QOTW #38 – Detailed Follow up to the DB9 Engine Tick

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Welcome to Bamford Rose and another question of the week. This week, it’s DB9 and it’s a continuation of the infamous ticking sound. Which if you haven’t watched already, click here for that video and then come back to this video. Because what we’ve got now in the workshop is a car that’s making a ticking sound. And we’re going to show on an engine block with some hardware exactly what’s causing this sound. Then just touch on what the rectification is unfortunately with the tick to this extent. Its piston slap in liner, it’s the little M bearing. This is going to be a comprehensive engine rebuild.

And it comes down to the parts and labor cost of each individual engine, what it needs to rebuild and correct the condition versus the complete remanufactured engine from the factory. Which you could purchase given to repair routes. So, let’s got the workshop and we can have a look at that car with this particular problem. So, obviously we’re underneath the car now. We’re going to start it from cold and you’ll hear that there’s no abnormal sound, no ticking when the engine is cold. When it’s up to fully warm operating temperature often with engines that have got this problem, they don’t exhibit the problem even at that condition.

We have to get the engine RPM up to about 3000 RPM. Hold it there for something like 2, 3 minutes and then come off the throttle. And when it then returns to idle is when the ticking noise will start to be more pronounced. You’ll probably find that if you start at a DB9 and get it fully warm and there was no ticking. And then when often had a drive, motorway cruise or just you know a road drive come to rest for the first time. That’s probably where you’ll hear the ticking. So, it’s just really important when you do a pre-purchase inspection on a DB9. Even though you’ve got it fully warm and the engine is sounding smooth, you want to increase the RPM. Get it to that 3,000 point for about two or three minutes and then idle see if it develops the ticking sound. Because there’s quite a lot of people that do miss the engine exhibiting this sound in an inspection of a car and then end up buying a car with this problem.

So, we’re underneath now. It’s just cold started, still on fast-idle directly underneath some absolutely no abnormal noises all so ever the engine sound, silky-smooth as sweet as they all do. So, now we’re warm and now we’re increasing the RPM and say we promote the condition. As you can hear, even at this speed there’s no abnormal noise, so the condition is even detected. So, now we can hear the cyclic tic as with the load the engine RPM has to get into considerable heat above the piston ground. And underneath, this is quite noticeable and quite audible.

If you were viewing this on the car that wasn’t up in the air, then just put your head behind either driver or pass the engine from the wheels. And there has been noise that is very noticeable from underneath the car, less so from above the car.

Okay, so this is an old block. It’s been on the shelf quite a while so there’s a little bit of corrosion on the liners. But this block was removed from a car that was making exactly the same sounds what we’ve just heard and it’s a combination of two things. We’ve never really found engines that exhibit this sound not to be a combination of both these errors. So, it makes the repair a little bit more difficult. Because if it was just the little end bush, then it’s quite a simple rebuild. You don’t need to go to the extent of machining out all the liners and then rebuilding with new liners, new Pistons. Which is extremely expensive, the parts are very dare the machining process is dare.

So, what’s happened is this is a V12 piston and due to whatever condition has caused the problem. There can be a few reasons why the liner distorts no one really knows for sure. And without machining outliner and measuring very accurately the bearing ball, we’re not going to know if there’s distortion in the bearing ball which is causing distortion in the liner or if this Valatie in the liner is purely in the line and is not a bearing ball. It’s quite a complex measurement activity process to go through to understand that. And even in our world here, we just repair what we see in front of us which is wrong.

So, with the liner that’s worn over, every time the piston reaches the top dead center. It’s going to slap in the bore as it transitions up and down. So, on the noise that we just heard, some of that noise could be only piston slap. If it wasn’t anything to do with the piston or liner going over, then it will be the small end Bush. And this type is the old type design it hasn’t got any oil channels in them on about 2008 engines they have an oil channel. Some of the noise that we heard could just be, when heat expansion takes place this pin rocking in the comb rod. Now on this particular one I am NOT going to pick it up on the camera but I can already feel in there an amount of play.

So, it stands to reason that when heat expansion is taking place, this is fully warm that this is going to exhibit the similar sort of ticking noise that we just heard. But as I said, as I experience really, I don’t see a little end we’re separate from the liner piston slap issue. It’s a little bit chicken-and-egg. Was it this one that caused the piston to move in the liner in a different way and wear it over. As I say, who knows that’s a quite big factory sort of research activity to understand what’s going wrong with a product. Obviously now years later, they’re not going to conduct that you know this engine is way out production and they’re out of any liability in terms of three-year maker warranty. Unfortunately, if the problem does occur then it’s down to the owner to resolve.

I hope that informed you a little bit more about the dreaded DB9 tick. If you liked this video and if you might get any of our other videos, then it really helps us if you can like, subscribe. And let us know some comments below.

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