I am looking at a 355 GTS w/ 19,000 miles and had a PPI done on it on Wednesday. Here are the results: Compression results: cyl 1-125, cyl 2125, cyl 3-125, cyl 4-125, cyl 5-130, cyl 6-125, cyl 7-105, cyl 8-125. Leakdown on 7 showing 30% loss thru intake, exh valves . Most likely valve guides need to be updated. I'm no expert on this, so I am looking for some guidance here please. Besides the obvious problem w/ cylinder #7, how could the compression POSSIBLY be that low? The car runs strong and has no visible smoke. Thanks, Jerry.
Because its a relative test not an absolute - check out some of the many other threads in the 355 section - essentially it is affected by everything upto and including the phase of the moon - spread is good - as I understand it 7 could be as little as a sticky valve I think
Comp test done on cold engine? I had low values when I did tested on cold engine, maybe not as low as these but not far from it. On warm engine I had between 200 and 211.
Actually those numbers are not bad, there could be many reasons that effects a single low compression reading not necessary means there is an issue. Through my own 355 purchase search I found that if there is a valve guide issue there would be more than one low compression reading.
Seems strange to me that 6 of the 8 were exactly the same. Mine were all close but not exactly the same. Mine were all in the 220 range I think. I did it a while ago when I had my second 30K done. I bought both of my Ferraris sight unseen. No PPI, no nothing. Both worked out perfect. It's just a car. Plan for the worst, hope for the best.
that's what i thought you might wanna consider what FatbillyBob said .........................."RUN" unless you got $20k laying around to make it right
The owner is getting a 2nd PPI done at another place for his own peace of mind. If cylinder #7 does turn out to have a major leak, then I will pass on it. We were quoted $11-$15K for the valve job.
I am amazed at the number of 355 owners who think in general that the 355 general population compression and leakdown numbers are not too bad. Many think a good feeling car is a good car. To me being a little pregnant and no showing yet is still pregnant. Anyway there are numerous cases and many discussions right here on FC about bad compression without burning oil out the tailpipe. It is very difficult to do these 355 PPI compression tests with a proper hot engine. Access is poor and a lift really helps IMO on my old body. The numbers posted are really not enough to make a determination. You need compression numbers on all 8 lungs as is and with oil squirted in the sparkplug hole. You need leakdown percentages on every lung. I'd do in a vacuum test eventhough some think it is of little value on these motors. It is so simple to do. Any more than that and you will get more invasive than an owner is going to let you go. Once you get numbers like that from a reliable source you can make a guess on the engine condition. We had a discussion here on FC where the famous Dave Helms has confirmed a bad engine even with good numbers because what is seen nearly static in our tests is not the same as what happens dynamically. As parts rattle in loose bores at 5000rpm these numbers can change. So you can't 100% rely on so your gather still more info which is a really good reason for info which Dave goes after which is boroscope the intake runners and look right down at the valves. Dave is always pushing beyond comsumer acceptable and is a great FC professional resource. I'd also be suspicious of non-functional exhaust bypass valve and funny sounds of leaking/rattling exhaust headers which may contribute to or be symptoms of guide issues. Well that's my non-professional 02 cents.
these numbers are not correct unless the compression was done improperly. The car was either cold, or the motor is injured. 125 psi would equate to a piston compression ratio of approx 7:1. so get another reading with the car warm. there are plenty of other NICE 355s on the road for you to open a can of worms
I think this is the right idea. I can't imagine a car that runs well that would have readings that low. I'd wait to see what the second test shows.
I thought the raw number just had to do with how much pressure you put in the cylinder, and you looked at the variation from cylinder to cylinder, which looks good here? I have also heard of valve deposits giving bad numbers because the car has not been driven enough and/or hard enough. I truly believe that many a valve guide has been changed because of misinformation. Of course, I am one that thinks just drive the car until it needs a major. It the valve guides need to be done with the major, it is not that much more money, and it sure won't be 11k. If it is that hard to tell that something's wrong, I'd just keep driving. I am not saying that valve guides are not a problem on 355s, as I have seen it happen to good cars. But it's not like the car is a total loss or something. I think the risks and costs are sometimes overblown.
This 95 problem has been beaten to death. People get on this bandwagon and ride it to death. http://www.ferrarichat.com/forum/showthread.php?t=5554&highlight=95+valve+guides John
I'm not on any "bandwagon". If you'll notice, I asked about the compression numbers, not the valve guide issue. I know about the valve guides for Christ's sake I've been a member here for many years. Show me ONE THREAD in the past that talked about compression figures in the 125 range.
Jerry If its in need of a belt service thats when its time to do the valve guides. Only a few more k to do them when the engines out for belt service. You may be able to squeeze a good deal for yourself outta this...........not necessarily a RUN situation.
Firstly, Ferrari's have dual overhead cams that are totally adjustable for valve timing. Compression test values are not only a product of the physical compression ratio, but also valve timing and not just rings and valve condition. If valve timing is late enough, all the compression ratio in the world wont be enough to make high numbers. So in my experience, an engine that has very equal but low compression, wouldnt be enough to scare me off, I would check the leakdown. Its when you see 135 here, 150 there, 125 over there, or an engine with all equal and then a low one, like this one, thats when you throw up your hands. That engine is bad. Smoking generally comes from poor rings or worn valve guides. Burned valves by themselves generally wont cause smoke. So its not at all surprising this engine seems to run well, its really only off a ways on one cylinder, and the later valve timing could push the power up on top and make it run pretty good. The problem is that cylinder will continue to deteriorate. Burned valves can lead to dropped valves, and if one drops while she's wound tight to redline there probably wont be an engine left worth rebuilding, if its not past that point already. IOW its time to stop driving it and drop the engine. Its NOT a driver at this point. If the rest of the car was decent and passed inspection, I would offer the seller $20K less and accept whatever I found upon tearing down the engine. If not I would just keep looking, there are enough good ones out there to keep from going over your head. The only other alternative is for the owner to pay for the work to YOUR satisfaction, with you buying the car at the agreed upon price. I dont like that idea, because if something is found after the heads are off, it could lead to an argument as to who will pay, how much they will pay or if it gets fixed properly. Better to take it "as is" and deal with it yourself with your own mechanic, or just look elsewhere.
No one is on the bandwagon here. He is asking peoples OPINIONS and is getting them. what im stating however is a fact. Those compression number are either wrong (because the engine was cold, they are WAY to low OVERALL), OR, something is very wrong with the engine
I think that this place must do the compression test w/ cold engines every time because the manager stated to me that he has never had a 355 get over 135. Thank you ALL very much for your input!
I had a PPI done in May '08 on a '98 F355 with these results: Compression: #1-231 #5-235 #2-231 #6-244 #3-224 #7-231 #4-232 #8-232 Leakdown on #3=7%; #6=3% Engine cold; 20,200 miles; Major service had not been performed. I had the major service performed after I purchased the car.
i wouldn't be running from the car (its prob fine at 19,0 miles) as much as the shop that did the comp.test..is someone trying to drum up business or just has a prob.doing the test correctly?
