Timing chain guides go out pretty often on these things and can definiteley cause rough idle and random misfires. Unfortunately this doesn’t seem to be your main issue since only one of the cylinders had low compression.

If your timing was the only thing screwed up you’d have lower compression in all cylinders not just the one.

The timing chain replacement cost is going to be around $500-$1200 or more depending on the shop. You might be throwing your money away if the cylinder, valves or pistons are toast. Have them find out for sure whether there is anything wrong with the cylinder or pistons before committing to the timing chain.

If only one cylinder has extremely low compression it would have nothing to do with timing. Timing affects all cylinders equally. The job of a timing chain is simply to make sure the valves open at the right time. The crankshaft turns the timing chain which turns your intake and exhaust camshafts. These camshafts have lobes on them that basically push your intake and exhaust valves open at different times in the combustion cycle. All intake valves are connected by the intake camshaft and all exhaust valves are connected by the exhaust camshaft. Both camshafts are connected by a chain to the crankshaft. Therefore one cylinder could not have a valve stuck open causing compression loss due to timing without all other cylinders being affected.


cylinder, piston, valve or ring.
Scored cylinder
cracked piston
damaged or obliterated piston ring
Burnt valve
damaged or dried out head gasket (doesn’t seem likely with such low compression)
Cracked head

Also labor for valves, rebuilds etc overlaps since the timing chain would have to be removed for that anyways so if it’s that you’d get a new timing chain and save several hundred on labor.

It depends on what they find with the borescope.

Best case scenario: everything looks good in the cylinder and you simply need new valves which would require pulling the head to verify with a valve leak down test and a head rebuild or replacement. $1k+

Worst case scenario: they find a crack in the piston, cylinder walls are scored and rings have failed which would require complete rebuild or replacement. $5k+

This information is not intended to be a substitute for professional automotive diagnosis or treatment. Always seek the advice of your mechanic or other qualified automotive provider with any questions about your vehicles mechanical condition.

[QUOTE=Pramuk;4380741]Timing chain, guide and tensioner need to be replaced for at least $2k.

Also they took apart my cylinder valve checking leak down and redo compression test each cylinder again. Cylinder 3 extremely low and they will use

scope to check inside tomorrow if have any damages at cylinder wall or piston rings and see if they can fix it or not.

How possible I will need new motor or new block ?[/

2k is rediculous for a timing chain, tensioner and guide. Even the dealer in Orlando only charges $1200.

Maybe give these guys a call.

http://northshoremotorwerks.com/mini-cooper-repair/

Did the car come with any kind of a power train warranty or did you buy it from an individual?

An n18 will not readily fit in your car. An n14 is an n14 whether it’s bolted to an automatic or manual and will work in either case. At least $1500-$2000 in labor and a new engine will set you back a pretty penny. You could always rebuild it yourself for around $5k including machining the block and head.

If you bought it from a dealership there is a good chance they offer some kind of short term power train warranty buried in your contract. It’s worth taking a look.

The $1500-$2000 would be for labor only. You’d still have to buy a new engine for around $5000. Rebuilding yourself would be the most cost effective option especially if you have tools but would take the most time.