hello all

Right went out last night to the shop 5min drive down the road. Coming back all fine but as i drive into my estate abit of a rumble nosie followed by loud tapping nosie. just trying to get hold of a compression tester.

Any idea what it could be?

Heres a sound clip. Its off my phone so not to good might have to turn your speakers up abit.

CaR.zip

Bump

Even I don't know what program plays ARM's.

real player

I cant really hear it that well but it may be bottom end, the crank could have gone?

and quicktime on my mac.

attached is an eddited mp3 of it.

car.mp3

Edited 19 June, 200719 yr by ollythedolly

Sounds bad, I'd say bottom end as above. If it was, I'm surprised if it hasn't done some obvious damage to the block.

Try and hear as best you can where it's coming from.

Edited 19 June, 200719 yr by Danny Lee

I've tried analysing the sound in sound forge, the best I can tell is the clicks are ~1/6 of a second apart. which means the noise is more likely to be cam related (tappets) than crank related. However, there is nothing to say that it's happening every revolution.

Assuming crank idle rpm is 1000

cam runs at 1/2 speed of crank therefore cam speed is approx 500rpm at idle

revs per second of cam = 8.33

approx time interval between clicks 0.15seconds

clicks per second 6.67 = 400 per minute.

Based on that, it's one of the tappets. But like I said above there's no garuntees. Few Questions to round off;

What mileage is the enigne?

When was the late oil change?

How much oil is in the engine?

I've tried analysing the sound in sound forge, the best I can tell is the clicks are ~1/6 of a second apart. which means the noise is more likely to be cam related (tappets) than crank related. However, there is nothing to say that it's happening every revolution.

Assuming crank idle rpm is 1000

cam runs at 1/2 speed of crank therefore cam speed is approx 500rpm at idle

revs per second of cam = 8.33

approx time interval between clicks 0.15seconds

clicks per second 6.67 = 400 per minute.

Based on that, it's one of the tappets. But like I said above there's no garuntees. Few Questions to round off;

What mileage is the enigne?

When was the late oil change?

How much oil is in the engine?

cheers gaz i have just done a compression test on it and I'm reading on cylinder 1 and 2 6bar and on cylinder 3 and 4 is 14 bar which is not good. As for the questions the mileage is on 121000 oil change two months ago. Oil level fine. To me i thinking tappets because it does sound like its at the top of th cylinder block.

i have better video that I'm going to up load now.

hmm well those numbers say bad things. If it was just low comp on one cylinder then id say it was a stuck valve which could be the result of a siezed tapper but if two are bad then could be the bottom end afterall. When I had a gt engine go, the knocking would get worse on overrun, as no load on the pistons allowed them to travel further up the bores. the knocking on mine turned out to be one of the pistons touching the cylinder head! Hence people thinking the issue was the head at first, 'cos that's where the noise was coming from.

One thing it could possibly be is you cambelt has slipped a few teeth and damaged a couple of valves a bit. Although that kind of thing would usually stop your engine completely. Might be worth checking cambelt tension

SV_A0001.zipheres a better clip of it. i have rang around a few places people have said it could be the head gasket gone pop? when you run it you have to hold the revs or it cuts out.

I guess there's only one way to find out... :)

the head gasket did go bang i will put a picture up in abit.

where'd it go? between the cylinders?

yep picture on its way

Heres the pictures

I'm going to get the head skimmed, new tappets etc. I know when i helped do a headgasket on a mates g40 he got a metel head gasket. Can you get one for a gt? Is there anything else i should do? cheers for the replys

Edited 20 June, 200719 yr by Daryl

No you have to use a normal gasket on a gt because the pistons stick out of the block. They would hit the head before tdc with a metal gasket.

The tops of your pistons are a bit shiny. I would look at the head surface to see if there's been any contact in the areas corresponding to the shiny areas on the pistons.