Hi all, can you help me with diagnosing the cause of engine noise from my52 bugeye please. The symptoms are on start up for around 5 seconds the top end seems to be chattery, once warmed up the tick over changes noise every 5 minutes or so becoming chattery again for around 5 seconds before disappearing (intermittent), the noise is what sounds like loose valve tappets, i have had no loss of power and when under load the car is quick, no smoke and no chattering but again on tick over the chatter returns and then disappears, i would like to resolve this before it burns a hole in my engine, my pride, my pocket, any ideas my friends.

 

Checked your oil levels?

 

Yes, checked the oil level and all good, in fact i changed the oil as well, she had a can of performance molyslip and that has reduced the noise by around half.

 

If it's a WRX iirc even the newages have hydraulic tappetts. If the change of oil has helped then I'd say it will get better the more the new oil has spread further.

 

Thank you thats good to know as we only done around twenty miles after changing the oil and adding the molyslip, even on start up the noise had dropped by half, I'm thinking of doing one more oil change now the carbon has been flushed by the new oil, do you think its worth a drain ??
regards Tony

 

They have solid followers from V3 so not that. what milage has it done? Big end bearings are a favorite over 70K. The cam belt tensioner can also cause a rattle. If the molyslip makes a difference it sounds like something internal, bearing/oil pressure related? I would warm it up and drain the oil into a clean container and strain it through some clean cloth to check for debrise, you can also 'swab' the bottom of the sump through the drain hole.

 

I have appeared to have fixed it!

Firstly, I found one of the nuts on the manifold to up-pipe join had worked itself clean off. So that was obviously leaking a load of exhaust and making noises. Given that it did it twice, I must have bolted the exhaust sections in a bad order, so I removed the turbo (coming on to that in sec...), and downpipe, and then tightened everything back up starting as the bottom of the up-pipe then onto the turbo to up-pipe, then onto the turbo to down-pipe. Hopefully this ensures the pipes and turbo are stressing each other and the nuts stay tight. I popped some new gaskets on for good measure.

Secondly, when checking the turbo I noticed that the wastegate flap wasn't tightly closed. So when it was shut, the circular flap still could be wobbled and rotated. So this was probably causing the high-pitched rattling sound. So I just applied half a turn to the arm and the flap could shut properly. This has got rid of the high pitched sound.

So the engine sound back to normal now at last! Just in time for the MOT in a few days. So I expect the brakes to fail, the headlights to explode and the floor to rust out tomorrow.

 

Well done, sometimes minor things can sound so serious.

I remember a few years ago with my forged 2.5 sitting at traffic lights, I thought I was about to throw a rod. Was on my way to the engine builder for an oil change as it happens.
Drove so carefully, bricking it.

Got there, he sat in the car and could hear the knocking too. "That's a fuel line" he says. "Huh....WTF...you sure?" I reply.

Sure enough, turned out to be a tiny fuel damper on the in or the out fuel line, I can't remember which. He crimped the line and the noise stopped, let go of the line and it started again.
Ordered the bits, fitted myself, sorted. It was causing pulses / vibrations through the bulkhead.

Seriously, it sounded so bad / terminal.

 

I hate noises, I have a rattle from the engine at certain revs, when I first had it I pooped my pants, but when I did a bit of investigation it just turned out to be the heat shield at the top of the up pipe. A very large hose clip did the trick and stopped me losing more sleep lol! I love it when it turns out to be the simple things.