Top end tappety type noise
Discussion
I have what appears to be a tappety noise that comes in only when getting to 3100 rpm and only when under acceleration. If I lift off at any revs over 3K it stops and on the gas again and its back
I believe its a lazy follower.
FYI I have eliiminated pinking.
4.6 top hatted pocketed ported stage 3 cross bolted stealth cam kent hydraulic tappets cam about 50k miles. Engine oil/filteralways changed about every 3k
So questions are
1. how can I determine if its a lazy follower ?
2. How do I find out which one ?
3. What do I do about it (thinking new cam kit and all the ancillaries) ?
Whats your thoughts wise people ?
I believe its a lazy follower.
FYI I have eliiminated pinking.
4.6 top hatted pocketed ported stage 3 cross bolted stealth cam kent hydraulic tappets cam about 50k miles. Engine oil/filteralways changed about every 3k
So questions are
1. how can I determine if its a lazy follower ?
2. How do I find out which one ?
3. What do I do about it (thinking new cam kit and all the ancillaries) ?
Whats your thoughts wise people ?
That is a very difficult one.
If the noise was there on light loads or lift off then it would point to a small end.
If the noise was there all the time then I would suggest a dodgy rocker.
If you have had pinking in the past, I wonder if you have damaged the top crown edge of the piston like the 5 L.? I had this when it broke a thin line of the piston above the ring gland.This from memory gave a slight tapping noise.
Unfortunately, the only way to check is firstly to remove the inlet manifold and check what you can. You're still very restricted in what you can see.
Ideally remove and strip down the engine. Not what you want to hear.
The Rover engine is very simple and when you strip them down, you can see how very few moving parts there actually are! Whatever it is will be obvious.
Just thinking, big ends knock under load but they are usually obvious when you hear it.
If the noise was there on light loads or lift off then it would point to a small end.
If the noise was there all the time then I would suggest a dodgy rocker.
If you have had pinking in the past, I wonder if you have damaged the top crown edge of the piston like the 5 L.? I had this when it broke a thin line of the piston above the ring gland.This from memory gave a slight tapping noise.
Unfortunately, the only way to check is firstly to remove the inlet manifold and check what you can. You're still very restricted in what you can see.
Ideally remove and strip down the engine. Not what you want to hear.
The Rover engine is very simple and when you strip them down, you can see how very few moving parts there actually are! Whatever it is will be obvious.
Just thinking, big ends knock under load but they are usually obvious when you hear it.
Daniel-vwbsa said:
Could it just be an exhaust manifold leak?
I believe from my mole that Frank has checked this thoroughly although sometimes they are difficult to locate.I certainly had an exhaust manifold leak at the end of a track day and thought that I'd totally lunched the engine by the noise. It was just a simple exhaust gasket
Thanks guys have had Al over as well aka classichimi for test drive listen.
We thought pinking so I advanced the timing to make it pink and now I know what that sounds like on this engine its not that and havent had pinking in the past.
If I have a lazy lifter is thère a way to identify it ir us it just by measurement of the ckearnces and cam lift ?
wrt exhaust bolts we couldnt find any evidence but its really difficult on my manifolds they are custom non standard stainless and really difficult to check.
Appreciate your thoughtd folks
I am tending towards new camshaft followers and timing gear but dti old cam before removal and measure clearances to see what that shows up.
We thought pinking so I advanced the timing to make it pink and now I know what that sounds like on this engine its not that and havent had pinking in the past.
If I have a lazy lifter is thère a way to identify it ir us it just by measurement of the ckearnces and cam lift ?
wrt exhaust bolts we couldnt find any evidence but its really difficult on my manifolds they are custom non standard stainless and really difficult to check.
Appreciate your thoughtd folks
I am tending towards new camshaft followers and timing gear but dti old cam before removal and measure clearances to see what that shows up.
The engine is generally very quiet and no apparent obvious noises until load is applied on engine and at 3100 revs like clockwork the noise comes in.
