Please can I have some help

[AntStark]

Thank you, Allan has been on lots of sites but we’re just worried about switching the engine, just in case it’s worse than my one , mine has only done 80000 miles

Worse than your one! . Call some of the larger reputable vehicle dismantlers. These guys are local to me and excellent. Engines will come with a warranty. https://silverlake.co.uk/

 

[Shelly]

Worse than your one! . Call some of the larger reputable vehicle dismantlers. These guys are local to me and excellent. Engines will come with a warranty. https://silverlake.co.uk/

Thank you

 

[Duncodin]

I don't know that engine but wouldn't it be possible to poke an endoscope camera down through spark plug hole to look at top surface of pistons. If there's been any contact with valves I'd expect to see clear marks.

USB endoscopes are pretty cheap.

If there's marks on the pistons I'd go the replacement engine route. If there's no evidence of contact then I'd invest the time to inspect the head, cam etc.

But if there was a warrantied low milage low cost engine right in front of me then I'd likely just chuck that in anyway.

 

[smiffy]

I can't remember, @Shelly do you have a garage at your place?

 

[FRANKIE]

We tried to jump start the car , and it turned over very well , but the car just wouldn’t start

Just saw this now. Did you ever get it started? Did you check if it was getting gas? Sometimes the gas gauge fails and tells you there's gas and it's empty. Happened to me once. Engines start to run rough as the fuel begins to stop flowing. Then doesn't start with no fuel. Just a thought..Frankie

 

[Shelly]

I can't remember, @Shelly do you have a garage at your place?

No , no garage

 

[Pond]

Is the engine specific to the Z4 or was it used in other BMWs ?

The N20 was used in every 2 litre petrol BMW from around 2010 to 2016, when it was superseded by the B48. They produced millions of N20s. They never put a B48 in an E89, as the cars went out of production just as the B48 was introduced. The 2 litre G29 Z4 uses the B48.
There has always been a potential issue with timing chains on these engines. Usually the issues were down to the chain guides which become brittle over time and break, causing the chain to jump or stretch. There is a theory that very regular oil changes help prevent chain damage, although don't think it has ever been proven.
The guides were re-designed in around mid 2014, so for the last two years of production they were much better.

 

[Shelly]

The N20 was used in every 2 litre petrol BMW from around 2010 to 2016, when it was superseded by the B48. They produced millions of N20s. They never put a B48 in an E89, as the cars went out of production just as the B48 was introduced. The 2 litre G29 Z4 uses the B48.
There has always been a potential issue with timing chains on these engines. Usually the issues were down to the chain guides which become brittle over time and break, causing the chain to jump or stretch. There is a theory that very regular oil changes help prevent chain damage, although don't think it has ever been proven.
The guides were re-designed in around mid 2014, so for the last two years of production they were much better.

Thank you for all the information

 

[Lee]

You just need to make a decision Shelly. That will depend on your budget.

 

[Shelly]

You just need to make a decision Shelly. That will depend on your budget.

Allan phoned the garage up today and we’re decided to have a vacuum test , I think that’s what it is called?
If it comes back ok , we will delve into the engine and have a new chain etc fitted , if it works it will be great but if not, because of the cost etc …… we will maybe sell the parts etc from my Z or sell it too we buy any car ……
I will then buy another Z for about £5k ……
Only because we were going to sell my Z in a few months time as I wanted a new Z which would be about 2020 plate ……
I’m some how pleased we didn’t sell my Z to another person as I’d been mortified if this would of happened to someone else

 

[Zephyr]

Too sad to hear all your trouble.
But within all these posts I didn't quite understand what is the approach of fhe garage you sent it.
So far you do not "actually" know what the problem is. A compression test to diagnose what exactly? Leaks on bent valves?
If the timing chain has skipped a tooth, why crank the engine some more and do more damage?
Most probably he is going to do a "leak down" test.
Anyway, I think that you are dealing with someone who doesn't care or diesn't know.
Be carefull.

 

[Lee]

Anyway, I think that you are dealing with someone who doesn't care or diesn't know.
Be carefull.

