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Read about the latest set of compression figures from my own car's engine, taken at the annual service in February 2007.
Before I purchased my car, I had a pre-purchase inspection carried out by QV London. QV are a well known specialist based in Ascot in the UK. They maintain race cars as well as road cars. At that time, which is now over three years ago, the compression figures were looking pretty healthy, so I bought the car since everything else checked out good as well. At that time the car had covered 14,000 miles. It has now covered 31,500 miles. You may have read elsewhere on this site that knowing the compression figures is important on a 355 because of the valve guide issues that some cars suffer. As any engine wears a reduced compression level is to be expected, but on a 355 the stakes are pretty high given the cost of a rebuild. If wear is occurring there is not much that can be done assuming the car is well looked after, but it is best to get an early indication rather than wait until the car begins to misfire due to too low compression, thus avoiding any knock on effects. Last year I promised myself I'd get a compression check done with the annual service, but I then duly forgot. This year I remembered. Here are the results: Cylinder
| 2003 | 2007
| 1
| 180 | 175
| | 2 | 190 | 155 | | 3 | 190 | 175 | | 4 | 170 | 150 | | 5 | 190 | 185 | | 6 | 180 | 185 | | 7 | 190 | 190 | | 8 | 190 | 175 |
So there we have it. Number 2 cylinder is showing some cause for concern, as is number 4. The others aren't too bad but clearly I'm heading for a top end rebuild - probably next year. I'd better start putting cash to one side! At the moment the loss of compression isn't enough for a leakdown test to reveal the cause (source: QV). I will have another compression check done next year and then take appropriate action - probably a leakdown test assuming I've done enough miles for a further drop in compression to have occurred. I do about 5,000 miles per annum. According to Mike @ QV, a misfire won't start until it gets to around 80psi - clearly performance will be poor before then and if worn valve guides are the cause then it will start using more oil over time. I had noticed this time around that it had used some oil between services, so worn valve guides would be my guess as to the cause. Needing a rebuild after less that 40,000 miles is hardly a great achievement for Ferrari, but we still love 'em don't we? ;-) |
