Noisy 4AGE after fresh rebuild

[sirsprinter]

Hey everyone, fresh rebuilt smallport with new rings & bearings and everything blue printed and honed etc. The motor then unfortunately sat around for a couple years dry (no oil or coolant) before anything happened. It was turned by hand now and then, and eventually when progress was made - run in oil was filled and the motor turned over by hand quite a lot, and then on the key without ignition and eventually when the microtech install was completed - she fired up. Unfortunately we were faced with this noise which inconsistently got better or worse without pattern irrespective of RPM or anything - it just came and went.

Now.... Oil pressure sensors (like all of the microtech sensors on the motor) are showing adequate pressure and everything operational/flowing and seemed to be perfectly fine. However. The scary noise gremlin is hangin around...

Is theoried to be a sticky lifter which failed to get/got hydraulic pressure? Im no mechanic unfortunately but the engine builder & handy mate of mine is. The car goes in for exhaust weld up and a dyno run in and dyno tune in the next week or two - but if we can throw ideas around and possibly trial and error eliminate potential issues before the car goes in to their workshop it may save some dramas and stress for my mate.

I have attached a link of the running of the motor - unfortunately the upload i made to youtube is of lower quality than the original and the second half of the video theres a second noise that happened but is hard to listen to on this upload.

https://youtu.be/DialhmViUNs

Thanks in advance everyone

[dnegative]

Pull plug wires and see if it goes away with a cylinder;
The noise sounds bottom endy mainly due to the speed, top end noises are half speed

[trdee]

doesnt sound particularly nice that's for sure. also 4As dont run hydraulic lifters so you can rule that out of your theory

[dnegative]

Only other thing to check would be its not a manifold leak?

[sirsprinter]

Thanks for the heads up, we will try the plugs on the weekend and check for any mannifold leaks also as the car isnt stored where I live.

Just a question; would i be removing 1 plug at a time to reduce the compression force onto the piston and there fore ring &/or bearing? If so determining the nature of the noise to be top or bottom end if anything changes? Im trying to guess and get my head around the theory of it.

Also, when you say about the speed of the noise? Whats the mechanical principles behind that? Im trying to learn as i go, appologies for my noobyness. Thanks

[jondee86]

If you remove the plug lead from the plug (not the plug from the engine) there will be no combustion event in that cylinder, and no "explosive" application of load to the piston or rod. Any "rattling" due to loose components should reduce on that cylinder, which may help to isolate the problem if only one cylinder is affected.

The camshafts rotate at half the speed of the crankshaft, meaning that any noises generated by cams or valves will be at half the frequency of noises from the main and bigend bearings.

A large screwdriver is good for using like a stethoscope to listen to the engine. Press the handle against your ear and place the tip on various solid parts of the head and block to hear the mechanical sounds of the engine.

Cheers... jondee86

[sirsprinter]

Ok mate thanks for the info will be having a look and listen tomorrow and hopefully establishing the issue... hopefully...

[petergoudie]

When in storage did you possibly turn the engine over backwards, possibly jumping a cam tooth or two?

[sirsprinter]

Mate im not 100% sure. It is a possibility? I doubt it but i have done stupiderest things from time to time...

[dnegative]

4A's dont seem to care which way you turn them

[DX20VT]

I have struck a noisy 4AGE lately too.
Was after a cambelt replacement.

Turns out that holding the camwheel while you line up the belt with a 14mm socket is not always a good idea,
as it actually cracked one of the bolts loose enough for the pulley to move a little.
It would create a ticking noise as the cam wheel drove the cam,
then at certain points the valve springs pushed the cam faster than the cam wheel,
and so the cam wheel rocked back and forth on the dowel.

By the time we found it the cam wheel needed to be replaced as it had slogged out the slot in the cam wheel a bit.

May pay to check your cam wheel bolts if you cant find any other reason?

[sirsprinter]

Oh cheers for the heads up DX; that is something else we will have to look at. Not much else has been done by way of investigation and diagnosis since this post - but all shall be considered! Thanks for the info & opinions so far everyone