Mystery grinding noise after rebuild 4g54

[jlee2336]

G'day all,

Car deets: 1985 SWB 4G54 originally 2.6L but now with increased bore sizes by 1mm, extractors, original carby, and few other mods.

I need a little help trying to identify a mystery sound emanating from the engine.

I've had a lot of fun rebuilding the 4G54 a couple of times. Brilliant learning curve. 1st time was by myself using basic hand tools (there was nothing wrong with it, I just wanted to learn how it all works). Then I drove around in it towing a trailer when the fan belt snapped and engine overheated which resulted in cylinder warp and engine blow by where exhaust or burnt oil had saturated back into air filter. 2nd rebuild was by the pros at an engine shop in Perth.

So engine is back in, managed to get it running and idling by itself finally, however there is an extremely loud grinding sound. I don't want to run the engine too long to try and find out where and what it could be for fear of extreme wear and tear on whatever it is. It is loud and scary.

One event that may have contributed is accidentally leaving a spanner on the crank shaft pulley bolt while starting the engine (I know, I'm an idiot, and became complacent and not checking everything when I was trying to get it running). Other end of the spanner caught the front sway bar shock absorber looking thing and the crank pulley bolt unwound itself and fell off. I re-attached it however ever since then, when turning the crank over by hand, there are 2 spots approx 180degs apart where I could use my pinky finger to pull the spanner over to turn the crankshaft. Absolutely no resistance. A soft "click click click" can be heard at this spot. Previously there was at least some resistance 360degrees over. At this soft spot, going counter clockwise (just a little bit to test the resistance) is ridiculously easy as well.

Ive checked: timing chain, crank pulley key, looked down the timing chain housing from the top with a torch and the timing chain sprocket looks intact with all teeth present, its very different to an engine knocking sound so I doubt it'll be the crank bearings, theres compression in all cylinders (only tested using thumb over spark plug hole and crank over by hand). Imagine a normal wheel bearing thats been worn out and that is how it sounds. Increases volume with engine revs. Its not a stuck starter motor (stuck starter motor sounds a lot more high pitched and even). This one is definitely grinding somewhere.

Can accidentally leaving the spanner on the crank pulley bolt cause something inside the engine block to break as the starter motor turned the crank shaft over? Could it somehow loosen the flywheel bolts or even crack the flywheel? I've youtubed flywheel cracked / loose bolt sounds and I'm not convinced it sounds like that. I am trying to not pull the engine for the 3rd time . Also, there are no accessories like water pump, alternator attached. No belts attached. I haven't re-installed the cooling parts yet either.

Any ideas would be appreciated thanks! Especially why I am able to turn the crankshaft so easily when I couldn't do so before accidentally taking the crank pulley off.

Cheers!

[Ryan175]

Could it be a stuffed bearing? like it's collapsed in certain spots?

[Ratbago]

That sounds like a headache and a half sorry to hear mate , do you have any warranty on the engine from the shop that rebuilt it ?

[disco stu]

Have you had timing cover off, or only looked from the top?

[pharb]

Have you had rocker cover off whilst turning notor over by hand?

Does the cam chain turn continuously whilst winding crank over?

[Tuba]

People remove that crank bolt by using a breaker bar and the chassis, then tap the key with the coil or similar disconnected so it wont start. I never have but its a wide spread practice. So no, I doubt it broke anything internal. If youve checked the keyway and made sure the woodruff is still installed (thats the sliver of metal in the keyway), then I would be looking elsewhere.



Im assuming manual, how well is the engine installed to the spigot bearing etc. ie Have you got a stuffed spigot bearing? Do you have the clutch assembled the right way?


Check ancillaries, a/c, water pump, idler pulleys, alternator. Even a new water pump could have a dud bearing.

[jlee2336]

People remove that crank bolt by using a breaker bar and the chassis, then tap the key with the coil or similar disconnected so it wont start. I never have but its a wide spread practice. So no, I doubt it broke anything internal. If youve checked the keyway and made sure the woodruff is still installed (thats the sliver of metal in the keyway), then I would be looking elsewhere.



Im assuming manual, how well is the engine installed to the spigot bearing etc. ie Have you got a stuffed spigot bearing? Do you have the clutch assembled the right way?


Check ancillaries, a/c, water pump, idler pulleys, alternator. Even a new water pump could have a dud bearing.

THANK YOU THANK YOU THANK YOU!!!!! I had a youtube of worn spigot bearing sounds. It is very similar!!! I've located the noise to be coming from the flywheel area. Checked the clearances for the starter motor and flywheel teeth and they all checked out fine. Upon reassembly of the clutch (myself), I did not use a clutch alignment tool and did the old electrical tape on the end of a steel pole to centre the clutch and I now remember at the time of aligning it all up, if I was doing damage to that tiny bearing which I now know as the spigot bearing. I did put a lot of pressure pushing the home made alignment tool to the spigot bearing.

So Future DIY engine rebuilder / clutch replacements / etc, dont skimp out on a $7 clutch alignment tool! Thank you Tuba!

[Tuba]

THANK YOU THANK YOU THANK YOU!!!!! I had a youtube of worn spigot bearing sounds. It is very similar!!! I've located the noise to be coming from the flywheel area. Checked the clearances for the starter motor and flywheel teeth and they all checked out fine. Upon reassembly of the clutch (myself), I did not use a clutch alignment tool and did the old electrical tape on the end of a steel pole to centre the clutch and I now remember at the time of aligning it all up, if I was doing damage to that tiny bearing which I now know as the spigot bearing. I did put a lot of pressure pushing the home made alignment tool to the spigot bearing.

So Future DIY engine rebuilder / clutch replacements / etc, dont skimp out on a $7 clutch alignment tool! Thank you Tuba!

Youre welcome... make sure you tension that bolt in the crank, and use a dab of blue loctite on the thread. Less is more with loctite, just a dot is more than enough, and dont use the red loctite, that stuff is near permanent. They had a habit of coming loose and tearing up the crank. If you dont have a tension wrench, take it to the mech and ask them to tension and loctite it.