I finally got my engine work done on my 2000MY XK8 and started her up today, but she's making a popping noise from what sounds like the rear of the left bank, though i know it can be difficult to tell by ear.
Hopefully the video i took will explain more clearly if it's viewable.

I took her for a spin round the block to see if she ran rough, but power delivery seemed ok, no rough running, the temp gauge went up to halfway and stayed there, the fans didn't come on.
Also the oil pressure gauge didn't drop to less than just under halfway even at tickover, which is an improvememnt on what she was like before the work, as it used to drop into the red giving the low pressure light and display message.
So the engine seems ok so far, it's just this noise.

It's engine speed related.

Anyone got any ideas please?


1Cosworth's Public Profile on Photobucket.com

 

It sounds like an exhaust leak to me, but I'm just going by the post, I saw no video.

 

Sounds like an exhaust leak at the cat..... But hard to tell for sure

 

I tried accessing the video myself after logging out of photobucket, but i couldn't, so i've logged back in.

Sorry, i didn't think i had to be logged in to photobucket for the video to be accessible.

Were you able to see the video XKRacer?

 

I can't!

 

I had no probs

 

I don't know what the problem with the video is Norri, i copied the link to my Photobucket profile from my previous Timing Chain Video post.

I'll check Photobucket again to see if i can make it viewable.

 

The Cats are underneath the car aren't they?.
This noise sounds like it's higher up, around the top of the engine, though i warmed her up again this morning after adding some coolant flusher, and the noise sounds like its coming from everywhere, or anywhere.

Tickover is steady, and as yesterday, the oil pressure is good, a needles width under halfway after a good warm up.

I'm baffled, and disappointed obviously, after my trials and tribulations with it, and the care i put in to try to make sure everything was done right.

 

I'm not able to see any video or hear any sound, and I imagine many others can't see or hear it either. Perhaps if you upload your video to YouTube and post here, you'll have better luck and we'll be able to help out.



.

 

What happens when you click the link?

Does it take you to the login screen?


I used photobucket to show another video on timing chains, and nobody reported any problems.

If the above doesn't work i'll have to set up a YouTube account as well.

 

OK, I was able to see the video, but in general you shouldn't post usernames and passwords on a public forum. Make sure your Photobucket settings are set to public viewing, or perhaps try YouTube next time.

It does seem like the noise is coming from the rear top, and to me does not sound like an exhaust leak. Of course we can only guess from this distance, but it sounds like it's coming from the cam / valve area, perhaps on the left bank. I will tell you that, in a certain way, I am familiar with this sound from my 1997, however it is MUCH quieter on my car than your video suggests.

No need to shoot another video, really, but we might benefit from hearing how the noise responds to engine speed.

Hmmmm. Keep us posted, I'm curious about this one.


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Try this

XK8 Engine Noise video by 1Cosworth | Photobucket

Sounds like a mechanical knock from the back of the motor to me, how does it respond to revs?

Looks like my link works so I've deleted your username and password from the previous post.

 

The noise accelerates with the revs, as if it is coming from one cylinder,

ie: whenever that particular cylinder fires.
I'll try another video tomorrow when i get home from work in the morning.

 

I listened to the video on Studio monitor speakers in a quiet recording studio and I could hear what sounded like tick tick tick valve tapping at the exact moment we can hear the more midrange thud thud thud sounds near the left rear bank.

It doesn't sound like exhaust or a loose plug too me. It really sounds valve/cam related - Just a guess: It could be a sticking cam follower. Also a bit like the rocker arm ever so slightly hitting the composite valve cover.... Could that even occur? Hmmmmm

 

I'm going for cam lobe or bucket , check the valve clearances and also that the cams are getting lubricated ,

NikasilNik

 

Hi,
can only suggest the obvious, im sure you have checked the timing since you started it up. if you have not yet I would check the flats just in case something has happened on the initial start up. the next idea is a misfire, check the plugs and coils, the coils have been out for a while and I would expect a lot of moisture in this weather

I cant see it being anything other than a timing or misfire issue. you did not remove the camshafts did you ?

well done on what you have done so far, I hope this noise is only a small issue to clear up.

best wishes
Steveeasy

 

The Coupe:

Re: the password, the only stuff on the account was meant for public viewing, but i appreciated someone could put malicious content on there so i'll change it.
I've checked the settings and selected public viewing, i don't know if it was already set or not.

I've put another video up that i took of the gauge readings from inside the car, just in case it helps with a diagnosis.
1Cosworth on Photobucket | Photobucket

I hope this link works.

I was hoping this would be something simple but its looking like whatever it is will mean removal of the cam covers and new gaskets.

maxwdg:

I'll find out what and where the cam followers and rocker arms are.

Would it be inadvisable to drive the car 70 miles in this condition?

It's due to go off to XKRacer for the steering and floor welding next week.

NikasilNik:

I'll also find out about the bits you advised (cam lobes and buckets), though i know what the cam lobes are already.

Would a worn or dry cam lobe make that kind of noise?

I had the cam covers off for months while doing the work, so i'd say it's quite possible something dried out.

But i thought that once the engine was running, everything would get re- oiled.

steveeasy:

I havent'checked the timing since starting it up, because to do that would mean taking off the cam covers again, which i was hoping to avoid.

To be honest i think the timing is ok, if the new video of the gauges is viewable you'll see oil pressure is good, tickover is steady (no misfire), engine pulls ok under acceleration, so everything seems normal, apart from the noise.
I did not remove the camshafts.

 

The cover gaskets do not need to be replaced, it's not like the old days with cork gaskets.

 

Hi Roadhogg,
the sound to me was a misfire, its either timing, an electrical missfire involving coils and or plugs, or a problem with a valve or associated item.

given the noise was not evident prior to doing the work, and the fact you have not removed the camshafts, personally id pull off those timming covers asap, start with the side the noise is coming from. if all is well then move on to coils and plugs.

In my opinion it did not sound anything like an exhaust leak. I would not drive it at all until you have checked the timing. have you or are you able to check for code faults.

Steveeasy

 

Hi Again,
If you do remove the cam covers, whilst there, check valve caps rotate freely by hand.

they should rotaten, when closed, easily by hand.

steveeasy