Drive around on 2500 revs and there’s no noise.
Can’t be sure about exhaust gaskets until better checks are done ( feather or similar)
but no noise with raised revs stationary or at idle from that area and no blackening around manifolds that I can see.
Now Frank has introduced some pinking and can discount the sound its looking more mechanical. Would a worn timing chain rattle in a similar fashion or be more constant.
More questions than answers, looks like a look see inside the engine is on the cards.
Drive around on 2500 revs and there’s no noise.
Can’t be sure about exhaust gaskets until better checks are done ( feather or similar)
but no noise with raised revs stationary or at idle from that area and no blackening around manifolds that I can see.
Now Frank has introduced some pinking and can discount the sound its looking more mechanical. Would a worn timing chain rattle in a similar fashion or be more constant.
More questions than answers, looks like a look see inside the engine is on the cards.
To check the valve lifters, you'll need to remove, the plenum, trumpet base and inlet manifold to remove the valley gasket.
Rocker covers off to give access to removing the rocker shafts means you'll be able to lift out the rods and then the hydraulic valve lifters. Easily done with the engine still in the car. You'll need to drain down some of the coolant (but not all) to avoid getting it inside the engine when the inlet manifold comes off.
Valve lifters should have less that 60 thou of free movement according to V8 wizard but I've read that up to 0.1" is acceptable too:
http://www.v8wizard.com/camshafts_Setting_Tappet_P...
Here's photos of the varying wear of tappet lifters
http://www.v8wizard.com/Camshaft_tappet_wear.php
Rocker covers off to give access to removing the rocker shafts means you'll be able to lift out the rods and then the hydraulic valve lifters. Easily done with the engine still in the car. You'll need to drain down some of the coolant (but not all) to avoid getting it inside the engine when the inlet manifold comes off.
Valve lifters should have less that 60 thou of free movement according to V8 wizard but I've read that up to 0.1" is acceptable too:
http://www.v8wizard.com/camshafts_Setting_Tappet_P...
Here's photos of the varying wear of tappet lifters
http://www.v8wizard.com/Camshaft_tappet_wear.php
When my exhaust gasket was blowing on my last Chimaera, it was more of a low frequency 'tap' rather than the higher frequency 'tappity' noise the rockers / valve lifters make. It was also there all the time.
checked by lowering a pencil with a feather taped to it close to the exhaust manifolds at idle. A leakage causes it to flutter.
checked by lowering a pencil with a feather taped to it close to the exhaust manifolds at idle. A leakage causes it to flutter.
Thanks for all the posts they are indeed helpful.
My approach this far will be
1. Check for leaks using the feather technique
2 Drop in a bottle of "lifter treatment" and see what its like after 200 miles
3. Whip the inlet manifold off and measure cam/lifter tolerances
Hope the answer lies in there
I'll be back.......
My approach this far will be
1. Check for leaks using the feather technique
2 Drop in a bottle of "lifter treatment" and see what its like after 200 miles
3. Whip the inlet manifold off and measure cam/lifter tolerances
Hope the answer lies in there
I'll be back.......
Exhaust leaks can be elusive, finding them by looking for where it's leaking can be hard to discover. This was my technique....
http://www.chimaerapages.com/technical-info.html Scroll down to 'Find that elusive exhaust manifold leak'
Later I used an easier way to prove I had a leak.
- Block one tail pipe
- Duct-tape a flexible pipe into the other tail pipe and make sure you have a seal.
- Blow in the pipe, you should be blowing against a dead end so you'll sense pressure building up. If you can keep blowing then you have a leak, you just need to find it
http://www.chimaerapages.com/technical-info.html Scroll down to 'Find that elusive exhaust manifold leak'
Later I used an easier way to prove I had a leak.
- Block one tail pipe
- Duct-tape a flexible pipe into the other tail pipe and make sure you have a seal.
- Blow in the pipe, you should be blowing against a dead end so you'll sense pressure building up. If you can keep blowing then you have a leak, you just need to find it
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