Weird Noise On Bottom End, Need Engine Builder Advice

[jacobs53 0]

I have been rebuilding this engine since Monday, and im still on the bottom end.... progress is really slow nearly snail pace, due to one small problem. I put the pistons inside cylinders and everything was o.k until I turned it over.

 

There is a mettalic knocking noise from each piston when it reaches TDC and BDC. I automatically thought the clearance between the big end was too large, so i measured it with plastigage to find each big end was 0.05mm (which is the upper tolerance permitted). So then i checked each small end for play and nothing there neither. And now im completly lost to what could be causing it.

 

You can literally feel each piston knocking/jumping at TDC, and if you apply pressure to the corwn of the piston this noise reduces. The crankshaft rotates very smoothly without pistons and with them also, so not a main bearing problem.

 

I can only assume at this point that the connecting rod big end is hitting the crankshaft counterweights, while rotating, even though you can't physically see this.... Or this is how the engine is designed and I have completly missed this noise on the other engines I have built up.

 

I have a video of the noise... Il try and host it... But i'm not happy with this noise!!!!

 

Any idea's???

 

cheers lee

[jacobs53 0]

Video one.

 

<img width="500" class="attach" src="http://img.photobucket.com/albums/v459/jacobs53/th_DSCF0929.jpg" border='0' alt="IPB Image" />

 

Video two.

 

<img width="500" class="attach" src="http://img.photobucket.com/albums/v459/jacobs53/th_DSCF0930.jpg" border='0' alt="IPB Image" />

 

cheers lee

Edited December 13, 2006 by jacobs53

[luggy 13]

Lack of oil pressure so no fluid between the shells and the crank surfaces. If youve done everything correct, double checked it it should be ok. The only way you can simulate it accurately is by adding oil and put the starter motor in an turning it over, I dont think you have anything to worry about there.

[jacobs53 0]

You recon thats the reason??? I turned over a 1600 TU engine without head and no noises were emitted... Everything has been checked and checked again, Iv'e had the crank in 3 times today along with the pistons.

 

lee

[luggy 13]

The knocking and jumping at TDC and BDC yes. The metallic noise is from the rings going up and down the liner and the popping noise is from excess oil in the bores.

[Sandy 191]

Small end/pin play? It's a nice relaxing video to listen to.

[nick 3]

Shut your eyes and it sounds like porn!!

 

Just going to have another listen.......

 

Nick

[smckeown 1]

Shut your eyes and it sounds like porn!!

 

Just going to have another listen.......

 

Nick

 

agreed, all that slurping and rythmic motion made me horny.....must get home to wife pronto

 

It's a nice relaxing video to listen to.?

 

 

I'm willing to bet money you've fallen asleep on the job before

Edited December 14, 2006 by smckeown

[Sandy 191]

Have I really been asleep for 2 and a half hours?