Quite the opposite, these engines are know to wear teeth and sprockets at this age, doing these tests will allow the garage to find out if its worth fixing the engine or not, If it holds vacuum you know the valves are not bent and a fresh set of sprockets n chains will see her good again, if not then its new engine or rebuild but all boils down to the budget of the owner.

Fair approach if I'm honest, albeit the garage is a little reluctant.

 

[Shelly]

Yes a leak down test
Allan is sorting it out , he tells me things , and what is happening, but I just drive the Z , lol

 

[Shelly]

Quite the opposite, these engines are know to wear teeth and sprockets at this age, doing these tests will allow the garage to find out if its worth fixing the engine or not, If it holds vacuum you know the valves are not bent and a fresh set of sprockets n chains will see her good again, if not then its new engine or rebuild but all boils down to the budget of the owner.

Fair approach if I'm honest, albeit the garage is a little reluctant.

Hopefully the test will done next week, and I’ll know what we will be doing

 

[Duncodin]

. . .
. . .
If the timing chain has skipped a tooth, why crank the engine some more and do more damage?
. . .
. . .

I suppose if the chain did skip a tooth then it did it while the engine was turning so any damage, if any, has already happened so can't really make it any worse.

 

[Pond]

Quite the opposite, these engines are know to wear teeth and sprockets at this age, doing these tests will allow the garage to find out if its worth fixing the engine or not, If it holds vacuum you know the valves are not bent and a fresh set of sprockets n chains will see her good again, if not then its new engine or rebuild but all boils down to the budget of the owner.

Fair approach if I'm honest, albeit the garage is a little reluctant.

Why would the garage have not just taken the cam cover off and checked it visually already, though? Bent valves are easy to spot (as they are bent) and they could whip a few out and check the piston crowns too. All from doing an easy bit of work.
Seems they have decided it is toast by looking in the oil filler cap so far and seeing bits of chain guide. Also, I don't see how they 'know' the camchain has jumped. They seem to be presuming this by the way the engine is behaving (and probably googling N20 engine problems).

 

[Lee]

Why would the garage have not just taken the cam cover off and checked it visually already, though? Bent valves are easy to spot (as they are bent) and they could whip a few out and check the piston crowns too. All from doing an easy bit of work.
Seems they have decided it is toast by looking in the oil filler cap so far and seeing bits of chain guide. Also, I don't see how they 'know' the camchain has jumped. They seem to be presuming this by the way the engine is behaving (and probably googling N20 engine problems).

Easy for us to say it's easy work, that's 2/4 hours and I would guess £80 an hour plus tax, to which I doubt Shelly would authorise. It's not just remove rocker cover on these, they have a central valvetronic sensor plus the low pressure fuel rail to remove.

I would have thought if they're competent the codes will be mis-alignment and timing related, pointing towards what's already obvious. Even simple things like how its turning over eg a good gallop or not. I'm by no means an expert so If I can make this out I'm sure a garage can that does this day n night.

 

[smiffy]

I was going to chip in last night with offering to bring my endoscope and leak down kit over to at least try and help with a diagnosis. I normally use these for my aeroplane engines, I try to avoid car engines these days! Even tested the endoscope!

Being so close, I want to help, half my head wants to come and rip it to bits for you, the other half keeps reminding me how complicated they've become, as Lee rightly highlights.

 

[B21]

FWIW….

The N20 isn’t really economically repairable with those faults…

The tear down / rebuild costs will be very significant.

Quite a few N20s are now going down with bore score..losing compression on one or more cylinders..that’s not repairable under any circumstances..

I know an E89 that had the same issues..£6.5k to supply and fit a 65k mile engine..

Sorry to be the bearer of bad opinions

 

[Shelly]

I was going to chip in last night with offering to bring my endoscope and leak down kit over to at least try and help with a diagnosis. I normally use these for my aeroplane engines, I try to avoid car engines these days! Even tested the endoscope!

Being so close, I want to help, half my head wants to come and rip it to bits for you, the other half keeps reminding me how complicated they've become, as Lee rightly highlights.

Thank you @smiffy, it’s very kind of you for wanting to help , but your right it will be complicated, hopefully by next weekend, we will know more about what is happening with my poor Z