.

    If you have access to a borescope, check each bore when the piston is down.

    A big end will typically be a low thud noise. Can you record the noise for us?

  • How sure are you that it hasn't blown a plug out of the head? That sounds like a bunga going off every second.

  • Ok

    Plugs out and turned it over. No noises and no oil or water in any cylinders.

    Plugs in and not connected and turn over with no noises.

    Hook up the leads and its knocking straight away.

    Sounds more top end. And the culprit cylinder is not firing. Touch the throttle and it gets loud quickly.

    I have time this week to look at it. Ive got most of the tools and hoist to get it out.

    I just cant fathom that it was fine when i turned it off and knocked straight away this morning.

    Do they ‘drop’ valves so to speak?

    While its apart I may as well treat it to a refresh for the next 10 years. Any pointers for lightly cleaning up the head/ports or are they ‘good enough’ as they are?

    I would say there will be a bigger turbo at some point so may as well build a smooth motor.

    Once its apart, who is the go to for bearing shells and rings etc?

    Cheers Cam

  • Sorry, replied late to the earlier posts.

    It really sounds like rod knock/piston hitting the head etc

  • Since it is turning freely by hand it could have parted a piston too, horizontally.

  • Lets see.

    head off first in situ to have a look?

    Or just whip it out all together?

  • Start with the basics

    Do a valve clearance test

    Compression test

    Bottom end noise = every revolution of the crank

    Top end noise = Half every revolution of the crank (cam turns at half crank speed)

  • Pulling the head off makes pulling the block out easier so you might as well just pull Mr head

    That said a $20 eBay borescope would answer all questions of you can wait 3 days for it to show up

  • SpacSpac (@Spac) Canberra-ish.

    Did you look at the plugs when they were out?

    I know of a 531 head that dropped a valve seat out when the motor cooled down. Was running perfectly until it was restarted - it missed badly (because the inlet valve was being held open) with no particular noises.

    Buuuut... this was a non-original valve seat in a modified motor. Never heard of it happening with a stock valve seat.

  • Good advice here.

    Ill check clearances and comp test in the morning.

    Ill also get up an audio clip. It sounds like crank stroke noise as its slow at idle.

    Im sure I can search this but..

    Best way to lock the timing of the head and loosen timing belt?

    Any thing to ‘look out for’ when taking off the head?

    Not a pro and certainly dont pretend to be. Ive opened only a few engines myself to will make sure to be as methodical as possible.

    Thanks again for all the responses.


  • What do you mean lock the timing? The belt is simple to remove. Loosen the tensioner with a 17mm socket then with one hand on the ratchet and the other on the belt push on the belt to fold back the tensioner, tighten it back up and the belt will slip off the cam nice and easy.

  • I used to mark and lock the timing of the cam sprockets on the 16v pug heads prior to lifting the head so when it goes back on you cam time it up easier I geass. They have dowel hols for this.

    Thanks for the info, sound fairly straight forward.


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