Tuesday, November 19, 2013 - 12:04 am, by: Ben Lipman(Ben12a)
Last Saturday at Mallala after a warm up lap in the third session of the day I dropped the hammer and got up to speed. As I went down the main straight and got on the gas in third (6800 rpm shift according to the log) I heard a tapping of knocking noise. I rolled another 100-200m to figure out if it was speed related or engine speed related. It was definitely engine revs related. In the pits there was a definite tap, tap, tap and it sounded like it was coming from the right rear top of the engine. (as best I could tell).
I have the cam covers off and cant see anything obvious. There are no wear marks or witness marks on the cams or surrounding area.
My next step tomorrow night is to pull the plugs and see if one looks different to the rest. I am going to ask around for a bore scope to borrow to have a look inside. If I cant see anything obvious then I will have absolutely no idea what to do next.
Happy for any suggestions from those in the know. What next?
Tuesday, November 19, 2013 - 07:21 pm, by: Ben Lipman(Ben12a)
Harmonic balancer 'looks' all right Peter.
Dave- not sure how the check that without pulling it completely apart...LOL
I turned the motor over via the crank pulley this afternoon with some light. Could not see anything out of the ordinary. There was also no discernible sticking points as I turned it over.
The shims are all still sitting under the cam lobes, and there is no metal debris anywhere in the top of the head.
I pulled the plugs this arvo and they are all identical.
I borrowed a bore scope/camera snake/whatever it is called from a bloke at work. I have inspected the tops of all pistons and there is no debris or witness marks etc. All the valves seem to be moving freely, and they are all intact as best I can see through the camera.
I could have sworn the noise was coming from the top of the motor, and towards the fire wall.
I might have to put it all back together and start it again to try and narrow it down. At least I know it isn't a valve or part there of bouncing around on the top of the piston.
Thursday, November 21, 2013 - 03:41 pm, by: Matt Newman(Soarersrock)
bugger was thinking it looked ok until i saw number 6 lol. with the wet test jumping that high on number 6 it sounds like it could be the case. but i wouldn't have thought that buggered piston rings would have caused a tapping noise.
Ben Lipman Goo Roo SA Soarer TT manual, plus TT track car, plus a spare shell
Thursday, November 21, 2013 - 04:50 pm, by: Ben Lipman(Ben12a)
Have been told it could be a cracked piston skirt. Apparently they make a tap tap noise before the break completely.
But yeah, could also be a piston ring.
I am well out of my depth and going on internet speculation mostly.
Matt - I was getting a good feeling as we went along. The numbers seemed to be the same as everyone else has reported, and they were all pretty close. Then we got to ole number six...
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