cylinder ring wear on a 3.2
Discussion
chaps, just had a full checkover on a potential purchase. this included a leakdown test.
The specialist said that on most 911s of this era (1988) then likely to be down on power a little & that they allow for about 20-25% cylinder ring wear.
This has about 30-35% on cylinder 3. He said this means its a little down on power.
Is this likely to get worse & will it cause any more problems?
thx
The specialist said that on most 911s of this era (1988) then likely to be down on power a little & that they allow for about 20-25% cylinder ring wear.
This has about 30-35% on cylinder 3. He said this means its a little down on power.
Is this likely to get worse & will it cause any more problems?
thx
Mileage???...Craig, put it this way....it ain't gonna get any better!
Not unusual to expect a top end overhaul at around 100k miles or so on a 3.2,,,,maybe less miles if much of the use has been short journeys with the oil not getting up to full operating temp.
Edit to add.....specialist can probably give exact ptice, in the past i have ben quoted £3-4k for top end overhaul......doesn't sound too dreadful,,,maybe ise it as a bargaining tool?
Not unusual to expect a top end overhaul at around 100k miles or so on a 3.2,,,,maybe less miles if much of the use has been short journeys with the oil not getting up to full operating temp.
Edit to add.....specialist can probably give exact ptice, in the past i have ben quoted £3-4k for top end overhaul......doesn't sound too dreadful,,,maybe ise it as a bargaining tool?
Edited by clubsport on Friday 23 March 15:40
3.2 Carreras tend to run regardless of engine condition. They also tend not to leak oil as say a 964 engine might which acts as a catalyst to get a top end done (the 3.2 has metal barrel base gaskets rather than the 964`s silicone which hardens over time).
The actual readings for leak tests can be a bit misleading as different systems & methods give different readings, so to say garage X tested a car and the readings were 17% accross all 6 cylinders and garage Y tested another car but got readings of 24% doesn`t really help as there is no comparison in the way the readings are achieved. Some garages class 10% as high, some 25% as high.
What is more relevant is if one cylinder gives a reading higher than all the others, that would indicate a fault, usually with a valve or possibly broken piston ring, (given all the cylinders were tested at the same time by the same method). My initial thoughts are that 30% plus sounds very high but as I said it`s impossible to comment not knowing what a typical reading for a fresh engine might be on that particular garage test. Certainly if one cylinder`s reading is high - as sounds the case here then that needs thinking about.
As I`ve said the 3.2 engine pretty much runs regardless of engine condition. You can get fouling of the plugs or in extreme cases difficult starting due to lack of compression but things have got to be pretty grim to get there !
By the sounds of things you need to be thinking along the lines of a top end in the not to distant future but exactly when you do the job will be your descision.
Henry
The actual readings for leak tests can be a bit misleading as different systems & methods give different readings, so to say garage X tested a car and the readings were 17% accross all 6 cylinders and garage Y tested another car but got readings of 24% doesn`t really help as there is no comparison in the way the readings are achieved. Some garages class 10% as high, some 25% as high.
What is more relevant is if one cylinder gives a reading higher than all the others, that would indicate a fault, usually with a valve or possibly broken piston ring, (given all the cylinders were tested at the same time by the same method). My initial thoughts are that 30% plus sounds very high but as I said it`s impossible to comment not knowing what a typical reading for a fresh engine might be on that particular garage test. Certainly if one cylinder`s reading is high - as sounds the case here then that needs thinking about.
As I`ve said the 3.2 engine pretty much runs regardless of engine condition. You can get fouling of the plugs or in extreme cases difficult starting due to lack of compression but things have got to be pretty grim to get there !
By the sounds of things you need to be thinking along the lines of a top end in the not to distant future but exactly when you do the job will be your descision.
Henry
I would say that almost definately needs a top end.
The figures of 15% sound ok and show that their testing methods will give 15% as a reading for less worn cylinders. You are looking at the spread of readings and 37% looks high if other cylinders on the same test gave 15%.
Your overhaul needs to allow for piston rings, valve guides, timing chains, tensioners, oil drain tubes, ideally a new set of head studs (certainly the lower ones as a must & you`d be a fool to not do the others whilst in there), and don`t be surprised to change some valves, the clutch, a flywheel (they crack) as well as the odd oil line etc, etc.
In valuing the car remember that once the work has been done the car will be in better shape engine-wise that most of it`s peers so it`s possibly unfair to penalise the car for the whole cost of the work (depending on the asking price of course).
Hope that helps.
Henry
ps not sure what you mean by head seals.
The figures of 15% sound ok and show that their testing methods will give 15% as a reading for less worn cylinders. You are looking at the spread of readings and 37% looks high if other cylinders on the same test gave 15%.
Your overhaul needs to allow for piston rings, valve guides, timing chains, tensioners, oil drain tubes, ideally a new set of head studs (certainly the lower ones as a must & you`d be a fool to not do the others whilst in there), and don`t be surprised to change some valves, the clutch, a flywheel (they crack) as well as the odd oil line etc, etc.
In valuing the car remember that once the work has been done the car will be in better shape engine-wise that most of it`s peers so it`s possibly unfair to penalise the car for the whole cost of the work (depending on the asking price of course).
Hope that helps.
Henry
ps not sure what you mean by head seals.
Edited by Henry-F on Friday 23 March 16:51
the deal is done, have factored in getting the work done as would like this car to be a keeper.
Am having a minor service and small cosmetic job then will run it for the summer and assuming nothing sinister happens get the work done over the winter.
As an aside, would a donor engine be an option? I did see that 3.2 that the chap put a 993 lump in.
Am having a minor service and small cosmetic job then will run it for the summer and assuming nothing sinister happens get the work done over the winter.
As an aside, would a donor engine be an option? I did see that 3.2 that the chap put a 993 lump in.
Not sure how valve stem seals would affect the leak test. When the valves are closed (and the cylinder is in compression) they have no bearing on the reading. They stop oil from the timing / cam area escaping into the cylinder bore. If the valves were at fault it would be the seal between the valve head and the valve seat in the cylinder head.
3 of the readings are high & whilst that could be down to specific damage (such as a buzzed engine where valve head and piston crown come into contact) given the car`s age and likely work I think it`s largely immaterial. You`re going to open the lump up and rebuild it regardless. I would agree with Colin and get the work done sooner rather than later as catastrophic failure will be infinately more expensive to fix than routine work.
Re: a replacement engine - unless you find a major problem with, say the crankshaft, then forget it. You`re spending money on a total unknown & given the age of even the youngest 3.2 Carrera these days it`s fair to say the replacement engine will need re-building before it`s popped into the car. Every second hand engine for sale has usually done 45k - 60k miles regardless of how old it is (yet oddly I`ve yet to come accross 45k mile 3.2 Carreras on a regular basis
As usual remember there is no link between work & miles.
Henry
3 of the readings are high & whilst that could be down to specific damage (such as a buzzed engine where valve head and piston crown come into contact) given the car`s age and likely work I think it`s largely immaterial. You`re going to open the lump up and rebuild it regardless. I would agree with Colin and get the work done sooner rather than later as catastrophic failure will be infinately more expensive to fix than routine work.
Re: a replacement engine - unless you find a major problem with, say the crankshaft, then forget it. You`re spending money on a total unknown & given the age of even the youngest 3.2 Carrera these days it`s fair to say the replacement engine will need re-building before it`s popped into the car. Every second hand engine for sale has usually done 45k - 60k miles regardless of how old it is (yet oddly I`ve yet to come accross 45k mile 3.2 Carreras on a regular basis
As usual remember there is no link between work & miles. Henry
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